/*
   * Register map access API - SPI support
   *
   * Copyright 2011 Wolfson Microelectronics plc
   *
   * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   *
   * 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/regmap.h>
  #include <linux/spi/spi.h>

  #include <linux/module.h>

  #include "internal.h"
  
  struct regmap_async_spi {
  	struct regmap_async core;
  	struct spi_message m;
  	struct spi_transfer t[2];
  };
  
  static void regmap_spi_complete(void *data)
  {
  	struct regmap_async_spi *async = data;
  
  	regmap_async_complete_cb(&async->core, async->m.status);
  }

  static int regmap_spi_write(void *context, const void *data, size_t count)

  {

  	struct device *dev = context;

  	struct spi_device *spi = to_spi_device(dev);
  
  	return spi_write(spi, data, count);
  }

  static int regmap_spi_gather_write(void *context,

  				   const void *reg, size_t reg_len,
  				   const void *val, size_t val_len)
  {

  	struct device *dev = context;

  	struct spi_device *spi = to_spi_device(dev);
  	struct spi_message m;
  	struct spi_transfer t[2] = { { .tx_buf = reg, .len = reg_len, },
  				     { .tx_buf = val, .len = val_len, }, };
  
  	spi_message_init(&m);
  	spi_message_add_tail(&t[0], &m);
  	spi_message_add_tail(&t[1], &m);
  
  	return spi_sync(spi, &m);
  }

  static int regmap_spi_async_write(void *context,
  				  const void *reg, size_t reg_len,
  				  const void *val, size_t val_len,
  				  struct regmap_async *a)
  {
  	struct regmap_async_spi *async = container_of(a,
  						      struct regmap_async_spi,
  						      core);
  	struct device *dev = context;
  	struct spi_device *spi = to_spi_device(dev);
  
  	async->t[0].tx_buf = reg;
  	async->t[0].len = reg_len;
  	async->t[1].tx_buf = val;
  	async->t[1].len = val_len;
  
  	spi_message_init(&async->m);
  	spi_message_add_tail(&async->t[0], &async->m);

  	if (val)
  		spi_message_add_tail(&async->t[1], &async->m);

  
  	async->m.complete = regmap_spi_complete;
  	async->m.context = async;
  
  	return spi_async(spi, &async->m);
  }
  
  static struct regmap_async *regmap_spi_async_alloc(void)
  {
  	struct regmap_async_spi *async_spi;
  
  	async_spi = kzalloc(sizeof(*async_spi), GFP_KERNEL);

  	if (!async_spi)
  		return NULL;

  
  	return &async_spi->core;
  }

  static int regmap_spi_read(void *context,

  			   const void *reg, size_t reg_size,
  			   void *val, size_t val_size)
  {

  	struct device *dev = context;

  	struct spi_device *spi = to_spi_device(dev);
  
  	return spi_write_then_read(spi, reg, reg_size, val, val_size);
  }
  
  static struct regmap_bus regmap_spi = {

  	.write = regmap_spi_write,
  	.gather_write = regmap_spi_gather_write,

  	.async_write = regmap_spi_async_write,
  	.async_alloc = regmap_spi_async_alloc,

  	.read = regmap_spi_read,

  	.read_flag_mask = 0x80,

  	.reg_format_endian_default = REGMAP_ENDIAN_BIG,
  	.val_format_endian_default = REGMAP_ENDIAN_BIG,

  };

  struct regmap *__regmap_init_spi(struct spi_device *spi,
  				 const struct regmap_config *config,
  				 struct lock_class_key *lock_key,
  				 const char *lock_name)

  {

  	return __regmap_init(&spi->dev, &regmap_spi, &spi->dev, config,
  			     lock_key, lock_name);

  }

  EXPORT_SYMBOL_GPL(__regmap_init_spi);

  struct regmap *__devm_regmap_init_spi(struct spi_device *spi,
  				      const struct regmap_config *config,
  				      struct lock_class_key *lock_key,
  				      const char *lock_name)

  {

  	return __devm_regmap_init(&spi->dev, &regmap_spi, &spi->dev, config,
  				  lock_key, lock_name);

  }

  EXPORT_SYMBOL_GPL(__devm_regmap_init_spi);

  MODULE_LICENSE("GPL");