[v2,3/5] spi: sunxi: Add Allwinner A31 SPI controller driver

Message ID	1390993850-9054-4-git-send-email-maxime.ripard@free-electrons.com (mailing list archive)
State	Changes Requested
Headers	show Return-Path: <linux-spi-owner@kernel.org> From: Maxime Ripard <maxime.ripard@free-electrons.com> To: Mark Brown <broonie@kernel.org>, Mike Turquette <mturquette@linaro.org>, Emilio Lopez <emilio@elopez.com.ar> Cc: linux-sunxi@googlegroups.com, linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, kevin.z.m.zh@gmail.com, sunny@allwinnertech.com, shuge@allwinnertech.com, zhuzhenhua@allwinnertech.com, Maxime Ripard <maxime.ripard@free-electrons.com> Subject: [PATCH v2 3/5] spi: sunxi: Add Allwinner A31 SPI controller driver Date: Wed, 29 Jan 2014 12:10:48 +0100 Message-Id: <1390993850-9054-4-git-send-email-maxime.ripard@free-electrons.com> In-Reply-To: <1390993850-9054-1-git-send-email-maxime.ripard@free-electrons.com> References: <1390993850-9054-1-git-send-email-maxime.ripard@free-electrons.com> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk

diff --git a/Documentation/devicetree/bindings/spi/spi-sun6i.txt b/Documentation/devicetree/bindings/spi/spi-sun6i.txt new file mode 100644 index 0000000..21de73d --- /dev/null +++ b/Documentation/devicetree/bindings/spi/spi-sun6i.txt @@ -0,0 +1,24 @@ +Allwinner A31 SPI controller + +Required properties: +- compatible: Should be "allwinner,sun6i-a31-spi". +- reg: Should contain register location and length. +- interrupts: Should contain interrupt. +- clocks: phandle to the clocks feeding the SPI controller. Two are + needed: + - "ahb": the gated AHB parent clock + - "mod": the parent module clock +- clock-names: Must contain the clock names described just above +- resets: phandle to the reset controller asserting this device in + reset + +Example: + +spi1: spi@01c69000 { + compatible = "allwinner,sun6i-a31-spi"; + reg = <0x01c69000 0x1000>; + interrupts = <0 66 4>; + clocks = <&ahb1_gates 21>, <&spi1_clk>; + clock-names = "ahb", "mod"; + resets = <&ahb1_rst 21>; +}; diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index eb1f1ef..004e3b0 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -438,6 +438,13 @@ config SPI_SIRF help SPI driver for CSR SiRFprimaII SoCs +config SPI_SUN6I + tristate "Allwinner A31 SPI controller" + depends on ARCH_SUNXI || COMPILE_TEST + select PM_RUNTIME + help + This enables using the SPI controller on the Allwinner A31 SoCs. + config SPI_MXS tristate "Freescale MXS SPI controller" depends on ARCH_MXS diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index ab8d864..658ec64 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_SPI_SH_HSPI) += spi-sh-hspi.o obj-$(CONFIG_SPI_SH_MSIOF) += spi-sh-msiof.o obj-$(CONFIG_SPI_SH_SCI) += spi-sh-sci.o obj-$(CONFIG_SPI_SIRF) += spi-sirf.o +obj-$(CONFIG_SPI_SUN6I) += spi-sun6i.o obj-$(CONFIG_SPI_TEGRA114) += spi-tegra114.o obj-$(CONFIG_SPI_TEGRA20_SFLASH) += spi-tegra20-sflash.o obj-$(CONFIG_SPI_TEGRA20_SLINK) += spi-tegra20-slink.o diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c new file mode 100644 index 0000000..32f3fc7 --- /dev/null +++ b/drivers/spi/spi-sun6i.c @@ -0,0 +1,478 @@ +/* + * Copyright (C) 2012 - 2014 Allwinner Tech + * Pan Nan <pannan@allwinnertech.com> + * + * Copyright (C) 2014 Maxime Ripard + * Maxime Ripard <maxime.ripard@free-electrons.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/reset.h> +#include <linux/workqueue.h> + +#include <linux/spi/spi.h> + +#define SUN6I_FIFO_DEPTH 128 + +#define SUN6I_GBL_CTL_REG 0x04 +#define SUN6I_GBL_CTL_BUS_ENABLE BIT(0) +#define SUN6I_GBL_CTL_MASTER BIT(1) +#define SUN6I_GBL_CTL_TP BIT(7) +#define SUN6I_GBL_CTL_RST BIT(31) + +#define SUN6I_TFR_CTL_REG 0x08 +#define SUN6I_TFR_CTL_CPHA BIT(0) +#define SUN6I_TFR_CTL_CPOL BIT(1) +#define SUN6I_TFR_CTL_SPOL BIT(2) +#define SUN6I_TFR_CTL_CS_MASK 0x3 +#define SUN6I_TFR_CTL_CS(cs) (((cs) & SUN6I_TFR_CTL_CS_MASK) << 4) +#define SUN6I_TFR_CTL_DHB BIT(8) +#define SUN6I_TFR_CTL_FBS BIT(12) +#define SUN6I_TFR_CTL_XCH BIT(31) + +#define SUN6I_INT_CTL_REG 0x10 +#define SUN6I_INT_CTL_RF_OVF BIT(8) +#define SUN6I_INT_CTL_TC BIT(12) + +#define SUN6I_INT_STA_REG 0x14 + +#define SUN6I_FIFO_CTL_REG 0x18 +#define SUN6I_FIFO_CTL_RF_RST BIT(15) +#define SUN6I_FIFO_CTL_TF_RST BIT(31) + +#define SUN6I_FIFO_STA_REG 0x1c +#define SUN6I_FIFO_STA_RF_CNT_MASK 0x7f +#define SUN6I_FIFO_STA_RF_CNT_BITS 0 +#define SUN6I_FIFO_STA_TF_CNT_MASK 0x7f +#define SUN6I_FIFO_STA_TF_CNT_BITS 16 + +#define SUN6I_CLK_CTL_REG 0x24 +#define SUN6I_CLK_CTL_CDR2_MASK 0xff +#define SUN6I_CLK_CTL_CDR2(div) (((div) & SUN6I_CLK_CTL_CDR2_MASK) << 0) +#define SUN6I_CLK_CTL_CDR1_MASK 0xf +#define SUN6I_CLK_CTL_CDR1(div) (((div) & SUN6I_CLK_CTL_CDR1_MASK) << 8) +#define SUN6I_CLK_CTL_DRS BIT(12) + +#define SUN6I_BURST_CNT_REG 0x30 +#define SUN6I_BURST_CNT(cnt) ((cnt) & 0xffffff) + +#define SUN6I_XMIT_CNT_REG 0x34 +#define SUN6I_XMIT_CNT(cnt) ((cnt) & 0xffffff) + +#define SUN6I_BURST_CTL_CNT_REG 0x38 +#define SUN6I_BURST_CTL_CNT_STC(cnt) ((cnt) & 0xffffff) + +#define SUN6I_TXDATA_REG 0x200 +#define SUN6I_RXDATA_REG 0x300 + +struct sun6i_spi { + struct spi_master *master; + void __iomem *base_addr; + struct clk *hclk; + struct clk *mclk; + struct reset_control *rstc; + + struct completion done; + + const u8 *tx_buf; + u8 *rx_buf; + int len; +}; + +static inline u32 sun6i_spi_read(struct sun6i_spi *sspi, u32 reg) +{ + return readl(sspi->base_addr + reg); +} + +static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value) +{ + writel(value, sspi->base_addr + reg); +} + +static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi, int len) +{ + u32 reg, cnt; + u8 byte; + + /* See how much data is available */ + reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG); + reg &= SUN6I_FIFO_STA_RF_CNT_MASK; + cnt = reg >> SUN6I_FIFO_STA_RF_CNT_BITS; + + if (len > cnt) + len = cnt; + + while (len--) { + byte = readb(sspi->base_addr + SUN6I_RXDATA_REG); + if (sspi->rx_buf) + *sspi->rx_buf++ = byte; + } +} + +static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi, int len) +{ + u8 byte; + + if (len > sspi->len) + len = sspi->len; + + while (len--) { + byte = sspi->tx_buf ? *sspi->tx_buf++ : 0; + writeb(byte, sspi->base_addr + SUN6I_TXDATA_REG); + sspi->len--; + } +} + +static void sun6i_spi_set_cs(struct spi_device *spi, bool enable) +{ + struct sun6i_spi *sspi = spi_master_get_devdata(spi->master); + u32 reg; + + if (!enable) + return; + + reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG); + reg &= ~SUN6I_TFR_CTL_CS_MASK; + reg |= SUN6I_TFR_CTL_CS(spi->chip_select); + sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg); +} + + +static int sun6i_spi_transfer_one(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *tfr) +{ + struct sun6i_spi *sspi = spi_master_get_devdata(master); + unsigned int mclk_rate, div, timeout; + unsigned int tx_len = 0; + int ret = 0; + u32 reg; + + /* We don't support transfer larger than the FIFO */ + if (tfr->len > SUN6I_FIFO_DEPTH) + return -EINVAL; + + reinit_completion(&sspi->done); + sspi->tx_buf = tfr->tx_buf; + sspi->rx_buf = tfr->rx_buf; + sspi->len = tfr->len; + + /* Clear pending interrupts */ + sun6i_spi_write(sspi, SUN6I_INT_STA_REG, ~0); + + /* Reset FIFO */ + sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG, + SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST); + + /* + * Setup the transfer control register: Chip Select, + * polarities, etc. + */ + reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG); + + if (spi->mode & SPI_CPOL) + reg |= SUN6I_TFR_CTL_CPOL; + else + reg &= ~SUN6I_TFR_CTL_CPOL; + + if (spi->mode & SPI_CPHA) + reg |= SUN6I_TFR_CTL_CPHA; + else + reg &= ~SUN6I_TFR_CTL_CPHA; + + if (spi->mode & SPI_CS_HIGH) + reg &= ~SUN6I_TFR_CTL_SPOL; + else + reg |= SUN6I_TFR_CTL_SPOL; + + if (spi->mode & SPI_LSB_FIRST) + reg |= SUN6I_TFR_CTL_FBS; + else + reg &= ~SUN6I_TFR_CTL_FBS; + + /* + * If it's a TX only transfer, we don't want to fill the RX + * FIFO with bogus data + */ + if (sspi->rx_buf) + reg &= ~SUN6I_TFR_CTL_DHB; + else + reg |= SUN6I_TFR_CTL_DHB; + + sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg); + + /* Ensure that we have a parent clock fast enough */ + mclk_rate = clk_get_rate(sspi->mclk); + if (mclk_rate < (2 * spi->max_speed_hz)) { + clk_set_rate(sspi->mclk, 2 * spi->max_speed_hz); + mclk_rate = clk_get_rate(sspi->mclk); + } + + /* + * Setup clock divider. + * + * We have two choices there. Either we can use the clock + * divide rate 1, which is calculated thanks to this formula: + * SPI_CLK = MOD_CLK / (2 ^ cdr) + * Or we can use CDR2, which is calculated with the formula: + * SPI_CLK = MOD_CLK / (2 * (cdr + 1)) + * Wether we use the former or the latter is set through the + * DRS bit. + * + * First try CDR2, and if we can't reach the expected + * frequency, fall back to CDR1. + */ + div = mclk_rate / (2 * spi->max_speed_hz); + if (div <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) { + if (div > 0) + div--; + + reg = SUN6I_CLK_CTL_CDR2(div) | SUN6I_CLK_CTL_DRS; + } else { + div = ilog2(mclk_rate) - ilog2(spi->max_speed_hz); + reg = SUN6I_CLK_CTL_CDR1(div); + } + + sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg); + + /* Setup the transfer now... */ + if (sspi->tx_buf) + tx_len = tfr->len; + + /* Setup the counters */ + sun6i_spi_write(sspi, SUN6I_BURST_CNT_REG, SUN6I_BURST_CNT(tfr->len)); + sun6i_spi_write(sspi, SUN6I_XMIT_CNT_REG, SUN6I_XMIT_CNT(tx_len)); + sun6i_spi_write(sspi, SUN6I_BURST_CTL_CNT_REG, + SUN6I_BURST_CTL_CNT_STC(tx_len)); + + /* Fill the TX FIFO */ + sun6i_spi_fill_fifo(sspi, SUN6I_FIFO_DEPTH); + + /* Enable the interrupts */ + sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, SUN6I_INT_CTL_TC); + + /* Start the transfer */ + reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG); + sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg | SUN6I_TFR_CTL_XCH); + + timeout = wait_for_completion_timeout(&sspi->done, + msecs_to_jiffies(1000)); + if (!timeout) { + ret = -ETIMEDOUT; + goto out; + } + + sun6i_spi_drain_fifo(sspi, SUN6I_FIFO_DEPTH); + +out: + sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0); + + return ret; +} + +static irqreturn_t sun6i_spi_handler(int irq, void *dev_id) +{ + struct sun6i_spi *sspi = dev_id; + u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG); + + /* Transfer complete */ + if (status & SUN6I_INT_CTL_TC) { + sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC); + complete(&sspi->done); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int sun6i_spi_runtime_resume(struct device *dev) +{ + struct spi_master *master = dev_get_drvdata(dev); + struct sun6i_spi *sspi = spi_master_get_devdata(master); + int ret; + + ret = clk_prepare_enable(sspi->hclk); + if (ret) { + dev_err(dev, "Couldn't enable clock 'ahb spi'\n"); + goto out; + } + + ret = clk_prepare_enable(sspi->mclk); + if (ret) { + dev_err(dev, "Couldn't enable clock 'ahb spi'\n"); + goto err; + } + + ret = reset_control_deassert(sspi->rstc); + if (ret) { + dev_err(dev, "Couldn't deassert the device from reset\n"); + goto err2; + } + + sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG, + SUN6I_GBL_CTL_BUS_ENABLE | SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP); + + return 0; + +err2: + clk_disable_unprepare(sspi->mclk); +err: + clk_disable_unprepare(sspi->hclk); +out: + return ret; +} + +static int sun6i_spi_runtime_suspend(struct device *dev) +{ + struct spi_master *master = dev_get_drvdata(dev); + struct sun6i_spi *sspi = spi_master_get_devdata(master); + + reset_control_assert(sspi->rstc); + clk_disable_unprepare(sspi->mclk); + clk_disable_unprepare(sspi->hclk); + + return 0; +} + +static int sun6i_spi_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct sun6i_spi *sspi; + struct resource *res; + int ret = 0, irq; + + master = spi_alloc_master(&pdev->dev, sizeof(struct sun6i_spi)); + if (!master) { + dev_err(&pdev->dev, "Unable to allocate SPI Master\n"); + return -ENOMEM; + } + + platform_set_drvdata(pdev, master); + sspi = spi_master_get_devdata(master); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + sspi->base_addr = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(sspi->base_addr)) { + ret = PTR_ERR(sspi->base_addr); + goto err; + } + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "No spi IRQ specified\n"); + ret = -ENXIO; + goto err; + } + + ret = devm_request_irq(&pdev->dev, irq, sun6i_spi_handler, + 0, "sun6i-spi", sspi); + if (ret) { + dev_err(&pdev->dev, "Cannot request IRQ\n"); + goto err; + } + + sspi->master = master; + master->bus_num = -1; + master->set_cs = sun6i_spi_set_cs; + master->transfer_one = sun6i_spi_transfer_one; + master->num_chipselect = 4; + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST; + master->dev.of_node = pdev->dev.of_node; + master->auto_runtime_pm = true; + + /* Setup clocks */ + sspi->hclk = devm_clk_get(&pdev->dev, "ahb"); + if (IS_ERR(sspi->hclk)) { + dev_err(&pdev->dev, "Unable to acquire AHB clock\n"); + ret = PTR_ERR(sspi->hclk); + goto err; + } + + sspi->mclk = devm_clk_get(&pdev->dev, "mod"); + if (IS_ERR(sspi->mclk)) { + dev_err(&pdev->dev, "Unable to acquire module clock\n"); + ret = PTR_ERR(sspi->mclk); + goto err2; + } + + init_completion(&sspi->done); + + sspi->rstc = devm_reset_control_get(&pdev->dev, NULL); + if (IS_ERR(sspi->rstc)) { + dev_err(&pdev->dev, "Couldn't get reset controller\n"); + ret = PTR_ERR(sspi->rstc); + goto err3; + } + + pm_runtime_enable(&pdev->dev); + + ret = spi_register_master(master); + if (ret) { + dev_err(&pdev->dev, "cannot register SPI master\n"); + goto err4; + } + + return 0; + +err4: + pm_runtime_disable(&pdev->dev); +err3: + clk_disable_unprepare(sspi->mclk); +err2: + clk_disable_unprepare(sspi->hclk); +err: + spi_master_put(master); + + return ret; +} + +static int sun6i_spi_remove(struct platform_device *pdev) +{ + struct spi_master *master = spi_master_get(platform_get_drvdata(pdev)); + + spi_unregister_master(master); + pm_runtime_disable(&pdev->dev); + spi_master_put(master); + + return 0; +} + +static const struct of_device_id sun6i_spi_match[] = { + { .compatible = "allwinner,sun6i-a31-spi", }, + {} +}; +MODULE_DEVICE_TABLE(of, sun6i_spi_match); + +static const struct dev_pm_ops sun6i_spi_pm_ops = { + .runtime_resume = sun6i_spi_runtime_resume, + .runtime_suspend = sun6i_spi_runtime_suspend, +}; + +static struct platform_driver sun6i_spi_driver = { + .probe = sun6i_spi_probe, + .remove = sun6i_spi_remove, + .driver = { + .name = "sun6i-spi", + .owner = THIS_MODULE, + .of_match_table = sun6i_spi_match, + .pm = &sun6i_spi_pm_ops, + }, +}; +module_platform_driver(sun6i_spi_driver); + +MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>"); +MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>"); +MODULE_DESCRIPTION("Allwinner A31 SPI controller driver"); +MODULE_LICENSE("GPL");

[v2,3/5] spi: sunxi: Add Allwinner A31 SPI controller driver

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