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ab8500-spi.c
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ab8500-spi.c
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/*
* Copyright (C) ST-Ericsson SA 2010
*
* License Terms: GNU General Public License v2
* Author: Srinidhi Kasagar <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/mfd/ab8500.h>
/*
* This funtion writes to any AB8500 registers using
* SPI protocol & before it writes it packs the data
* in the below 24 bit frame format
*
* *|------------------------------------|
* *| 23|22...18|17.......10|9|8|7......0|
* *| r/w bank adr data |
* * ------------------------------------
*
* This function shouldn't be called from interrupt
* context
*/
static int ab8500_spi_write(struct ab8500 *ab8500, u16 addr, u8 data)
{
struct spi_device *spi = container_of(ab8500->dev, struct spi_device,
dev);
unsigned long spi_data = addr << 10 | data;
struct spi_transfer xfer;
struct spi_message msg;
ab8500->tx_buf[0] = spi_data;
ab8500->rx_buf[0] = 0;
xfer.tx_buf = ab8500->tx_buf;
xfer.rx_buf = NULL;
xfer.len = sizeof(unsigned long);
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
return spi_sync(spi, &msg);
}
static int ab8500_spi_read(struct ab8500 *ab8500, u16 addr)
{
struct spi_device *spi = container_of(ab8500->dev, struct spi_device,
dev);
unsigned long spi_data = 1 << 23 | addr << 10;
struct spi_transfer xfer;
struct spi_message msg;
int ret;
ab8500->tx_buf[0] = spi_data;
ab8500->rx_buf[0] = 0;
xfer.tx_buf = ab8500->tx_buf;
xfer.rx_buf = ab8500->rx_buf;
xfer.len = sizeof(unsigned long);
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
ret = spi_sync(spi, &msg);
if (!ret)
ret = ab8500->rx_buf[0];
return ret;
}
static int __devinit ab8500_spi_probe(struct spi_device *spi)
{
struct ab8500 *ab8500;
int ret;
ab8500 = kzalloc(sizeof *ab8500, GFP_KERNEL);
if (!ab8500)
return -ENOMEM;
ab8500->dev = &spi->dev;
ab8500->irq = spi->irq;
ab8500->read = ab8500_spi_read;
ab8500->write = ab8500_spi_write;
spi_set_drvdata(spi, ab8500);
ret = ab8500_init(ab8500);
if (ret)
kfree(ab8500);
return ret;
}
static int __devexit ab8500_spi_remove(struct spi_device *spi)
{
struct ab8500 *ab8500 = spi_get_drvdata(spi);
ab8500_exit(ab8500);
kfree(ab8500);
return 0;
}
static struct spi_driver ab8500_spi_driver = {
.driver = {
.name = "ab8500",
.owner = THIS_MODULE,
},
.probe = ab8500_spi_probe,
.remove = __devexit_p(ab8500_spi_remove)
};
static int __init ab8500_spi_init(void)
{
return spi_register_driver(&ab8500_spi_driver);
}
subsys_initcall(ab8500_spi_init);
static void __exit ab8500_spi_exit(void)
{
spi_unregister_driver(&ab8500_spi_driver);
}
module_exit(ab8500_spi_exit);
MODULE_AUTHOR("Srinidhi KASAGAR <[email protected]");
MODULE_DESCRIPTION("AB8500 SPI");
MODULE_LICENSE("GPL v2");