/*
   * SH SCI SPI interface
   *
   * Copyright (c) 2008 Magnus Damm
   *
   * Based on S3C24XX GPIO based SPI driver, which is:
   *   Copyright (c) 2006 Ben Dooks
   *   Copyright (c) 2006 Simtec Electronics
   *
   * 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/spinlock.h>
  #include <linux/workqueue.h>
  #include <linux/platform_device.h>
  
  #include <linux/spi/spi.h>
  #include <linux/spi/spi_bitbang.h>

  #include <linux/module.h>

  
  #include <asm/spi.h>
  #include <asm/io.h>
  
  struct sh_sci_spi {
  	struct spi_bitbang bitbang;
  
  	void __iomem *membase;
  	unsigned char val;
  	struct sh_spi_info *info;
  	struct platform_device *dev;
  };
  
  #define SCSPTR(sp)	(sp->membase + 0x1c)
  #define PIN_SCK		(1 << 2)
  #define PIN_TXD		(1 << 0)
  #define PIN_RXD		PIN_TXD
  #define PIN_INIT	((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD)
  
  static inline void setbits(struct sh_sci_spi *sp, int bits, int on)
  {
  	/*
  	 * We are the only user of SCSPTR so no locking is required.
  	 * Reading bit 2 and 0 in SCSPTR gives pin state as input.
  	 * Writing the same bits sets the output value.
  	 * This makes regular read-modify-write difficult so we
  	 * use sp->val to keep track of the latest register value.
  	 */
  
  	if (on)
  		sp->val |= bits;
  	else
  		sp->val &= ~bits;
  
  	iowrite8(sp->val, SCSPTR(sp));
  }
  
  static inline void setsck(struct spi_device *dev, int on)
  {
  	setbits(spi_master_get_devdata(dev->master), PIN_SCK, on);
  }
  
  static inline void setmosi(struct spi_device *dev, int on)
  {
  	setbits(spi_master_get_devdata(dev->master), PIN_TXD, on);
  }
  
  static inline u32 getmiso(struct spi_device *dev)
  {
  	struct sh_sci_spi *sp = spi_master_get_devdata(dev->master);
  
  	return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0;
  }
  
  #define spidelay(x) ndelay(x)

  #include "spi-bitbang-txrx.h"

  
  static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi,
  				      unsigned nsecs, u32 word, u8 bits)
  {

  	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);

  }
  
  static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi,
  				      unsigned nsecs, u32 word, u8 bits)
  {

  	return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);

  }
  
  static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi,
  				      unsigned nsecs, u32 word, u8 bits)
  {

  	return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);

  }
  
  static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi,
  				      unsigned nsecs, u32 word, u8 bits)
  {

  	return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);

  }
  
  static void sh_sci_spi_chipselect(struct spi_device *dev, int value)
  {
  	struct sh_sci_spi *sp = spi_master_get_devdata(dev->master);
  
  	if (sp->info && sp->info->chip_select)
  		(sp->info->chip_select)(sp->info, dev->chip_select, value);
  }
  
  static int sh_sci_spi_probe(struct platform_device *dev)
  {
  	struct resource	*r;
  	struct spi_master *master;
  	struct sh_sci_spi *sp;
  	int ret;
  
  	master = spi_alloc_master(&dev->dev, sizeof(struct sh_sci_spi));
  	if (master == NULL) {
  		dev_err(&dev->dev, "failed to allocate spi master
  ");
  		ret = -ENOMEM;
  		goto err0;
  	}
  
  	sp = spi_master_get_devdata(master);
  
  	platform_set_drvdata(dev, sp);
  	sp->info = dev->dev.platform_data;
  
  	/* setup spi bitbang adaptor */
  	sp->bitbang.master = spi_master_get(master);
  	sp->bitbang.master->bus_num = sp->info->bus_num;
  	sp->bitbang.master->num_chipselect = sp->info->num_chipselect;
  	sp->bitbang.chipselect = sh_sci_spi_chipselect;
  
  	sp->bitbang.txrx_word[SPI_MODE_0] = sh_sci_spi_txrx_mode0;
  	sp->bitbang.txrx_word[SPI_MODE_1] = sh_sci_spi_txrx_mode1;
  	sp->bitbang.txrx_word[SPI_MODE_2] = sh_sci_spi_txrx_mode2;
  	sp->bitbang.txrx_word[SPI_MODE_3] = sh_sci_spi_txrx_mode3;
  
  	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
  	if (r == NULL) {
  		ret = -ENOENT;
  		goto err1;
  	}

  	sp->membase = ioremap(r->start, resource_size(r));

  	if (!sp->membase) {
  		ret = -ENXIO;
  		goto err1;
  	}
  	sp->val = ioread8(SCSPTR(sp));
  	setbits(sp, PIN_INIT, 1);
  
  	ret = spi_bitbang_start(&sp->bitbang);
  	if (!ret)
  		return 0;
  
  	setbits(sp, PIN_INIT, 0);
  	iounmap(sp->membase);
   err1:
  	spi_master_put(sp->bitbang.master);
   err0:
  	return ret;
  }
  
  static int sh_sci_spi_remove(struct platform_device *dev)
  {
  	struct sh_sci_spi *sp = platform_get_drvdata(dev);
  
  	iounmap(sp->membase);
  	setbits(sp, PIN_INIT, 0);
  	spi_bitbang_stop(&sp->bitbang);
  	spi_master_put(sp->bitbang.master);
  	return 0;
  }
  
  static struct platform_driver sh_sci_spi_drv = {
  	.probe		= sh_sci_spi_probe,
  	.remove		= sh_sci_spi_remove,
  	.driver		= {
  		.name	= "spi_sh_sci",
  		.owner	= THIS_MODULE,
  	},
  };

  module_platform_driver(sh_sci_spi_drv);

  
  MODULE_DESCRIPTION("SH SCI SPI Driver");
  MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:spi_sh_sci");