From patchwork Thu Mar 18 17:00:00 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mika Westerberg X-Patchwork-Id: 86756 Received: from lists.sourceforge.net (lists.sourceforge.net [216.34.181.88]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o2IH0Ikw003541 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 18 Mar 2010 17:00:54 GMT Received: from localhost ([127.0.0.1] helo=sfs-ml-3.v29.ch3.sourceforge.com) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.69) (envelope-from ) id 1NsJ50-0006Bf-Dl; Thu, 18 Mar 2010 17:00:18 +0000 Received: from sfi-mx-2.v28.ch3.sourceforge.com ([172.29.28.122] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.69) (envelope-from ) id 1NsJ4z-0006BV-4A for spi-devel-general@lists.sourceforge.net; Thu, 18 Mar 2010 17:00:17 +0000 Received-SPF: pass (sfi-mx-2.v28.ch3.sourceforge.com: domain of gmail.com designates 72.14.220.152 as permitted sender) client-ip=72.14.220.152; envelope-from=mika.westerberg@gmail.com; helo=fg-out-1718.google.com; Received: from fg-out-1718.google.com ([72.14.220.152]) by sfi-mx-2.v28.ch3.sourceforge.com with esmtp (Exim 4.69) id 1NsJ4x-0001vH-D9 for spi-devel-general@lists.sourceforge.net; Thu, 18 Mar 2010 17:00:17 +0000 Received: by fg-out-1718.google.com with SMTP id d23so16264fga.10 for ; Thu, 18 Mar 2010 10:00:08 -0700 (PDT) Received: by 10.87.47.3 with SMTP id z3mr4886285fgj.70.1268931608338; Thu, 18 Mar 2010 10:00:08 -0700 (PDT) Received: from localhost.localdomain (a88-115-42-115.elisa-laajakaista.fi [88.115.42.115]) by mx.google.com with ESMTPS id 2sm238437fks.12.2010.03.18.10.00.06 (version=SSLv3 cipher=RC4-MD5); Thu, 18 Mar 2010 10:00:07 -0700 (PDT) From: Mika Westerberg To: spi-devel-general@lists.sourceforge.net Date: Thu, 18 Mar 2010 19:00:00 +0200 Message-Id: <9de3769ae253830fb0eebc98d299137c59c69b8c.1268930557.git.mika.westerberg@iki.fi> X-Mailer: git-send-email 1.5.6.5 In-Reply-To: References: In-Reply-To: References: X-Spam-Score: -1.2 (-) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain -0.0 SPF_PASS SPF: sender matches SPF record -0.0 DKIM_VERIFIED Domain Keys Identified Mail: signature passes verification 0.0 DKIM_SIGNED Domain Keys Identified Mail: message has a signature 0.4 AWL AWL: From: address is in the auto white-list X-Headers-End: 1NsJ4x-0001vH-D9 Cc: linux-arm-kernel@lists.infradead.org Subject: [spi-devel-general] [PATCH v2 1/3] spi: implemented driver for Cirrus EP93xx SPI controller X-BeenThere: spi-devel-general@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: Linux SPI core/device drivers discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: spi-devel-general-bounces@lists.sourceforge.net X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Thu, 18 Mar 2010 17:00:55 +0000 (UTC) diff --git a/arch/arm/mach-ep93xx/include/mach/ep93xx_spi.h b/arch/arm/mach-ep93xx/include/mach/ep93xx_spi.h new file mode 100644 index 0000000..fe93d2e --- /dev/null +++ b/arch/arm/mach-ep93xx/include/mach/ep93xx_spi.h @@ -0,0 +1,34 @@ +#ifndef __ASM_MACH_EP93XX_SPI_H +#define __ASM_MACH_EP93XX_SPI_H + +/** + * struct ep93xx_spi_info - EP93xx specific SPI descriptor + * @num_chipselect: number of chip select GPIOs on this board + * @cs_control: chip select control function + * @data: pointer to data that is passed to @cs_control function. + * Can be %NULL if not needed. + * + * This structure is passed from board support files to EP93xx SPI controller + * driver. It provides callback hook to control chip select GPIOs that are + * allocated in board support files during board initialization. + */ +struct ep93xx_spi_info { + int num_chipselect; + /* + * cs_control() - control board chipselect GPIO lines + * @cs: chip select to control + * @value: value to set the chip select line to + * @data: optional data + * + * This function is used to control board specific GPIO lines that + * are allocated as SPI chipselects. @value is either %0 or %1. It + * is possibled to pass additional information using @data. + * + * This function is called from thread context and can sleep if + * necessary. + */ + void (*cs_control)(unsigned cs, unsigned value, void *data); + void *data; +}; + +#endif /* __ASM_MACH_EP93XX_SPI_H */ diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index a191fa2..5852340 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -117,6 +117,17 @@ config SPI_DAVINCI help SPI master controller for DaVinci and DA8xx SPI modules. +config SPI_EP93XX + tristate "Cirrus Logic EP93xx SPI controller" + depends on ARCH_EP93XX + help + This enables using the Cirrus EP93xx SPI controller in master + mode. This driver supports EP9301, EP9302, EP9307, EP9312 and EP9315 + chips. + + To compile this driver as a module, choose M here. The module will be + called ep93xx_spi. + config SPI_GPIO tristate "GPIO-based bitbanging SPI Master" depends on GENERIC_GPIO diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index d7d0f89..377f845 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -21,6 +21,7 @@ obj-$(CONFIG_SPI_DAVINCI) += davinci_spi.o obj-$(CONFIG_SPI_DESIGNWARE) += dw_spi.o obj-$(CONFIG_SPI_DW_PCI) += dw_spi_pci.o obj-$(CONFIG_SPI_DW_MMIO) += dw_spi_mmio.o +obj-$(CONFIG_SPI_EP93XX) += ep93xx_spi.o obj-$(CONFIG_SPI_GPIO) += spi_gpio.o obj-$(CONFIG_SPI_IMX) += spi_imx.o obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o diff --git a/drivers/spi/ep93xx_spi.c b/drivers/spi/ep93xx_spi.c new file mode 100644 index 0000000..17935f3 --- /dev/null +++ b/drivers/spi/ep93xx_spi.c @@ -0,0 +1,1063 @@ +/* + * Driver for Cirrus Logic EP93xx SPI controller. + * + * Copyright (c) 2010 Mika Westerberg + * + * For more information about the SPI controller see documentation on Cirrus + * Logic web site: + * http://www.cirrus.com/en/pubs/manual/EP93xx_Users_Guide_UM1.pdf + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#define SSPCR0 0x0000 +#define SSPCR0_MODE_SHIFT 6 +#define SSPCR0_SCR_SHIFT 8 + +#define SSPCR1 0x0004 +#define SSPCR1_RIE BIT(0) +#define SSPCR1_TIE BIT(1) +#define SSPCR1_RORIE BIT(2) +#define SSPCR1_LBM BIT(3) +#define SSPCR1_SSE BIT(4) +#define SSPCR1_MS BIT(5) +#define SSPCR1_SOD BIT(6) + +#define SSPDR 0x0008 + +#define SSPSR 0x000c +#define SSPSR_TFE BIT(0) +#define SSPSR_TNF BIT(1) +#define SSPSR_RNE BIT(2) +#define SSPSR_RFF BIT(3) +#define SSPSR_BSY BIT(4) +#define SSPCPSR 0x0010 + +#define SSPIIR 0x0014 +#define SSPIIR_RIS BIT(0) +#define SSPIIR_TIS BIT(1) +#define SSPIIR_RORIS BIT(2) +#define SSPICR SSPIIR + +/* timeout in milliseconds */ +#define SPI_TIMEOUT 100 + +/** + * struct ep93xx_spi - EP93xx SPI controller structure + * @lock: spinlock that protects concurrent accesses to fields @running, + * @current_msg and @msg_queue + * @pdev: pointer to platform device + * @info: platform specific info + * @clk: clock for the controller + * @regs_base: pointer to ioremap()'d registers + * @irq: IRQ number used by the driver + * @min_rate: minimum clock rate (in Hz) supported by the controller + * @max_rate: maximum clock rate (in Hz) supported by the controller + * @running: is the queue running + * @msg_queue: queue for the messages + * @wq: workqueue used by the driver + * @msg_work: work that is queued for the driver + * @wait: wait here until given transfer is completed + * @current_msg: message that is currently processed (or %NULL if none) + * @spi_dev: pointer to device that was previously selected. + * @tx: current byte in transfer to transmit + * @rx: current byte in transfer to receive + * + * This structure holds EP93xx SPI controller specific information. When + * @running is %true, driver accepts transfer requests from protocol drivers. + * @current_msg is used to hold pointer to the message that is currently + * processed. If @current_msg is %NULL, it means that no processing is going + * on. + * + * Most of the fields are only written once and they can be accessed without + * taking the @lock. Fields that are accessed concurrently are: @current_msg, + * @running and @msg_queue. + */ +struct ep93xx_spi { + spinlock_t lock; + const struct platform_device *pdev; + const struct ep93xx_spi_info *info; + struct clk *clk; + void __iomem *regs_base; + int irq; + unsigned long min_rate; + unsigned long max_rate; + bool running; + struct workqueue_struct *wq; + struct work_struct msg_work; + struct completion wait; + struct list_head msg_queue; + struct spi_message *current_msg; + size_t tx; + size_t rx; +}; + +/** + * struct ep93xx_spi_chip - SPI device hardware settings + * @rate: max rate in hz this chip supports + * @div_cpsr: cpsr (pre-scaler) divider + * @div_scr: scr divider + * @dss: bits per word (4 - 16 bits) + * @mode: chip SPI mode (see also &struct spi_device) + * + * This structure is used to store hardware register specific settings for each + * SPI device. Settings are written to hardware by function + * ep93xx_spi_chip_setup(). + */ +struct ep93xx_spi_chip { + unsigned long rate; + u8 div_cpsr; + u8 div_scr; + u8 dss; + u8 mode; +}; + +/* converts bits per word to CR0.DSS value */ +#define bits_per_word_to_dss(bpw) ((bpw) - 1) + +static inline void +ep93xx_spi_write_u8(const struct ep93xx_spi *espi, u16 reg, u8 value) +{ + __raw_writeb(value, espi->regs_base + reg); +} + +static inline u8 +ep93xx_spi_read_u8(const struct ep93xx_spi *spi, u16 reg) +{ + return __raw_readb(spi->regs_base + reg); +} + +static inline void +ep93xx_spi_write_u16(const struct ep93xx_spi *espi, u16 reg, u16 value) +{ + __raw_writew(value, espi->regs_base + reg); +} + +static inline u16 +ep93xx_spi_read_u16(const struct ep93xx_spi *spi, u16 reg) +{ + return __raw_readw(spi->regs_base + reg); +} + +/** + * ep93xx_spi_enable() - enables the SPI controller and clock + * @espi: ep93xx SPI controller struct + * + * This function enables the SPI controller and its clock. Returns %0 in case + * of success and negative error in case if failure. + */ +static int ep93xx_spi_enable(const struct ep93xx_spi *espi) +{ + u16 regval; + int err; + + err = clk_enable(espi->clk); + if (err) + return err; + + regval = ep93xx_spi_read_u16(espi, SSPCR1); + regval |= SSPCR1_SSE; + ep93xx_spi_write_u16(espi, SSPCR1, regval); + + return 0; +} + +/** + * ep93xx_spi_disable() - disables the SPI controller and clock + * @espi: ep93xx SPI controller struct + * + * Function disables SPI controller and its clock. + */ +static void ep93xx_spi_disable(const struct ep93xx_spi *espi) +{ + u16 regval; + + regval = ep93xx_spi_read_u16(espi, SSPCR1); + regval &= ~SSPCR1_SSE; + ep93xx_spi_write_u16(espi, SSPCR1, regval); + + clk_disable(espi->clk); +} + +/** + * ep93xx_spi_enable_interrupts() - enables all SPI interrupts + * @espi: ep93xx SPI controller struct + * + * Enables all SPI interrupts: receive overrun (ROR), transmit and receive. + */ +static inline void +ep93xx_spi_enable_interrupts(const struct ep93xx_spi *espi) +{ + u8 regval; + + regval = ep93xx_spi_read_u8(espi, SSPCR1); + regval |= (SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE); + ep93xx_spi_write_u8(espi, SSPCR1, regval); +} + +/** + * ep93xx_spi_disable_interrupts() - disables all SPI interrupts + * @espi: ep93xx SPI controller struct + * + * Disables all SPI interrupts. + */ +static inline void +ep93xx_spi_disable_interrupts(const struct ep93xx_spi *espi) +{ + u8 regval; + + regval = ep93xx_spi_read_u8(espi, SSPCR1); + regval &= ~(SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE); + ep93xx_spi_write_u8(espi, SSPCR1, regval); +} + +/** + * ep93xx_spi_flush() - flushes SPI RX fifo + * @espi: ep93xx SPI controller struct + * @msecs: timeout in milliseconds to wait + * + * This function flushes RX FIFO. Returns %0 in case of success and %-ETIMEDOUT + * when timeout occured. Wait is implemented in busylooping so this function can + * also be called from atomic context. + */ +static int ep93xx_spi_flush(const struct ep93xx_spi *espi, unsigned long msecs) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(msecs); + + while (ep93xx_spi_read_u16(espi, SSPSR) & SSPSR_RNE) { + if (time_after(jiffies, timeout)) + return -ETIMEDOUT; + + ep93xx_spi_read_u16(espi, SSPDR); + } + + return 0; +} + +/** + * ep93xx_spi_wait_busy() - waits SPI controller while it is busy + * @espi: ep93xx SPI controller struct + * @msecs: timeout in milliseconds to wait + * + * Function waits while SPI controller is busy in transferring frames. Returns + * %0 when controller is not busy anymore and %-ETIMEDOUT on timeout. Wait is + * implemented by busylooping so this function can also be called in atomic + * context. + */ +static int ep93xx_spi_wait_busy(const struct ep93xx_spi *espi, + unsigned long msecs) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(msecs); + + while (time_before(jiffies, timeout)) { + if ((ep93xx_spi_read_u16(espi, SSPSR) & SSPSR_BSY) == 0) + return 0; + cpu_relax(); + } + + return -ETIMEDOUT; +} + +/** + * ep93xx_spi_calc_divisors() - calculates SPI clock divisors + * @espi: ep93xx SPI controller struct + * @chip: divisors are calculated for this chip + * @rate: maximum rate (in Hz) that this chip supports + * + * Function calculates cpsr (clock pre-scaler) and scr divisors based on + * given @rate and places them to @chip->div_cpsr and @chip->div_scr. If, + * for some reason, divisors cannot be calculated nothing is stored and + * %-EINVAL is returned. + */ +static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi, + struct ep93xx_spi_chip *chip, + unsigned long rate) +{ + int cpsr, scr; + + /* + * Make sure that max value is between values supported by the + * controller. Note that minimum value is already checked in + * ep93xx_spi_transfer(). + */ + rate = clamp(rate, espi->min_rate, espi->max_rate); + + /* + * Calculate divisors so that we can get speed according the + * following formula: + * rate = max_speed / (cpsr * (1 + scr)) + * where max_speed is same as SPI clock rate. + * + * cpsr must be even number and starts from 2, scr can be any number + * between 0 and 255. + */ + for (cpsr = 2; cpsr <= 254; cpsr += 2) { + for (scr = 0; scr <= 255; scr++) { + if ((espi->max_rate / (cpsr * (scr + 1))) < rate) { + chip->div_scr = (u8)scr; + chip->div_cpsr = (u8)cpsr; + return 0; + } + } + } + + return -EINVAL; +} + +/** + * ep93xx_spi_select_device() - select given SPI device + * @espi: ep93xx SPI controller struct + * @spi: SPI device to select + * + * Function asserts GPIO chipselect line as specified in @spi->chip_select in + * board specific manner (calls @info->cs_control()). + * + * Note that this function is called from a thread context and can sleep. + */ +static void ep93xx_spi_select_device(const struct ep93xx_spi *espi, + struct spi_device *spi) +{ + const struct ep93xx_spi_info *info = espi->info; + unsigned value = (spi->mode & SPI_CS_HIGH) ? 1 : 0; + + info->cs_control(spi->chip_select, value, info->data); +} + +/** + * ep93xx_spi_deselect_device() - deselects given SPI device + * @espi: ep93xx SPI controller struct + * @spi: SPI device to deselect + * + * Function deasserts GPIO chipselect line as specified in @spi->chip_select in + * board specific manner (calls @info->cs_control()). + * + * Note that this function is called from a thread context and can sleep. + */ +static void ep93xx_spi_deselect_device(const struct ep93xx_spi *espi, + struct spi_device *spi) +{ + const struct ep93xx_spi_info *info = espi->info; + unsigned value = (spi->mode & SPI_CS_HIGH) ? 0 : 1; + + info->cs_control(spi->chip_select, value, info->data); +} + +/** + * ep93xx_spi_setup() - setup an SPI device + * @spi: SPI device to setup + * + * This function sets up SPI device mode, speed etc. Can be called multiple + * times for a single device. Returns %0 in case of success, negative error in + * case of failure. When this function returns success, the device is + * deselected. + */ +static int ep93xx_spi_setup(struct spi_device *spi) +{ + struct ep93xx_spi *espi = spi_master_get_devdata(spi->master); + struct ep93xx_spi_chip *chip; + + if (spi->bits_per_word < 4 || spi->bits_per_word > 16) { + dev_err(&espi->pdev->dev, "invalid bits per word %d\n", + spi->bits_per_word); + return -EINVAL; + } + + chip = spi_get_ctldata(spi); + if (!chip) { + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + spi_set_ctldata(spi, chip); + } + + if (spi->max_speed_hz != chip->rate) { + int err; + + err = ep93xx_spi_calc_divisors(espi, chip, spi->max_speed_hz); + if (err != 0) { + spi_set_ctldata(spi, NULL); + kfree(chip); + return err; + } + chip->rate = spi->max_speed_hz; + } + + chip->mode = spi->mode; + chip->dss = bits_per_word_to_dss(spi->bits_per_word); + + ep93xx_spi_deselect_device(espi, spi); + return 0; +} + +/** + * ep93xx_spi_transfer() - queue message to be transferred + * @spi: target SPI device + * @msg: message to be transferred + * + * This function is called by SPI device drivers when they are going to transfer + * a new message. It simply puts the message in the queue and schedules + * workqueue to perform the actual transfer later on. + * + * Returns %0 on success and negative error in case of failure. + */ +static int ep93xx_spi_transfer(struct spi_device *spi, struct spi_message *msg) +{ + struct ep93xx_spi *espi = spi_master_get_devdata(spi->master); + struct spi_transfer *t; + unsigned long flags; + + if (!msg || !msg->complete) + return -EINVAL; + + spin_lock_irqsave(&espi->lock, flags); + if (!espi->running) { + spin_unlock_irqrestore(&espi->lock, flags); + return -ESHUTDOWN; + } + spin_unlock_irqrestore(&espi->lock, flags); + + /* first validate each transfer */ + list_for_each_entry(t, &msg->transfers, transfer_list) { + if (t->bits_per_word) { + if (t->bits_per_word < 4 || t->bits_per_word > 16) + return -EINVAL; + } + if (t->speed_hz && t->speed_hz < espi->min_rate) + return -EINVAL; + } + + /* + * Now that we own the message, let's initialize it so that it is + * suitable for us. We use @msg->status to signal whether there was + * error in transfer and @msg->state is used to hold pointer to the + * current transfer (or %NULL if no active current transfer). + */ + msg->state = NULL; + msg->status = 0; + msg->actual_length = 0; + + spin_lock_irqsave(&espi->lock, flags); + list_add_tail(&msg->queue, &espi->msg_queue); + queue_work(espi->wq, &espi->msg_work); + spin_unlock_irqrestore(&espi->lock, flags); + + return 0; +} + +/** + * ep93xx_spi_cleanup() - cleans up master controller specific state + * @spi: SPI device to cleanup + * + * This function releases master controller specific state for given @spi + * device. + */ +static void ep93xx_spi_cleanup(struct spi_device *spi) +{ + struct ep93xx_spi_chip *chip; + + chip = spi_get_ctldata(spi); + if (chip) { + spi_set_ctldata(spi, NULL); + kfree(chip); + } +} + +/** + * ep93xx_spi_chip_setup() - configures hardware according to given @chip + * @espi: ep93xx SPI controller struct + * @chip: chip specific settings + * + * This function sets up the actual hardware registers with settings given in + * @chip. Note that no validation is done so make sure that callers validate + * settings before calling this. + */ +static void ep93xx_spi_chip_setup(const struct ep93xx_spi *espi, + const struct ep93xx_spi_chip *chip) +{ + u16 cr0; + + cr0 = chip->div_scr << SSPCR0_SCR_SHIFT; + cr0 |= (chip->mode & (SPI_CPHA | SPI_CPOL)) << SSPCR0_MODE_SHIFT; + cr0 |= chip->dss; + + dev_dbg(&espi->pdev->dev, "setup: mode %d, cpsr %d, scr %d, dss %d\n", + chip->mode, chip->div_cpsr, chip->div_scr, chip->dss); + dev_dbg(&espi->pdev->dev, "setup: cr0 %#x", cr0); + + ep93xx_spi_write_u8(espi, SSPCPSR, chip->div_cpsr); + ep93xx_spi_write_u16(espi, SSPCR0, cr0); +} + +/** + * ep93xx_spi_process_transfer() - processes one SPI transfer + * @espi: ep93xx SPI controller struct + * @msg: current message + * @t: transfer to process + * + * This function processes one SPI transfer given in @t. Function waits until + * transfer is complete (may sleep) and updates @msg->status based on whether + * transfer was succesfully processed or not. + */ +static void ep93xx_spi_process_transfer(struct ep93xx_spi *espi, + struct spi_message *msg, + struct spi_transfer *t) +{ + struct ep93xx_spi_chip *chip = spi_get_ctldata(msg->spi); + + msg->state = t; + + /* + * Handle any transfer specific settings if needed. We use + * temporary chip settings here and restore original later when + * the transfer is finished. + */ + if (t->speed_hz || t->bits_per_word) { + struct ep93xx_spi_chip tmp_chip = *chip; + + if (t->speed_hz) { + int err; + + err = ep93xx_spi_calc_divisors(espi, &tmp_chip, + t->speed_hz); + if (err) { + dev_err(&espi->pdev->dev, + "failed to adjust speed\n"); + msg->status = err; + return; + } + } + + if (t->bits_per_word) + tmp_chip.dss = bits_per_word_to_dss(t->bits_per_word); + + /* + * Set up temporary new hw settings for this transfer. + */ + ep93xx_spi_chip_setup(espi, &tmp_chip); + } + + espi->rx = 0; + espi->tx = 0; + + /* + * Now everything is set up for the current transfer. Enable + * interrupts and wait for the transfer to complete. + */ + ep93xx_spi_enable_interrupts(espi); + wait_for_completion(&espi->wait); + + /* + * In case of error during transmit, we bail out from processing + * the message. + */ + if (msg->status) + return; + + /* + * After this transfer is finished, perform any possible + * post-transfer actions requested by the protocol driver. + */ + if (t->delay_usecs) + udelay(t->delay_usecs); + if (t->cs_change) { + /* + * In case protocol driver is asking us to drop the + * chipselect briefly, we let the scheduler to handle + * any "delay" here. + */ + if (!list_is_last(&t->transfer_list, &msg->transfers)) { + ep93xx_spi_deselect_device(espi, msg->spi); + cond_resched(); + ep93xx_spi_select_device(espi, msg->spi); + } + } + + if (t->speed_hz || t->bits_per_word) + ep93xx_spi_chip_setup(espi, chip); +} + +/* + * ep93xx_spi_process_message() - process one SPI message + * @espi: ep93xx SPI controller struct + * @msg: message to process + * + * This function processes a single SPI message. We go through all transfers in + * the message and pass them to ep93xx_spi_process_transfer(). Chipselect is + * asserted during the whole message (unless per transfer cs_change is set). + * + * @msg->status contains %0 in case of success or negative error code in case of + * failure. + */ +static void ep93xx_spi_process_message(struct ep93xx_spi *espi, + struct spi_message *msg) +{ + struct spi_transfer *t; + int err; + + /* + * Enable the SPI controller and its clock. + */ + err = ep93xx_spi_enable(espi); + if (err) { + dev_err(&espi->pdev->dev, "failed to enable SPI controller\n"); + msg->status = err; + return; + } + + /* + * Just to be sure: flush any data from RX FIFO. + */ + err = ep93xx_spi_flush(espi, SPI_TIMEOUT); + if (err) { + dev_warn(&espi->pdev->dev, "timeout while flushing RX fifo\n"); + msg->status = err; + return; + } + + /* + * Update SPI controller registers according to spi device and assert + * the chipselect. + */ + ep93xx_spi_chip_setup(espi, spi_get_ctldata(msg->spi)); + ep93xx_spi_select_device(espi, msg->spi); + + list_for_each_entry(t, &msg->transfers, transfer_list) { + ep93xx_spi_process_transfer(espi, msg, t); + if (msg->status) + break; + } + + /* + * Now the whole message is transferred (or failed for some reason). We + * deselect the device and disable the SPI controller. + */ + ep93xx_spi_deselect_device(espi, msg->spi); + ep93xx_spi_disable(espi); +} + +#define work_to_espi(work) (container_of((work), struct ep93xx_spi, msg_work)) + +/** + * ep93xx_spi_work() - EP93xx SPI workqueue worker function + * @work: work struct + * + * Workqueue worker function. This function is called when there are new + * SPI messages to be processed. Message is taken out from the queue and then + * passed to ep93xx_spi_process_message(). + * + * After message is transferred, protocol driver is notified by calling + * @msg->complete(). In case of error, @msg->status is set to negative error + * number, otherwise it contains zero (and @msg->actual_length is updated). + */ +static void ep93xx_spi_work(struct work_struct *work) +{ + struct ep93xx_spi *espi = work_to_espi(work); + struct spi_message *msg; + + spin_lock_irq(&espi->lock); + if (!espi->running || espi->current_msg || + list_empty(&espi->msg_queue)) { + spin_unlock_irq(&espi->lock); + return; + } + msg = list_first_entry(&espi->msg_queue, struct spi_message, queue); + list_del_init(&msg->queue); + espi->current_msg = msg; + spin_unlock_irq(&espi->lock); + + ep93xx_spi_process_message(espi, msg); + + /* + * Update the current message and re-schedule ourselves if there are + * more messages in the queue. + */ + spin_lock_irq(&espi->lock); + espi->current_msg = NULL; + if (espi->running && !list_empty(&espi->msg_queue)) + queue_work(espi->wq, &espi->msg_work); + spin_unlock_irq(&espi->lock); + + /* notify the protocol driver that we are done with this message */ + msg->complete(msg->context); +} + +static void u8_writer(struct ep93xx_spi *espi, + const struct spi_transfer *t) +{ + u8 tx_val = 0; + + if (t->tx_buf) + tx_val = ((u8 *)t->tx_buf)[espi->tx]; + ep93xx_spi_write_u8(espi, SSPDR, tx_val); + espi->tx += sizeof(tx_val); +} + +static void u8_reader(struct ep93xx_spi *espi, + struct spi_transfer *t) +{ + u8 rx_val; + + rx_val = ep93xx_spi_read_u8(espi, SSPDR); + if (t->rx_buf) + ((u8 *)t->rx_buf)[espi->rx] = rx_val; + espi->rx += sizeof(rx_val); +} + +static void u16_writer(struct ep93xx_spi *espi, + const struct spi_transfer *t) +{ + u16 tx_val = 0; + + if (t->tx_buf) + tx_val = ((u16 *)t->tx_buf)[espi->tx]; + ep93xx_spi_write_u16(espi, SSPDR, tx_val); + espi->tx += sizeof(tx_val); +} + +static void u16_reader(struct ep93xx_spi *espi, + struct spi_transfer *t) +{ + u16 rx_val; + + rx_val = ep93xx_spi_read_u16(espi, SSPDR); + if (t->rx_buf) + ((u16 *)t->rx_buf)[espi->rx] = rx_val; + espi->rx += sizeof(rx_val); +} + +/** + * bits_per_word() - returns bits per word for current message + */ +static inline int bits_per_word(const struct ep93xx_spi *espi) +{ + struct spi_message *msg = espi->current_msg; + struct spi_transfer *t = msg->state; + + return t->bits_per_word ?: msg->spi->bits_per_word; +} + +static void ep93xx_do_write(struct ep93xx_spi *espi, + struct spi_transfer *t) +{ + if (bits_per_word(espi) > 8) + u16_writer(espi, t); + else + u8_writer(espi, t); +} + +static void ep93xx_do_read(struct ep93xx_spi *espi, + struct spi_transfer *t) +{ + if (bits_per_word(espi) > 8) + u16_reader(espi, t); + else + u8_reader(espi, t); +} + +/** + * ep93xx_spi_read_write() - perform next RX/TX transfer + * @espi: ep93xx SPI controller struct + * + * This function transfers next bytes (or words) to/from RX/TX FIFOs. If called + * several times, the whole transfer will be completed. Returns %0 when current + * transfer was not yet completed otherwise length of the transfer (>%0). In + * case of error negative errno is returned. + * + * Although this function is currently only used by interrupt handler it is + * possible that in future we support polling transfers as well: hence calling + * context can be thread or atomic. + */ +static int ep93xx_spi_read_write(struct ep93xx_spi *espi) +{ + struct spi_message *msg; + struct spi_transfer *t; + unsigned long flags; + + spin_lock_irqsave(&espi->lock, flags); + msg = espi->current_msg; + spin_unlock_irqrestore(&espi->lock, flags); + + t = msg->state; + + /* + * Write as long as TX FIFO is not full. After every write we check + * whether RX FIFO has any new data in it (and in that case we read what + * ever was in the RX FIFO). + */ + while ((ep93xx_spi_read_u8(espi, SSPSR) & SSPSR_TNF) && + espi->tx < t->len) { + ep93xx_do_write(espi, t); + + if (ep93xx_spi_wait_busy(espi, SPI_TIMEOUT)) { + msg->status = -ETIMEDOUT; + return msg->status; + } + + while ((ep93xx_spi_read_u8(espi, SSPSR) & SSPSR_RNE) && + espi->rx < t->len) { + ep93xx_do_read(espi, t); + } + } + + /* is transfer finished? */ + if (espi->tx == t->len && espi->rx == t->len) { + msg->actual_length += t->len; + return t->len; + } + + return 0; +} + +/** + * ep93xx_spi_interrupt() - SPI interrupt handler + * @irq: IRQ number (not used) + * @dev_id: pointer to EP93xx controller struct + * + * This function handles TX/RX/ROR interrupts that come from the SPI controller. + * Returns %IRQ_HANDLED when interrupt was handled and %IRQ_NONE in case the + * @irq was not handled. + */ +static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id) +{ + struct ep93xx_spi *espi = dev_id; + u8 irq_status; + + irq_status = ep93xx_spi_read_u8(espi, SSPIIR); + + if (!(irq_status & (SSPIIR_RORIS | SSPIIR_TIS | SSPIIR_RIS))) + return IRQ_NONE; /* not for us */ + + /* + * If we got ROR (receive overrun) interrupt we know that something is + * wrong. Just abort the message. + */ + if (unlikely(irq_status & SSPIIR_RORIS)) { + dev_warn(&espi->pdev->dev, + "receive overrun, aborting the message\n"); + + spin_lock(&espi->lock); + espi->current_msg->status = -EIO; + spin_unlock(&espi->lock); + } else { + /* + * Interrupt is either RX (RIS) or TX (TIS). For both cases we + * simply execute next data transfer. + */ + if (!ep93xx_spi_read_write(espi)) { + /* + * In normal case, there still is some processing left + * for current transfer. Let's wait for the next + * interrupt then. + */ + return IRQ_HANDLED; + } + } + + /* + * Current transfer is finished, either with error or with success. In + * any case we disable interrupts and notify the worker to handle + * any post-processing of the message. + */ + ep93xx_spi_disable_interrupts(espi); + complete(&espi->wait); + return IRQ_HANDLED; +} + +static int __init ep93xx_spi_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct ep93xx_spi_info *info; + struct ep93xx_spi *espi; + struct resource *res; + int error; + + info = pdev->dev.platform_data; + + master = spi_alloc_master(&pdev->dev, sizeof(*espi)); + if (!master) { + dev_err(&pdev->dev, "failed to allocate spi master\n"); + return -ENOMEM; + } + + master->setup = ep93xx_spi_setup; + master->transfer = ep93xx_spi_transfer; + master->cleanup = ep93xx_spi_cleanup; + master->bus_num = 0; + master->num_chipselect = info->num_chipselect; + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; + + platform_set_drvdata(pdev, master); + + espi = spi_master_get_devdata(master); + + espi->clk = clk_get(&pdev->dev, NULL); + if (IS_ERR(espi->clk)) { + dev_err(&pdev->dev, "unable to get spi clock\n"); + error = PTR_ERR(espi->clk); + goto fail_release_master; + } + + spin_lock_init(&espi->lock); + init_completion(&espi->wait); + + /* + * Calculate maximum and minimum supported clock rates + * for the controller. + */ + espi->max_rate = clk_get_rate(espi->clk) / 2; + espi->min_rate = clk_get_rate(espi->clk) / (254 * 255); + espi->info = info; + espi->pdev = pdev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "unable to get iomem resource\n"); + error = -ENODEV; + goto fail_put_clock; + } + + res = request_mem_region(res->start, resource_size(res), pdev->name); + if (!res) { + dev_err(&pdev->dev, "unable to request iomem resources\n"); + error = -EBUSY; + goto fail_put_clock; + } + + espi->regs_base = ioremap(res->start, resource_size(res)); + if (!espi->regs_base) { + dev_err(&pdev->dev, "failed to map resources\n"); + error = -ENODEV; + goto fail_free_mem; + } + + espi->irq = platform_get_irq(pdev, 0); + if (espi->irq < 0) { + error = -EBUSY; + dev_err(&pdev->dev, "failed to get irq resources\n"); + goto fail_unmap_regs; + } + + error = request_irq(espi->irq, ep93xx_spi_interrupt, 0, "ep93xx-spi", + espi); + if (error) { + dev_err(&pdev->dev, "failed to request rx irq\n"); + goto fail_unmap_regs; + } + + espi->wq = create_singlethread_workqueue("ep93xx_spid"); + if (!espi->wq) { + dev_err(&pdev->dev, "unable to create workqueue\n"); + goto fail_free_irq; + } + INIT_WORK(&espi->msg_work, ep93xx_spi_work); + INIT_LIST_HEAD(&espi->msg_queue); + espi->running = true; + + error = spi_register_master(master); + if (error) + goto fail_free_queue; + + dev_info(&pdev->dev, "EP93xx SPI Controller at 0x%08lx irq %d\n", + (unsigned long)res->start, espi->irq); + + return 0; + +fail_free_queue: + destroy_workqueue(espi->wq); +fail_free_irq: + free_irq(espi->irq, espi); +fail_unmap_regs: + iounmap(espi->regs_base); +fail_free_mem: + release_mem_region(res->start, resource_size(res)); +fail_put_clock: + clk_put(espi->clk); +fail_release_master: + spi_master_put(master); + platform_set_drvdata(pdev, NULL); + + return error; +} + +static int __exit ep93xx_spi_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct ep93xx_spi *espi = spi_master_get_devdata(master); + struct resource *res; + + spin_lock_irq(&espi->lock); + espi->running = false; + spin_unlock_irq(&espi->lock); + + destroy_workqueue(espi->wq); + + /* + * Complete remaining messages with %-ESHUTDOWN status. + */ + spin_lock_irq(&espi->lock); + while (!list_empty(&espi->msg_queue)) { + struct spi_message *msg; + + msg = list_first_entry(&espi->msg_queue, + struct spi_message, queue); + list_del_init(&msg->queue); + msg->status = -ESHUTDOWN; + spin_unlock_irq(&espi->lock); + msg->complete(msg->context); + spin_lock_irq(&espi->lock); + } + spin_unlock_irq(&espi->lock); + + free_irq(espi->irq, espi); + iounmap(espi->regs_base); + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + release_mem_region(res->start, resource_size(res)); + clk_put(espi->clk); + platform_set_drvdata(pdev, NULL); + + spi_unregister_master(master); + return 0; +} + +static struct platform_driver ep93xx_spi_driver = { + .driver = { + .name = "ep93xx-spi", + .owner = THIS_MODULE, + }, + .remove = __exit_p(ep93xx_spi_remove), +}; + +static int __init ep93xx_spi_init(void) +{ + return platform_driver_probe(&ep93xx_spi_driver, ep93xx_spi_probe); +} +module_init(ep93xx_spi_init); + +static void __exit ep93xx_spi_exit(void) +{ + platform_driver_unregister(&ep93xx_spi_driver); +} +module_exit(ep93xx_spi_exit); + +MODULE_DESCRIPTION("EP93xx SPI Controller driver"); +MODULE_AUTHOR("Mika Westerberg "); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:ep93xx-spi");