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Input: sx8654 - add reset-gpio support 

The sx8654 features a NRST input which may be connected to a GPIO.
Therefore add support for hard-resetting the sx8654 via this NRST.

If the reset-gpio property is provided the sx8654 is resetted via NRST
instead of the soft-reset via I2C.

Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Richard Leitner 2019-01-28 14:49:37 -08:00 committed by Dmitry Torokhov
parent 4dbb71195b
commit c3a39380a3
2 changed files with 42 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/devicetree/bindings/input/touchscreen/sx8654.txt
View File

@ -5,6 +5,9 @@ Required properties:
- reg: i2c slave address
- interrupts: touch controller interrupt
Optional properties:
- reset-gpios: GPIO specification for the NRST input
Example:
sx8654@48 {
@ -12,4 +15,5 @@ Example:
reg = <0x48>;
interrupt-parent = <&gpio6>;
interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
reset-gpios = <&gpio4 2 GPIO_ACTIVE_LOW>;
};

44
drivers/input/touchscreen/sx8654.c
View File

@ -27,12 +27,14 @@
* published by the Free Software Foundation.
*/
#include <linux/input.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
/* register addresses */
#define I2C_REG_TOUCH0 0x00
@ -74,6 +76,7 @@
struct sx8654 {
struct input_dev *input;
struct i2c_client *client;
struct gpio_desc *gpio_reset;
};
static irqreturn_t sx8654_irq(int irq, void *handle)
@ -124,6 +127,25 @@ out:
return IRQ_HANDLED;
}
static int sx8654_reset(struct sx8654 *ts)
{
int err;
if (ts->gpio_reset) {
gpiod_set_value_cansleep(ts->gpio_reset, 1);
udelay(2); /* Tpulse > 1µs */
gpiod_set_value_cansleep(ts->gpio_reset, 0);
} else {
dev_dbg(&ts->client->dev, "NRST unavailable, try softreset\n");
err = i2c_smbus_write_byte_data(ts->client, I2C_REG_SOFTRESET,
SOFTRESET_VALUE);
if (err)
return err;
}
return 0;
}
static int sx8654_open(struct input_dev *dev)
{
struct sx8654 *sx8654 = input_get_drvdata(dev);
@ -186,6 +208,17 @@ static int sx8654_probe(struct i2c_client *client,
if (!sx8654)
return -ENOMEM;
sx8654->gpio_reset = devm_gpiod_get_optional(&client->dev, "reset",
GPIOD_OUT_HIGH);
if (IS_ERR(sx8654->gpio_reset)) {
error = PTR_ERR(sx8654->gpio_reset);
if (error != -EPROBE_DEFER)
dev_err(&client->dev, "unable to get reset-gpio: %d\n",
error);
return error;
}
dev_dbg(&client->dev, "got GPIO reset pin\n");
input = devm_input_allocate_device(&client->dev);
if (!input)
return -ENOMEM;
@ -206,10 +239,9 @@ static int sx8654_probe(struct i2c_client *client,
input_set_drvdata(sx8654->input, sx8654);
error = i2c_smbus_write_byte_data(client, I2C_REG_SOFTRESET,
SOFTRESET_VALUE);
error = sx8654_reset(sx8654);
if (error) {
dev_err(&client->dev, "writing softreset value failed");
dev_err(&client->dev, "reset failed");
return error;
}