linux-kernel - Re: [PATCH v2 2/7] iio: pressure: bmp280: Add support for bmp280 soft reset

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Message-ID: <20240728164901.1f325aa2@jic23-huawei>
Date: Sun, 28 Jul 2024 16:49:01 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Vasileios Amoiridis <vassilisamir@...il.com>
Cc: lars@...afoo.de, robh@...nel.org, krzk+dt@...nel.org,
 conor+dt@...nel.org, andriy.shevchenko@...ux.intel.com,
 ang.iglesiasg@...il.com, linus.walleij@...aro.org,
 biju.das.jz@...renesas.com, javier.carrasco.cruz@...il.com,
 semen.protsenko@...aro.org, 579lpy@...il.com, ak@...klinger.de,
 linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/7] iio: pressure: bmp280: Add support for bmp280
 soft reset

On Fri, 26 Jul 2024 01:10:34 +0200
Vasileios Amoiridis <vassilisamir@...il.com> wrote:

> The BM(P/E)28x devices have an option for soft reset which is also
> recommended by the Bosch Sensortech BME2 Sensor API to be used before the
> initial configuration of the device.
> 
> Link: https://github.com/boschsensortec/BME280_SensorAPI/blob/bme280_v3.5.1/bme280.c#L429
> Signed-off-by: Vasileios Amoiridis <vassilisamir@...il.com>
Trivial passing comment seeing as you are going do be doing a v3 anyway.

Jonathan

> ---
>  drivers/iio/pressure/bmp280-core.c | 28 ++++++++++++++++++++++++++++
>  drivers/iio/pressure/bmp280.h      |  3 +++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
> index d5e5eb22667a..acbc33aacc09 100644
> --- a/drivers/iio/pressure/bmp280-core.c
> +++ b/drivers/iio/pressure/bmp280-core.c
> @@ -963,6 +963,32 @@ static const unsigned long bme280_avail_scan_masks[] = {
>  	0
>  };
>  
> +static int bmp280_preinit(struct bmp280_data *data)
> +{
> +	unsigned int reg;
> +	int ret;
> +
> +	ret = regmap_write(data->regmap, BMP280_REG_RESET, BMP280_RST_SOFT_CMD);
> +	if (ret) {
> +		dev_err(data->dev, "Failed to reset device.\n");
> +		return ret;
Is this only ever called from probe?

If so, return dev_err_probe() which will save a few lines of code.

> +	}
> +
> +	usleep_range(data->start_up_time, data->start_up_time + 500);
> +
> +	ret = regmap_read(data->regmap, BMP280_REG_STATUS, &reg);
> +	if (ret) {
> +		dev_err(data->dev, "Failed to read status register.\n");
> +		return ret;
> +	}
> +	if (reg & BMP280_REG_STATUS_IM_UPDATE) {
> +		dev_err(data->dev, "Failed to copy NVM contents.\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  static int bmp280_chip_config(struct bmp280_data *data)
>  {
>  	u8 osrs = FIELD_PREP(BMP280_OSRS_TEMP_MASK, data->oversampling_temp + 1) |
> @@ -1079,6 +1105,7 @@ const struct bmp280_chip_info bmp280_chip_info = {
>  	.read_temp = bmp280_read_temp,
>  	.read_press = bmp280_read_press,
>  	.read_calib = bmp280_read_calib,
> +	.preinit = bmp280_preinit,
>  
>  	.trigger_handler = bmp280_trigger_handler,
>  };
> @@ -1196,6 +1223,7 @@ const struct bmp280_chip_info bme280_chip_info = {
>  	.read_press = bmp280_read_press,
>  	.read_humid = bme280_read_humid,
>  	.read_calib = bme280_read_calib,
> +	.preinit = bmp280_preinit,
>  
>  	.trigger_handler = bme280_trigger_handler,
>  };
> diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
> index 9bea0b84d2f4..a9f220c1f77a 100644
> --- a/drivers/iio/pressure/bmp280.h
> +++ b/drivers/iio/pressure/bmp280.h
> @@ -205,6 +205,9 @@
>  #define BMP280_REG_CONFIG		0xF5
>  #define BMP280_REG_CTRL_MEAS		0xF4
>  #define BMP280_REG_STATUS		0xF3
> +#define BMP280_REG_STATUS_IM_UPDATE	BIT(0)
> +#define BMP280_REG_RESET		0xE0
> +#define BMP280_RST_SOFT_CMD		0xB6
>  
>  #define BMP280_REG_COMP_TEMP_START	0x88
>  #define BMP280_COMP_TEMP_REG_COUNT	6