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Message-ID: <795736e9c25b836c5939d9117a3a2580ed4e22f8.camel@gmail.com>
Subject: Re: [PATCH] drivers: iio: pressure: Add SPI support for BMP38x and
 BMP390
From: Angel Iglesias <ang.iglesiasg@gmail.com>
To: Vasileios Amoiridis <vassilisamir@gmail.com>, jic23@kernel.org
Cc: lars@metafoo.de, andriy.shevchenko@linux.intel.com, 579lpy@gmail.com, 
	linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Date: Thu, 15 Feb 2024 18:20:00 +0100
In-Reply-To: <20240215164332.506736-1-vassilisamir@gmail.com>
References: <20240215164332.506736-1-vassilisamir@gmail.com>
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On Thu, 2024-02-15 at 17:43 +0100, Vasileios Amoiridis wrote:
> According to the datasheet of BMP38x and BMP390 devices, in SPI
> operation, the first byte that returns after a read operation is
> garbage and it needs to be dropped and return the rest of the
> bytes.

Hey good catch! It flew past me when I added this devices because I tested =
only
on i2c at the time.

Kind regards,
Angel

> Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
> ---
> =C2=A0drivers/iio/pressure/bmp280-spi.c | 47 ++++++++++++++++++++++++++++=
++-
> =C2=A0drivers/iio/pressure/bmp280.h=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0 2 ++
> =C2=A02 files changed, 48 insertions(+), 1 deletion(-)
>=20
> diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp=
280-
> spi.c
> index 433d6fac83c4..c4b4a5d67f94 100644
> --- a/drivers/iio/pressure/bmp280-spi.c
> +++ b/drivers/iio/pressure/bmp280-spi.c
> @@ -35,6 +35,32 @@ static int bmp280_regmap_spi_read(void *context, const=
 void
> *reg,
> =C2=A0	return spi_write_then_read(spi, reg, reg_size, val, val_size);
> =C2=A0}
> =C2=A0
> +static int bmp380_regmap_spi_read(void *context, const void *reg,
> +				=C2=A0 size_t reg_size, void *val, size_t
> val_size)
> +{
> +	struct spi_device *spi =3D to_spi_device(context);
> +	u8 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
> +	ssize_t status;
> +	u8 buf;
> +
> +	memcpy(&buf, reg, reg_size);
> +	buf |=3D 0x80;
> +
> +	/*
> +	 * According to the BMP380, BMP388, BMP390 datasheets, for a basic
> +	 * read operation, after the write is done, 2 bytes are received and
> +	 * the first one has to be dropped. The 2nd one is the requested
> +	 * value.
> +	 */
> +	status =3D spi_write_then_read(spi, &buf, 1, ret, val_size + 1);
> +	if (status)
> +		return status;
> +
> +	memcpy(val, ret + 1, val_size);
> +
> +	return 0;
> +}
> +
> =C2=A0static struct regmap_bus bmp280_regmap_bus =3D {
> =C2=A0	.write =3D bmp280_regmap_spi_write,
> =C2=A0	.read =3D bmp280_regmap_spi_read,
> @@ -42,10 +68,18 @@ static struct regmap_bus bmp280_regmap_bus =3D {
> =C2=A0	.val_format_endian_default =3D REGMAP_ENDIAN_BIG,
> =C2=A0};
> =C2=A0
> +static struct regmap_bus bmp380_regmap_bus =3D {
> +	.write =3D bmp280_regmap_spi_write,
> +	.read =3D bmp380_regmap_spi_read,
> +	.reg_format_endian_default =3D REGMAP_ENDIAN_BIG,
> +	.val_format_endian_default =3D REGMAP_ENDIAN_BIG,
> +};
> +
> =C2=A0static int bmp280_spi_probe(struct spi_device *spi)
> =C2=A0{
> =C2=A0	const struct spi_device_id *id =3D spi_get_device_id(spi);
> =C2=A0	const struct bmp280_chip_info *chip_info;
> +	struct regmap_bus *bmp_regmap_bus;
> =C2=A0	struct regmap *regmap;
> =C2=A0	int ret;
> =C2=A0
> @@ -58,8 +92,19 @@ static int bmp280_spi_probe(struct spi_device *spi)
> =C2=A0
> =C2=A0	chip_info =3D spi_get_device_match_data(spi);
> =C2=A0
> +	switch (chip_info->chip_id[0]) {
> +	case BMP380_CHIP_ID:
> +	case BMP390_CHIP_ID:
> +		bmp_regmap_bus =3D &bmp380_regmap_bus;
> +		break;
> +	default:
> +		bmp_regmap_bus =3D &bmp280_regmap_bus;
> +		break;
> +	}
> +
> +
> =C2=A0	regmap =3D devm_regmap_init(&spi->dev,
> -				=C2=A0 &bmp280_regmap_bus,
> +				=C2=A0 bmp_regmap_bus,
> =C2=A0				=C2=A0 &spi->dev,
> =C2=A0				=C2=A0 chip_info->regmap_config);
> =C2=A0	if (IS_ERR(regmap)) {
> diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.=
h
> index 4012387d7956..ca482b7e4295 100644
> --- a/drivers/iio/pressure/bmp280.h
> +++ b/drivers/iio/pressure/bmp280.h
> @@ -191,6 +191,8 @@
> =C2=A0#define BMP380_TEMP_SKIPPED		0x800000
> =C2=A0#define BMP380_PRESS_SKIPPED		0x800000
> =C2=A0
> +#define BMP380_SPI_MAX_REG_COUNT_READ=C2=A0=C2=A0 3
> +
> =C2=A0/* BMP280 specific registers */
> =C2=A0#define BMP280_REG_HUMIDITY_LSB		0xFE
> =C2=A0#define BMP280_REG_HUMIDITY_MSB		0xFD