drivers/spi/spi_sh_msiof.c - kernel/msm-4.9 - Gitiles

 /*
  * SuperH MSIOF SPI Master Interface
  *
  * Copyright (c) 2009 Magnus Damm
  *
  * 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 <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/completion.h>
 #include <linux/pm_runtime.h>
 #include <linux/gpio.h>
 #include <linux/bitmap.h>
 #include <linux/clk.h>
 #include <linux/io.h>

 #include <linux/spi/spi.h>
 #include <linux/spi/spi_bitbang.h>
 #include <linux/spi/sh_msiof.h>

 #include <asm/spi.h>
 #include <asm/unaligned.h>

 struct sh_msiof_spi_priv {
 	struct spi_bitbang bitbang; /* must be first for spi_bitbang.c */
 	void __iomem *mapbase;
 	struct clk *clk;
 	struct platform_device *pdev;
 	struct sh_msiof_spi_info *info;
 	struct completion done;
 	unsigned long flags;
 	int tx_fifo_size;
 	int rx_fifo_size;
 };

 #define TMDR1	0x00
 #define TMDR2	0x04
 #define TMDR3	0x08
 #define RMDR1	0x10
 #define RMDR2	0x14
 #define RMDR3	0x18
 #define TSCR	0x20
 #define RSCR	0x22
 #define CTR	0x28
 #define FCTR	0x30
 #define STR	0x40
 #define IER	0x44
 #define TDR1	0x48
 #define TDR2	0x4c
 #define TFDR	0x50
 #define RDR1	0x58
 #define RDR2	0x5c
 #define RFDR	0x60

 #define CTR_TSCKE (1 << 15)
 #define CTR_TFSE  (1 << 14)
 #define CTR_TXE   (1 << 9)
 #define CTR_RXE   (1 << 8)

 #define STR_TEOF  (1 << 23)
 #define STR_REOF  (1 << 7)

 static unsigned long sh_msiof_read(struct sh_msiof_spi_priv *p, int reg_offs)
 {
 	switch (reg_offs) {
 	case TSCR:
 	case RSCR:
 		return ioread16(p->mapbase + reg_offs);
 	default:
 		return ioread32(p->mapbase + reg_offs);
 	}
 }

 static void sh_msiof_write(struct sh_msiof_spi_priv *p, int reg_offs,
 			   unsigned long value)
 {
 	switch (reg_offs) {
 	case TSCR:
 	case RSCR:
 		iowrite16(value, p->mapbase + reg_offs);
 		break;
 	default:
 		iowrite32(value, p->mapbase + reg_offs);
 		break;
 	}
 }

 static int sh_msiof_modify_ctr_wait(struct sh_msiof_spi_priv *p,
 				    unsigned long clr, unsigned long set)
 {
 	unsigned long mask = clr | set;
 	unsigned long data;
 	int k;

 	data = sh_msiof_read(p, CTR);
 	data &= ~clr;
 	data |= set;
 	sh_msiof_write(p, CTR, data);

 	for (k = 100; k > 0; k--) {
 		if ((sh_msiof_read(p, CTR) & mask) == set)
 			break;

 		udelay(10);
 	}

 	return k > 0 ? 0 : -ETIMEDOUT;
 }

 static irqreturn_t sh_msiof_spi_irq(int irq, void *data)
 {
 	struct sh_msiof_spi_priv *p = data;

 	/* just disable the interrupt and wake up */
 	sh_msiof_write(p, IER, 0);
 	complete(&p->done);

 	return IRQ_HANDLED;
 }

 static struct {
 	unsigned short div;
 	unsigned short scr;
 } const sh_msiof_spi_clk_table[] = {
 	{ 1, 0x0007 },
 	{ 2, 0x0000 },
 	{ 4, 0x0001 },
 	{ 8, 0x0002 },
 	{ 16, 0x0003 },
 	{ 32, 0x0004 },
 	{ 64, 0x1f00 },
 	{ 128, 0x1f01 },
 	{ 256, 0x1f02 },
 	{ 512, 0x1f03 },
 	{ 1024, 0x1f04 },
 };

 static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p,
 				      unsigned long parent_rate,
 				      unsigned long spi_hz)
 {
 	unsigned long div = 1024;
 	size_t k;

 	if (!WARN_ON(!spi_hz || !parent_rate))
 		div = parent_rate / spi_hz;

 	/* TODO: make more fine grained */

 	for (k = 0; k < ARRAY_SIZE(sh_msiof_spi_clk_table); k++) {
 		if (sh_msiof_spi_clk_table[k].div >= div)
 			break;
 	}

 	k = min_t(int, k, ARRAY_SIZE(sh_msiof_spi_clk_table) - 1);

 	sh_msiof_write(p, TSCR, sh_msiof_spi_clk_table[k].scr);
 	sh_msiof_write(p, RSCR, sh_msiof_spi_clk_table[k].scr);
 }

 static void sh_msiof_spi_set_pin_regs(struct sh_msiof_spi_priv *p,
 				      int cpol, int cpha,
 				      int tx_hi_z, int lsb_first)
 {
 	unsigned long tmp;
 	int edge;

 	/*
 	 * CPOL CPHA     TSCKIZ RSCKIZ TEDG REDG(!)
 	 *    0    0         10     10    1    0
 	 *    0    1         10     10    0    1
 	 *    1    0         11     11    0    1
 	 *    1    1         11     11    1    0
 	 *
 	 * (!) Note: REDG is inverted recommended data sheet setting
 	 */

 	sh_msiof_write(p, FCTR, 0);
 	sh_msiof_write(p, TMDR1, 0xe2000005 | (lsb_first << 24));
 	sh_msiof_write(p, RMDR1, 0x22000005 | (lsb_first << 24));

 	tmp = 0xa0000000;
 	tmp |= cpol << 30; /* TSCKIZ */
 	tmp |= cpol << 28; /* RSCKIZ */

 	edge = cpol ? cpha : !cpha;

 	tmp |= edge << 27; /* TEDG */
 	tmp |= !edge << 26; /* REDG */
 	tmp |= (tx_hi_z ? 2 : 0) << 22; /* TXDIZ */
 	sh_msiof_write(p, CTR, tmp);
 }

 static void sh_msiof_spi_set_mode_regs(struct sh_msiof_spi_priv *p,
 				       const void *tx_buf, void *rx_buf,
 				       int bits, int words)
 {
 	unsigned long dr2;

 	dr2 = ((bits - 1) << 24) | ((words - 1) << 16);

 	if (tx_buf)
 		sh_msiof_write(p, TMDR2, dr2);
 	else
 		sh_msiof_write(p, TMDR2, dr2 | 1);

 	if (rx_buf)
 		sh_msiof_write(p, RMDR2, dr2);

 	sh_msiof_write(p, IER, STR_TEOF | STR_REOF);
 }

 static void sh_msiof_reset_str(struct sh_msiof_spi_priv *p)
 {
 	sh_msiof_write(p, STR, sh_msiof_read(p, STR));
 }

 static void sh_msiof_spi_write_fifo_8(struct sh_msiof_spi_priv *p,
 				      const void *tx_buf, int words, int fs)
 {
 	const unsigned char *buf_8 = tx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		sh_msiof_write(p, TFDR, buf_8[k] << fs);
 }

 static void sh_msiof_spi_write_fifo_16(struct sh_msiof_spi_priv *p,
 				       const void *tx_buf, int words, int fs)
 {
 	const unsigned short *buf_16 = tx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		sh_msiof_write(p, TFDR, buf_16[k] << fs);
 }

 static void sh_msiof_spi_write_fifo_16u(struct sh_msiof_spi_priv *p,
 					const void *tx_buf, int words, int fs)
 {
 	const unsigned short *buf_16 = tx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		sh_msiof_write(p, TFDR, get_unaligned(&buf_16[k]) << fs);
 }

 static void sh_msiof_spi_write_fifo_32(struct sh_msiof_spi_priv *p,
 				       const void *tx_buf, int words, int fs)
 {
 	const unsigned int *buf_32 = tx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		sh_msiof_write(p, TFDR, buf_32[k] << fs);
 }

 static void sh_msiof_spi_write_fifo_32u(struct sh_msiof_spi_priv *p,
 					const void *tx_buf, int words, int fs)
 {
 	const unsigned int *buf_32 = tx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		sh_msiof_write(p, TFDR, get_unaligned(&buf_32[k]) << fs);
 }

 static void sh_msiof_spi_read_fifo_8(struct sh_msiof_spi_priv *p,
 				     void *rx_buf, int words, int fs)
 {
 	unsigned char *buf_8 = rx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		buf_8[k] = sh_msiof_read(p, RFDR) >> fs;
 }

 static void sh_msiof_spi_read_fifo_16(struct sh_msiof_spi_priv *p,
 				      void *rx_buf, int words, int fs)
 {
 	unsigned short *buf_16 = rx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		buf_16[k] = sh_msiof_read(p, RFDR) >> fs;
 }

 static void sh_msiof_spi_read_fifo_16u(struct sh_msiof_spi_priv *p,
 				       void *rx_buf, int words, int fs)
 {
 	unsigned short *buf_16 = rx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_16[k]);
 }

 static void sh_msiof_spi_read_fifo_32(struct sh_msiof_spi_priv *p,
 				      void *rx_buf, int words, int fs)
 {
 	unsigned int *buf_32 = rx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		buf_32[k] = sh_msiof_read(p, RFDR) >> fs;
 }

 static void sh_msiof_spi_read_fifo_32u(struct sh_msiof_spi_priv *p,
 				       void *rx_buf, int words, int fs)
 {
 	unsigned int *buf_32 = rx_buf;
 	int k;

 	for (k = 0; k < words; k++)
 		put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_32[k]);
 }

 static int sh_msiof_spi_bits(struct spi_device *spi, struct spi_transfer *t)
 {
 	int bits;

 	bits = t ? t->bits_per_word : 0;
 	bits = bits ? bits : spi->bits_per_word;
 	return bits;
 }

 static unsigned long sh_msiof_spi_hz(struct spi_device *spi,
 				     struct spi_transfer *t)
 {
 	unsigned long hz;

 	hz = t ? t->speed_hz : 0;
 	hz = hz ? hz : spi->max_speed_hz;
 	return hz;
 }

 static int sh_msiof_spi_setup_transfer(struct spi_device *spi,
 				       struct spi_transfer *t)
 {
 	int bits;

 	/* noting to check hz values against since parent clock is disabled */

 	bits = sh_msiof_spi_bits(spi, t);
 	if (bits < 8)
 		return -EINVAL;
 	if (bits > 32)
 		return -EINVAL;

 	return spi_bitbang_setup_transfer(spi, t);
 }

 static void sh_msiof_spi_chipselect(struct spi_device *spi, int is_on)
 {
 	struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);
 	int value;

 	/* chip select is active low unless SPI_CS_HIGH is set */
 	if (spi->mode & SPI_CS_HIGH)
 		value = (is_on == BITBANG_CS_ACTIVE) ? 1 : 0;
 	else
 		value = (is_on == BITBANG_CS_ACTIVE) ? 0 : 1;

 	if (is_on == BITBANG_CS_ACTIVE) {
 		if (!test_and_set_bit(0, &p->flags)) {
 			pm_runtime_get_sync(&p->pdev->dev);
 			clk_enable(p->clk);
 		}

 		/* Configure pins before asserting CS */
 		sh_msiof_spi_set_pin_regs(p, !!(spi->mode & SPI_CPOL),
 					  !!(spi->mode & SPI_CPHA),
 					  !!(spi->mode & SPI_3WIRE),
 					  !!(spi->mode & SPI_LSB_FIRST));
 	}

 	/* use spi->controller data for CS (same strategy as spi_gpio) */
 	gpio_set_value((unsigned)spi->controller_data, value);

 	if (is_on == BITBANG_CS_INACTIVE) {
 		if (test_and_clear_bit(0, &p->flags)) {
 			clk_disable(p->clk);
 			pm_runtime_put(&p->pdev->dev);
 		}
 	}
 }

 static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
 				  void (*tx_fifo)(struct sh_msiof_spi_priv *,
 						  const void *, int, int),
 				  void (*rx_fifo)(struct sh_msiof_spi_priv *,
 						  void *, int, int),
 				  const void *tx_buf, void *rx_buf,
 				  int words, int bits)
 {
 	int fifo_shift;
 	int ret;

 	/* limit maximum word transfer to rx/tx fifo size */
 	if (tx_buf)
 		words = min_t(int, words, p->tx_fifo_size);
 	if (rx_buf)
 		words = min_t(int, words, p->rx_fifo_size);

 	/* the fifo contents need shifting */
 	fifo_shift = 32 - bits;

 	/* setup msiof transfer mode registers */
 	sh_msiof_spi_set_mode_regs(p, tx_buf, rx_buf, bits, words);

 	/* write tx fifo */
 	if (tx_buf)
 		tx_fifo(p, tx_buf, words, fifo_shift);

 	/* setup clock and rx/tx signals */
 	ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TSCKE);
 	if (rx_buf)
 		ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_RXE);
 	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_TXE);

 	/* start by setting frame bit */
 	INIT_COMPLETION(p->done);
 	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_TFSE);
 	if (ret) {
 		dev_err(&p->pdev->dev, "failed to start hardware\n");
 		goto err;
 	}

 	/* wait for tx fifo to be emptied / rx fifo to be filled */
 	wait_for_completion(&p->done);

 	/* read rx fifo */
 	if (rx_buf)
 		rx_fifo(p, rx_buf, words, fifo_shift);

 	/* clear status bits */
 	sh_msiof_reset_str(p);

 	/* shut down frame, tx/tx and clock signals */
 	ret = sh_msiof_modify_ctr_wait(p, CTR_TFSE, 0);
 	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_TXE, 0);
 	if (rx_buf)
 		ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_RXE, 0);
 	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_TSCKE, 0);
 	if (ret) {
 		dev_err(&p->pdev->dev, "failed to shut down hardware\n");
 		goto err;
 	}

 	return words;

  err:
 	sh_msiof_write(p, IER, 0);
 	return ret;
 }

 static int sh_msiof_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
 {
 	struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);
 	void (*tx_fifo)(struct sh_msiof_spi_priv *, const void *, int, int);
 	void (*rx_fifo)(struct sh_msiof_spi_priv *, void *, int, int);
 	int bits;
 	int bytes_per_word;
 	int bytes_done;
 	int words;
 	int n;

 	bits = sh_msiof_spi_bits(spi, t);

 	/* setup bytes per word and fifo read/write functions */
 	if (bits <= 8) {
 		bytes_per_word = 1;
 		tx_fifo = sh_msiof_spi_write_fifo_8;
 		rx_fifo = sh_msiof_spi_read_fifo_8;
 	} else if (bits <= 16) {
 		bytes_per_word = 2;
 		if ((unsigned long)t->tx_buf & 0x01)
 			tx_fifo = sh_msiof_spi_write_fifo_16u;
 		else
 			tx_fifo = sh_msiof_spi_write_fifo_16;

 		if ((unsigned long)t->rx_buf & 0x01)
 			rx_fifo = sh_msiof_spi_read_fifo_16u;
 		else
 			rx_fifo = sh_msiof_spi_read_fifo_16;
 	} else {
 		bytes_per_word = 4;
 		if ((unsigned long)t->tx_buf & 0x03)
 			tx_fifo = sh_msiof_spi_write_fifo_32u;
 		else
 			tx_fifo = sh_msiof_spi_write_fifo_32;

 		if ((unsigned long)t->rx_buf & 0x03)
 			rx_fifo = sh_msiof_spi_read_fifo_32u;
 		else
 			rx_fifo = sh_msiof_spi_read_fifo_32;
 	}

 	/* setup clocks (clock already enabled in chipselect()) */
 	sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk),
 				  sh_msiof_spi_hz(spi, t));

 	/* transfer in fifo sized chunks */
 	words = t->len / bytes_per_word;
 	bytes_done = 0;

 	while (bytes_done < t->len) {
 		n = sh_msiof_spi_txrx_once(p, tx_fifo, rx_fifo,
 					   t->tx_buf + bytes_done,
 					   t->rx_buf + bytes_done,
 					   words, bits);
 		if (n < 0)
 			break;

 		bytes_done += n * bytes_per_word;
 		words -= n;
 	}

 	return bytes_done;
 }

 static u32 sh_msiof_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
 				  u32 word, u8 bits)
 {
 	BUG(); /* unused but needed by bitbang code */
 	return 0;
 }

 static int sh_msiof_spi_probe(struct platform_device *pdev)
 {
 	struct resource	*r;
 	struct spi_master *master;
 	struct sh_msiof_spi_priv *p;
 	char clk_name[16];
 	int i;
 	int ret;

 	master = spi_alloc_master(&pdev->dev, sizeof(struct sh_msiof_spi_priv));
 	if (master == NULL) {
 		dev_err(&pdev->dev, "failed to allocate spi master\n");
 		ret = -ENOMEM;
 		goto err0;
 	}

 	p = spi_master_get_devdata(master);

 	platform_set_drvdata(pdev, p);
 	p->info = pdev->dev.platform_data;
 	init_completion(&p->done);

 	snprintf(clk_name, sizeof(clk_name), "msiof%d", pdev->id);
 	p->clk = clk_get(&pdev->dev, clk_name);
 	if (IS_ERR(p->clk)) {
 		dev_err(&pdev->dev, "cannot get clock \"%s\"\n", clk_name);
 		ret = PTR_ERR(p->clk);
 		goto err1;
 	}

 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	i = platform_get_irq(pdev, 0);
 	if (!r || i < 0) {
 		dev_err(&pdev->dev, "cannot get platform resources\n");
 		ret = -ENOENT;
 		goto err2;
 	}
 	p->mapbase = ioremap_nocache(r->start, resource_size(r));
 	if (!p->mapbase) {
 		dev_err(&pdev->dev, "unable to ioremap\n");
 		ret = -ENXIO;
 		goto err2;
 	}

 	ret = request_irq(i, sh_msiof_spi_irq, IRQF_DISABLED,
 			  dev_name(&pdev->dev), p);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to request irq\n");
 		goto err3;
 	}

 	p->pdev = pdev;
 	pm_runtime_enable(&pdev->dev);

 	/* The standard version of MSIOF use 64 word FIFOs */
 	p->tx_fifo_size = 64;
 	p->rx_fifo_size = 64;

 	/* Platform data may override FIFO sizes */
 	if (p->info->tx_fifo_override)
 		p->tx_fifo_size = p->info->tx_fifo_override;
 	if (p->info->rx_fifo_override)
 		p->rx_fifo_size = p->info->rx_fifo_override;

 	/* init master and bitbang code */
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 	master->mode_bits |= SPI_LSB_FIRST | SPI_3WIRE;
 	master->flags = 0;
 	master->bus_num = pdev->id;
 	master->num_chipselect = p->info->num_chipselect;
 	master->setup = spi_bitbang_setup;
 	master->cleanup = spi_bitbang_cleanup;

 	p->bitbang.master = master;
 	p->bitbang.chipselect = sh_msiof_spi_chipselect;
 	p->bitbang.setup_transfer = sh_msiof_spi_setup_transfer;
 	p->bitbang.txrx_bufs = sh_msiof_spi_txrx;
 	p->bitbang.txrx_word[SPI_MODE_0] = sh_msiof_spi_txrx_word;
 	p->bitbang.txrx_word[SPI_MODE_1] = sh_msiof_spi_txrx_word;
 	p->bitbang.txrx_word[SPI_MODE_2] = sh_msiof_spi_txrx_word;
 	p->bitbang.txrx_word[SPI_MODE_3] = sh_msiof_spi_txrx_word;

 	ret = spi_bitbang_start(&p->bitbang);
 	if (ret == 0)
 		return 0;

 	pm_runtime_disable(&pdev->dev);
  err3:
 	iounmap(p->mapbase);
  err2:
 	clk_put(p->clk);
  err1:
 	spi_master_put(master);
  err0:
 	return ret;
 }

 static int sh_msiof_spi_remove(struct platform_device *pdev)
 {
 	struct sh_msiof_spi_priv *p = platform_get_drvdata(pdev);
 	int ret;

 	ret = spi_bitbang_stop(&p->bitbang);
 	if (!ret) {
 		pm_runtime_disable(&pdev->dev);
 		free_irq(platform_get_irq(pdev, 0), sh_msiof_spi_irq);
 		iounmap(p->mapbase);
 		clk_put(p->clk);
 		spi_master_put(p->bitbang.master);
 	}
 	return ret;
 }

 static int sh_msiof_spi_runtime_nop(struct device *dev)
 {
 	/* Runtime PM callback shared between ->runtime_suspend()
 	 * and ->runtime_resume(). Simply returns success.
 	 *
 	 * This driver re-initializes all registers after
 	 * pm_runtime_get_sync() anyway so there is no need
 	 * to save and restore registers here.
 	 */
 	return 0;
 }

 static struct dev_pm_ops sh_msiof_spi_dev_pm_ops = {
 	.runtime_suspend = sh_msiof_spi_runtime_nop,
 	.runtime_resume = sh_msiof_spi_runtime_nop,
 };

 static struct platform_driver sh_msiof_spi_drv = {
 	.probe		= sh_msiof_spi_probe,
 	.remove		= sh_msiof_spi_remove,
 	.driver		= {
 		.name		= "spi_sh_msiof",
 		.owner		= THIS_MODULE,
 		.pm		= &sh_msiof_spi_dev_pm_ops,
 	},
 };

 static int __init sh_msiof_spi_init(void)
 {
 	return platform_driver_register(&sh_msiof_spi_drv);
 }
 module_init(sh_msiof_spi_init);

 static void __exit sh_msiof_spi_exit(void)
 {
 	platform_driver_unregister(&sh_msiof_spi_drv);
 }
 module_exit(sh_msiof_spi_exit);

 MODULE_DESCRIPTION("SuperH MSIOF SPI Master Interface Driver");
 MODULE_AUTHOR("Magnus Damm");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:spi_sh_msiof");
	/*
	* SuperH MSIOF SPI Master Interface
	*
	* Copyright (c) 2009 Magnus Damm
	*
	* 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 <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/delay.h>
	#include <linux/interrupt.h>
	#include <linux/platform_device.h>
	#include <linux/completion.h>
	#include <linux/pm_runtime.h>
	#include <linux/gpio.h>
	#include <linux/bitmap.h>
	#include <linux/clk.h>
	#include <linux/io.h>

	#include <linux/spi/spi.h>
	#include <linux/spi/spi_bitbang.h>
	#include <linux/spi/sh_msiof.h>

	#include <asm/spi.h>
	#include <asm/unaligned.h>

	struct sh_msiof_spi_priv {
	struct spi_bitbang bitbang; /* must be first for spi_bitbang.c */
	void __iomem *mapbase;
	struct clk *clk;
	struct platform_device *pdev;
	struct sh_msiof_spi_info *info;
	struct completion done;
	unsigned long flags;
	int tx_fifo_size;
	int rx_fifo_size;
	};

	#define TMDR1 0x00
	#define TMDR2 0x04
	#define TMDR3 0x08
	#define RMDR1 0x10
	#define RMDR2 0x14
	#define RMDR3 0x18
	#define TSCR 0x20
	#define RSCR 0x22
	#define CTR 0x28
	#define FCTR 0x30
	#define STR 0x40
	#define IER 0x44
	#define TDR1 0x48
	#define TDR2 0x4c
	#define TFDR 0x50
	#define RDR1 0x58
	#define RDR2 0x5c
	#define RFDR 0x60

	#define CTR_TSCKE (1 << 15)
	#define CTR_TFSE (1 << 14)
	#define CTR_TXE (1 << 9)
	#define CTR_RXE (1 << 8)

	#define STR_TEOF (1 << 23)
	#define STR_REOF (1 << 7)

	static unsigned long sh_msiof_read(struct sh_msiof_spi_priv *p, int reg_offs)
	{
	switch (reg_offs) {
	case TSCR:
	case RSCR:
	return ioread16(p->mapbase + reg_offs);
	default:
	return ioread32(p->mapbase + reg_offs);
	}
	}

	static void sh_msiof_write(struct sh_msiof_spi_priv *p, int reg_offs,
	unsigned long value)
	{
	switch (reg_offs) {
	case TSCR:
	case RSCR:
	iowrite16(value, p->mapbase + reg_offs);
	break;
	default:
	iowrite32(value, p->mapbase + reg_offs);
	break;
	}
	}

	static int sh_msiof_modify_ctr_wait(struct sh_msiof_spi_priv *p,
	unsigned long clr, unsigned long set)
	{
	unsigned long mask = clr \| set;
	unsigned long data;
	int k;

	data = sh_msiof_read(p, CTR);
	data &= ~clr;
	data \|= set;
	sh_msiof_write(p, CTR, data);

	for (k = 100; k > 0; k--) {
	if ((sh_msiof_read(p, CTR) & mask) == set)
	break;

	udelay(10);
	}

	return k > 0 ? 0 : -ETIMEDOUT;
	}

	static irqreturn_t sh_msiof_spi_irq(int irq, void *data)
	{
	struct sh_msiof_spi_priv *p = data;

	/* just disable the interrupt and wake up */
	sh_msiof_write(p, IER, 0);
	complete(&p->done);

	return IRQ_HANDLED;
	}

	static struct {
	unsigned short div;
	unsigned short scr;
	} const sh_msiof_spi_clk_table[] = {
	{ 1, 0x0007 },
	{ 2, 0x0000 },
	{ 4, 0x0001 },
	{ 8, 0x0002 },
	{ 16, 0x0003 },
	{ 32, 0x0004 },
	{ 64, 0x1f00 },
	{ 128, 0x1f01 },
	{ 256, 0x1f02 },
	{ 512, 0x1f03 },
	{ 1024, 0x1f04 },
	};

	static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p,
	unsigned long parent_rate,
	unsigned long spi_hz)
	{
	unsigned long div = 1024;
	size_t k;

	if (!WARN_ON(!spi_hz \|\| !parent_rate))
	div = parent_rate / spi_hz;

	/* TODO: make more fine grained */

	for (k = 0; k < ARRAY_SIZE(sh_msiof_spi_clk_table); k++) {
	if (sh_msiof_spi_clk_table[k].div >= div)
	break;
	}

	k = min_t(int, k, ARRAY_SIZE(sh_msiof_spi_clk_table) - 1);

	sh_msiof_write(p, TSCR, sh_msiof_spi_clk_table[k].scr);
	sh_msiof_write(p, RSCR, sh_msiof_spi_clk_table[k].scr);
	}

	static void sh_msiof_spi_set_pin_regs(struct sh_msiof_spi_priv *p,
	int cpol, int cpha,
	int tx_hi_z, int lsb_first)
	{
	unsigned long tmp;
	int edge;

	/*
	* CPOL CPHA TSCKIZ RSCKIZ TEDG REDG(!)
	* 0 0 10 10 1 0
	* 0 1 10 10 0 1
	* 1 0 11 11 0 1
	* 1 1 11 11 1 0
	*
	* (!) Note: REDG is inverted recommended data sheet setting
	*/

	sh_msiof_write(p, FCTR, 0);
	sh_msiof_write(p, TMDR1, 0xe2000005 \| (lsb_first << 24));
	sh_msiof_write(p, RMDR1, 0x22000005 \| (lsb_first << 24));

	tmp = 0xa0000000;
	tmp \|= cpol << 30; /* TSCKIZ */
	tmp \|= cpol << 28; /* RSCKIZ */

	edge = cpol ? cpha : !cpha;

	tmp \|= edge << 27; /* TEDG */
	tmp \|= !edge << 26; /* REDG */
	tmp \|= (tx_hi_z ? 2 : 0) << 22; /* TXDIZ */
	sh_msiof_write(p, CTR, tmp);
	}

	static void sh_msiof_spi_set_mode_regs(struct sh_msiof_spi_priv *p,
	const void tx_buf, void rx_buf,
	int bits, int words)
	{
	unsigned long dr2;

	dr2 = ((bits - 1) << 24) \| ((words - 1) << 16);

	if (tx_buf)
	sh_msiof_write(p, TMDR2, dr2);
	else
	sh_msiof_write(p, TMDR2, dr2 \| 1);

	if (rx_buf)
	sh_msiof_write(p, RMDR2, dr2);

	sh_msiof_write(p, IER, STR_TEOF \| STR_REOF);
	}

	static void sh_msiof_reset_str(struct sh_msiof_spi_priv *p)
	{
	sh_msiof_write(p, STR, sh_msiof_read(p, STR));
	}

	static void sh_msiof_spi_write_fifo_8(struct sh_msiof_spi_priv *p,
	const void *tx_buf, int words, int fs)
	{
	const unsigned char *buf_8 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
	sh_msiof_write(p, TFDR, buf_8[k] << fs);
	}

	static void sh_msiof_spi_write_fifo_16(struct sh_msiof_spi_priv *p,
	const void *tx_buf, int words, int fs)
	{
	const unsigned short *buf_16 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
	sh_msiof_write(p, TFDR, buf_16[k] << fs);
	}

	static void sh_msiof_spi_write_fifo_16u(struct sh_msiof_spi_priv *p,
	const void *tx_buf, int words, int fs)
	{
	const unsigned short *buf_16 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
	sh_msiof_write(p, TFDR, get_unaligned(&buf_16[k]) << fs);
	}

	static void sh_msiof_spi_write_fifo_32(struct sh_msiof_spi_priv *p,
	const void *tx_buf, int words, int fs)
	{
	const unsigned int *buf_32 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
	sh_msiof_write(p, TFDR, buf_32[k] << fs);
	}

	static void sh_msiof_spi_write_fifo_32u(struct sh_msiof_spi_priv *p,
	const void *tx_buf, int words, int fs)
	{
	const unsigned int *buf_32 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
	sh_msiof_write(p, TFDR, get_unaligned(&buf_32[k]) << fs);
	}

	static void sh_msiof_spi_read_fifo_8(struct sh_msiof_spi_priv *p,
	void *rx_buf, int words, int fs)
	{
	unsigned char *buf_8 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
	buf_8[k] = sh_msiof_read(p, RFDR) >> fs;
	}

	static void sh_msiof_spi_read_fifo_16(struct sh_msiof_spi_priv *p,
	void *rx_buf, int words, int fs)
	{
	unsigned short *buf_16 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
	buf_16[k] = sh_msiof_read(p, RFDR) >> fs;
	}

	static void sh_msiof_spi_read_fifo_16u(struct sh_msiof_spi_priv *p,
	void *rx_buf, int words, int fs)
	{
	unsigned short *buf_16 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
	put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_16[k]);
	}

	static void sh_msiof_spi_read_fifo_32(struct sh_msiof_spi_priv *p,
	void *rx_buf, int words, int fs)
	{
	unsigned int *buf_32 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
	buf_32[k] = sh_msiof_read(p, RFDR) >> fs;
	}

	static void sh_msiof_spi_read_fifo_32u(struct sh_msiof_spi_priv *p,
	void *rx_buf, int words, int fs)
	{
	unsigned int *buf_32 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
	put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_32[k]);
	}

	static int sh_msiof_spi_bits(struct spi_device spi, struct spi_transfer t)
	{
	int bits;

	bits = t ? t->bits_per_word : 0;
	bits = bits ? bits : spi->bits_per_word;
	return bits;
	}

	static unsigned long sh_msiof_spi_hz(struct spi_device *spi,
	struct spi_transfer *t)
	{
	unsigned long hz;

	hz = t ? t->speed_hz : 0;
	hz = hz ? hz : spi->max_speed_hz;
	return hz;
	}

	static int sh_msiof_spi_setup_transfer(struct spi_device *spi,
	struct spi_transfer *t)
	{
	int bits;

	/* noting to check hz values against since parent clock is disabled */

	bits = sh_msiof_spi_bits(spi, t);
	if (bits < 8)
	return -EINVAL;
	if (bits > 32)
	return -EINVAL;

	return spi_bitbang_setup_transfer(spi, t);
	}

	static void sh_msiof_spi_chipselect(struct spi_device *spi, int is_on)
	{
	struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);
	int value;

	/* chip select is active low unless SPI_CS_HIGH is set */
	if (spi->mode & SPI_CS_HIGH)
	value = (is_on == BITBANG_CS_ACTIVE) ? 1 : 0;
	else
	value = (is_on == BITBANG_CS_ACTIVE) ? 0 : 1;

	if (is_on == BITBANG_CS_ACTIVE) {
	if (!test_and_set_bit(0, &p->flags)) {
	pm_runtime_get_sync(&p->pdev->dev);
	clk_enable(p->clk);
	}

	/* Configure pins before asserting CS */
	sh_msiof_spi_set_pin_regs(p, !!(spi->mode & SPI_CPOL),
	!!(spi->mode & SPI_CPHA),
	!!(spi->mode & SPI_3WIRE),
	!!(spi->mode & SPI_LSB_FIRST));
	}

	/* use spi->controller data for CS (same strategy as spi_gpio) */
	gpio_set_value((unsigned)spi->controller_data, value);

	if (is_on == BITBANG_CS_INACTIVE) {
	if (test_and_clear_bit(0, &p->flags)) {
	clk_disable(p->clk);
	pm_runtime_put(&p->pdev->dev);
	}
	}
	}

	static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
	void (tx_fifo)(struct sh_msiof_spi_priv ,
	const void *, int, int),
	void (rx_fifo)(struct sh_msiof_spi_priv ,
	void *, int, int),
	const void tx_buf, void rx_buf,
	int words, int bits)
	{
	int fifo_shift;
	int ret;

	/* limit maximum word transfer to rx/tx fifo size */
	if (tx_buf)
	words = min_t(int, words, p->tx_fifo_size);
	if (rx_buf)
	words = min_t(int, words, p->rx_fifo_size);

	/* the fifo contents need shifting */
	fifo_shift = 32 - bits;

	/* setup msiof transfer mode registers */
	sh_msiof_spi_set_mode_regs(p, tx_buf, rx_buf, bits, words);

	/* write tx fifo */
	if (tx_buf)
	tx_fifo(p, tx_buf, words, fifo_shift);

	/* setup clock and rx/tx signals */
	ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TSCKE);
	if (rx_buf)
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_RXE);
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_TXE);

	/* start by setting frame bit */
	INIT_COMPLETION(p->done);
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_TFSE);
	if (ret) {
	dev_err(&p->pdev->dev, "failed to start hardware\n");
	goto err;
	}

	/* wait for tx fifo to be emptied / rx fifo to be filled */
	wait_for_completion(&p->done);

	/* read rx fifo */
	if (rx_buf)
	rx_fifo(p, rx_buf, words, fifo_shift);

	/* clear status bits */
	sh_msiof_reset_str(p);

	/* shut down frame, tx/tx and clock signals */
	ret = sh_msiof_modify_ctr_wait(p, CTR_TFSE, 0);
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_TXE, 0);
	if (rx_buf)
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_RXE, 0);
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_TSCKE, 0);
	if (ret) {
	dev_err(&p->pdev->dev, "failed to shut down hardware\n");
	goto err;
	}

	return words;

	err:
	sh_msiof_write(p, IER, 0);
	return ret;
	}

	static int sh_msiof_spi_txrx(struct spi_device spi, struct spi_transfer t)
	{
	struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);
	void (tx_fifo)(struct sh_msiof_spi_priv , const void *, int, int);
	void (rx_fifo)(struct sh_msiof_spi_priv , void *, int, int);
	int bits;
	int bytes_per_word;
	int bytes_done;
	int words;
	int n;

	bits = sh_msiof_spi_bits(spi, t);

	/* setup bytes per word and fifo read/write functions */
	if (bits <= 8) {
	bytes_per_word = 1;
	tx_fifo = sh_msiof_spi_write_fifo_8;
	rx_fifo = sh_msiof_spi_read_fifo_8;
	} else if (bits <= 16) {
	bytes_per_word = 2;
	if ((unsigned long)t->tx_buf & 0x01)
	tx_fifo = sh_msiof_spi_write_fifo_16u;
	else
	tx_fifo = sh_msiof_spi_write_fifo_16;

	if ((unsigned long)t->rx_buf & 0x01)
	rx_fifo = sh_msiof_spi_read_fifo_16u;
	else
	rx_fifo = sh_msiof_spi_read_fifo_16;
	} else {
	bytes_per_word = 4;
	if ((unsigned long)t->tx_buf & 0x03)
	tx_fifo = sh_msiof_spi_write_fifo_32u;
	else
	tx_fifo = sh_msiof_spi_write_fifo_32;

	if ((unsigned long)t->rx_buf & 0x03)
	rx_fifo = sh_msiof_spi_read_fifo_32u;
	else
	rx_fifo = sh_msiof_spi_read_fifo_32;
	}

	/* setup clocks (clock already enabled in chipselect()) */
	sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk),
	sh_msiof_spi_hz(spi, t));

	/* transfer in fifo sized chunks */
	words = t->len / bytes_per_word;
	bytes_done = 0;

	while (bytes_done < t->len) {
	n = sh_msiof_spi_txrx_once(p, tx_fifo, rx_fifo,
	t->tx_buf + bytes_done,
	t->rx_buf + bytes_done,
	words, bits);
	if (n < 0)
	break;

	bytes_done += n * bytes_per_word;
	words -= n;
	}

	return bytes_done;
	}

	static u32 sh_msiof_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
	u32 word, u8 bits)
	{
	BUG(); /* unused but needed by bitbang code */
	return 0;
	}

	static int sh_msiof_spi_probe(struct platform_device *pdev)
	{
	struct resource *r;
	struct spi_master *master;
	struct sh_msiof_spi_priv *p;
	char clk_name[16];
	int i;
	int ret;

	master = spi_alloc_master(&pdev->dev, sizeof(struct sh_msiof_spi_priv));
	if (master == NULL) {
	dev_err(&pdev->dev, "failed to allocate spi master\n");
	ret = -ENOMEM;
	goto err0;
	}

	p = spi_master_get_devdata(master);

	platform_set_drvdata(pdev, p);
	p->info = pdev->dev.platform_data;
	init_completion(&p->done);

	snprintf(clk_name, sizeof(clk_name), "msiof%d", pdev->id);
	p->clk = clk_get(&pdev->dev, clk_name);
	if (IS_ERR(p->clk)) {
	dev_err(&pdev->dev, "cannot get clock \"%s\"\n", clk_name);
	ret = PTR_ERR(p->clk);
	goto err1;
	}

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	i = platform_get_irq(pdev, 0);
	if (!r \|\| i < 0) {
	dev_err(&pdev->dev, "cannot get platform resources\n");
	ret = -ENOENT;
	goto err2;
	}
	p->mapbase = ioremap_nocache(r->start, resource_size(r));
	if (!p->mapbase) {
	dev_err(&pdev->dev, "unable to ioremap\n");
	ret = -ENXIO;
	goto err2;
	}

	ret = request_irq(i, sh_msiof_spi_irq, IRQF_DISABLED,
	dev_name(&pdev->dev), p);
	if (ret) {
	dev_err(&pdev->dev, "unable to request irq\n");
	goto err3;
	}

	p->pdev = pdev;
	pm_runtime_enable(&pdev->dev);

	/* The standard version of MSIOF use 64 word FIFOs */
	p->tx_fifo_size = 64;
	p->rx_fifo_size = 64;

	/* Platform data may override FIFO sizes */
	if (p->info->tx_fifo_override)
	p->tx_fifo_size = p->info->tx_fifo_override;
	if (p->info->rx_fifo_override)
	p->rx_fifo_size = p->info->rx_fifo_override;

	/* init master and bitbang code */
	master->mode_bits = SPI_CPOL \| SPI_CPHA \| SPI_CS_HIGH;
	master->mode_bits \|= SPI_LSB_FIRST \| SPI_3WIRE;
	master->flags = 0;
	master->bus_num = pdev->id;
	master->num_chipselect = p->info->num_chipselect;
	master->setup = spi_bitbang_setup;
	master->cleanup = spi_bitbang_cleanup;

	p->bitbang.master = master;
	p->bitbang.chipselect = sh_msiof_spi_chipselect;
	p->bitbang.setup_transfer = sh_msiof_spi_setup_transfer;
	p->bitbang.txrx_bufs = sh_msiof_spi_txrx;
	p->bitbang.txrx_word[SPI_MODE_0] = sh_msiof_spi_txrx_word;
	p->bitbang.txrx_word[SPI_MODE_1] = sh_msiof_spi_txrx_word;
	p->bitbang.txrx_word[SPI_MODE_2] = sh_msiof_spi_txrx_word;
	p->bitbang.txrx_word[SPI_MODE_3] = sh_msiof_spi_txrx_word;

	ret = spi_bitbang_start(&p->bitbang);
	if (ret == 0)
	return 0;

	pm_runtime_disable(&pdev->dev);
	err3:
	iounmap(p->mapbase);
	err2:
	clk_put(p->clk);
	err1:
	spi_master_put(master);
	err0:
	return ret;
	}

	static int sh_msiof_spi_remove(struct platform_device *pdev)
	{
	struct sh_msiof_spi_priv *p = platform_get_drvdata(pdev);
	int ret;

	ret = spi_bitbang_stop(&p->bitbang);
	if (!ret) {
	pm_runtime_disable(&pdev->dev);
	free_irq(platform_get_irq(pdev, 0), sh_msiof_spi_irq);
	iounmap(p->mapbase);
	clk_put(p->clk);
	spi_master_put(p->bitbang.master);
	}
	return ret;
	}

	static int sh_msiof_spi_runtime_nop(struct device *dev)
	{
	/* Runtime PM callback shared between ->runtime_suspend()
	* and ->runtime_resume(). Simply returns success.
	*
	* This driver re-initializes all registers after
	* pm_runtime_get_sync() anyway so there is no need
	* to save and restore registers here.
	*/
	return 0;
	}

	static struct dev_pm_ops sh_msiof_spi_dev_pm_ops = {
	.runtime_suspend = sh_msiof_spi_runtime_nop,
	.runtime_resume = sh_msiof_spi_runtime_nop,
	};

	static struct platform_driver sh_msiof_spi_drv = {
	.probe = sh_msiof_spi_probe,
	.remove = sh_msiof_spi_remove,
	.driver = {
	.name = "spi_sh_msiof",
	.owner = THIS_MODULE,
	.pm = &sh_msiof_spi_dev_pm_ops,
	},
	};

	static int __init sh_msiof_spi_init(void)
	{
	return platform_driver_register(&sh_msiof_spi_drv);
	}
	module_init(sh_msiof_spi_init);

	static void __exit sh_msiof_spi_exit(void)
	{
	platform_driver_unregister(&sh_msiof_spi_drv);
	}
	module_exit(sh_msiof_spi_exit);

	MODULE_DESCRIPTION("SuperH MSIOF SPI Master Interface Driver");
	MODULE_AUTHOR("Magnus Damm");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:spi_sh_msiof");