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/*
* AD7879/AD7889 touchscreen (SPI bus)
*
* Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <linux/input.h> /* BUS_SPI */
#include <linux/pm.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include "ad7879.h"
#define AD7879_DEVID 0x7A /* AD7879/AD7889 */
#define MAX_SPI_FREQ_HZ 5000000
#define AD7879_CMD_MAGIC 0xE000
#define AD7879_CMD_READ (1 << 10)
#define AD7879_CMD(reg) (AD7879_CMD_MAGIC | ((reg) & 0xF))
#define AD7879_WRITECMD(reg) (AD7879_CMD(reg))
#define AD7879_READCMD(reg) (AD7879_CMD(reg) | AD7879_CMD_READ)
/*
* ad7879_read/write are only used for initial setup and for sysfs controls.
* The main traffic is done in ad7879_collect().
*/
static int ad7879_spi_xfer(struct spi_device *spi,
u16 cmd, u8 count, u16 *tx_buf, u16 *rx_buf)
{
struct spi_message msg;
struct spi_transfer *xfers;
void *spi_data;
u16 *command;
u16 *_rx_buf = _rx_buf; /* shut gcc up */
u8 idx;
int ret;
xfers = spi_data = kzalloc(sizeof(*xfers) * (count + 2), GFP_KERNEL);
if (!spi_data)
return -ENOMEM;
spi_message_init(&msg);
command = spi_data;
command[0] = cmd;
if (count == 1) {
/* ad7879_spi_{read,write} gave us buf on stack */
command[1] = *tx_buf;
tx_buf = &command[1];
_rx_buf = rx_buf;
rx_buf = &command[2];
}
++xfers;
xfers[0].tx_buf = command;
xfers[0].len = 2;
spi_message_add_tail(&xfers[0], &msg);
++xfers;
for (idx = 0; idx < count; ++idx) {
if (rx_buf)
xfers[idx].rx_buf = &rx_buf[idx];
if (tx_buf)
xfers[idx].tx_buf = &tx_buf[idx];
xfers[idx].len = 2;
spi_message_add_tail(&xfers[idx], &msg);
}
ret = spi_sync(spi, &msg);
if (count == 1)
_rx_buf[0] = command[2];
kfree(spi_data);
return ret;
}
static int ad7879_spi_multi_read(struct device *dev,
u8 first_reg, u8 count, u16 *buf)
{
struct spi_device *spi = to_spi_device(dev);
return ad7879_spi_xfer(spi, AD7879_READCMD(first_reg), count, NULL, buf);
}
static int ad7879_spi_read(struct device *dev, u8 reg)
{
struct spi_device *spi = to_spi_device(dev);
u16 ret, dummy;
return ad7879_spi_xfer(spi, AD7879_READCMD(reg), 1, &dummy, &ret) ? : ret;
}
static int ad7879_spi_write(struct device *dev, u8 reg, u16 val)
{
struct spi_device *spi = to_spi_device(dev);
u16 dummy;
return ad7879_spi_xfer(spi, AD7879_WRITECMD(reg), 1, &val, &dummy);
}
static const struct ad7879_bus_ops ad7879_spi_bus_ops = {
.bustype = BUS_SPI,
.read = ad7879_spi_read,
.multi_read = ad7879_spi_multi_read,
.write = ad7879_spi_write,
};
static int ad7879_spi_probe(struct spi_device *spi)
{
struct ad7879 *ts;
int err;
/* don't exceed max specified SPI CLK frequency */
if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
return -EINVAL;
}
spi->bits_per_word = 16;
err = spi_setup(spi);
if (err) {
dev_dbg(&spi->dev, "spi master doesn't support 16 bits/word\n");
return err;
}
ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops);
if (IS_ERR(ts))
return PTR_ERR(ts);
spi_set_drvdata(spi, ts);
return 0;
}
static int __devexit ad7879_spi_remove(struct spi_device *spi)
{
struct ad7879 *ts = spi_get_drvdata(spi);
ad7879_remove(ts);
spi_set_drvdata(spi, NULL);
return 0;
}
static struct spi_driver ad7879_spi_driver = {
.driver = {
.name = "ad7879",
.owner = THIS_MODULE,
.pm = &ad7879_pm_ops,
},
.probe = ad7879_spi_probe,
.remove = ad7879_spi_remove,
};
module_spi_driver(ad7879_spi_driver);
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:ad7879");
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