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linux-next/drivers/base/regmap/regmap-spi.c
Mark Brown cd1b9dd022 regmap: spi: Handle async writes of only one buffer
If the value is zero then assume it has been included in the register data
and don't send anything, minimising the number of interactions with the
hardware.

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-10-14 22:09:26 +01:00

149 lines
3.7 KiB
C

/*
* 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/init.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,
};
/**
* regmap_init_spi(): Initialise register map
*
* @spi: Device that will be interacted with
* @config: Configuration for register map
*
* The return value will be an ERR_PTR() on error or a valid pointer to
* a struct regmap.
*/
struct regmap *regmap_init_spi(struct spi_device *spi,
const struct regmap_config *config)
{
return regmap_init(&spi->dev, &regmap_spi, &spi->dev, config);
}
EXPORT_SYMBOL_GPL(regmap_init_spi);
/**
* devm_regmap_init_spi(): Initialise register map
*
* @spi: Device that will be interacted with
* @config: Configuration for register map
*
* The return value will be an ERR_PTR() on error or a valid pointer
* to a struct regmap. The map will be automatically freed by the
* device management code.
*/
struct regmap *devm_regmap_init_spi(struct spi_device *spi,
const struct regmap_config *config)
{
return devm_regmap_init(&spi->dev, &regmap_spi, &spi->dev, config);
}
EXPORT_SYMBOL_GPL(devm_regmap_init_spi);
MODULE_LICENSE("GPL");