drivers/spi/spi-omap-100k.c - kernel/msm-4.19 - Gitiles

 /*
  * OMAP7xx SPI 100k controller driver
  * Author: Fabrice Crohas <fcrohas@gmail.com>
  * from original omap1_mcspi driver
  *
  * Copyright (C) 2005, 2006 Nokia Corporation
  * Author:      Samuel Ortiz <samuel.ortiz@nokia.com> and
  *              Juha Yrj�l� <juha.yrjola@nokia.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.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU General Public License for more details.
  */
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/gpio.h>
 #include <linux/slab.h>

 #include <linux/spi/spi.h>

 #define OMAP1_SPI100K_MAX_FREQ          48000000

 #define ICR_SPITAS      (OMAP7XX_ICR_BASE + 0x12)

 #define SPI_SETUP1      0x00
 #define SPI_SETUP2      0x02
 #define SPI_CTRL        0x04
 #define SPI_STATUS      0x06
 #define SPI_TX_LSB      0x08
 #define SPI_TX_MSB      0x0a
 #define SPI_RX_LSB      0x0c
 #define SPI_RX_MSB      0x0e

 #define SPI_SETUP1_INT_READ_ENABLE      (1UL << 5)
 #define SPI_SETUP1_INT_WRITE_ENABLE     (1UL << 4)
 #define SPI_SETUP1_CLOCK_DIVISOR(x)     ((x) << 1)
 #define SPI_SETUP1_CLOCK_ENABLE         (1UL << 0)

 #define SPI_SETUP2_ACTIVE_EDGE_FALLING  (0UL << 0)
 #define SPI_SETUP2_ACTIVE_EDGE_RISING   (1UL << 0)
 #define SPI_SETUP2_NEGATIVE_LEVEL       (0UL << 5)
 #define SPI_SETUP2_POSITIVE_LEVEL       (1UL << 5)
 #define SPI_SETUP2_LEVEL_TRIGGER        (0UL << 10)
 #define SPI_SETUP2_EDGE_TRIGGER         (1UL << 10)

 #define SPI_CTRL_SEN(x)                 ((x) << 7)
 #define SPI_CTRL_WORD_SIZE(x)           (((x) - 1) << 2)
 #define SPI_CTRL_WR                     (1UL << 1)
 #define SPI_CTRL_RD                     (1UL << 0)

 #define SPI_STATUS_WE                   (1UL << 1)
 #define SPI_STATUS_RD                   (1UL << 0)

 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
  * cache operations; better heuristics consider wordsize and bitrate.
  */
 #define DMA_MIN_BYTES                   8

 #define SPI_RUNNING	0
 #define SPI_SHUTDOWN	1

 struct omap1_spi100k {
 	struct clk              *ick;
 	struct clk              *fck;

 	/* Virtual base address of the controller */
 	void __iomem            *base;
 };

 struct omap1_spi100k_cs {
 	void __iomem            *base;
 	int                     word_len;
 };

 static void spi100k_enable_clock(struct spi_master *master)
 {
 	unsigned int val;
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

 	/* enable SPI */
 	val = readw(spi100k->base + SPI_SETUP1);
 	val |= SPI_SETUP1_CLOCK_ENABLE;
 	writew(val, spi100k->base + SPI_SETUP1);
 }

 static void spi100k_disable_clock(struct spi_master *master)
 {
 	unsigned int val;
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

 	/* disable SPI */
 	val = readw(spi100k->base + SPI_SETUP1);
 	val &= ~SPI_SETUP1_CLOCK_ENABLE;
 	writew(val, spi100k->base + SPI_SETUP1);
 }

 static void spi100k_write_data(struct spi_master *master, int len, int data)
 {
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

 	/* write 16-bit word, shifting 8-bit data if necessary */
 	if (len <= 8) {
 		data <<= 8;
 		len = 16;
 	}

 	spi100k_enable_clock(master);
 	writew(data , spi100k->base + SPI_TX_MSB);

 	writew(SPI_CTRL_SEN(0) |
 	       SPI_CTRL_WORD_SIZE(len) |
 	       SPI_CTRL_WR,
 	       spi100k->base + SPI_CTRL);

 	/* Wait for bit ack send change */
 	while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE)
 		;
 	udelay(1000);

 	spi100k_disable_clock(master);
 }

 static int spi100k_read_data(struct spi_master *master, int len)
 {
 	int dataH, dataL;
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

 	/* Always do at least 16 bits */
 	if (len <= 8)
 		len = 16;

 	spi100k_enable_clock(master);
 	writew(SPI_CTRL_SEN(0) |
 	       SPI_CTRL_WORD_SIZE(len) |
 	       SPI_CTRL_RD,
 	       spi100k->base + SPI_CTRL);

 	while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD)
 		;
 	udelay(1000);

 	dataL = readw(spi100k->base + SPI_RX_LSB);
 	dataH = readw(spi100k->base + SPI_RX_MSB);
 	spi100k_disable_clock(master);

 	return dataL;
 }

 static void spi100k_open(struct spi_master *master)
 {
 	/* get control of SPI */
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

 	writew(SPI_SETUP1_INT_READ_ENABLE |
 	       SPI_SETUP1_INT_WRITE_ENABLE |
 	       SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);

 	/* configure clock and interrupts */
 	writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
 	       SPI_SETUP2_NEGATIVE_LEVEL |
 	       SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
 }

 static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
 {
 	if (enable)
 		writew(0x05fc, spi100k->base + SPI_CTRL);
 	else
 		writew(0x05fd, spi100k->base + SPI_CTRL);
 }

 static unsigned
 omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 {
 	struct omap1_spi100k_cs *cs = spi->controller_state;
 	unsigned int            count, c;
 	int                     word_len;

 	count = xfer->len;
 	c = count;
 	word_len = cs->word_len;

 	if (word_len <= 8) {
 		u8              *rx;
 		const u8        *tx;

 		rx = xfer->rx_buf;
 		tx = xfer->tx_buf;
 		do {
 			c -= 1;
 			if (xfer->tx_buf != NULL)
 				spi100k_write_data(spi->master, word_len, *tx++);
 			if (xfer->rx_buf != NULL)
 				*rx++ = spi100k_read_data(spi->master, word_len);
 		} while (c);
 	} else if (word_len <= 16) {
 		u16             *rx;
 		const u16       *tx;

 		rx = xfer->rx_buf;
 		tx = xfer->tx_buf;
 		do {
 			c -= 2;
 			if (xfer->tx_buf != NULL)
 				spi100k_write_data(spi->master, word_len, *tx++);
 			if (xfer->rx_buf != NULL)
 				*rx++ = spi100k_read_data(spi->master, word_len);
 		} while (c);
 	} else if (word_len <= 32) {
 		u32             *rx;
 		const u32       *tx;

 		rx = xfer->rx_buf;
 		tx = xfer->tx_buf;
 		do {
 			c -= 4;
 			if (xfer->tx_buf != NULL)
 				spi100k_write_data(spi->master, word_len, *tx);
 			if (xfer->rx_buf != NULL)
 				*rx = spi100k_read_data(spi->master, word_len);
 		} while (c);
 	}
 	return count - c;
 }

 /* called only when no transfer is active to this device */
 static int omap1_spi100k_setup_transfer(struct spi_device *spi,
 		struct spi_transfer *t)
 {
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
 	struct omap1_spi100k_cs *cs = spi->controller_state;
 	u8 word_len;

 	if (t != NULL)
 		word_len = t->bits_per_word;
 	else
 		word_len = spi->bits_per_word;

 	if (spi->bits_per_word > 32)
 		return -EINVAL;
 	cs->word_len = word_len;

 	/* SPI init before transfer */
 	writew(0x3e , spi100k->base + SPI_SETUP1);
 	writew(0x00 , spi100k->base + SPI_STATUS);
 	writew(0x3e , spi100k->base + SPI_CTRL);

 	return 0;
 }

 /* the spi->mode bits understood by this driver: */
 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)

 static int omap1_spi100k_setup(struct spi_device *spi)
 {
 	int                     ret;
 	struct omap1_spi100k    *spi100k;
 	struct omap1_spi100k_cs *cs = spi->controller_state;

 	spi100k = spi_master_get_devdata(spi->master);

 	if (!cs) {
 		cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL);
 		if (!cs)
 			return -ENOMEM;
 		cs->base = spi100k->base + spi->chip_select * 0x14;
 		spi->controller_state = cs;
 	}

 	spi100k_open(spi->master);

 	clk_prepare_enable(spi100k->ick);
 	clk_prepare_enable(spi100k->fck);

 	ret = omap1_spi100k_setup_transfer(spi, NULL);

 	clk_disable_unprepare(spi100k->ick);
 	clk_disable_unprepare(spi100k->fck);

 	return ret;
 }

 static int omap1_spi100k_transfer_one_message(struct spi_master *master,
 					      struct spi_message *m)
 {
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 	struct spi_device *spi = m->spi;
 	struct spi_transfer *t = NULL;
 	int cs_active = 0;
 	int status = 0;

 	list_for_each_entry(t, &m->transfers, transfer_list) {
 		if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
 			status = -EINVAL;
 			break;
 		}
 		status = omap1_spi100k_setup_transfer(spi, t);
 		if (status < 0)
 			break;

 		if (!cs_active) {
 			omap1_spi100k_force_cs(spi100k, 1);
 			cs_active = 1;
 		}

 		if (t->len) {
 			unsigned count;

 			count = omap1_spi100k_txrx_pio(spi, t);
 			m->actual_length += count;

 			if (count != t->len) {
 				status = -EIO;
 				break;
 			}
 		}

 		if (t->delay_usecs)
 			udelay(t->delay_usecs);

 		/* ignore the "leave it on after last xfer" hint */

 		if (t->cs_change) {
 			omap1_spi100k_force_cs(spi100k, 0);
 			cs_active = 0;
 		}
 	}

 	status = omap1_spi100k_setup_transfer(spi, NULL);

 	if (cs_active)
 		omap1_spi100k_force_cs(spi100k, 0);

 	m->status = status;

 	spi_finalize_current_message(master);

 	return status;
 }

 static int omap1_spi100k_probe(struct platform_device *pdev)
 {
 	struct spi_master       *master;
 	struct omap1_spi100k    *spi100k;
 	int                     status = 0;

 	if (!pdev->id)
 		return -EINVAL;

 	master = spi_alloc_master(&pdev->dev, sizeof(*spi100k));
 	if (master == NULL) {
 		dev_dbg(&pdev->dev, "master allocation failed\n");
 		return -ENOMEM;
 	}

 	if (pdev->id != -1)
 		master->bus_num = pdev->id;

 	master->setup = omap1_spi100k_setup;
 	master->transfer_one_message = omap1_spi100k_transfer_one_message;
 	master->num_chipselect = 2;
 	master->mode_bits = MODEBITS;
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
 	master->min_speed_hz = OMAP1_SPI100K_MAX_FREQ/(1<<16);
 	master->max_speed_hz = OMAP1_SPI100K_MAX_FREQ;
 	master->auto_runtime_pm = true;

 	spi100k = spi_master_get_devdata(master);

 	/*
 	 * The memory region base address is taken as the platform_data.
 	 * You should allocate this with ioremap() before initializing
 	 * the SPI.
 	 */
 	spi100k->base = (void __iomem *)dev_get_platdata(&pdev->dev);

 	spi100k->ick = devm_clk_get(&pdev->dev, "ick");
 	if (IS_ERR(spi100k->ick)) {
 		dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
 		status = PTR_ERR(spi100k->ick);
 		goto err;
 	}

 	spi100k->fck = devm_clk_get(&pdev->dev, "fck");
 	if (IS_ERR(spi100k->fck)) {
 		dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
 		status = PTR_ERR(spi100k->fck);
 		goto err;
 	}

 	status = clk_prepare_enable(spi100k->ick);
 	if (status != 0) {
 		dev_err(&pdev->dev, "failed to enable ick: %d\n", status);
 		goto err;
 	}

 	status = clk_prepare_enable(spi100k->fck);
 	if (status != 0) {
 		dev_err(&pdev->dev, "failed to enable fck: %d\n", status);
 		goto err_ick;
 	}

 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);

 	status = devm_spi_register_master(&pdev->dev, master);
 	if (status < 0)
 		goto err_fck;

 	return status;

 err_fck:
 	clk_disable_unprepare(spi100k->fck);
 err_ick:
 	clk_disable_unprepare(spi100k->ick);
 err:
 	spi_master_put(master);
 	return status;
 }

 static int omap1_spi100k_remove(struct platform_device *pdev)
 {
 	struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

 	pm_runtime_disable(&pdev->dev);

 	clk_disable_unprepare(spi100k->fck);
 	clk_disable_unprepare(spi100k->ick);

 	return 0;
 }

 #ifdef CONFIG_PM
 static int omap1_spi100k_runtime_suspend(struct device *dev)
 {
 	struct spi_master *master = spi_master_get(dev_get_drvdata(dev));
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

 	clk_disable_unprepare(spi100k->ick);
 	clk_disable_unprepare(spi100k->fck);

 	return 0;
 }

 static int omap1_spi100k_runtime_resume(struct device *dev)
 {
 	struct spi_master *master = spi_master_get(dev_get_drvdata(dev));
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 	int ret;

 	ret = clk_prepare_enable(spi100k->ick);
 	if (ret != 0) {
 		dev_err(dev, "Failed to enable ick: %d\n", ret);
 		return ret;
 	}

 	ret = clk_prepare_enable(spi100k->fck);
 	if (ret != 0) {
 		dev_err(dev, "Failed to enable fck: %d\n", ret);
 		clk_disable_unprepare(spi100k->ick);
 		return ret;
 	}

 	return 0;
 }
 #endif

 static const struct dev_pm_ops omap1_spi100k_pm = {
 	SET_RUNTIME_PM_OPS(omap1_spi100k_runtime_suspend,
 			   omap1_spi100k_runtime_resume, NULL)
 };

 static struct platform_driver omap1_spi100k_driver = {
 	.driver = {
 		.name		= "omap1_spi100k",
 		.pm		= &omap1_spi100k_pm,
 	},
 	.probe		= omap1_spi100k_probe,
 	.remove		= omap1_spi100k_remove,
 };

 module_platform_driver(omap1_spi100k_driver);

 MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
 MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
 MODULE_LICENSE("GPL");
	/*
	* OMAP7xx SPI 100k controller driver
	* Author: Fabrice Crohas <fcrohas@gmail.com>
	* from original omap1_mcspi driver
	*
	* Copyright (C) 2005, 2006 Nokia Corporation
	* Author: Samuel Ortiz <samuel.ortiz@nokia.com> and
	* Juha Yrj�l� <juha.yrjola@nokia.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.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/module.h>
	#include <linux/device.h>
	#include <linux/delay.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>
	#include <linux/err.h>
	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/gpio.h>
	#include <linux/slab.h>

	#include <linux/spi/spi.h>

	#define OMAP1_SPI100K_MAX_FREQ 48000000

	#define ICR_SPITAS (OMAP7XX_ICR_BASE + 0x12)

	#define SPI_SETUP1 0x00
	#define SPI_SETUP2 0x02
	#define SPI_CTRL 0x04
	#define SPI_STATUS 0x06
	#define SPI_TX_LSB 0x08
	#define SPI_TX_MSB 0x0a
	#define SPI_RX_LSB 0x0c
	#define SPI_RX_MSB 0x0e

	#define SPI_SETUP1_INT_READ_ENABLE (1UL << 5)
	#define SPI_SETUP1_INT_WRITE_ENABLE (1UL << 4)
	#define SPI_SETUP1_CLOCK_DIVISOR(x) ((x) << 1)
	#define SPI_SETUP1_CLOCK_ENABLE (1UL << 0)

	#define SPI_SETUP2_ACTIVE_EDGE_FALLING (0UL << 0)
	#define SPI_SETUP2_ACTIVE_EDGE_RISING (1UL << 0)
	#define SPI_SETUP2_NEGATIVE_LEVEL (0UL << 5)
	#define SPI_SETUP2_POSITIVE_LEVEL (1UL << 5)
	#define SPI_SETUP2_LEVEL_TRIGGER (0UL << 10)
	#define SPI_SETUP2_EDGE_TRIGGER (1UL << 10)

	#define SPI_CTRL_SEN(x) ((x) << 7)
	#define SPI_CTRL_WORD_SIZE(x) (((x) - 1) << 2)
	#define SPI_CTRL_WR (1UL << 1)
	#define SPI_CTRL_RD (1UL << 0)

	#define SPI_STATUS_WE (1UL << 1)
	#define SPI_STATUS_RD (1UL << 0)

	/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
	* cache operations; better heuristics consider wordsize and bitrate.
	*/
	#define DMA_MIN_BYTES 8

	#define SPI_RUNNING 0
	#define SPI_SHUTDOWN 1

	struct omap1_spi100k {
	struct clk *ick;
	struct clk *fck;

	/* Virtual base address of the controller */
	void __iomem *base;
	};

	struct omap1_spi100k_cs {
	void __iomem *base;
	int word_len;
	};

	static void spi100k_enable_clock(struct spi_master *master)
	{
	unsigned int val;
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	/* enable SPI */
	val = readw(spi100k->base + SPI_SETUP1);
	val \|= SPI_SETUP1_CLOCK_ENABLE;
	writew(val, spi100k->base + SPI_SETUP1);
	}

	static void spi100k_disable_clock(struct spi_master *master)
	{
	unsigned int val;
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	/* disable SPI */
	val = readw(spi100k->base + SPI_SETUP1);
	val &= ~SPI_SETUP1_CLOCK_ENABLE;
	writew(val, spi100k->base + SPI_SETUP1);
	}

	static void spi100k_write_data(struct spi_master *master, int len, int data)
	{
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	/* write 16-bit word, shifting 8-bit data if necessary */
	if (len <= 8) {
	data <<= 8;
	len = 16;
	}

	spi100k_enable_clock(master);
	writew(data , spi100k->base + SPI_TX_MSB);

	writew(SPI_CTRL_SEN(0) \|
	SPI_CTRL_WORD_SIZE(len) \|
	SPI_CTRL_WR,
	spi100k->base + SPI_CTRL);

	/* Wait for bit ack send change */
	while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE)
	;
	udelay(1000);

	spi100k_disable_clock(master);
	}

	static int spi100k_read_data(struct spi_master *master, int len)
	{
	int dataH, dataL;
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	/* Always do at least 16 bits */
	if (len <= 8)
	len = 16;

	spi100k_enable_clock(master);
	writew(SPI_CTRL_SEN(0) \|
	SPI_CTRL_WORD_SIZE(len) \|
	SPI_CTRL_RD,
	spi100k->base + SPI_CTRL);

	while ((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD)
	;
	udelay(1000);

	dataL = readw(spi100k->base + SPI_RX_LSB);
	dataH = readw(spi100k->base + SPI_RX_MSB);
	spi100k_disable_clock(master);

	return dataL;
	}

	static void spi100k_open(struct spi_master *master)
	{
	/* get control of SPI */
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	writew(SPI_SETUP1_INT_READ_ENABLE \|
	SPI_SETUP1_INT_WRITE_ENABLE \|
	SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);

	/* configure clock and interrupts */
	writew(SPI_SETUP2_ACTIVE_EDGE_FALLING \|
	SPI_SETUP2_NEGATIVE_LEVEL \|
	SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
	}

	static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
	{
	if (enable)
	writew(0x05fc, spi100k->base + SPI_CTRL);
	else
	writew(0x05fd, spi100k->base + SPI_CTRL);
	}

	static unsigned
	omap1_spi100k_txrx_pio(struct spi_device spi, struct spi_transfer xfer)
	{
	struct omap1_spi100k_cs *cs = spi->controller_state;
	unsigned int count, c;
	int word_len;

	count = xfer->len;
	c = count;
	word_len = cs->word_len;

	if (word_len <= 8) {
	u8 *rx;
	const u8 *tx;

	rx = xfer->rx_buf;
	tx = xfer->tx_buf;
	do {
	c -= 1;
	if (xfer->tx_buf != NULL)
	spi100k_write_data(spi->master, word_len, *tx++);
	if (xfer->rx_buf != NULL)
	*rx++ = spi100k_read_data(spi->master, word_len);
	} while (c);
	} else if (word_len <= 16) {
	u16 *rx;
	const u16 *tx;

	rx = xfer->rx_buf;
	tx = xfer->tx_buf;
	do {
	c -= 2;
	if (xfer->tx_buf != NULL)
	spi100k_write_data(spi->master, word_len, *tx++);
	if (xfer->rx_buf != NULL)
	*rx++ = spi100k_read_data(spi->master, word_len);
	} while (c);
	} else if (word_len <= 32) {
	u32 *rx;
	const u32 *tx;

	rx = xfer->rx_buf;
	tx = xfer->tx_buf;
	do {
	c -= 4;
	if (xfer->tx_buf != NULL)
	spi100k_write_data(spi->master, word_len, *tx);
	if (xfer->rx_buf != NULL)
	*rx = spi100k_read_data(spi->master, word_len);
	} while (c);
	}
	return count - c;
	}

	/* called only when no transfer is active to this device */
	static int omap1_spi100k_setup_transfer(struct spi_device *spi,
	struct spi_transfer *t)
	{
	struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
	struct omap1_spi100k_cs *cs = spi->controller_state;
	u8 word_len;

	if (t != NULL)
	word_len = t->bits_per_word;
	else
	word_len = spi->bits_per_word;

	if (spi->bits_per_word > 32)
	return -EINVAL;
	cs->word_len = word_len;

	/* SPI init before transfer */
	writew(0x3e , spi100k->base + SPI_SETUP1);
	writew(0x00 , spi100k->base + SPI_STATUS);
	writew(0x3e , spi100k->base + SPI_CTRL);

	return 0;
	}

	/* the spi->mode bits understood by this driver: */
	#define MODEBITS (SPI_CPOL \| SPI_CPHA \| SPI_CS_HIGH)

	static int omap1_spi100k_setup(struct spi_device *spi)
	{
	int ret;
	struct omap1_spi100k *spi100k;
	struct omap1_spi100k_cs *cs = spi->controller_state;

	spi100k = spi_master_get_devdata(spi->master);

	if (!cs) {
	cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL);
	if (!cs)
	return -ENOMEM;
	cs->base = spi100k->base + spi->chip_select * 0x14;
	spi->controller_state = cs;
	}

	spi100k_open(spi->master);

	clk_prepare_enable(spi100k->ick);
	clk_prepare_enable(spi100k->fck);

	ret = omap1_spi100k_setup_transfer(spi, NULL);

	clk_disable_unprepare(spi100k->ick);
	clk_disable_unprepare(spi100k->fck);

	return ret;
	}

	static int omap1_spi100k_transfer_one_message(struct spi_master *master,
	struct spi_message *m)
	{
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
	struct spi_device *spi = m->spi;
	struct spi_transfer *t = NULL;
	int cs_active = 0;
	int status = 0;

	list_for_each_entry(t, &m->transfers, transfer_list) {
	if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
	status = -EINVAL;
	break;
	}
	status = omap1_spi100k_setup_transfer(spi, t);
	if (status < 0)
	break;

	if (!cs_active) {
	omap1_spi100k_force_cs(spi100k, 1);
	cs_active = 1;
	}

	if (t->len) {
	unsigned count;

	count = omap1_spi100k_txrx_pio(spi, t);
	m->actual_length += count;

	if (count != t->len) {
	status = -EIO;
	break;
	}
	}

	if (t->delay_usecs)
	udelay(t->delay_usecs);

	/* ignore the "leave it on after last xfer" hint */

	if (t->cs_change) {
	omap1_spi100k_force_cs(spi100k, 0);
	cs_active = 0;
	}
	}

	status = omap1_spi100k_setup_transfer(spi, NULL);

	if (cs_active)
	omap1_spi100k_force_cs(spi100k, 0);

	m->status = status;

	spi_finalize_current_message(master);

	return status;
	}

	static int omap1_spi100k_probe(struct platform_device *pdev)
	{
	struct spi_master *master;
	struct omap1_spi100k *spi100k;
	int status = 0;

	if (!pdev->id)
	return -EINVAL;

	master = spi_alloc_master(&pdev->dev, sizeof(*spi100k));
	if (master == NULL) {
	dev_dbg(&pdev->dev, "master allocation failed\n");
	return -ENOMEM;
	}

	if (pdev->id != -1)
	master->bus_num = pdev->id;

	master->setup = omap1_spi100k_setup;
	master->transfer_one_message = omap1_spi100k_transfer_one_message;
	master->num_chipselect = 2;
	master->mode_bits = MODEBITS;
	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
	master->min_speed_hz = OMAP1_SPI100K_MAX_FREQ/(1<<16);
	master->max_speed_hz = OMAP1_SPI100K_MAX_FREQ;
	master->auto_runtime_pm = true;

	spi100k = spi_master_get_devdata(master);

	/*
	* The memory region base address is taken as the platform_data.
	* You should allocate this with ioremap() before initializing
	* the SPI.
	*/
	spi100k->base = (void __iomem *)dev_get_platdata(&pdev->dev);

	spi100k->ick = devm_clk_get(&pdev->dev, "ick");
	if (IS_ERR(spi100k->ick)) {
	dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
	status = PTR_ERR(spi100k->ick);
	goto err;
	}

	spi100k->fck = devm_clk_get(&pdev->dev, "fck");
	if (IS_ERR(spi100k->fck)) {
	dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
	status = PTR_ERR(spi100k->fck);
	goto err;
	}

	status = clk_prepare_enable(spi100k->ick);
	if (status != 0) {
	dev_err(&pdev->dev, "failed to enable ick: %d\n", status);
	goto err;
	}

	status = clk_prepare_enable(spi100k->fck);
	if (status != 0) {
	dev_err(&pdev->dev, "failed to enable fck: %d\n", status);
	goto err_ick;
	}

	pm_runtime_enable(&pdev->dev);
	pm_runtime_set_active(&pdev->dev);

	status = devm_spi_register_master(&pdev->dev, master);
	if (status < 0)
	goto err_fck;

	return status;

	err_fck:
	clk_disable_unprepare(spi100k->fck);
	err_ick:
	clk_disable_unprepare(spi100k->ick);
	err:
	spi_master_put(master);
	return status;
	}

	static int omap1_spi100k_remove(struct platform_device *pdev)
	{
	struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	pm_runtime_disable(&pdev->dev);

	clk_disable_unprepare(spi100k->fck);
	clk_disable_unprepare(spi100k->ick);

	return 0;
	}

	#ifdef CONFIG_PM
	static int omap1_spi100k_runtime_suspend(struct device *dev)
	{
	struct spi_master *master = spi_master_get(dev_get_drvdata(dev));
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);

	clk_disable_unprepare(spi100k->ick);
	clk_disable_unprepare(spi100k->fck);

	return 0;
	}

	static int omap1_spi100k_runtime_resume(struct device *dev)
	{
	struct spi_master *master = spi_master_get(dev_get_drvdata(dev));
	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
	int ret;

	ret = clk_prepare_enable(spi100k->ick);
	if (ret != 0) {
	dev_err(dev, "Failed to enable ick: %d\n", ret);
	return ret;
	}

	ret = clk_prepare_enable(spi100k->fck);
	if (ret != 0) {
	dev_err(dev, "Failed to enable fck: %d\n", ret);
	clk_disable_unprepare(spi100k->ick);
	return ret;
	}

	return 0;
	}
	#endif

	static const struct dev_pm_ops omap1_spi100k_pm = {
	SET_RUNTIME_PM_OPS(omap1_spi100k_runtime_suspend,
	omap1_spi100k_runtime_resume, NULL)
	};

	static struct platform_driver omap1_spi100k_driver = {
	.driver = {
	.name = "omap1_spi100k",
	.pm = &omap1_spi100k_pm,
	},
	.probe = omap1_spi100k_probe,
	.remove = omap1_spi100k_remove,
	};

	module_platform_driver(omap1_spi100k_driver);

	MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
	MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
	MODULE_LICENSE("GPL");