From 0b0f8f0f7988eccb6b4ed42984c5bde092b1d5fe Mon Sep 17 00:00:00 2001 From: Sergio Perez Date: Tue, 18 Mar 2025 01:12:05 +0100 Subject: [PATCH] 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 patch 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. Update the devicetree binding documentation to include the new reset-gpios property with examples. Signed-off-by: Sergio Perez --- .../devicetree/bindings/iio/light/bh1750.yaml | 5 ++++ drivers/iio/light/bh1750.c | 23 +++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/Documentation/devicetree/bindings/iio/light/bh1750.yaml b/Documentation/devicetree/bindings/iio/light/bh1750.yaml index 1a88b3c253d5..f7a8dcd7d2a1 100644 --- a/Documentation/devicetree/bindings/iio/light/bh1750.yaml +++ b/Documentation/devicetree/bindings/iio/light/bh1750.yaml @@ -24,6 +24,10 @@ properties: reg: maxItems: 1 + reset-gpios: + description: GPIO connected to the sensor's reset line (active low) + maxItems: 1 + required: - compatible - reg @@ -39,6 +43,7 @@ examples: light-sensor@23 { compatible = "rohm,bh1750"; reg = <0x23>; + reset-gpios = <&gpio2 17 0>; }; }; diff --git a/drivers/iio/light/bh1750.c b/drivers/iio/light/bh1750.c index 4b869fa9e5b1..cfcce0c73aa2 100644 --- a/drivers/iio/light/bh1750.c +++ b/drivers/iio/light/bh1750.c @@ -22,12 +22,16 @@ #include #include #include +#include #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 +253,24 @@ 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, 0); + fsleep(BH1750_RESET_DELAY_US); + gpiod_set_value_cansleep(data->reset_gpio, 1); + 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) -- 2.43.0