drivers/iio/pressure/bmp280-spi.c | 47 ++++++++++++++++++++++++++++++- drivers/iio/pressure/bmp280.h | 2 ++ 2 files changed, 48 insertions(+), 1 deletion(-)
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.
Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
---
drivers/iio/pressure/bmp280-spi.c | 47 ++++++++++++++++++++++++++++++-
drivers/iio/pressure/bmp280.h | 2 ++
2 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp280-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,
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 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
+ ssize_t status;
+ u8 buf;
+
+ memcpy(&buf, reg, reg_size);
+ buf |= 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 = spi_write_then_read(spi, &buf, 1, ret, val_size + 1);
+ if (status)
+ return status;
+
+ memcpy(val, ret + 1, val_size);
+
+ return 0;
+}
+
static struct regmap_bus bmp280_regmap_bus = {
.write = bmp280_regmap_spi_write,
.read = bmp280_regmap_spi_read,
@@ -42,10 +68,18 @@ 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,
+ .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 +92,19 @@ 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)) {
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 @@
#define BMP380_TEMP_SKIPPED 0x800000
#define BMP380_PRESS_SKIPPED 0x800000
+#define BMP380_SPI_MAX_REG_COUNT_READ 3
+
/* BMP280 specific registers */
#define BMP280_REG_HUMIDITY_LSB 0xFE
#define BMP280_REG_HUMIDITY_MSB 0xFD
--
2.25.1On Thu, 15 Feb 2024 17:43:32 +0100
Vasileios Amoiridis <vassilisamir@gmail.com> 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.
Make it clear in the patch title that this is a fix and add a fixes tag.
>
> Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
> ---
> drivers/iio/pressure/bmp280-spi.c | 47 ++++++++++++++++++++++++++++++-
> drivers/iio/pressure/bmp280.h | 2 ++
> 2 files changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp280-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,
> 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 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
Given you rely on val_size < 3 you should check for that explcitly rather than
potentially overflowing the buffer.
ret is not a good naming choice for this variable as it's commonly used for
integer return values. Call it read_buf or something like that.
> + ssize_t status;
> + u8 buf;
> +
> + memcpy(&buf, reg, reg_size);
> + buf |= 0x80;
Can you use regmap_bus read_flag_mask for this? Seems to apply to
all devices supported. + that's common for spi regmaps
Mind you I note the bmp280_regmap_spi_write() is masking the bit out which seems
backwards - all the registers are defined with the bit set for that part
but not the 380. Ah well - not part of this fix even if it's odd.
> +
> + /*
> + * 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 = spi_write_then_read(spi, &buf, 1, ret, val_size + 1);
> + if (status)
> + return status;
> +
> + memcpy(val, ret + 1, val_size);
> +
> + return 0;
> +}
> +
> static struct regmap_bus bmp280_regmap_bus = {
> .write = bmp280_regmap_spi_write,
> .read = bmp280_regmap_spi_read,
> @@ -42,10 +68,18 @@ 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,
> + .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 +92,19 @@ 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)) {
> 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 @@
> #define BMP380_TEMP_SKIPPED 0x800000
> #define BMP380_PRESS_SKIPPED 0x800000
>
> +#define BMP380_SPI_MAX_REG_COUNT_READ 3
This doesn't seem useful as only used in one place.
> +
> /* BMP280 specific registers */
> #define BMP280_REG_HUMIDITY_LSB 0xFE
> #define BMP280_REG_HUMIDITY_MSB 0xFD
On Fri, Feb 16, 2024 at 11:18:34AM +0000, Jonathan Cameron wrote:
> On Thu, 15 Feb 2024 17:43:32 +0100
> Vasileios Amoiridis <vassilisamir@gmail.com> 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.
>
> Make it clear in the patch title that this is a fix and add a fixes tag.
>
The original support for SPI was added 8 years ago. Should I include that commit
of 8 years ago in the fixes tag or just use a the word "fixes" with the rest of the
title?
> >
> > Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
> > ---
> > drivers/iio/pressure/bmp280-spi.c | 47 ++++++++++++++++++++++++++++++-
> > drivers/iio/pressure/bmp280.h | 2 ++
> > 2 files changed, 48 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp280-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,
> > 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 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
>
> Given you rely on val_size < 3 you should check for that explcitly rather than
> potentially overflowing the buffer.
> ret is not a good naming choice for this variable as it's commonly used for
> integer return values. Call it read_buf or something like that.
>
Thanks for pointing this out it makes a lot of sense.
> > + ssize_t status;
> > + u8 buf;
> > +
> > + memcpy(&buf, reg, reg_size);
> > + buf |= 0x80;
>
> Can you use regmap_bus read_flag_mask for this? Seems to apply to
> all devices supported. + that's common for spi regmaps
>
Yes I noticed it yesterday in my tests that this was missing and it actually
applies to all the devices. So the read_flag_mask should be added to both
regmap_bus structs.
>
> Mind you I note the bmp280_regmap_spi_write() is masking the bit out which seems
> backwards - all the registers are defined with the bit set for that part
> but not the 380. Ah well - not part of this fix even if it's odd.
>
>
> > +
> > + /*
> > + * 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 = spi_write_then_read(spi, &buf, 1, ret, val_size + 1);
> > + if (status)
> > + return status;
> > +
> > + memcpy(val, ret + 1, val_size);
> > +
> > + return 0;
> > +}
> > +
> > static struct regmap_bus bmp280_regmap_bus = {
> > .write = bmp280_regmap_spi_write,
> > .read = bmp280_regmap_spi_read,
> > @@ -42,10 +68,18 @@ 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,
> > + .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 +92,19 @@ 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)) {
> > 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 @@
> > #define BMP380_TEMP_SKIPPED 0x800000
> > #define BMP380_PRESS_SKIPPED 0x800000
> >
> > +#define BMP380_SPI_MAX_REG_COUNT_READ 3
> This doesn't seem useful as only used in one place.
Could this define be moved in the bmp280-spi.c file or to not even use a define?
> > +
> > /* BMP280 specific registers */
> > #define BMP280_REG_HUMIDITY_LSB 0xFE
> > #define BMP280_REG_HUMIDITY_MSB 0xFD
>
On Fri, 16 Feb 2024 14:26:44 +0100 Vasileios Amoiridis <vassilisamir@gmail.com> wrote: > On Fri, Feb 16, 2024 at 11:18:34AM +0000, Jonathan Cameron wrote: > > On Thu, 15 Feb 2024 17:43:32 +0100 > > Vasileios Amoiridis <vassilisamir@gmail.com> 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. > > > > Make it clear in the patch title that this is a fix and add a fixes tag. > > > > The original support for SPI was added 8 years ago. Should I include that commit > of 8 years ago in the fixes tag or just use a the word "fixes" with the rest of the > title? > Original git commit for the fixes tag. Lets us know this wants to go in all stable kernels. Also fixes in the title. > > > + ssize_t status; > > > + u8 buf; > > > + > > > + memcpy(&buf, reg, reg_size); > > > + buf |= 0x80; > > > > Can you use regmap_bus read_flag_mask for this? Seems to apply to > > all devices supported. + that's common for spi regmaps > > > > Yes I noticed it yesterday in my tests that this was missing and it actually > applies to all the devices. So the read_flag_mask should be added to both > regmap_bus structs. It's there sort of indirectly for the bmp280 - the register addresses all happen to include that bit, then it is cleared explicitly for the other direction. > > > > Mind you I note the bmp280_regmap_spi_write() is masking the bit out which seems > > backwards - all the registers are defined with the bit set for that part > > but not the 380. Ah well - not part of this fix even if it's odd. > > > > > 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 @@ > > > #define BMP380_TEMP_SKIPPED 0x800000 > > > #define BMP380_PRESS_SKIPPED 0x800000 > > > > > > +#define BMP380_SPI_MAX_REG_COUNT_READ 3 > > This doesn't seem useful as only used in one place. > > Could this define be moved in the bmp280-spi.c file or to not even use a define? Not use it. Don't see how it is helpful. Just check that the thing will fit in the array using an ARRAY_SIZE()... > > > > + > > > /* BMP280 specific registers */ > > > #define BMP280_REG_HUMIDITY_LSB 0xFE > > > #define BMP280_REG_HUMIDITY_MSB 0xFD > >
On Fri, Feb 16, 2024 at 03:47:42PM +0000, Jonathan Cameron wrote: > On Fri, 16 Feb 2024 14:26:44 +0100 > Vasileios Amoiridis <vassilisamir@gmail.com> wrote: > > > On Fri, Feb 16, 2024 at 11:18:34AM +0000, Jonathan Cameron wrote: > > > On Thu, 15 Feb 2024 17:43:32 +0100 > > > Vasileios Amoiridis <vassilisamir@gmail.com> 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. > > > > > > Make it clear in the patch title that this is a fix and add a fixes tag. > > > > > > > The original support for SPI was added 8 years ago. Should I include that commit > > of 8 years ago in the fixes tag or just use a the word "fixes" with the rest of the > > title? > > > Original git commit for the fixes tag. Lets us know this wants to go in all stable kernels. > Also fixes in the title. Ok, will do that! > > > > > > + ssize_t status; > > > > + u8 buf; > > > > + > > > > + memcpy(&buf, reg, reg_size); > > > > + buf |= 0x80; > > > > > > Can you use regmap_bus read_flag_mask for this? Seems to apply to > > > all devices supported. + that's common for spi regmaps > > > > > > > Yes I noticed it yesterday in my tests that this was missing and it actually > > applies to all the devices. So the read_flag_mask should be added to both > > regmap_bus structs. > > It's there sort of indirectly for the bmp280 - the register addresses all happen > to include that bit, then it is cleared explicitly for the other direction. Oh okay, now I understand what you mean. Ok then I can also send a different patch for this as well just to keep the code consistent. > > > > > > > > > Mind you I note the bmp280_regmap_spi_write() is masking the bit out which seems > > > backwards - all the registers are defined with the bit set for that part > > > but not the 380. Ah well - not part of this fix even if it's odd. > > > > > > > > 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 @@ > > > > #define BMP380_TEMP_SKIPPED 0x800000 > > > > #define BMP380_PRESS_SKIPPED 0x800000 > > > > > > > > +#define BMP380_SPI_MAX_REG_COUNT_READ 3 > > > This doesn't seem useful as only used in one place. > > > > Could this define be moved in the bmp280-spi.c file or to not even use a define? > Not use it. Don't see how it is helpful. Just check that the > thing will fit in the array using an ARRAY_SIZE()... Understood. > > > > > > + > > > > /* BMP280 specific registers */ > > > > #define BMP280_REG_HUMIDITY_LSB 0xFE > > > > #define BMP280_REG_HUMIDITY_MSB 0xFD > > > > Thank you very much for the feedback, I'll work on the patches and submit them again. Best regards, Vasileios Amoiridis
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>
> ---
> drivers/iio/pressure/bmp280-spi.c | 47 ++++++++++++++++++++++++++++++-
> drivers/iio/pressure/bmp280.h | 2 ++
> 2 files changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/pressure/bmp280-spi.c b/drivers/iio/pressure/bmp280-
> 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,
> 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 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
> + ssize_t status;
> + u8 buf;
> +
> + memcpy(&buf, reg, reg_size);
> + buf |= 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 = spi_write_then_read(spi, &buf, 1, ret, val_size + 1);
> + if (status)
> + return status;
> +
> + memcpy(val, ret + 1, val_size);
> +
> + return 0;
> +}
> +
> static struct regmap_bus bmp280_regmap_bus = {
> .write = bmp280_regmap_spi_write,
> .read = bmp280_regmap_spi_read,
> @@ -42,10 +68,18 @@ 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,
> + .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 +92,19 @@ 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)) {
> 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 @@
> #define BMP380_TEMP_SKIPPED 0x800000
> #define BMP380_PRESS_SKIPPED 0x800000
>
> +#define BMP380_SPI_MAX_REG_COUNT_READ 3
> +
> /* BMP280 specific registers */
> #define BMP280_REG_HUMIDITY_LSB 0xFE
> #define BMP280_REG_HUMIDITY_MSB 0xFD
On Thu, Feb 15, 2024 at 05:43:32PM +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.
Thank you for the patch, my comments below.
...
> +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 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
> + ssize_t status;
> + u8 buf;
AFAIU this buffer is not DMA-capable.
> + memcpy(&buf, reg, reg_size);
I prefer to see a switch case with cases based on allowed sizes and proper
endianess accessors.
> + buf |= 0x80;
This is done by regmap, no?
> + /*
> + * 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 = spi_write_then_read(spi, &buf, 1, ret, val_size + 1);
sizeof() ?
> + if (status)
> + return status;
> + memcpy(val, ret + 1, val_size);
As per above.
> + return 0;
> +}
--
With Best Regards,
Andy Shevchenko
On Thu, 15 Feb 2024 19:03:27 +0200
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> On Thu, Feb 15, 2024 at 05:43:32PM +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.
>
> Thank you for the patch, my comments below.
>
> ...
>
> > +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 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
> > + ssize_t status;
> > + u8 buf;
>
> AFAIU this buffer is not DMA-capable.
Doesn't matter in this case as spi_write_then_read() bounces anyway so you don't need
to provide it with a dma safe buffer. It's in the docs, so we can rely
on this not changing.
https://elixir.bootlin.com/linux/latest/source/drivers/spi/spi.c#L4391
On Fri, Feb 16, 2024 at 11:05:43AM +0000, Jonathan Cameron wrote:
> On Thu, 15 Feb 2024 19:03:27 +0200
> Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
>
> > On Thu, Feb 15, 2024 at 05:43:32PM +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.
> >
> > Thank you for the patch, my comments below.
> >
> > ...
> >
> > > +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 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
> > > + ssize_t status;
> > > + u8 buf;
> >
> > AFAIU this buffer is not DMA-capable.
>
> Doesn't matter in this case as spi_write_then_read() bounces anyway so you don't need
> to provide it with a dma safe buffer. It's in the docs, so we can rely
> on this not changing.
>
> https://elixir.bootlin.com/linux/latest/source/drivers/spi/spi.c#L4391
>
Since the read_flag_mask can be used in the struct regmap_bus, there is no need for an
extra u8 buffer to manipulate the bits. Instead, the reg value from the function inputs
can be used as in any other case.
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