Commit 50e4d7a2 authored by Luca Ceresoli's avatar Luca Ceresoli Committed by Lee Jones
Browse files

mfd: lp87565: Handle optional reset pin 



Optionally handle the NRST pin (active low reset) in order to start from a
known state during boot and to shut down the chip when rebooting.

Signed-off-by: default avatarLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 4700ef32

drivers/mfd/lp87565.c

+27 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 * Author: Keerthy <j-keerthy@ti.com>

 */



#include <linux/gpio/consumer.h>

#include <linux/interrupt.h>

#include <linux/mfd/core.h>

#include <linux/module.h>
@@ -64,6 +65,24 @@ static int lp87565_probe(struct i2c_client *client, 
		return ret;

	}



	lp87565->reset_gpio = devm_gpiod_get_optional(lp87565->dev, "reset",

						      GPIOD_OUT_LOW);

	if (IS_ERR(lp87565->reset_gpio)) {

		ret = PTR_ERR(lp87565->reset_gpio);

		if (ret == -EPROBE_DEFER)

			return ret;

	}



	if (lp87565->reset_gpio) {

		gpiod_set_value_cansleep(lp87565->reset_gpio, 1);

		/* The minimum assertion time is undocumented, just guess */

		usleep_range(2000, 4000);



		gpiod_set_value_cansleep(lp87565->reset_gpio, 0);

		/* Min 1.2 ms before first I2C transaction */

		usleep_range(1500, 3000);

	}



	ret = regmap_read(lp87565->regmap, LP87565_REG_OTP_REV, &otpid);

	if (ret) {

		dev_err(lp87565->dev, "Failed to read OTP ID\n");
@@ -83,6 +102,13 @@ static int lp87565_probe(struct i2c_client *client, 
				    NULL, 0, NULL);

}



static void lp87565_shutdown(struct i2c_client *client)

{

	struct lp87565 *lp87565 = i2c_get_clientdata(client);



	gpiod_set_value_cansleep(lp87565->reset_gpio, 1);

}



static const struct i2c_device_id lp87565_id_table[] = {

	{ "lp87565-q1", 0 },

	{ },
@@ -95,6 +121,7 @@ static struct i2c_driver lp87565_driver = { 
		.of_match_table = of_lp87565_match_table,

	},

	.probe = lp87565_probe,

	.shutdown = lp87565_shutdown,

	.id_table = lp87565_id_table,

};

module_i2c_driver(lp87565_driver);

include/linux/mfd/lp87565.h

+1 −0
Original line number Diff line number Diff line
@@ -252,5 +252,6 @@ struct lp87565 { 
	u8 rev;

	u8 dev_type;

	struct regmap *regmap;

	struct gpio_desc *reset_gpio;

};

#endif /* __LINUX_MFD_LP87565_H */