linux-kernel - Re: [PATCH] drivers: iio: pressure: Fixes BMP38x and BMP390 SPI support

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Message-ID: <20240219195145.GA18787@vamoiridPC>
Date: Mon, 19 Feb 2024 20:51:45 +0100
From: Vasileios Amoiridis <vassilisamir@...il.com>
To: Jonathan Cameron <jic23@...nel.org>
Cc: Vasileios Amoiridis <vassilisamir@...il.com>, lars@...afoo.de,
	ang.iglesiasg@...il.com, andriy.shevchenko@...ux.intel.com,
	linus.walleij@...aro.org, semen.protsenko@...aro.org,
	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drivers: iio: pressure: Fixes BMP38x and BMP390 SPI
 support

On Mon, Feb 19, 2024 at 07:42:36PM +0000, Jonathan Cameron wrote:
> On Mon, 19 Feb 2024 20:13:59 +0100
> Vasileios Amoiridis <vassilisamir@...il.com> 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")
> No line break. The fixes tag is part of the main tag block.
> I can fix that whilst applying.
> Otherwise this looks fine to me.
> 
> I'll leave it on list a little longer though as both Linus and Angel
> are still about and might have time to also take a look at this.
>

Thank you very much again for the quick answer. Since you can fix it while applying,
I should not annoy the mailing list with more e-mails. Just for future reference,
when you mean no line break you mean between the main block and the "Fixes" line
or between the "Fixes" line and the "Signed-off-by: ...." ? 
> > 
> > Signed-off-by: Vasileios Amoiridis <vassilisamir@...il.com>
> > ---
> >  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)) {
> 

Best regards,
Vasileios Amoiridis