linux-stable/drivers/input/touchscreen/ad7879-spi.c
Stefan Agner fa6e3ca274 Input: ad7879 - add device tree support
Add device tree support for the I2C and SPI variant of AD7879(-1).
This allows to specify the touchscreen controller as a I2C client
node or SPI slave device. Most of the options available in platform
data are also available as device tree properties, the only exception
being GPIO capabilities, which can not be activated through device
tree currently.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2016-03-08 10:51:18 -08:00

173 lines
3.8 KiB
C

/*
* 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 <linux/of.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 ad7879_spi_remove(struct spi_device *spi)
{
struct ad7879 *ts = spi_get_drvdata(spi);
ad7879_remove(ts);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id ad7879_spi_dt_ids[] = {
{ .compatible = "adi,ad7879", },
{ }
};
MODULE_DEVICE_TABLE(of, ad7879_spi_dt_ids);
#endif
static struct spi_driver ad7879_spi_driver = {
.driver = {
.name = "ad7879",
.pm = &ad7879_pm_ops,
.of_match_table = of_match_ptr(ad7879_spi_dt_ids),
},
.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");