| Message ID | 20241112-k1-i2c-master-v3-2-5005b70dc208@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | riscv: spacemit: add i2c support to K1 SoC | expand |
On 11:07 Tue 12 Nov , Troy Mitchell wrote: > From: Troy Mitchell <troymitchell988@gmail.com> > > This patch introduces basic I2C support for the SpacemiT K1 SoC, > utilizing interrupts for transfers. > > The driver has been tested using i2c-tools on a Bananapi-F3 board, > and basic I2C read/write operations have been confirmed to work. > > Signed-off-by: Troy Mitchell <TroyMitchell988@gmail.com> > --- > drivers/i2c/busses/Kconfig | 19 ++ > drivers/i2c/busses/Makefile | 1 + > drivers/i2c/busses/i2c-k1.c | 656 ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 676 insertions(+) > > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig > index 6b3ba7e5723a..91630f55667f 100644 > --- a/drivers/i2c/busses/Kconfig > +++ b/drivers/i2c/busses/Kconfig > @@ -779,6 +779,25 @@ config I2C_JZ4780 > > If you don't know what to do here, say N. > > +config I2C_K1 > + tristate "Spacemit K1 I2C adapter" > + depends on ARCH_SPACEMIT || COMPILE_TEST > + depends on OF > + help > + This option enables support for the I2C interface on the Spacemit K1 > + platform. > + > + If you enable this configuration, the kernel will include support for > + the I2C adapter specific to the Spacemit K1 platform. This driver ca > + be used to manage I2C bus transactions, which are necessary for > + interfacing with I2C peripherals such as sensors, EEPROMs, and other > + devices. > + > + This driver can also be compiled as a module. If you choose to build > + it as a module, the resulting kernel module will be named `i2c-k1`. > + Loading this module will enable the I2C functionality for the K1 > + platform dynamically, without requiring a rebuild of the kernel. > + > config I2C_KEBA > tristate "KEBA I2C controller support" > depends on HAS_IOMEM > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile > index ecc07c50f2a0..9744b0e58598 100644 > --- a/drivers/i2c/busses/Makefile > +++ b/drivers/i2c/busses/Makefile > @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_IMX) += i2c-imx.o > obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o > obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o > obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o > +obj-$(CONFIG_I2C_K1) += i2c-k1.o > obj-$(CONFIG_I2C_KEBA) += i2c-keba.o > obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o > obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o > diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c > new file mode 100644 > index 000000000000..12bb71625e0a > --- /dev/null > +++ b/drivers/i2c/busses/i2c-k1.c > @@ -0,0 +1,656 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2024 Troy Mitchell <troymitchell988@gmail.com> > + */ > + > + #include <linux/clk.h> > + #include <linux/i2c.h> > + #include <linux/iopoll.h> > + #include <linux/module.h> > + #include <linux/of_address.h> > + #include <linux/platform_device.h> > + > +/* spacemit i2c registers */ > +#define ICR 0x0 /* Control Register */ > +#define ISR 0x4 /* Status Register */ > +#define ISAR 0x8 /* Slave Address Register */ > +#define IDBR 0xc /* Data Buffer Register */ > +#define ILCR 0x10 /* Load Count Register */ > +#define IWCR 0x14 /* Wait Count Register */ > +#define IRST_CYC 0x18 /* Bus reset cycle counter */ > +#define IBMR 0x1c /* Bus monitor register */ > +#define IWFIFO 0x20 /* Write FIFO Register */ > +#define IWFIFO_WPTR 0x24 /* Write FIFO Write Pointer Register */ > +#define IWFIFO_RPTR 0x28 /* Write FIFO Read Pointer Register */ > +#define IRFIFO 0x2c /* Read FIFO Register */ > +#define IRFIFO_WPTR 0x30 /* Read FIFO Write Pointer Register */ > +#define IRFIFO_RPTR 0x34 /* Read FIFO Read Pointer Register */ > + > +/* register ICR fields */ > +#define CR_START BIT(0) /* start bit */ > +#define CR_STOP BIT(1) /* stop bit */ > +#define CR_ACKNAK BIT(2) /* send ACK(0) or NAK(1) */ > +#define CR_TB BIT(3) /* transfer byte bit */ > +#define CR_TXBEGIN BIT(4) /* transaction begin */ > +#define CR_FIFOEN BIT(5) /* enable FIFO mode */ > +#define CR_GPIOEN BIT(6) /* enable GPIO mode for SCL in HS */ > +#define CR_DMAEN BIT(7) /* enable DMA for TX and RX FIFOs */ > +#define CR_MODE_FAST BIT(8) /* bus mode (master operation) */ > +#define CR_MODE_HIGH BIT(9) /* bus mode (master operation) */ > +#define CR_UR BIT(10) /* unit reset */ > +#define CR_RSTREQ BIT(11) /* i2c bus reset request */ > +#define CR_MA BIT(12) /* master abort */ > +#define CR_SCLE BIT(13) /* master clock enable */ > +#define CR_IUE BIT(14) /* unit enable */ > +#define CR_HS_STRETCH BIT(16) /* I2C hs stretch */ > +#define CR_ALDIE BIT(18) /* enable arbitration interrupt */ > +#define CR_DTEIE BIT(19) /* enable tx interrupts */ > +#define CR_DRFIE BIT(20) /* enable rx interrupts */ > +#define CR_GCD BIT(21) /* general call disable */ > +#define CR_BEIE BIT(22) /* enable bus error ints */ > +#define CR_SADIE BIT(23) /* slave address detected int enable */ > +#define CR_SSDIE BIT(24) /* slave STOP detected int enable */ > +#define CR_MSDIE BIT(25) /* master STOP detected int enable */ > +#define CR_MSDE BIT(26) /* master STOP detected enable */ > +#define CR_TXDONEIE BIT(27) /* transaction done int enable */ > +#define CR_TXEIE BIT(28) /* transmit FIFO empty int enable */ > +#define CR_RXHFIE BIT(29) /* receive FIFO half-full int enable */ > +#define CR_RXFIE BIT(30) /* receive FIFO full int enable */ > +#define CR_RXOVIE BIT(31) /* receive FIFO overrun int enable */ > + > +/* register ISR fields */ > +#define SR_RWM BIT(13) /* read/write mode */ > +#define SR_ACKNAK BIT(14) /* ACK/NACK status */ > +#define SR_UB BIT(15) /* unit busy */ > +#define SR_IBB BIT(16) /* i2c bus busy */ > +#define SR_EBB BIT(17) /* early bus busy */ > +#define SR_ALD BIT(18) /* arbitration loss detected */ > +#define SR_ITE BIT(19) /* tx buffer empty */ > +#define SR_IRF BIT(20) /* rx buffer full */ > +#define SR_GCAD BIT(21) /* general call address detected */ > +#define SR_BED BIT(22) /* bus error no ACK/NAK */ > +#define SR_SAD BIT(23) /* slave address detected */ > +#define SR_SSD BIT(24) /* slave stop detected */ > +#define SR_MSD BIT(26) /* master stop detected */ > +#define SR_TXDONE BIT(27) /* transaction done */ > +#define SR_TXE BIT(28) /* tx FIFO empty */ > +#define SR_RXHF BIT(29) /* rx FIFO half-full */ > +#define SR_RXF BIT(30) /* rx FIFO full */ > +#define SR_RXOV BIT(31) /* RX FIFO overrun */ > + > +/* register ILCR fields */ > +#define LCR_SLV 0x000001FF /* SLV: bit[8:0] */ > +#define LCR_FLV 0x0003FE00 /* FLV: bit[17:9] */ > +#define LCR_HLVH 0x07FC0000 /* HLVH: bit[26:18] */ > +#define LCR_HLVL 0xF8000000 /* HLVL: bit[31:27] */ > + > +/* register IWCR fields */ > +#define WCR_COUNT 0x0000001F /* COUNT: bit[4:0] */ > +#define WCR_COUNT1 0x000003E0 /* HS_COUNT1: bit[9:5] */ > +#define WCR_COUNT2 0x00007C00 /* HS_COUNT2: bit[14:10] */ > + > +/* register IBMR fields */ > +#define BMR_SDA BIT(0) /* SDA line level */ > +#define BMR_SCL BIT(1) /* SCL line level */ > + > +/* register IWFIFO fields */ > +#define WFIFO_DATA_MSK 0x000000FF /* data: bit[7:0] */ > +#define WFIFO_CTRL_MSK 0x000003E0 /* control: bit[11:8] */ > +#define WFIFO_CTRL_START BIT(8) /* start bit */ > +#define WFIFO_CTRL_STOP BIT(9) /* stop bit */ > +#define WFIFO_CTRL_ACKNAK BIT(10) /* send ACK(0) or NAK(1) */ > +#define WFIFO_CTRL_TB BIT(11) /* transfer byte bit */ > + > +/* status register init value */ > +#define I2C_INT_STATUS_MASK 0xfffc0000 /* SR bits[31:18] */ > +#define I2C_INT_CTRL_MASK (CR_ALDIE | CR_DTEIE | CR_DRFIE | \ > + CR_BEIE | CR_TXDONEIE | CR_TXEIE | \ > + CR_RXHFIE | CR_RXFIE | CR_RXOVIE | \ > + CR_MSDIE) > + > +/* i2c bus recover timeout: us */ > +#define I2C_BUS_RECOVER_TIMEOUT (100000) > + > +#define I2C_FAST_MODE_FREQ (400000) > + > +enum spacemit_i2c_state { > + STATE_IDLE, > + STATE_START, > + STATE_READ, > + STATE_WRITE, > +}; > + > +enum spacemit_i2c_dir { > + DIR_WRITE, > + DIR_READ > +}; > + > +/* i2c-spacemit driver's main struct */ > +struct spacemit_i2c_dev { > + struct device *dev; > + struct i2c_adapter adapt; > + > + /* hardware resources */ > + void __iomem *base; > + int irq; > + > + struct i2c_msg *msgs; > + int msg_num; > + struct i2c_msg *cur_msg; > + > + /* index of the current message being processed */ > + int msg_idx; > + u8 *msg_buf; > + /* the number of unprocessed bytes remaining in each message */ > + size_t unprocessed; > + > + enum spacemit_i2c_state state; > + enum spacemit_i2c_dir dir; > + struct completion complete; > + u32 status; > + u32 err; > +}; > + > +static void spacemit_i2c_enable(struct spacemit_i2c_dev *i2c) > +{ > + u32 val; > + > + val = readl(i2c->base + ICR); > + writel(val | CR_IUE, i2c->base + ICR); > +} > + > +static void spacemit_i2c_disable(struct spacemit_i2c_dev *i2c) > +{ > + u32 val; > + > + val = readl(i2c->base + ICR); > + val &= ~CR_IUE; > + writel(val, i2c->base + ICR); > +} > + > +static void spacemit_i2c_reset(struct spacemit_i2c_dev *i2c) > +{ > + writel(CR_UR, i2c->base + ICR); > + udelay(5); > + writel(0, i2c->base + ICR); > +} > + > +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c); > + > +static void spacemit_i2c_bus_reset(struct spacemit_i2c_dev *i2c) > +{ > + u32 status; > + > + /* if bus is locked, reset unit. 0: locked */ > + status = readl(i2c->base + IBMR); > + if ((status & BMR_SDA) && (status & BMR_SCL)) > + return; > + > + spacemit_i2c_reset(i2c); > + usleep_range(10, 20); > + > + /* check scl status again */ > + status = readl(i2c->base + IBMR); > + if (!(status & BMR_SCL)) > + dev_warn_ratelimited(i2c->dev, "unit reset failed\n"); > +} > + > +static int spacemit_i2c_recover_bus_busy(struct spacemit_i2c_dev *i2c) > +{ > + int ret = 0; > + u32 val; > + > + val = readl(i2c->base + ISR); > + if (likely(!(val & (SR_UB | SR_IBB)))) > + return 0; > + > + ret = readl_poll_timeout(i2c->base + ISR, val, !(val & (SR_UB | SR_IBB)), > + 1500, I2C_BUS_RECOVER_TIMEOUT); > + if (unlikely(ret)) { > + spacemit_i2c_reset(i2c); > + ret = -EAGAIN; > + } > + > + return ret; > +} > + > +static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c) > +{ > + /* in case bus is not released after transfer completes */ > + if (unlikely(readl(i2c->base + ISR) & SR_EBB)) { > + spacemit_i2c_bus_reset(i2c); > + usleep_range(90, 150); > + } > +} > + > +static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c) > +{ > + u32 val = 0; > + > + /* > + * Unmask interrupt bits for all xfer mode: > + * bus error, arbitration loss detected. > + * For transaction complete signal, we use master stop > + * interrupt, so we don't need to unmask CR_TXDONEIE. > + */ > + val |= CR_BEIE | CR_ALDIE; > + > + /* > + * Unmask interrupt bits for interrupt xfer mode: > + * DBR rx full. > + * For tx empty interrupt CR_DTEIE, we only > + * need to enable when trigger byte transfer to start > + * data sending. > + */ > + val |= CR_DRFIE; > + > + /* set speed bits: default fast mode */ > + val |= CR_MODE_FAST; > + > + /* disable response to general call */ > + val |= CR_GCD; > + > + /* enable SCL clock output */ > + val |= CR_SCLE; > + > + /* enable master stop detected */ > + val |= CR_MSDE | CR_MSDIE; > + > + writel(val, i2c->base + ICR); > +} > + > +static inline void > +spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask) > +{ > + writel(mask & I2C_INT_STATUS_MASK, i2c->base + ISR); > +} > + > +static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c) > +{ > + u32 slave_addr_rw, val; > + > + i2c->dir = i2c->cur_msg->flags & I2C_M_RD; > + i2c->state = STATE_START; > + > + if (i2c->cur_msg->flags & I2C_M_RD) > + slave_addr_rw = ((i2c->cur_msg->addr & 0x7f) << 1) | 1; > + else > + slave_addr_rw = (i2c->cur_msg->addr & 0x7f) << 1; > + > + writel(slave_addr_rw, i2c->base + IDBR); > + > + val = readl(i2c->base + ICR); > + > + /* send start pulse */ > + val &= ~CR_STOP; > + val |= CR_START | CR_TB | CR_DTEIE; > + writel(val, i2c->base + ICR); > +} > + > +static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c) > +{ > + u32 val; > + > + val = readl(i2c->base + ICR); > + > + val |= CR_STOP | CR_ALDIE | CR_TB; > + > + if (i2c->dir == DIR_READ) > + val |= CR_ACKNAK; > + > + writel(val, i2c->base + ICR); > +} > + > +static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c) > +{ > + unsigned long time_left; > + > + for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) { > + i2c->cur_msg = i2c->msgs + i2c->msg_idx; > + i2c->msg_buf = i2c->cur_msg->buf; > + i2c->err = 0; > + i2c->status = 0; > + i2c->unprocessed = i2c->cur_msg->len; > + > + reinit_completion(&i2c->complete); > + > + spacemit_i2c_start(i2c); > + > + time_left = wait_for_completion_timeout(&i2c->complete, > + i2c->adapt.timeout); > + if (unlikely(time_left == 0)) { > + dev_alert(i2c->dev, "msg completion timeout\n"); > + spacemit_i2c_bus_reset(i2c); > + spacemit_i2c_reset(i2c); > + return -ETIMEDOUT; > + } > + > + if (unlikely(i2c->err)) > + return spacemit_i2c_handle_err(i2c); > + } > + > + return 0; > +} > + > +static int spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c) > +{ > + if (i2c->dir == DIR_READ) { > + if (i2c->unprocessed == 1 && i2c->msg_idx == i2c->msg_num - 1) > + return 1; > + } else if (i2c->dir == DIR_WRITE) { > + if (!i2c->unprocessed && i2c->msg_idx == i2c->msg_num - 1) > + return 1; > + } > + > + return 0; > +} > + > +static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c) > +{ > + /* if transfer completes, ISR will handle it */ > + if (i2c->status & SR_MSD) > + return; > + > + if (i2c->unprocessed) { > + writel(*i2c->msg_buf++, i2c->base + IDBR); > + i2c->unprocessed--; > + return; > + } > + > + /* STATE_IDLE avoids trigger next byte */ > + i2c->state = STATE_IDLE; > + complete(&i2c->complete); > +} > + > +static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c) > +{ > + if (i2c->unprocessed) { > + *i2c->msg_buf++ = readl(i2c->base + IDBR); > + i2c->unprocessed--; > + } > + > + /* if transfer completes, ISR will handle it */ > + if (i2c->status & (SR_MSD | SR_ACKNAK)) > + return; > + > + /* it has to append stop bit in icr that read last byte */ > + if (i2c->unprocessed) > + return; > + > + /* STATE_IDLE avoids trigger next byte */ > + i2c->state = STATE_IDLE; > + complete(&i2c->complete); > +} > + > +static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c) > +{ > + if (i2c->dir == DIR_READ) { > + i2c->state = STATE_READ; > + return; > + } > + > + if (i2c->dir == DIR_WRITE) { > + i2c->state = STATE_WRITE; > + spacemit_i2c_handle_write(i2c); > + } > +} > + > +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c) > +{ > + if (!i2c->err) > + return 0; > + > + dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status); > + > + if (i2c->err & (SR_BED | SR_ALD)) > + spacemit_i2c_reset(i2c); > + > + if (i2c->err & (SR_RXOV | SR_ALD)) > + return -EAGAIN; > + > + return (i2c->status & SR_ACKNAK) ? -ENXIO : -EIO; > +} > + > +static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c) > +{ > + u32 val; > + /* > + * send transaction complete signal: > + * error happens, detect master stop > + */ > + if (likely(i2c->err || (i2c->status & SR_MSD))) { > + /* > + * Here the transaction is already done, we don't need any > + * other interrupt signals from now, in case any interrupt > + * happens before spacemit_i2c_xfer to disable irq and i2c unit, > + * we mask all the interrupt signals and clear the interrupt > + * status. > + */ > + val = readl(i2c->base + ICR); > + val &= ~I2C_INT_CTRL_MASK; > + writel(val, i2c->base + ICR); > + > + spacemit_i2c_clear_int_status(i2c, I2C_INT_STATUS_MASK); > + > + i2c->state = STATE_IDLE; > + complete(&i2c->complete); > + } > +} > + > +static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid) > +{ > + struct spacemit_i2c_dev *i2c = devid; > + u32 status, val; > + > + status = readl(i2c->base + ISR); > + if (!status) > + return IRQ_HANDLED; > + > + i2c->status = status; > + > + i2c->err = status & (SR_BED | SR_RXOV | SR_ALD); > + > + spacemit_i2c_clear_int_status(i2c, status); > + > + if (unlikely(i2c->err)) > + goto err_out; > + > + val = readl(i2c->base + ICR); > + > + val &= ~(CR_TB | CR_ACKNAK | CR_STOP | CR_START); > + writel(val, i2c->base + ICR); > + > + switch (i2c->state) { > + case STATE_START: > + spacemit_i2c_handle_start(i2c); > + break; > + case STATE_READ: > + spacemit_i2c_handle_read(i2c); > + break; > + case STATE_WRITE: > + spacemit_i2c_handle_write(i2c); > + break; > + default: > + break; > + } > + > + if (i2c->state != STATE_IDLE) { > + if (spacemit_i2c_is_last_msg(i2c)) { > + /* trigger next byte with stop */ > + spacemit_i2c_stop(i2c); > + } else { > + /* trigger next byte */ > + val |= CR_ALDIE | CR_TB; > + writel(val, i2c->base + ICR); > + } > + } > + > +err_out: > + spacemit_i2c_err_check(i2c); > + return IRQ_HANDLED; > +} > + > +static void spacemit_i2c_calc_timeout(struct spacemit_i2c_dev *i2c) > +{ > + unsigned long timeout; > + int idx = 0, cnt = 0, freq; > + > + while (idx < i2c->msg_num) { > + cnt += (i2c->msgs + idx)->len + 1; > + idx++; > + } > + > + freq = I2C_FAST_MODE_FREQ; so this will set frequency to fast mode (400K), this contradict with PATCH[1/2] which says default clock-frequency is 100000, either you need to change the code? or update the dt-binding? > + /* > + * multiply by 9 because each byte in I2C transmission requires > + * 9 clock cycles: 8 bits of data plus 1 ACK/NACK bit. > + */ > + timeout = cnt * 9 * USEC_PER_SEC / freq; > + > + i2c->adapt.timeout = usecs_to_jiffies(timeout + USEC_PER_SEC / 2) / i2c->msg_num; > +} > + > +static inline int spacemit_i2c_xfer_core(struct spacemit_i2c_dev *i2c) drop inline? IMO, it isn't worth here for long function > +{ > + int ret = 0; no need to initilize to 0 > + > + spacemit_i2c_reset(i2c); > + > + spacemit_i2c_calc_timeout(i2c); > + > + spacemit_i2c_init(i2c); > + > + spacemit_i2c_enable(i2c); > + enable_irq(i2c->irq); > + > + /* i2c wait for bus busy */ > + ret = spacemit_i2c_recover_bus_busy(i2c); > + if (unlikely(ret)) > + return ret; > + > + ret = spacemit_i2c_xfer_msg(i2c); > + if (unlikely(ret < 0)) { > + dev_dbg(i2c->dev, "i2c transfer error\n"); > + /* timeout error should not be overridden, and the transfer > + * error will be confirmed by err handle function latter, > + * the reset should be invalid argument error. > + */ > + if (ret != -ETIMEDOUT) > + ret = -EINVAL; > + } > + > + return ret; > +} > + > +static int > +spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg msgs[], int num) no need to wrap the line, it makes the code a little bit weird.. current policy increase to 100characters, the old 80-column is not enforced https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bdc48fa11e46f867ea4d75fa59ee87a7f48be144 > +{ > + struct spacemit_i2c_dev *i2c = i2c_get_adapdata(adapt); > + int ret; > + > + i2c->msgs = msgs; > + i2c->msg_num = num; > + > + ret = spacemit_i2c_xfer_core(i2c); > + if (likely(!ret)) > + spacemit_i2c_check_bus_release(i2c); > + > + disable_irq(i2c->irq); > + > + spacemit_i2c_disable(i2c); > + > + if (unlikely((ret == -ETIMEDOUT || ret == -EAGAIN))) > + dev_alert(i2c->dev, "i2c transfer failed, ret %d err 0x%x\n", ret, i2c->err); > + > + return ret < 0 ? ret : num; > +} > + > +static u32 spacemit_i2c_func(struct i2c_adapter *adap) > +{ > + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); > +} > + > +static const struct i2c_algorithm spacemit_i2c_algo = { > + .xfer = spacemit_i2c_xfer, > + .functionality = spacemit_i2c_func, > +}; > + > +static int spacemit_i2c_probe(struct platform_device *pdev) > +{ > + struct spacemit_i2c_dev *i2c; > + struct device_node *of_node = pdev->dev.of_node; > + struct clk *clk; > + int ret = 0; > + > + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); > + if (!i2c) > + return -ENOMEM; > + > + i2c->dev = &pdev->dev; > + > + i2c->base = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(i2c->base)) > + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap"); > + > + i2c->irq = platform_get_irq(pdev, 0); > + if (i2c->irq < 0) > + return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource"); > + > + ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler, > + IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c); > + if (ret) > + return dev_err_probe(&pdev->dev, ret, "failed to request irq"); > + > + disable_irq(i2c->irq); > + > + clk = devm_clk_get_enabled(&pdev->dev, NULL); > + if (IS_ERR(clk)) > + return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock"); > + I'd suggest also to handle pin request here, since pinctrl driver is merged https://lore.kernel.org/all/CACRpkdYnaJsKKfcdhHeMGTTp86M+wNODzZx2e=OYbxQ4Jc4Rjw@mail.gmail.com/ > + i2c_set_adapdata(&i2c->adapt, i2c); > + i2c->adapt.owner = THIS_MODULE; > + i2c->adapt.algo = &spacemit_i2c_algo; > + i2c->adapt.dev.parent = i2c->dev; > + i2c->adapt.nr = pdev->id; > + > + i2c->adapt.dev.of_node = of_node; > + i2c->adapt.algo_data = i2c; > + > + strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name)); > + > + init_completion(&i2c->complete); > + > + ret = i2c_add_numbered_adapter(&i2c->adapt); > + if (ret) > + return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter"); > + > + platform_set_drvdata(pdev, i2c); > + > + return 0; > +} > + > +static void spacemit_i2c_remove(struct platform_device *pdev) > +{ > + struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev); > + > + i2c_del_adapter(&i2c->adapt); > +} > + > +static const struct of_device_id spacemit_i2c_of_match[] = { > + { .compatible = "spacemit,k1-i2c", }, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match); > + > +static struct platform_driver spacemit_i2c_driver = { > + .probe = spacemit_i2c_probe, > + .remove = spacemit_i2c_remove, > + .driver = { > + .name = "i2c-k1", > + .of_match_table = spacemit_i2c_of_match, > + }, > +}; > +module_platform_driver(spacemit_i2c_driver); > + > +MODULE_LICENSE("GPL"); > +MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC"); > > -- > 2.34.1 >
Hi, Yixun. thanks for ur review. On 2024/11/14 14:49, Yixun Lan wrote: > On 11:07 Tue 12 Nov , Troy Mitchell wrote: >> From: Troy Mitchell <troymitchell988@gmail.com> >> >> This patch introduces basic I2C support for the SpacemiT K1 SoC, >> utilizing interrupts for transfers. >> >> The driver has been tested using i2c-tools on a Bananapi-F3 board, >> and basic I2C read/write operations have been confirmed to work. >> >> Signed-off-by: Troy Mitchell <TroyMitchell988@gmail.com> >> --- >> drivers/i2c/busses/Kconfig | 19 ++ >> drivers/i2c/busses/Makefile | 1 + >> drivers/i2c/busses/i2c-k1.c | 656 ++++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 676 insertions(+) >> >> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig >> index 6b3ba7e5723a..91630f55667f 100644 >> --- a/drivers/i2c/busses/Kconfig >> +++ b/drivers/i2c/busses/Kconfig >> @@ -779,6 +779,25 @@ config I2C_JZ4780 >> >> If you don't know what to do here, say N. >> >> +config I2C_K1 >> + tristate "Spacemit K1 I2C adapter" >> + depends on ARCH_SPACEMIT || COMPILE_TEST >> + depends on OF >> + help >> + This option enables support for the I2C interface on the Spacemit K1 >> + platform. >> + >> + If you enable this configuration, the kernel will include support for >> + the I2C adapter specific to the Spacemit K1 platform. This driver ca >> + be used to manage I2C bus transactions, which are necessary for >> + interfacing with I2C peripherals such as sensors, EEPROMs, and other >> + devices. >> + >> + This driver can also be compiled as a module. If you choose to build >> + it as a module, the resulting kernel module will be named `i2c-k1`. >> + Loading this module will enable the I2C functionality for the K1 >> + platform dynamically, without requiring a rebuild of the kernel. >> + >> config I2C_KEBA >> tristate "KEBA I2C controller support" >> depends on HAS_IOMEM >> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile >> index ecc07c50f2a0..9744b0e58598 100644 >> --- a/drivers/i2c/busses/Makefile >> +++ b/drivers/i2c/busses/Makefile >> @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_IMX) += i2c-imx.o >> obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o >> obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o >> obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o >> +obj-$(CONFIG_I2C_K1) += i2c-k1.o >> obj-$(CONFIG_I2C_KEBA) += i2c-keba.o >> obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o >> obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o >> diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c >> new file mode 100644 >> index 000000000000..12bb71625e0a >> --- /dev/null >> +++ b/drivers/i2c/busses/i2c-k1.c >> @@ -0,0 +1,656 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (C) 2024 Troy Mitchell <troymitchell988@gmail.com> >> + */ >> + >> + #include <linux/clk.h> >> + #include <linux/i2c.h> >> + #include <linux/iopoll.h> >> + #include <linux/module.h> >> + #include <linux/of_address.h> >> + #include <linux/platform_device.h> >> + >> +/* spacemit i2c registers */ >> +#define ICR 0x0 /* Control Register */ >> +#define ISR 0x4 /* Status Register */ >> +#define ISAR 0x8 /* Slave Address Register */ >> +#define IDBR 0xc /* Data Buffer Register */ >> +#define ILCR 0x10 /* Load Count Register */ >> +#define IWCR 0x14 /* Wait Count Register */ >> +#define IRST_CYC 0x18 /* Bus reset cycle counter */ >> +#define IBMR 0x1c /* Bus monitor register */ >> +#define IWFIFO 0x20 /* Write FIFO Register */ >> +#define IWFIFO_WPTR 0x24 /* Write FIFO Write Pointer Register */ >> +#define IWFIFO_RPTR 0x28 /* Write FIFO Read Pointer Register */ >> +#define IRFIFO 0x2c /* Read FIFO Register */ >> +#define IRFIFO_WPTR 0x30 /* Read FIFO Write Pointer Register */ >> +#define IRFIFO_RPTR 0x34 /* Read FIFO Read Pointer Register */ >> + >> +/* register ICR fields */ >> +#define CR_START BIT(0) /* start bit */ >> +#define CR_STOP BIT(1) /* stop bit */ >> +#define CR_ACKNAK BIT(2) /* send ACK(0) or NAK(1) */ >> +#define CR_TB BIT(3) /* transfer byte bit */ >> +#define CR_TXBEGIN BIT(4) /* transaction begin */ >> +#define CR_FIFOEN BIT(5) /* enable FIFO mode */ >> +#define CR_GPIOEN BIT(6) /* enable GPIO mode for SCL in HS */ >> +#define CR_DMAEN BIT(7) /* enable DMA for TX and RX FIFOs */ >> +#define CR_MODE_FAST BIT(8) /* bus mode (master operation) */ >> +#define CR_MODE_HIGH BIT(9) /* bus mode (master operation) */ >> +#define CR_UR BIT(10) /* unit reset */ >> +#define CR_RSTREQ BIT(11) /* i2c bus reset request */ >> +#define CR_MA BIT(12) /* master abort */ >> +#define CR_SCLE BIT(13) /* master clock enable */ >> +#define CR_IUE BIT(14) /* unit enable */ >> +#define CR_HS_STRETCH BIT(16) /* I2C hs stretch */ >> +#define CR_ALDIE BIT(18) /* enable arbitration interrupt */ >> +#define CR_DTEIE BIT(19) /* enable tx interrupts */ >> +#define CR_DRFIE BIT(20) /* enable rx interrupts */ >> +#define CR_GCD BIT(21) /* general call disable */ >> +#define CR_BEIE BIT(22) /* enable bus error ints */ >> +#define CR_SADIE BIT(23) /* slave address detected int enable */ >> +#define CR_SSDIE BIT(24) /* slave STOP detected int enable */ >> +#define CR_MSDIE BIT(25) /* master STOP detected int enable */ >> +#define CR_MSDE BIT(26) /* master STOP detected enable */ >> +#define CR_TXDONEIE BIT(27) /* transaction done int enable */ >> +#define CR_TXEIE BIT(28) /* transmit FIFO empty int enable */ >> +#define CR_RXHFIE BIT(29) /* receive FIFO half-full int enable */ >> +#define CR_RXFIE BIT(30) /* receive FIFO full int enable */ >> +#define CR_RXOVIE BIT(31) /* receive FIFO overrun int enable */ >> + >> +/* register ISR fields */ >> +#define SR_RWM BIT(13) /* read/write mode */ >> +#define SR_ACKNAK BIT(14) /* ACK/NACK status */ >> +#define SR_UB BIT(15) /* unit busy */ >> +#define SR_IBB BIT(16) /* i2c bus busy */ >> +#define SR_EBB BIT(17) /* early bus busy */ >> +#define SR_ALD BIT(18) /* arbitration loss detected */ >> +#define SR_ITE BIT(19) /* tx buffer empty */ >> +#define SR_IRF BIT(20) /* rx buffer full */ >> +#define SR_GCAD BIT(21) /* general call address detected */ >> +#define SR_BED BIT(22) /* bus error no ACK/NAK */ >> +#define SR_SAD BIT(23) /* slave address detected */ >> +#define SR_SSD BIT(24) /* slave stop detected */ >> +#define SR_MSD BIT(26) /* master stop detected */ >> +#define SR_TXDONE BIT(27) /* transaction done */ >> +#define SR_TXE BIT(28) /* tx FIFO empty */ >> +#define SR_RXHF BIT(29) /* rx FIFO half-full */ >> +#define SR_RXF BIT(30) /* rx FIFO full */ >> +#define SR_RXOV BIT(31) /* RX FIFO overrun */ >> + >> +/* register ILCR fields */ >> +#define LCR_SLV 0x000001FF /* SLV: bit[8:0] */ >> +#define LCR_FLV 0x0003FE00 /* FLV: bit[17:9] */ >> +#define LCR_HLVH 0x07FC0000 /* HLVH: bit[26:18] */ >> +#define LCR_HLVL 0xF8000000 /* HLVL: bit[31:27] */ >> + >> +/* register IWCR fields */ >> +#define WCR_COUNT 0x0000001F /* COUNT: bit[4:0] */ >> +#define WCR_COUNT1 0x000003E0 /* HS_COUNT1: bit[9:5] */ >> +#define WCR_COUNT2 0x00007C00 /* HS_COUNT2: bit[14:10] */ >> + >> +/* register IBMR fields */ >> +#define BMR_SDA BIT(0) /* SDA line level */ >> +#define BMR_SCL BIT(1) /* SCL line level */ >> + >> +/* register IWFIFO fields */ >> +#define WFIFO_DATA_MSK 0x000000FF /* data: bit[7:0] */ >> +#define WFIFO_CTRL_MSK 0x000003E0 /* control: bit[11:8] */ >> +#define WFIFO_CTRL_START BIT(8) /* start bit */ >> +#define WFIFO_CTRL_STOP BIT(9) /* stop bit */ >> +#define WFIFO_CTRL_ACKNAK BIT(10) /* send ACK(0) or NAK(1) */ >> +#define WFIFO_CTRL_TB BIT(11) /* transfer byte bit */ >> + >> +/* status register init value */ >> +#define I2C_INT_STATUS_MASK 0xfffc0000 /* SR bits[31:18] */ >> +#define I2C_INT_CTRL_MASK (CR_ALDIE | CR_DTEIE | CR_DRFIE | \ >> + CR_BEIE | CR_TXDONEIE | CR_TXEIE | \ >> + CR_RXHFIE | CR_RXFIE | CR_RXOVIE | \ >> + CR_MSDIE) >> + >> +/* i2c bus recover timeout: us */ >> +#define I2C_BUS_RECOVER_TIMEOUT (100000) >> + >> +#define I2C_FAST_MODE_FREQ (400000) >> + >> +enum spacemit_i2c_state { >> + STATE_IDLE, >> + STATE_START, >> + STATE_READ, >> + STATE_WRITE, >> +}; >> + >> +enum spacemit_i2c_dir { >> + DIR_WRITE, >> + DIR_READ >> +}; >> + >> +/* i2c-spacemit driver's main struct */ >> +struct spacemit_i2c_dev { >> + struct device *dev; >> + struct i2c_adapter adapt; >> + >> + /* hardware resources */ >> + void __iomem *base; >> + int irq; >> + >> + struct i2c_msg *msgs; >> + int msg_num; >> + struct i2c_msg *cur_msg; >> + >> + /* index of the current message being processed */ >> + int msg_idx; >> + u8 *msg_buf; >> + /* the number of unprocessed bytes remaining in each message */ >> + size_t unprocessed; >> + >> + enum spacemit_i2c_state state; >> + enum spacemit_i2c_dir dir; >> + struct completion complete; >> + u32 status; >> + u32 err; >> +}; >> + >> +static void spacemit_i2c_enable(struct spacemit_i2c_dev *i2c) >> +{ >> + u32 val; >> + >> + val = readl(i2c->base + ICR); >> + writel(val | CR_IUE, i2c->base + ICR); >> +} >> + >> +static void spacemit_i2c_disable(struct spacemit_i2c_dev *i2c) >> +{ >> + u32 val; >> + >> + val = readl(i2c->base + ICR); >> + val &= ~CR_IUE; >> + writel(val, i2c->base + ICR); >> +} >> + >> +static void spacemit_i2c_reset(struct spacemit_i2c_dev *i2c) >> +{ >> + writel(CR_UR, i2c->base + ICR); >> + udelay(5); >> + writel(0, i2c->base + ICR); >> +} >> + >> +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c); >> + >> +static void spacemit_i2c_bus_reset(struct spacemit_i2c_dev *i2c) >> +{ >> + u32 status; >> + >> + /* if bus is locked, reset unit. 0: locked */ >> + status = readl(i2c->base + IBMR); >> + if ((status & BMR_SDA) && (status & BMR_SCL)) >> + return; >> + >> + spacemit_i2c_reset(i2c); >> + usleep_range(10, 20); >> + >> + /* check scl status again */ >> + status = readl(i2c->base + IBMR); >> + if (!(status & BMR_SCL)) >> + dev_warn_ratelimited(i2c->dev, "unit reset failed\n"); >> +} >> + >> +static int spacemit_i2c_recover_bus_busy(struct spacemit_i2c_dev *i2c) >> +{ >> + int ret = 0; >> + u32 val; >> + >> + val = readl(i2c->base + ISR); >> + if (likely(!(val & (SR_UB | SR_IBB)))) >> + return 0; >> + >> + ret = readl_poll_timeout(i2c->base + ISR, val, !(val & (SR_UB | SR_IBB)), >> + 1500, I2C_BUS_RECOVER_TIMEOUT); >> + if (unlikely(ret)) { >> + spacemit_i2c_reset(i2c); >> + ret = -EAGAIN; >> + } >> + >> + return ret; >> +} >> + >> +static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c) >> +{ >> + /* in case bus is not released after transfer completes */ >> + if (unlikely(readl(i2c->base + ISR) & SR_EBB)) { >> + spacemit_i2c_bus_reset(i2c); >> + usleep_range(90, 150); >> + } >> +} >> + >> +static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c) >> +{ >> + u32 val = 0; >> + >> + /* >> + * Unmask interrupt bits for all xfer mode: >> + * bus error, arbitration loss detected. >> + * For transaction complete signal, we use master stop >> + * interrupt, so we don't need to unmask CR_TXDONEIE. >> + */ >> + val |= CR_BEIE | CR_ALDIE; >> + >> + /* >> + * Unmask interrupt bits for interrupt xfer mode: >> + * DBR rx full. >> + * For tx empty interrupt CR_DTEIE, we only >> + * need to enable when trigger byte transfer to start >> + * data sending. >> + */ >> + val |= CR_DRFIE; >> + >> + /* set speed bits: default fast mode */ >> + val |= CR_MODE_FAST; >> + >> + /* disable response to general call */ >> + val |= CR_GCD; >> + >> + /* enable SCL clock output */ >> + val |= CR_SCLE; >> + >> + /* enable master stop detected */ >> + val |= CR_MSDE | CR_MSDIE; >> + >> + writel(val, i2c->base + ICR); >> +} >> + >> +static inline void >> +spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask) >> +{ >> + writel(mask & I2C_INT_STATUS_MASK, i2c->base + ISR); >> +} >> + >> +static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c) >> +{ >> + u32 slave_addr_rw, val; >> + >> + i2c->dir = i2c->cur_msg->flags & I2C_M_RD; >> + i2c->state = STATE_START; >> + >> + if (i2c->cur_msg->flags & I2C_M_RD) >> + slave_addr_rw = ((i2c->cur_msg->addr & 0x7f) << 1) | 1; >> + else >> + slave_addr_rw = (i2c->cur_msg->addr & 0x7f) << 1; >> + >> + writel(slave_addr_rw, i2c->base + IDBR); >> + >> + val = readl(i2c->base + ICR); >> + >> + /* send start pulse */ >> + val &= ~CR_STOP; >> + val |= CR_START | CR_TB | CR_DTEIE; >> + writel(val, i2c->base + ICR); >> +} >> + >> +static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c) >> +{ >> + u32 val; >> + >> + val = readl(i2c->base + ICR); >> + >> + val |= CR_STOP | CR_ALDIE | CR_TB; >> + >> + if (i2c->dir == DIR_READ) >> + val |= CR_ACKNAK; >> + >> + writel(val, i2c->base + ICR); >> +} >> + >> +static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c) >> +{ >> + unsigned long time_left; >> + >> + for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) { >> + i2c->cur_msg = i2c->msgs + i2c->msg_idx; >> + i2c->msg_buf = i2c->cur_msg->buf; >> + i2c->err = 0; >> + i2c->status = 0; >> + i2c->unprocessed = i2c->cur_msg->len; >> + >> + reinit_completion(&i2c->complete); >> + >> + spacemit_i2c_start(i2c); >> + >> + time_left = wait_for_completion_timeout(&i2c->complete, >> + i2c->adapt.timeout); >> + if (unlikely(time_left == 0)) { >> + dev_alert(i2c->dev, "msg completion timeout\n"); >> + spacemit_i2c_bus_reset(i2c); >> + spacemit_i2c_reset(i2c); >> + return -ETIMEDOUT; >> + } >> + >> + if (unlikely(i2c->err)) >> + return spacemit_i2c_handle_err(i2c); >> + } >> + >> + return 0; >> +} >> + >> +static int spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c) >> +{ >> + if (i2c->dir == DIR_READ) { >> + if (i2c->unprocessed == 1 && i2c->msg_idx == i2c->msg_num - 1) >> + return 1; >> + } else if (i2c->dir == DIR_WRITE) { >> + if (!i2c->unprocessed && i2c->msg_idx == i2c->msg_num - 1) >> + return 1; >> + } >> + >> + return 0; >> +} >> + >> +static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c) >> +{ >> + /* if transfer completes, ISR will handle it */ >> + if (i2c->status & SR_MSD) >> + return; >> + >> + if (i2c->unprocessed) { >> + writel(*i2c->msg_buf++, i2c->base + IDBR); >> + i2c->unprocessed--; >> + return; >> + } >> + >> + /* STATE_IDLE avoids trigger next byte */ >> + i2c->state = STATE_IDLE; >> + complete(&i2c->complete); >> +} >> + >> +static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c) >> +{ >> + if (i2c->unprocessed) { >> + *i2c->msg_buf++ = readl(i2c->base + IDBR); >> + i2c->unprocessed--; >> + } >> + >> + /* if transfer completes, ISR will handle it */ >> + if (i2c->status & (SR_MSD | SR_ACKNAK)) >> + return; >> + >> + /* it has to append stop bit in icr that read last byte */ >> + if (i2c->unprocessed) >> + return; >> + >> + /* STATE_IDLE avoids trigger next byte */ >> + i2c->state = STATE_IDLE; >> + complete(&i2c->complete); >> +} >> + >> +static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c) >> +{ >> + if (i2c->dir == DIR_READ) { >> + i2c->state = STATE_READ; >> + return; >> + } >> + >> + if (i2c->dir == DIR_WRITE) { >> + i2c->state = STATE_WRITE; >> + spacemit_i2c_handle_write(i2c); >> + } >> +} >> + >> +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c) >> +{ >> + if (!i2c->err) >> + return 0; >> + >> + dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status); >> + >> + if (i2c->err & (SR_BED | SR_ALD)) >> + spacemit_i2c_reset(i2c); >> + >> + if (i2c->err & (SR_RXOV | SR_ALD)) >> + return -EAGAIN; >> + >> + return (i2c->status & SR_ACKNAK) ? -ENXIO : -EIO; >> +} >> + >> +static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c) >> +{ >> + u32 val; >> + /* >> + * send transaction complete signal: >> + * error happens, detect master stop >> + */ >> + if (likely(i2c->err || (i2c->status & SR_MSD))) { >> + /* >> + * Here the transaction is already done, we don't need any >> + * other interrupt signals from now, in case any interrupt >> + * happens before spacemit_i2c_xfer to disable irq and i2c unit, >> + * we mask all the interrupt signals and clear the interrupt >> + * status. >> + */ >> + val = readl(i2c->base + ICR); >> + val &= ~I2C_INT_CTRL_MASK; >> + writel(val, i2c->base + ICR); >> + >> + spacemit_i2c_clear_int_status(i2c, I2C_INT_STATUS_MASK); >> + >> + i2c->state = STATE_IDLE; >> + complete(&i2c->complete); >> + } >> +} >> + >> +static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid) >> +{ >> + struct spacemit_i2c_dev *i2c = devid; >> + u32 status, val; >> + >> + status = readl(i2c->base + ISR); >> + if (!status) >> + return IRQ_HANDLED; >> + >> + i2c->status = status; >> + >> + i2c->err = status & (SR_BED | SR_RXOV | SR_ALD); >> + >> + spacemit_i2c_clear_int_status(i2c, status); >> + >> + if (unlikely(i2c->err)) >> + goto err_out; >> + >> + val = readl(i2c->base + ICR); >> + >> + val &= ~(CR_TB | CR_ACKNAK | CR_STOP | CR_START); >> + writel(val, i2c->base + ICR); >> + >> + switch (i2c->state) { >> + case STATE_START: >> + spacemit_i2c_handle_start(i2c); >> + break; >> + case STATE_READ: >> + spacemit_i2c_handle_read(i2c); >> + break; >> + case STATE_WRITE: >> + spacemit_i2c_handle_write(i2c); >> + break; >> + default: >> + break; >> + } >> + >> + if (i2c->state != STATE_IDLE) { >> + if (spacemit_i2c_is_last_msg(i2c)) { >> + /* trigger next byte with stop */ >> + spacemit_i2c_stop(i2c); >> + } else { >> + /* trigger next byte */ >> + val |= CR_ALDIE | CR_TB; >> + writel(val, i2c->base + ICR); >> + } >> + } >> + >> +err_out: >> + spacemit_i2c_err_check(i2c); >> + return IRQ_HANDLED; >> +} >> + >> +static void spacemit_i2c_calc_timeout(struct spacemit_i2c_dev *i2c) >> +{ >> + unsigned long timeout; >> + int idx = 0, cnt = 0, freq; >> + >> + while (idx < i2c->msg_num) { >> + cnt += (i2c->msgs + idx)->len + 1; >> + idx++; >> + } >> + >> + freq = I2C_FAST_MODE_FREQ; > so this will set frequency to fast mode (400K), this contradict with PATCH[1/2] which > says default clock-frequency is 100000, either you need to change the code? or > update the dt-binding? I will update the dt-binding in next version. > >> + /* >> + * multiply by 9 because each byte in I2C transmission requires >> + * 9 clock cycles: 8 bits of data plus 1 ACK/NACK bit. >> + */ >> + timeout = cnt * 9 * USEC_PER_SEC / freq; >> + >> + i2c->adapt.timeout = usecs_to_jiffies(timeout + USEC_PER_SEC / 2) / i2c->msg_num; >> +} >> + >> +static inline int spacemit_i2c_xfer_core(struct spacemit_i2c_dev *i2c) > drop inline? IMO, it isn't worth here for long function okay > >> +{ >> + int ret = 0; > no need to initilize to 0 ok >> + >> + spacemit_i2c_reset(i2c); >> + >> + spacemit_i2c_calc_timeout(i2c); >> + >> + spacemit_i2c_init(i2c); >> + >> + spacemit_i2c_enable(i2c); >> + enable_irq(i2c->irq); >> + >> + /* i2c wait for bus busy */ >> + ret = spacemit_i2c_recover_bus_busy(i2c); >> + if (unlikely(ret)) >> + return ret; >> + >> + ret = spacemit_i2c_xfer_msg(i2c); >> + if (unlikely(ret < 0)) { >> + dev_dbg(i2c->dev, "i2c transfer error\n"); >> + /* timeout error should not be overridden, and the transfer >> + * error will be confirmed by err handle function latter, >> + * the reset should be invalid argument error. >> + */ >> + if (ret != -ETIMEDOUT) >> + ret = -EINVAL; >> + } >> + >> + return ret; >> +} >> + >> +static int >> +spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg msgs[], int num) > no need to wrap the line, it makes the code a little bit weird.. > > current policy increase to 100characters, the old 80-column is not enforced > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bdc48fa11e46f867ea4d75fa59ee87a7f48be144 ok > >> +{ >> + struct spacemit_i2c_dev *i2c = i2c_get_adapdata(adapt); >> + int ret; >> + >> + i2c->msgs = msgs; >> + i2c->msg_num = num; >> + >> + ret = spacemit_i2c_xfer_core(i2c); >> + if (likely(!ret)) >> + spacemit_i2c_check_bus_release(i2c); >> + >> + disable_irq(i2c->irq); >> + >> + spacemit_i2c_disable(i2c); >> + >> + if (unlikely((ret == -ETIMEDOUT || ret == -EAGAIN))) >> + dev_alert(i2c->dev, "i2c transfer failed, ret %d err 0x%x\n", ret, i2c->err); >> + >> + return ret < 0 ? ret : num; >> +} >> + >> +static u32 spacemit_i2c_func(struct i2c_adapter *adap) >> +{ >> + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); >> +} >> + >> +static const struct i2c_algorithm spacemit_i2c_algo = { >> + .xfer = spacemit_i2c_xfer, >> + .functionality = spacemit_i2c_func, >> +}; >> + >> +static int spacemit_i2c_probe(struct platform_device *pdev) >> +{ >> + struct spacemit_i2c_dev *i2c; >> + struct device_node *of_node = pdev->dev.of_node; >> + struct clk *clk; >> + int ret = 0; >> + >> + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); >> + if (!i2c) >> + return -ENOMEM; >> + >> + i2c->dev = &pdev->dev; >> + >> + i2c->base = devm_platform_ioremap_resource(pdev, 0); >> + if (IS_ERR(i2c->base)) >> + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap"); >> + >> + i2c->irq = platform_get_irq(pdev, 0); >> + if (i2c->irq < 0) >> + return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource"); >> + >> + ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler, >> + IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c); >> + if (ret) >> + return dev_err_probe(&pdev->dev, ret, "failed to request irq"); >> + >> + disable_irq(i2c->irq); >> + >> + clk = devm_clk_get_enabled(&pdev->dev, NULL); >> + if (IS_ERR(clk)) >> + return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock"); >> + > I'd suggest also to handle pin request here, since pinctrl driver is merged > > https://lore.kernel.org/all/CACRpkdYnaJsKKfcdhHeMGTTp86M+wNODzZx2e=OYbxQ4Jc4Rjw@mail.gmail.com/ sry, I don't understand what pin I need to request? > >> + i2c_set_adapdata(&i2c->adapt, i2c); >> + i2c->adapt.owner = THIS_MODULE; >> + i2c->adapt.algo = &spacemit_i2c_algo; >> + i2c->adapt.dev.parent = i2c->dev; >> + i2c->adapt.nr = pdev->id; >> + >> + i2c->adapt.dev.of_node = of_node; >> + i2c->adapt.algo_data = i2c; >> + >> + strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name)); >> + >> + init_completion(&i2c->complete); >> + >> + ret = i2c_add_numbered_adapter(&i2c->adapt); >> + if (ret) >> + return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter"); >> + >> + platform_set_drvdata(pdev, i2c); >> + >> + return 0; >> +} >> + >> +static void spacemit_i2c_remove(struct platform_device *pdev) >> +{ >> + struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev); >> + >> + i2c_del_adapter(&i2c->adapt); >> +} >> + >> +static const struct of_device_id spacemit_i2c_of_match[] = { >> + { .compatible = "spacemit,k1-i2c", }, >> + { /* sentinel */ } >> +}; >> +MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match); >> + >> +static struct platform_driver spacemit_i2c_driver = { >> + .probe = spacemit_i2c_probe, >> + .remove = spacemit_i2c_remove, >> + .driver = { >> + .name = "i2c-k1", >> + .of_match_table = spacemit_i2c_of_match, >> + }, >> +}; >> +module_platform_driver(spacemit_i2c_driver); >> + >> +MODULE_LICENSE("GPL"); >> +MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC"); >> >> -- >> 2.34.1 >> >
Hi Troy: On 12:11 Thu 21 Nov , Troy Mitchell wrote: > Hi, Yixun. thanks for ur review. > > On 2024/11/14 14:49, Yixun Lan wrote: > > On 11:07 Tue 12 Nov , Troy Mitchell wrote: > >> From: Troy Mitchell <troymitchell988@gmail.com> > >> > >> This patch introduces basic I2C support for the SpacemiT K1 SoC, > >> utilizing interrupts for transfers. > >> > >> The driver has been tested using i2c-tools on a Bananapi-F3 board, > >> and basic I2C read/write operations have been confirmed to work. > >> > >> Signed-off-by: Troy Mitchell <TroyMitchell988@gmail.com> > >> --- > >> drivers/i2c/busses/Kconfig | 19 ++ > >> drivers/i2c/busses/Makefile | 1 + > >> drivers/i2c/busses/i2c-k1.c | 656 ++++++++++++++++++++++++++++++++++++++++++++ > >> 3 files changed, 676 insertions(+) > >> ... > >> + > >> +static int spacemit_i2c_probe(struct platform_device *pdev) > >> +{ > >> + struct spacemit_i2c_dev *i2c; > >> + struct device_node *of_node = pdev->dev.of_node; > >> + struct clk *clk; > >> + int ret = 0; > >> + > >> + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); > >> + if (!i2c) > >> + return -ENOMEM; > >> + > >> + i2c->dev = &pdev->dev; > >> + > >> + i2c->base = devm_platform_ioremap_resource(pdev, 0); > >> + if (IS_ERR(i2c->base)) > >> + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap"); > >> + > >> + i2c->irq = platform_get_irq(pdev, 0); > >> + if (i2c->irq < 0) > >> + return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource"); > >> + > >> + ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler, > >> + IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c); > >> + if (ret) > >> + return dev_err_probe(&pdev->dev, ret, "failed to request irq"); > >> + > >> + disable_irq(i2c->irq); > >> + > >> + clk = devm_clk_get_enabled(&pdev->dev, NULL); > >> + if (IS_ERR(clk)) > >> + return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock"); > >> + > > I'd suggest also to handle pin request here, since pinctrl driver is merged > > > > https://lore.kernel.org/all/CACRpkdYnaJsKKfcdhHeMGTTp86M+wNODzZx2e=OYbxQ4Jc4Rjw@mail.gmail.com/ > sry, I don't understand what pin I need to request? > > I was suggesting to add devm_pinctrl_get(), but after checking, this is not needed anymore since it's already handled by device core, so no need to change here.. check drivers/core/pinctrl.c -> pinctrl_bind_pins() > >> + i2c_set_adapdata(&i2c->adapt, i2c); > >> + i2c->adapt.owner = THIS_MODULE; > >> + i2c->adapt.algo = &spacemit_i2c_algo; > >> + i2c->adapt.dev.parent = i2c->dev; > >> + i2c->adapt.nr = pdev->id; > >> + > >> + i2c->adapt.dev.of_node = of_node; > >> + i2c->adapt.algo_data = i2c; > >> + > >> + strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name)); > >> + > >> + init_completion(&i2c->complete); > >> + > >> + ret = i2c_add_numbered_adapter(&i2c->adapt); > >> + if (ret) > >> + return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter"); > >> + > >> + platform_set_drvdata(pdev, i2c); > >> + > >> + return 0; > >> +} > >> + > >> +static void spacemit_i2c_remove(struct platform_device *pdev) > >> +{ > >> + struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev); > >> + > >> + i2c_del_adapter(&i2c->adapt); > >> +} > >> + > >> +static const struct of_device_id spacemit_i2c_of_match[] = { > >> + { .compatible = "spacemit,k1-i2c", }, > >> + { /* sentinel */ } > >> +}; > >> +MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match); > >> + > >> +static struct platform_driver spacemit_i2c_driver = { > >> + .probe = spacemit_i2c_probe, > >> + .remove = spacemit_i2c_remove, > >> + .driver = { > >> + .name = "i2c-k1", > >> + .of_match_table = spacemit_i2c_of_match, > >> + }, > >> +}; > >> +module_platform_driver(spacemit_i2c_driver); > >> + > >> +MODULE_LICENSE("GPL"); > >> +MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC"); > >> > >> -- > >> 2.34.1 > >> > > > > -- > Troy Mitchell
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 6b3ba7e5723a..91630f55667f 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -779,6 +779,25 @@ config I2C_JZ4780 If you don't know what to do here, say N. +config I2C_K1 + tristate "Spacemit K1 I2C adapter" + depends on ARCH_SPACEMIT || COMPILE_TEST + depends on OF + help + This option enables support for the I2C interface on the Spacemit K1 + platform. + + If you enable this configuration, the kernel will include support for + the I2C adapter specific to the Spacemit K1 platform. This driver ca + be used to manage I2C bus transactions, which are necessary for + interfacing with I2C peripherals such as sensors, EEPROMs, and other + devices. + + This driver can also be compiled as a module. If you choose to build + it as a module, the resulting kernel module will be named `i2c-k1`. + Loading this module will enable the I2C functionality for the K1 + platform dynamically, without requiring a rebuild of the kernel. + config I2C_KEBA tristate "KEBA I2C controller support" depends on HAS_IOMEM diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index ecc07c50f2a0..9744b0e58598 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_IMX) += i2c-imx.o obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o +obj-$(CONFIG_I2C_K1) += i2c-k1.o obj-$(CONFIG_I2C_KEBA) += i2c-keba.o obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c new file mode 100644 index 000000000000..12bb71625e0a --- /dev/null +++ b/drivers/i2c/busses/i2c-k1.c @@ -0,0 +1,656 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024 Troy Mitchell <troymitchell988@gmail.com> + */ + + #include <linux/clk.h> + #include <linux/i2c.h> + #include <linux/iopoll.h> + #include <linux/module.h> + #include <linux/of_address.h> + #include <linux/platform_device.h> + +/* spacemit i2c registers */ +#define ICR 0x0 /* Control Register */ +#define ISR 0x4 /* Status Register */ +#define ISAR 0x8 /* Slave Address Register */ +#define IDBR 0xc /* Data Buffer Register */ +#define ILCR 0x10 /* Load Count Register */ +#define IWCR 0x14 /* Wait Count Register */ +#define IRST_CYC 0x18 /* Bus reset cycle counter */ +#define IBMR 0x1c /* Bus monitor register */ +#define IWFIFO 0x20 /* Write FIFO Register */ +#define IWFIFO_WPTR 0x24 /* Write FIFO Write Pointer Register */ +#define IWFIFO_RPTR 0x28 /* Write FIFO Read Pointer Register */ +#define IRFIFO 0x2c /* Read FIFO Register */ +#define IRFIFO_WPTR 0x30 /* Read FIFO Write Pointer Register */ +#define IRFIFO_RPTR 0x34 /* Read FIFO Read Pointer Register */ + +/* register ICR fields */ +#define CR_START BIT(0) /* start bit */ +#define CR_STOP BIT(1) /* stop bit */ +#define CR_ACKNAK BIT(2) /* send ACK(0) or NAK(1) */ +#define CR_TB BIT(3) /* transfer byte bit */ +#define CR_TXBEGIN BIT(4) /* transaction begin */ +#define CR_FIFOEN BIT(5) /* enable FIFO mode */ +#define CR_GPIOEN BIT(6) /* enable GPIO mode for SCL in HS */ +#define CR_DMAEN BIT(7) /* enable DMA for TX and RX FIFOs */ +#define CR_MODE_FAST BIT(8) /* bus mode (master operation) */ +#define CR_MODE_HIGH BIT(9) /* bus mode (master operation) */ +#define CR_UR BIT(10) /* unit reset */ +#define CR_RSTREQ BIT(11) /* i2c bus reset request */ +#define CR_MA BIT(12) /* master abort */ +#define CR_SCLE BIT(13) /* master clock enable */ +#define CR_IUE BIT(14) /* unit enable */ +#define CR_HS_STRETCH BIT(16) /* I2C hs stretch */ +#define CR_ALDIE BIT(18) /* enable arbitration interrupt */ +#define CR_DTEIE BIT(19) /* enable tx interrupts */ +#define CR_DRFIE BIT(20) /* enable rx interrupts */ +#define CR_GCD BIT(21) /* general call disable */ +#define CR_BEIE BIT(22) /* enable bus error ints */ +#define CR_SADIE BIT(23) /* slave address detected int enable */ +#define CR_SSDIE BIT(24) /* slave STOP detected int enable */ +#define CR_MSDIE BIT(25) /* master STOP detected int enable */ +#define CR_MSDE BIT(26) /* master STOP detected enable */ +#define CR_TXDONEIE BIT(27) /* transaction done int enable */ +#define CR_TXEIE BIT(28) /* transmit FIFO empty int enable */ +#define CR_RXHFIE BIT(29) /* receive FIFO half-full int enable */ +#define CR_RXFIE BIT(30) /* receive FIFO full int enable */ +#define CR_RXOVIE BIT(31) /* receive FIFO overrun int enable */ + +/* register ISR fields */ +#define SR_RWM BIT(13) /* read/write mode */ +#define SR_ACKNAK BIT(14) /* ACK/NACK status */ +#define SR_UB BIT(15) /* unit busy */ +#define SR_IBB BIT(16) /* i2c bus busy */ +#define SR_EBB BIT(17) /* early bus busy */ +#define SR_ALD BIT(18) /* arbitration loss detected */ +#define SR_ITE BIT(19) /* tx buffer empty */ +#define SR_IRF BIT(20) /* rx buffer full */ +#define SR_GCAD BIT(21) /* general call address detected */ +#define SR_BED BIT(22) /* bus error no ACK/NAK */ +#define SR_SAD BIT(23) /* slave address detected */ +#define SR_SSD BIT(24) /* slave stop detected */ +#define SR_MSD BIT(26) /* master stop detected */ +#define SR_TXDONE BIT(27) /* transaction done */ +#define SR_TXE BIT(28) /* tx FIFO empty */ +#define SR_RXHF BIT(29) /* rx FIFO half-full */ +#define SR_RXF BIT(30) /* rx FIFO full */ +#define SR_RXOV BIT(31) /* RX FIFO overrun */ + +/* register ILCR fields */ +#define LCR_SLV 0x000001FF /* SLV: bit[8:0] */ +#define LCR_FLV 0x0003FE00 /* FLV: bit[17:9] */ +#define LCR_HLVH 0x07FC0000 /* HLVH: bit[26:18] */ +#define LCR_HLVL 0xF8000000 /* HLVL: bit[31:27] */ + +/* register IWCR fields */ +#define WCR_COUNT 0x0000001F /* COUNT: bit[4:0] */ +#define WCR_COUNT1 0x000003E0 /* HS_COUNT1: bit[9:5] */ +#define WCR_COUNT2 0x00007C00 /* HS_COUNT2: bit[14:10] */ + +/* register IBMR fields */ +#define BMR_SDA BIT(0) /* SDA line level */ +#define BMR_SCL BIT(1) /* SCL line level */ + +/* register IWFIFO fields */ +#define WFIFO_DATA_MSK 0x000000FF /* data: bit[7:0] */ +#define WFIFO_CTRL_MSK 0x000003E0 /* control: bit[11:8] */ +#define WFIFO_CTRL_START BIT(8) /* start bit */ +#define WFIFO_CTRL_STOP BIT(9) /* stop bit */ +#define WFIFO_CTRL_ACKNAK BIT(10) /* send ACK(0) or NAK(1) */ +#define WFIFO_CTRL_TB BIT(11) /* transfer byte bit */ + +/* status register init value */ +#define I2C_INT_STATUS_MASK 0xfffc0000 /* SR bits[31:18] */ +#define I2C_INT_CTRL_MASK (CR_ALDIE | CR_DTEIE | CR_DRFIE | \ + CR_BEIE | CR_TXDONEIE | CR_TXEIE | \ + CR_RXHFIE | CR_RXFIE | CR_RXOVIE | \ + CR_MSDIE) + +/* i2c bus recover timeout: us */ +#define I2C_BUS_RECOVER_TIMEOUT (100000) + +#define I2C_FAST_MODE_FREQ (400000) + +enum spacemit_i2c_state { + STATE_IDLE, + STATE_START, + STATE_READ, + STATE_WRITE, +}; + +enum spacemit_i2c_dir { + DIR_WRITE, + DIR_READ +}; + +/* i2c-spacemit driver's main struct */ +struct spacemit_i2c_dev { + struct device *dev; + struct i2c_adapter adapt; + + /* hardware resources */ + void __iomem *base; + int irq; + + struct i2c_msg *msgs; + int msg_num; + struct i2c_msg *cur_msg; + + /* index of the current message being processed */ + int msg_idx; + u8 *msg_buf; + /* the number of unprocessed bytes remaining in each message */ + size_t unprocessed; + + enum spacemit_i2c_state state; + enum spacemit_i2c_dir dir; + struct completion complete; + u32 status; + u32 err; +}; + +static void spacemit_i2c_enable(struct spacemit_i2c_dev *i2c) +{ + u32 val; + + val = readl(i2c->base + ICR); + writel(val | CR_IUE, i2c->base + ICR); +} + +static void spacemit_i2c_disable(struct spacemit_i2c_dev *i2c) +{ + u32 val; + + val = readl(i2c->base + ICR); + val &= ~CR_IUE; + writel(val, i2c->base + ICR); +} + +static void spacemit_i2c_reset(struct spacemit_i2c_dev *i2c) +{ + writel(CR_UR, i2c->base + ICR); + udelay(5); + writel(0, i2c->base + ICR); +} + +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c); + +static void spacemit_i2c_bus_reset(struct spacemit_i2c_dev *i2c) +{ + u32 status; + + /* if bus is locked, reset unit. 0: locked */ + status = readl(i2c->base + IBMR); + if ((status & BMR_SDA) && (status & BMR_SCL)) + return; + + spacemit_i2c_reset(i2c); + usleep_range(10, 20); + + /* check scl status again */ + status = readl(i2c->base + IBMR); + if (!(status & BMR_SCL)) + dev_warn_ratelimited(i2c->dev, "unit reset failed\n"); +} + +static int spacemit_i2c_recover_bus_busy(struct spacemit_i2c_dev *i2c) +{ + int ret = 0; + u32 val; + + val = readl(i2c->base + ISR); + if (likely(!(val & (SR_UB | SR_IBB)))) + return 0; + + ret = readl_poll_timeout(i2c->base + ISR, val, !(val & (SR_UB | SR_IBB)), + 1500, I2C_BUS_RECOVER_TIMEOUT); + if (unlikely(ret)) { + spacemit_i2c_reset(i2c); + ret = -EAGAIN; + } + + return ret; +} + +static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c) +{ + /* in case bus is not released after transfer completes */ + if (unlikely(readl(i2c->base + ISR) & SR_EBB)) { + spacemit_i2c_bus_reset(i2c); + usleep_range(90, 150); + } +} + +static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c) +{ + u32 val = 0; + + /* + * Unmask interrupt bits for all xfer mode: + * bus error, arbitration loss detected. + * For transaction complete signal, we use master stop + * interrupt, so we don't need to unmask CR_TXDONEIE. + */ + val |= CR_BEIE | CR_ALDIE; + + /* + * Unmask interrupt bits for interrupt xfer mode: + * DBR rx full. + * For tx empty interrupt CR_DTEIE, we only + * need to enable when trigger byte transfer to start + * data sending. + */ + val |= CR_DRFIE; + + /* set speed bits: default fast mode */ + val |= CR_MODE_FAST; + + /* disable response to general call */ + val |= CR_GCD; + + /* enable SCL clock output */ + val |= CR_SCLE; + + /* enable master stop detected */ + val |= CR_MSDE | CR_MSDIE; + + writel(val, i2c->base + ICR); +} + +static inline void +spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask) +{ + writel(mask & I2C_INT_STATUS_MASK, i2c->base + ISR); +} + +static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c) +{ + u32 slave_addr_rw, val; + + i2c->dir = i2c->cur_msg->flags & I2C_M_RD; + i2c->state = STATE_START; + + if (i2c->cur_msg->flags & I2C_M_RD) + slave_addr_rw = ((i2c->cur_msg->addr & 0x7f) << 1) | 1; + else + slave_addr_rw = (i2c->cur_msg->addr & 0x7f) << 1; + + writel(slave_addr_rw, i2c->base + IDBR); + + val = readl(i2c->base + ICR); + + /* send start pulse */ + val &= ~CR_STOP; + val |= CR_START | CR_TB | CR_DTEIE; + writel(val, i2c->base + ICR); +} + +static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c) +{ + u32 val; + + val = readl(i2c->base + ICR); + + val |= CR_STOP | CR_ALDIE | CR_TB; + + if (i2c->dir == DIR_READ) + val |= CR_ACKNAK; + + writel(val, i2c->base + ICR); +} + +static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c) +{ + unsigned long time_left; + + for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) { + i2c->cur_msg = i2c->msgs + i2c->msg_idx; + i2c->msg_buf = i2c->cur_msg->buf; + i2c->err = 0; + i2c->status = 0; + i2c->unprocessed = i2c->cur_msg->len; + + reinit_completion(&i2c->complete); + + spacemit_i2c_start(i2c); + + time_left = wait_for_completion_timeout(&i2c->complete, + i2c->adapt.timeout); + if (unlikely(time_left == 0)) { + dev_alert(i2c->dev, "msg completion timeout\n"); + spacemit_i2c_bus_reset(i2c); + spacemit_i2c_reset(i2c); + return -ETIMEDOUT; + } + + if (unlikely(i2c->err)) + return spacemit_i2c_handle_err(i2c); + } + + return 0; +} + +static int spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c) +{ + if (i2c->dir == DIR_READ) { + if (i2c->unprocessed == 1 && i2c->msg_idx == i2c->msg_num - 1) + return 1; + } else if (i2c->dir == DIR_WRITE) { + if (!i2c->unprocessed && i2c->msg_idx == i2c->msg_num - 1) + return 1; + } + + return 0; +} + +static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c) +{ + /* if transfer completes, ISR will handle it */ + if (i2c->status & SR_MSD) + return; + + if (i2c->unprocessed) { + writel(*i2c->msg_buf++, i2c->base + IDBR); + i2c->unprocessed--; + return; + } + + /* STATE_IDLE avoids trigger next byte */ + i2c->state = STATE_IDLE; + complete(&i2c->complete); +} + +static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c) +{ + if (i2c->unprocessed) { + *i2c->msg_buf++ = readl(i2c->base + IDBR); + i2c->unprocessed--; + } + + /* if transfer completes, ISR will handle it */ + if (i2c->status & (SR_MSD | SR_ACKNAK)) + return; + + /* it has to append stop bit in icr that read last byte */ + if (i2c->unprocessed) + return; + + /* STATE_IDLE avoids trigger next byte */ + i2c->state = STATE_IDLE; + complete(&i2c->complete); +} + +static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c) +{ + if (i2c->dir == DIR_READ) { + i2c->state = STATE_READ; + return; + } + + if (i2c->dir == DIR_WRITE) { + i2c->state = STATE_WRITE; + spacemit_i2c_handle_write(i2c); + } +} + +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c) +{ + if (!i2c->err) + return 0; + + dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status); + + if (i2c->err & (SR_BED | SR_ALD)) + spacemit_i2c_reset(i2c); + + if (i2c->err & (SR_RXOV | SR_ALD)) + return -EAGAIN; + + return (i2c->status & SR_ACKNAK) ? -ENXIO : -EIO; +} + +static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c) +{ + u32 val; + /* + * send transaction complete signal: + * error happens, detect master stop + */ + if (likely(i2c->err || (i2c->status & SR_MSD))) { + /* + * Here the transaction is already done, we don't need any + * other interrupt signals from now, in case any interrupt + * happens before spacemit_i2c_xfer to disable irq and i2c unit, + * we mask all the interrupt signals and clear the interrupt + * status. + */ + val = readl(i2c->base + ICR); + val &= ~I2C_INT_CTRL_MASK; + writel(val, i2c->base + ICR); + + spacemit_i2c_clear_int_status(i2c, I2C_INT_STATUS_MASK); + + i2c->state = STATE_IDLE; + complete(&i2c->complete); + } +} + +static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid) +{ + struct spacemit_i2c_dev *i2c = devid; + u32 status, val; + + status = readl(i2c->base + ISR); + if (!status) + return IRQ_HANDLED; + + i2c->status = status; + + i2c->err = status & (SR_BED | SR_RXOV | SR_ALD); + + spacemit_i2c_clear_int_status(i2c, status); + + if (unlikely(i2c->err)) + goto err_out; + + val = readl(i2c->base + ICR); + + val &= ~(CR_TB | CR_ACKNAK | CR_STOP | CR_START); + writel(val, i2c->base + ICR); + + switch (i2c->state) { + case STATE_START: + spacemit_i2c_handle_start(i2c); + break; + case STATE_READ: + spacemit_i2c_handle_read(i2c); + break; + case STATE_WRITE: + spacemit_i2c_handle_write(i2c); + break; + default: + break; + } + + if (i2c->state != STATE_IDLE) { + if (spacemit_i2c_is_last_msg(i2c)) { + /* trigger next byte with stop */ + spacemit_i2c_stop(i2c); + } else { + /* trigger next byte */ + val |= CR_ALDIE | CR_TB; + writel(val, i2c->base + ICR); + } + } + +err_out: + spacemit_i2c_err_check(i2c); + return IRQ_HANDLED; +} + +static void spacemit_i2c_calc_timeout(struct spacemit_i2c_dev *i2c) +{ + unsigned long timeout; + int idx = 0, cnt = 0, freq; + + while (idx < i2c->msg_num) { + cnt += (i2c->msgs + idx)->len + 1; + idx++; + } + + freq = I2C_FAST_MODE_FREQ; + /* + * multiply by 9 because each byte in I2C transmission requires + * 9 clock cycles: 8 bits of data plus 1 ACK/NACK bit. + */ + timeout = cnt * 9 * USEC_PER_SEC / freq; + + i2c->adapt.timeout = usecs_to_jiffies(timeout + USEC_PER_SEC / 2) / i2c->msg_num; +} + +static inline int spacemit_i2c_xfer_core(struct spacemit_i2c_dev *i2c) +{ + int ret = 0; + + spacemit_i2c_reset(i2c); + + spacemit_i2c_calc_timeout(i2c); + + spacemit_i2c_init(i2c); + + spacemit_i2c_enable(i2c); + enable_irq(i2c->irq); + + /* i2c wait for bus busy */ + ret = spacemit_i2c_recover_bus_busy(i2c); + if (unlikely(ret)) + return ret; + + ret = spacemit_i2c_xfer_msg(i2c); + if (unlikely(ret < 0)) { + dev_dbg(i2c->dev, "i2c transfer error\n"); + /* timeout error should not be overridden, and the transfer + * error will be confirmed by err handle function latter, + * the reset should be invalid argument error. + */ + if (ret != -ETIMEDOUT) + ret = -EINVAL; + } + + return ret; +} + +static int +spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg msgs[], int num) +{ + struct spacemit_i2c_dev *i2c = i2c_get_adapdata(adapt); + int ret; + + i2c->msgs = msgs; + i2c->msg_num = num; + + ret = spacemit_i2c_xfer_core(i2c); + if (likely(!ret)) + spacemit_i2c_check_bus_release(i2c); + + disable_irq(i2c->irq); + + spacemit_i2c_disable(i2c); + + if (unlikely((ret == -ETIMEDOUT || ret == -EAGAIN))) + dev_alert(i2c->dev, "i2c transfer failed, ret %d err 0x%x\n", ret, i2c->err); + + return ret < 0 ? ret : num; +} + +static u32 spacemit_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); +} + +static const struct i2c_algorithm spacemit_i2c_algo = { + .xfer = spacemit_i2c_xfer, + .functionality = spacemit_i2c_func, +}; + +static int spacemit_i2c_probe(struct platform_device *pdev) +{ + struct spacemit_i2c_dev *i2c; + struct device_node *of_node = pdev->dev.of_node; + struct clk *clk; + int ret = 0; + + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + i2c->dev = &pdev->dev; + + i2c->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(i2c->base)) + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap"); + + i2c->irq = platform_get_irq(pdev, 0); + if (i2c->irq < 0) + return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource"); + + ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler, + IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c); + if (ret) + return dev_err_probe(&pdev->dev, ret, "failed to request irq"); + + disable_irq(i2c->irq); + + clk = devm_clk_get_enabled(&pdev->dev, NULL); + if (IS_ERR(clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock"); + + i2c_set_adapdata(&i2c->adapt, i2c); + i2c->adapt.owner = THIS_MODULE; + i2c->adapt.algo = &spacemit_i2c_algo; + i2c->adapt.dev.parent = i2c->dev; + i2c->adapt.nr = pdev->id; + + i2c->adapt.dev.of_node = of_node; + i2c->adapt.algo_data = i2c; + + strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name)); + + init_completion(&i2c->complete); + + ret = i2c_add_numbered_adapter(&i2c->adapt); + if (ret) + return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter"); + + platform_set_drvdata(pdev, i2c); + + return 0; +} + +static void spacemit_i2c_remove(struct platform_device *pdev) +{ + struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev); + + i2c_del_adapter(&i2c->adapt); +} + +static const struct of_device_id spacemit_i2c_of_match[] = { + { .compatible = "spacemit,k1-i2c", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match); + +static struct platform_driver spacemit_i2c_driver = { + .probe = spacemit_i2c_probe, + .remove = spacemit_i2c_remove, + .driver = { + .name = "i2c-k1", + .of_match_table = spacemit_i2c_of_match, + }, +}; +module_platform_driver(spacemit_i2c_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC");