Commit 61f013df authored by Sergio Perez's avatar Sergio Perez Committed by Jonathan Cameron
Browse files

iio: light: bh1750: Add hardware reset support via GPIO 



Some BH1750 sensors require a hardware reset before they can be
detected on the I2C bus. This implementation adds support for an
optional reset GPIO that can be specified in the device tree.

The reset sequence pulls the GPIO low and then high before initializing
the sensor, which enables proper detection with tools like i2cdetect.
This is particularly important for sensors that power on in an
undefined state.

Signed-off-by: default avatarSergio Perez <sergio@pereznus.es>
Link: https://patch.msgid.link/20250324135920.6802-2-sergio@pereznus.es


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 3e09eb53

drivers/iio/light/bh1750.c

+24 −0
Original line number Diff line number Diff line
@@ -22,12 +22,16 @@ 
#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

#include <linux/module.h>

#include <linux/gpio/consumer.h>



#define BH1750_POWER_DOWN		0x00

#define BH1750_ONE_TIME_H_RES_MODE	0x20 /* auto-mode for BH1721 */

#define BH1750_CHANGE_INT_TIME_H_BIT	0x40

#define BH1750_CHANGE_INT_TIME_L_BIT	0x60



/* Define the reset delay time in microseconds */

#define BH1750_RESET_DELAY_US 10000 /* 10ms */



enum {

	BH1710,

	BH1721,
@@ -40,6 +44,7 @@ struct bh1750_data { 
	struct mutex lock;

	const struct bh1750_chip_info *chip_info;

	u16 mtreg;

	struct gpio_desc *reset_gpio;

};



struct bh1750_chip_info {
@@ -248,6 +253,25 @@ static int bh1750_probe(struct i2c_client *client) 
	data->client = client;

	data->chip_info = &bh1750_chip_info_tbl[id->driver_data];



	/* Get reset GPIO from device tree */

	data->reset_gpio = devm_gpiod_get_optional(&client->dev,

						   "reset", GPIOD_OUT_HIGH);



	if (IS_ERR(data->reset_gpio))

		return dev_err_probe(&client->dev, PTR_ERR(data->reset_gpio),

				     "Failed to get reset GPIO\n");



	/* Perform hardware reset if GPIO is provided */

	if (data->reset_gpio) {

		/* Perform reset sequence: low-high */

		gpiod_set_value_cansleep(data->reset_gpio, 1);

		fsleep(BH1750_RESET_DELAY_US);

		gpiod_set_value_cansleep(data->reset_gpio, 0);

		fsleep(BH1750_RESET_DELAY_US);



		dev_dbg(&client->dev, "BH1750 reset completed via GPIO\n");

	}



	usec = data->chip_info->mtreg_to_usec * data->chip_info->mtreg_default;

	ret = bh1750_change_int_time(data, usec);

	if (ret < 0)