On Mon, 19 Feb 2024 20:13:59 +0100
Vasileios Amoiridis <vassilisamir@xxxxxxxxx> wrote:
> According to the datasheet of BMP38x and BMP390 devices, for an SPI
> read operation the first byte that is returned needs to be dropped,
> and the rest of the bytes are the actual data returned from the
> sensor.
>
> Fixes: 8d329309184d ("iio: pressure: bmp280: Add support for BMP380 sensor family")
>
> Signed-off-by: Vasileios Amoiridis <vassilisamir@xxxxxxxxx>
Applied and marked for stable - with tweaks to header order and the space above
as per discussion.
> ---
> drivers/iio/pressure/bmp280-spi.c | 49 ++++++++++++++++++++++++++++++-
> 1 file changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp280-spi.c
> index e8a5fed07e88..1972014dca93 100644
> --- a/drivers/iio/pressure/bmp280-spi.c
> +++ b/drivers/iio/pressure/bmp280-spi.c
> @@ -8,6 +8,7 @@
> #include <linux/spi/spi.h>
> #include <linux/err.h>
> #include <linux/regmap.h>
> +#include <linux/bits.h>
>
> #include "bmp280.h"
>
> @@ -35,6 +36,33 @@ static int bmp280_regmap_spi_read(void *context, const void *reg,
> return spi_write_then_read(spi, reg, reg_size, val, val_size);
> }
>
> +static int bmp380_regmap_spi_read(void *context, const void *reg,
> + size_t reg_size, void *val, size_t val_size)
> +{
> + struct spi_device *spi = to_spi_device(context);
> + u8 rx_buf[4];
> + ssize_t status;
> +
> + /*
> + * Maximum number of consecutive bytes read for a temperature or
> + * pressure measurement is 3.
> + */
> + if (val_size > 3)
> + return -EINVAL;
> + /*
> + * According to the BMP3xx datasheets, for a basic SPI read opertion,
> + * the first byte needs to be dropped and the rest are the requested
> + * data.
> + */
> + status = spi_write_then_read(spi, reg, 1, rx_buf, val_size + 1);
> + if (status)
> + return status;
> +
> + memcpy(val, rx_buf + 1, val_size);
> +
> + return 0;
> +}
> +
> static struct regmap_bus bmp280_regmap_bus = {
> .write = bmp280_regmap_spi_write,
> .read = bmp280_regmap_spi_read,
> @@ -42,10 +70,19 @@ static struct regmap_bus bmp280_regmap_bus = {
> .val_format_endian_default = REGMAP_ENDIAN_BIG,
> };
>
> +static struct regmap_bus bmp380_regmap_bus = {
> + .write = bmp280_regmap_spi_write,
> + .read = bmp380_regmap_spi_read,
> + .read_flag_mask = BIT(7),
> + .reg_format_endian_default = REGMAP_ENDIAN_BIG,
> + .val_format_endian_default = REGMAP_ENDIAN_BIG,
> +};
> +
> static int bmp280_spi_probe(struct spi_device *spi)
> {
> const struct spi_device_id *id = spi_get_device_id(spi);
> const struct bmp280_chip_info *chip_info;
> + struct regmap_bus *bmp_regmap_bus;
> struct regmap *regmap;
> int ret;
>
> @@ -58,8 +95,18 @@ static int bmp280_spi_probe(struct spi_device *spi)
>
> chip_info = spi_get_device_match_data(spi);
>
> + switch (chip_info->chip_id[0]) {
> + case BMP380_CHIP_ID:
> + case BMP390_CHIP_ID:
> + bmp_regmap_bus = &bmp380_regmap_bus;
> + break;
> + default:
> + bmp_regmap_bus = &bmp280_regmap_bus;
> + break;
> + }
> +
> regmap = devm_regmap_init(&spi->dev,
> - &bmp280_regmap_bus,
> + bmp_regmap_bus,
> &spi->dev,
> chip_info->regmap_config);
> if (IS_ERR(regmap)) {
