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Date:   Sat, 17 Sep 2022 14:16:09 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     Angel Iglesias <ang.iglesiasg@gmail.com>
Cc:     linux-iio <linux-iio@vger.kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Paul Cercueil <paul@crapouillou.net>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 4/9] iio: pressure: bmp280: simplify driver
 initialization logic
Message-ID: <20220917141609.7e5fe374@jic23-huawei>
In-Reply-To: <584c90f309e4f24bf2e4aa2b15c8577d288f978d.1663025017.git.ang.iglesiasg@gmail.com>
References: <cover.1663025017.git.ang.iglesiasg@gmail.com>
        <584c90f309e4f24bf2e4aa2b15c8577d288f978d.1663025017.git.ang.iglesiasg@gmail.com>
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On Tue, 13 Sep 2022 01:47:31 +0200
Angel Iglesias <ang.iglesiasg@gmail.com> wrote:

> Simplified common initialization logic of different sensor types
> unifying calibration and initial configuration recovery.
> 
> Default config param values of each sensor type are stored inside
> chip_info structure and used to initialize sensor data struct instance.
> 
> The helper functions for read each sensor type calibration are converted
> to a callback available on the chip_info struct.
> 
> Separated bme280 specific calibration code from bmp280 function. Dropped
> the additional chip_id argument in bmp280 code as is not longer required.
> Now both bmp280/bme280 calibration function use same signature as bmp180.
> 
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>
Applied
> ---
>  drivers/iio/pressure/bmp280-core.c | 126 +++++++++++++++++++----------
>  1 file changed, 83 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
> index 4793bcd9f0b3..203623d32032 100644
> --- a/drivers/iio/pressure/bmp280-core.c
> +++ b/drivers/iio/pressure/bmp280-core.c
> @@ -109,19 +109,28 @@ struct bmp280_data {
>  };
>  
>  struct bmp280_chip_info {
> +	unsigned int id_reg;
> +
> +	int num_channels;
> +	unsigned int start_up_time;
> +
>  	const int *oversampling_temp_avail;
>  	int num_oversampling_temp_avail;
> +	int oversampling_temp_default;
>  
>  	const int *oversampling_press_avail;
>  	int num_oversampling_press_avail;
> +	int oversampling_press_default;
>  
>  	const int *oversampling_humid_avail;
>  	int num_oversampling_humid_avail;
> +	int oversampling_humid_default;
>  
>  	int (*chip_config)(struct bmp280_data *);
>  	int (*read_temp)(struct bmp280_data *, int *);
>  	int (*read_press)(struct bmp280_data *, int *, int *);
>  	int (*read_humid)(struct bmp280_data *, int *, int *);
> +	int (*read_calib)(struct bmp280_data *);
>  };
>  
>  /*
> @@ -148,15 +157,10 @@ static const struct iio_chan_spec bmp280_channels[] = {
>  	},
>  };
>  
> -static int bmp280_read_calib(struct bmp280_data *data,
> -			     struct bmp280_calib *calib,
> -			     unsigned int chip)
> +static int bmp280_read_calib(struct bmp280_data *data)
>  {
> +	struct bmp280_calib *calib = &data->calib.bmp280;
>  	__le16 c_buf[BMP280_CONTIGUOUS_CALIB_REGS / 2];
> -	struct device *dev = data->dev;
> -	unsigned int tmp;
> -	__le16 l16;
> -	__be16 b16;
>  	int ret;
>  
>  
> @@ -188,6 +192,25 @@ static int bmp280_read_calib(struct bmp280_data *data,
>  	calib->P8 = le16_to_cpu(c_buf[P8]);
>  	calib->P9 = le16_to_cpu(c_buf[P9]);
>  
> +	return 0;
> +}
> +
> +static int bme280_read_calib(struct bmp280_data *data)
> +{
> +	struct bmp280_calib *calib = &data->calib.bmp280;
> +	struct device *dev = data->dev;
> +	unsigned int tmp;
> +	__le16 l16;
> +	__be16 b16;
> +	int ret;
> +
> +	/* Load shared calibration params with bmp280 first */
> +	ret = bmp280_read_calib(data);
> +	if  (ret < 0) {
> +		dev_err(dev, "failed to read common bmp280 calibration parameters\n");
> +		return ret;
> +	}
> +
>  	/*
>  	 * Read humidity calibration values.
>  	 * Due to some odd register addressing we cannot just
> @@ -195,8 +218,6 @@ static int bmp280_read_calib(struct bmp280_data *data,
>  	 * value separately and sometimes do some bit shifting...
>  	 * Humidity data is only available on BME280.
>  	 */
> -	if (chip != BME280_CHIP_ID)
> -		return 0;
>  
>  	ret = regmap_read(data->regmap, BMP280_REG_COMP_H1, &tmp);
>  	if (ret < 0) {
> @@ -631,15 +652,32 @@ static int bmp280_chip_config(struct bmp280_data *data)
>  static const int bmp280_oversampling_avail[] = { 1, 2, 4, 8, 16 };
>  
>  static const struct bmp280_chip_info bmp280_chip_info = {
> +	.id_reg = BMP280_REG_ID,
> +	.start_up_time = 2000,
> +	.num_channels = 2,
> +
>  	.oversampling_temp_avail = bmp280_oversampling_avail,
>  	.num_oversampling_temp_avail = ARRAY_SIZE(bmp280_oversampling_avail),
> +	/*
> +	 * Oversampling config values on BMx280 have one additional setting
> +	 * that other generations of the family don't:
> +	 * The value 0 means the measurement is bypassed instead of
> +	 * oversampling set to x1.
> +	 *
> +	 * To account for this difference, and preserve the same common
> +	 * config logic, this is handled later on chip_config callback
> +	 * incrementing one unit the oversampling setting.
> +	 */
> +	.oversampling_temp_default = BMP280_OSRS_TEMP_2X - 1,
>  
>  	.oversampling_press_avail = bmp280_oversampling_avail,
>  	.num_oversampling_press_avail = ARRAY_SIZE(bmp280_oversampling_avail),
> +	.oversampling_press_default = BMP280_OSRS_PRESS_16X - 1,
>  
>  	.chip_config = bmp280_chip_config,
>  	.read_temp = bmp280_read_temp,
>  	.read_press = bmp280_read_press,
> +	.read_calib = bmp280_read_calib,
>  };
>  
>  static int bme280_chip_config(struct bmp280_data *data)
> @@ -661,19 +699,27 @@ static int bme280_chip_config(struct bmp280_data *data)
>  }
>  
>  static const struct bmp280_chip_info bme280_chip_info = {
> +	.id_reg = BMP280_REG_ID,
> +	.start_up_time = 2000,
> +	.num_channels = 3,
> +
>  	.oversampling_temp_avail = bmp280_oversampling_avail,
>  	.num_oversampling_temp_avail = ARRAY_SIZE(bmp280_oversampling_avail),
> +	.oversampling_temp_default = BMP280_OSRS_TEMP_2X - 1,
>  
>  	.oversampling_press_avail = bmp280_oversampling_avail,
>  	.num_oversampling_press_avail = ARRAY_SIZE(bmp280_oversampling_avail),
> +	.oversampling_press_default = BMP280_OSRS_PRESS_16X - 1,
>  
>  	.oversampling_humid_avail = bmp280_oversampling_avail,
>  	.num_oversampling_humid_avail = ARRAY_SIZE(bmp280_oversampling_avail),
> +	.oversampling_humid_default = BMP280_OSRS_HUMIDITY_16X - 1,
>  
>  	.chip_config = bme280_chip_config,
>  	.read_temp = bmp280_read_temp,
>  	.read_press = bmp280_read_press,
>  	.read_humid = bmp280_read_humid,
> +	.read_calib = bme280_read_calib,
>  };
>  
>  static int bmp180_measure(struct bmp280_data *data, u8 ctrl_meas)
> @@ -741,9 +787,9 @@ static int bmp180_read_adc_temp(struct bmp280_data *data, int *val)
>  	return 0;
>  }
>  
> -static int bmp180_read_calib(struct bmp280_data *data,
> -			     struct bmp180_calib *calib)
> +static int bmp180_read_calib(struct bmp280_data *data)
>  {
> +	struct bmp180_calib *calib = &data->calib.bmp180;
>  	__be16 buf[BMP180_REG_CALIB_COUNT / 2];
>  	int ret;
>  	int i;
> @@ -909,17 +955,24 @@ static const int bmp180_oversampling_temp_avail[] = { 1 };
>  static const int bmp180_oversampling_press_avail[] = { 1, 2, 4, 8 };
>  
>  static const struct bmp280_chip_info bmp180_chip_info = {
> +	.id_reg = BMP280_REG_ID,
> +	.start_up_time = 2000,
> +	.num_channels = 2,
> +
>  	.oversampling_temp_avail = bmp180_oversampling_temp_avail,
>  	.num_oversampling_temp_avail =
>  		ARRAY_SIZE(bmp180_oversampling_temp_avail),
> +	.oversampling_temp_default = 0,
>  
>  	.oversampling_press_avail = bmp180_oversampling_press_avail,
>  	.num_oversampling_press_avail =
>  		ARRAY_SIZE(bmp180_oversampling_press_avail),
> +	.oversampling_press_default = BMP180_MEAS_PRESS_8X,
>  
>  	.chip_config = bmp180_chip_config,
>  	.read_temp = bmp180_read_temp,
>  	.read_press = bmp180_read_press,
> +	.read_calib = bmp180_read_calib,
>  };
>  
>  static irqreturn_t bmp085_eoc_irq(int irq, void *d)
> @@ -986,6 +1039,7 @@ int bmp280_common_probe(struct device *dev,
>  			const char *name,
>  			int irq)
>  {
> +	const struct bmp280_chip_info *chip_info;
>  	struct iio_dev *indio_dev;
>  	struct bmp280_data *data;
>  	struct gpio_desc *gpiod;
> @@ -1007,30 +1061,25 @@ int bmp280_common_probe(struct device *dev,
>  
>  	switch (chip) {
>  	case BMP180_CHIP_ID:
> -		indio_dev->num_channels = 2;
> -		data->chip_info = &bmp180_chip_info;
> -		data->oversampling_press = ilog2(8);
> -		data->oversampling_temp = ilog2(1);
> -		data->start_up_time = 10000;
> +		chip_info = &bmp180_chip_info;
>  		break;
>  	case BMP280_CHIP_ID:
> -		indio_dev->num_channels = 2;
> -		data->chip_info = &bmp280_chip_info;
> -		data->oversampling_press = ilog2(16);
> -		data->oversampling_temp = ilog2(2);
> -		data->start_up_time = 2000;
> +		chip_info = &bmp280_chip_info;
>  		break;
>  	case BME280_CHIP_ID:
> -		indio_dev->num_channels = 3;
> -		data->chip_info = &bme280_chip_info;
> -		data->oversampling_press = ilog2(16);
> -		data->oversampling_humid = ilog2(16);
> -		data->oversampling_temp = ilog2(2);
> -		data->start_up_time = 2000;
> +		chip_info = &bme280_chip_info;
>  		break;
>  	default:
>  		return -EINVAL;
>  	}
> +	data->chip_info = chip_info;
> +
> +	/* Apply initial values from chip info structure */
> +	indio_dev->num_channels = chip_info->num_channels;
> +	data->oversampling_press = chip_info->oversampling_press_default;
> +	data->oversampling_humid = chip_info->oversampling_humid_default;
> +	data->oversampling_temp = chip_info->oversampling_temp_default;
> +	data->start_up_time = chip_info->start_up_time;
>  
>  	/* Bring up regulators */
>  	regulator_bulk_set_supply_names(data->supplies,
> @@ -1067,7 +1116,8 @@ int bmp280_common_probe(struct device *dev,
>  	}
>  
>  	data->regmap = regmap;
> -	ret = regmap_read(regmap, BMP280_REG_ID, &chip_id);
> +
> +	ret = regmap_read(regmap, data->chip_info->id_reg, &chip_id);
>  	if (ret < 0)
>  		return ret;
>  	if (chip_id != chip) {
> @@ -1087,21 +1137,11 @@ int bmp280_common_probe(struct device *dev,
>  	 * non-volatile memory during production". Let's read them out at probe
>  	 * time once. They will not change.
>  	 */
> -	if (chip_id  == BMP180_CHIP_ID) {
> -		ret = bmp180_read_calib(data, &data->calib.bmp180);
> -		if (ret < 0) {
> -			dev_err(data->dev,
> -				"failed to read calibration coefficients\n");
> -			return ret;
> -		}
> -	} else if (chip_id == BMP280_CHIP_ID || chip_id == BME280_CHIP_ID) {
> -		ret = bmp280_read_calib(data, &data->calib.bmp280, chip_id);
> -		if (ret < 0) {
> -			dev_err(data->dev,
> -				"failed to read calibration coefficients\n");
> -			return ret;
> -		}
> -	}
> +
> +	ret = data->chip_info->read_calib(data);
> +	if (ret < 0)
> +		return dev_err_probe(data->dev, ret,
> +				     "failed to read calibration coefficients\n");
>  
>  	/*
>  	 * Attempt to grab an optional EOC IRQ - only the BMP085 has this