This adcxx communicates with a host processor via an SPI/Microwire Bus
interface. The device family responds with 12-bit data, of which the LSB bits
are transmitted by the lower resolution devices as 0. The unavailable bits are
0 in LSB. Shift is calculated per resolution and used in scaling and raw data
read.
Create a separate structure for each device type instead of an array.
These changes help to reuse the driver to support the family of devices with
name ADC<bb><c>S<sss>, where
* bb is the resolution in number of bits (8, 10, 12)
* c is the number of channels (1, 2, 4, 8)
* sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
and 101 for 1 MSPS)
Complete datasheets are available at TI's website here:
https://www.ti.com/lit/ds/symlink/adc<bb><c>s<sss>.pdf
Co-developed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Sukrut Bellary <sbellary@baylibre.com>
---
drivers/iio/adc/ti-adc128s052.c | 115 ++++++++++++++++++--------------
1 file changed, 66 insertions(+), 49 deletions(-)
diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
index 1b46a8155803..2b206745e53d 100644
--- a/drivers/iio/adc/ti-adc128s052.c
+++ b/drivers/iio/adc/ti-adc128s052.c
@@ -41,13 +41,14 @@ struct adc128 {
} __aligned(IIO_DMA_MINALIGN);
};
-static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
+static int adc128_adc_conversion(struct adc128 *adc,
+ struct iio_chan_spec const *channel)
{
int ret;
guard(mutex)(&adc->lock);
- adc->buffer[0] = channel << 3;
+ adc->buffer[0] = channel->channel << 3;
adc->buffer[1] = 0;
ret = spi_write(adc->spi, &adc->buffer, sizeof(adc->buffer));
@@ -58,7 +59,10 @@ static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
if (ret < 0)
return ret;
- return be16_to_cpu(adc->buffer16) & 0xFFF;
+ ret = (be16_to_cpu(adc->buffer16) >> channel->scan_type.shift) &
+ GENMASK(channel->scan_type.realbits - 1, 0);
+
+ return ret;
}
static int adc128_read_raw(struct iio_dev *indio_dev,
@@ -71,7 +75,7 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
switch (mask) {
case IIO_CHAN_INFO_RAW:
- ret = adc128_adc_conversion(adc, channel->channel);
+ ret = adc128_adc_conversion(adc, channel);
if (ret < 0)
return ret;
@@ -81,7 +85,7 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
case IIO_CHAN_INFO_SCALE:
*val = adc->vref_mv;
- *val2 = 12;
+ *val2 = channel->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
default:
@@ -90,15 +94,24 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
}
-#define ADC128_VOLTAGE_CHANNEL(num) \
- { \
- .type = IIO_VOLTAGE, \
- .indexed = 1, \
- .channel = (num), \
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
- .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
+#define _ADC128_VOLTAGE_CHANNEL(num, real_bits) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = (num), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_index = (num), \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = (real_bits), \
+ .storagebits = 16, \
+ .shift = (12 - real_bits), \
+ }, \
}
+#define ADC128_VOLTAGE_CHANNEL(num) _ADC128_VOLTAGE_CHANNEL(num, 12)
+
static const struct iio_chan_spec adc128s052_channels[] = {
ADC128_VOLTAGE_CHANNEL(0),
ADC128_VOLTAGE_CHANNEL(1),
@@ -124,26 +137,30 @@ static const struct iio_chan_spec adc124s021_channels[] = {
static const char * const bd79104_regulators[] = { "iovdd" };
-static const struct adc128_configuration adc128_config[] = {
- {
- .channels = adc128s052_channels,
- .num_channels = ARRAY_SIZE(adc128s052_channels),
- .refname = "vref",
- }, {
- .channels = adc122s021_channels,
- .num_channels = ARRAY_SIZE(adc122s021_channels),
- .refname = "vref",
- }, {
- .channels = adc124s021_channels,
- .num_channels = ARRAY_SIZE(adc124s021_channels),
- .refname = "vref",
- }, {
- .channels = adc128s052_channels,
- .num_channels = ARRAY_SIZE(adc128s052_channels),
- .refname = "vdd",
- .other_regulators = &bd79104_regulators,
- .num_other_regulators = 1,
- },
+static const struct adc128_configuration adc122s021_config = {
+ .channels = adc122s021_channels,
+ .num_channels = ARRAY_SIZE(adc122s021_channels),
+ .refname = "vref",
+};
+
+static const struct adc128_configuration adc124s021_config = {
+ .channels = adc124s021_channels,
+ .num_channels = ARRAY_SIZE(adc124s021_channels),
+ .refname = "vref",
+};
+
+static const struct adc128_configuration adc128s052_config = {
+ .channels = adc128s052_channels,
+ .num_channels = ARRAY_SIZE(adc128s052_channels),
+ .refname = "vref",
+};
+
+static const struct adc128_configuration bd79104_config = {
+ .channels = adc128s052_channels,
+ .num_channels = ARRAY_SIZE(adc128s052_channels),
+ .refname = "vdd",
+ .other_regulators = &bd79104_regulators,
+ .num_other_regulators = 1,
};
static const struct iio_info adc128_info = {
@@ -199,33 +216,33 @@ static int adc128_probe(struct spi_device *spi)
}
static const struct of_device_id adc128_of_match[] = {
- { .compatible = "ti,adc128s052", .data = &adc128_config[0] },
- { .compatible = "ti,adc122s021", .data = &adc128_config[1] },
- { .compatible = "ti,adc122s051", .data = &adc128_config[1] },
- { .compatible = "ti,adc122s101", .data = &adc128_config[1] },
- { .compatible = "ti,adc124s021", .data = &adc128_config[2] },
- { .compatible = "ti,adc124s051", .data = &adc128_config[2] },
- { .compatible = "ti,adc124s101", .data = &adc128_config[2] },
- { .compatible = "rohm,bd79104", .data = &adc128_config[3] },
+ { .compatible = "ti,adc128s052", .data = &adc128s052_config },
+ { .compatible = "ti,adc122s021", .data = &adc122s021_config },
+ { .compatible = "ti,adc122s051", .data = &adc122s021_config },
+ { .compatible = "ti,adc122s101", .data = &adc122s021_config },
+ { .compatible = "ti,adc124s021", .data = &adc124s021_config },
+ { .compatible = "ti,adc124s051", .data = &adc124s021_config },
+ { .compatible = "ti,adc124s101", .data = &adc124s021_config },
+ { .compatible = "rohm,bd79104", .data = &bd79104_config },
{ }
};
MODULE_DEVICE_TABLE(of, adc128_of_match);
static const struct spi_device_id adc128_id[] = {
- { "adc128s052", (kernel_ulong_t)&adc128_config[0] },
- { "adc122s021", (kernel_ulong_t)&adc128_config[1] },
- { "adc122s051", (kernel_ulong_t)&adc128_config[1] },
- { "adc122s101", (kernel_ulong_t)&adc128_config[1] },
- { "adc124s021", (kernel_ulong_t)&adc128_config[2] },
- { "adc124s051", (kernel_ulong_t)&adc128_config[2] },
- { "adc124s101", (kernel_ulong_t)&adc128_config[2] },
- { "bd79104", (kernel_ulong_t)&adc128_config[3] },
+ { "adc128s052", (kernel_ulong_t)&adc128s052_config },
+ { "adc122s021", (kernel_ulong_t)&adc122s021_config },
+ { "adc122s051", (kernel_ulong_t)&adc122s021_config },
+ { "adc122s101", (kernel_ulong_t)&adc122s021_config },
+ { "adc124s021", (kernel_ulong_t)&adc124s021_config },
+ { "adc124s051", (kernel_ulong_t)&adc124s021_config },
+ { "adc124s101", (kernel_ulong_t)&adc124s021_config },
+ { "bd79104", (kernel_ulong_t)&bd79104_config },
{ }
};
MODULE_DEVICE_TABLE(spi, adc128_id);
static const struct acpi_device_id adc128_acpi_match[] = {
- { "AANT1280", (kernel_ulong_t)&adc128_config[2] },
+ { "AANT1280", (kernel_ulong_t)&adc124s021_config },
{ }
};
MODULE_DEVICE_TABLE(acpi, adc128_acpi_match);
--
2.34.1On Sat, 14 Jun 2025 02:15:01 -0700
Sukrut Bellary <sbellary@baylibre.com> wrote:
> This adcxx communicates with a host processor via an SPI/Microwire Bus
> interface. The device family responds with 12-bit data, of which the LSB bits
> are transmitted by the lower resolution devices as 0. The unavailable bits are
> 0 in LSB. Shift is calculated per resolution and used in scaling and raw data
> read.
>
> Create a separate structure for each device type instead of an array.
> These changes help to reuse the driver to support the family of devices with
> name ADC<bb><c>S<sss>, where
> * bb is the resolution in number of bits (8, 10, 12)
> * c is the number of channels (1, 2, 4, 8)
> * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
> and 101 for 1 MSPS)
>
> Complete datasheets are available at TI's website here:
> https://www.ti.com/lit/ds/symlink/adc<bb><c>s<sss>.pdf
>
> Co-developed-by: Nishanth Menon <nm@ti.com>
> Signed-off-by: Nishanth Menon <nm@ti.com>
> Signed-off-by: Sukrut Bellary <sbellary@baylibre.com>
> ---
> drivers/iio/adc/ti-adc128s052.c | 115 ++++++++++++++++++--------------
> 1 file changed, 66 insertions(+), 49 deletions(-)
>
> diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
> index 1b46a8155803..2b206745e53d 100644
> --- a/drivers/iio/adc/ti-adc128s052.c
> +++ b/drivers/iio/adc/ti-adc128s052.c
> @@ -41,13 +41,14 @@ struct adc128 {
> } __aligned(IIO_DMA_MINALIGN);
> };
>
> -static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
> +static int adc128_adc_conversion(struct adc128 *adc,
> + struct iio_chan_spec const *channel)
> {
> int ret;
>
> guard(mutex)(&adc->lock);
>
> - adc->buffer[0] = channel << 3;
> + adc->buffer[0] = channel->channel << 3;
> adc->buffer[1] = 0;
>
> ret = spi_write(adc->spi, &adc->buffer, sizeof(adc->buffer));
> @@ -58,7 +59,10 @@ static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
> if (ret < 0)
> return ret;
>
> - return be16_to_cpu(adc->buffer16) & 0xFFF;
> + ret = (be16_to_cpu(adc->buffer16) >> channel->scan_type.shift) &
> + GENMASK(channel->scan_type.realbits - 1, 0);
> +
Even though it is a bit long I'd go with
return (be16_to_cpu(adc->buffer16) >> channel->scan_type.shift) &
GENMASK();
> + return ret;
> }
>
> static int adc128_read_raw(struct iio_dev *indio_dev,
> @@ -71,7 +75,7 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
>
> - ret = adc128_adc_conversion(adc, channel->channel);
> + ret = adc128_adc_conversion(adc, channel);
> if (ret < 0)
> return ret;
>
> @@ -81,7 +85,7 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
> case IIO_CHAN_INFO_SCALE:
>
> *val = adc->vref_mv;
> - *val2 = 12;
> + *val2 = channel->scan_type.realbits;
> return IIO_VAL_FRACTIONAL_LOG2;
>
> default:
> @@ -90,15 +94,24 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
>
> }
>
> -#define ADC128_VOLTAGE_CHANNEL(num) \
> - { \
> - .type = IIO_VOLTAGE, \
> - .indexed = 1, \
> - .channel = (num), \
> - .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
> +#define _ADC128_VOLTAGE_CHANNEL(num, real_bits) \
> + { \
I would minimise the churn and stick to existing style of one space then \
I don't think we have any specific style guidance around this.
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .channel = (num), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> + .scan_index = (num), \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = (real_bits), \
> + .storagebits = 16, \
> + .shift = (12 - real_bits), \
> + }, \
> }
>
> +#define ADC128_VOLTAGE_CHANNEL(num) _ADC128_VOLTAGE_CHANNEL(num, 12)
I wonder if it would be clearer to just have the 12 explicit in each entry
and skip this two levels of macro thing?
> +
> static const struct iio_chan_spec adc128s052_channels[] = {
> ADC128_VOLTAGE_CHANNEL(0),
> ADC128_VOLTAGE_CHANNEL(1),
> @@ -124,26 +137,30 @@ static const struct iio_chan_spec adc124s021_channels[] = {
>
> static const char * const bd79104_regulators[] = { "iovdd" };
>
> -static const struct adc128_configuration adc128_config[] = {
> - {
> - .channels = adc128s052_channels,
> - .num_channels = ARRAY_SIZE(adc128s052_channels),
> - .refname = "vref",
> - }, {
> - .channels = adc122s021_channels,
> - .num_channels = ARRAY_SIZE(adc122s021_channels),
> - .refname = "vref",
> - }, {
> - .channels = adc124s021_channels,
> - .num_channels = ARRAY_SIZE(adc124s021_channels),
> - .refname = "vref",
> - }, {
> - .channels = adc128s052_channels,
> - .num_channels = ARRAY_SIZE(adc128s052_channels),
> - .refname = "vdd",
> - .other_regulators = &bd79104_regulators,
> - .num_other_regulators = 1,
> - },
> +static const struct adc128_configuration adc122s021_config = {
> + .channels = adc122s021_channels,
> + .num_channels = ARRAY_SIZE(adc122s021_channels),
> + .refname = "vref",
> +};
Ideal would be to have this as a precursor patch rather than adding complexity
to this one which is focused on the bits related stuff.
It's a good change to have but does make it harder to spot the main
content in here.
> +
> +static const struct adc128_configuration adc124s021_config = {
> + .channels = adc124s021_channels,
> + .num_channels = ARRAY_SIZE(adc124s021_channels),
> + .refname = "vref",
> +};
On Sat, Jun 14, 2025 at 02:27:43PM +0100, Jonathan Cameron wrote:
> On Sat, 14 Jun 2025 02:15:01 -0700
> Sukrut Bellary <sbellary@baylibre.com> wrote:
>
> > This adcxx communicates with a host processor via an SPI/Microwire Bus
> > interface. The device family responds with 12-bit data, of which the LSB bits
> > are transmitted by the lower resolution devices as 0. The unavailable bits are
> > 0 in LSB. Shift is calculated per resolution and used in scaling and raw data
> > read.
> >
> > Create a separate structure for each device type instead of an array.
> > These changes help to reuse the driver to support the family of devices with
> > name ADC<bb><c>S<sss>, where
> > * bb is the resolution in number of bits (8, 10, 12)
> > * c is the number of channels (1, 2, 4, 8)
> > * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
> > and 101 for 1 MSPS)
> >
> > Complete datasheets are available at TI's website here:
> > https://www.ti.com/lit/ds/symlink/adc<bb><c>s<sss>.pdf
> >
> > Co-developed-by: Nishanth Menon <nm@ti.com>
> > Signed-off-by: Nishanth Menon <nm@ti.com>
> > Signed-off-by: Sukrut Bellary <sbellary@baylibre.com>
> > ---
> > drivers/iio/adc/ti-adc128s052.c | 115 ++++++++++++++++++--------------
> > 1 file changed, 66 insertions(+), 49 deletions(-)
> >
> > diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
> > index 1b46a8155803..2b206745e53d 100644
> > --- a/drivers/iio/adc/ti-adc128s052.c
> > +++ b/drivers/iio/adc/ti-adc128s052.c
> > @@ -41,13 +41,14 @@ struct adc128 {
> > } __aligned(IIO_DMA_MINALIGN);
> > };
> >
> > -static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
> > +static int adc128_adc_conversion(struct adc128 *adc,
> > + struct iio_chan_spec const *channel)
> > {
> > int ret;
> >
> > guard(mutex)(&adc->lock);
> >
> > - adc->buffer[0] = channel << 3;
> > + adc->buffer[0] = channel->channel << 3;
> > adc->buffer[1] = 0;
> >
> > ret = spi_write(adc->spi, &adc->buffer, sizeof(adc->buffer));
> > @@ -58,7 +59,10 @@ static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
> > if (ret < 0)
> > return ret;
> >
> > - return be16_to_cpu(adc->buffer16) & 0xFFF;
> > + ret = (be16_to_cpu(adc->buffer16) >> channel->scan_type.shift) &
> > + GENMASK(channel->scan_type.realbits - 1, 0);
> > +
> Even though it is a bit long I'd go with
>
> return (be16_to_cpu(adc->buffer16) >> channel->scan_type.shift) &
> GENMASK();
>
Thanks for the review.
I will fix this in v5.
> > + return ret;
> > }
> >
> > static int adc128_read_raw(struct iio_dev *indio_dev,
> > @@ -71,7 +75,7 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
> > switch (mask) {
> > case IIO_CHAN_INFO_RAW:
> >
> > - ret = adc128_adc_conversion(adc, channel->channel);
> > + ret = adc128_adc_conversion(adc, channel);
> > if (ret < 0)
> > return ret;
> >
> > @@ -81,7 +85,7 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
> > case IIO_CHAN_INFO_SCALE:
> >
> > *val = adc->vref_mv;
> > - *val2 = 12;
> > + *val2 = channel->scan_type.realbits;
> > return IIO_VAL_FRACTIONAL_LOG2;
> >
> > default:
> > @@ -90,15 +94,24 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
> >
> > }
> >
> > -#define ADC128_VOLTAGE_CHANNEL(num) \
> > - { \
> > - .type = IIO_VOLTAGE, \
> > - .indexed = 1, \
> > - .channel = (num), \
> > - .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> > - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
> > +#define _ADC128_VOLTAGE_CHANNEL(num, real_bits) \
> > + { \
>
> I would minimise the churn and stick to existing style of one space then \
> I don't think we have any specific style guidance around this.
>
I will fix this in v5.
> > + .type = IIO_VOLTAGE, \
> > + .indexed = 1, \
> > + .channel = (num), \
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> > + .scan_index = (num), \
> > + .scan_type = { \
> > + .sign = 'u', \
> > + .realbits = (real_bits), \
> > + .storagebits = 16, \
> > + .shift = (12 - real_bits), \
> > + }, \
> > }
> >
> > +#define ADC128_VOLTAGE_CHANNEL(num) _ADC128_VOLTAGE_CHANNEL(num, 12)
>
> I wonder if it would be clearer to just have the 12 explicit in each entry
> and skip this two levels of macro thing?
>
Do you mean to pass realbits to
ADC128_VOLTAGE_CHANNEL/_ADC128_VOLTAGE_CHANNEL as e.g.,
static const struct iio_chan_spec adc122s021_channels[] = {
ADC128_VOLTAGE_CHANNEL(0, 12),
ADC128_VOLTAGE_CHANNEL(1, 12),
};
I think we added 2nd level macros as ADC082_VOLTAGE_CHANNEL,
ADC102_VOLTAGE_CHANNEL, etc., to have a visual distinction for a different
part nos.
But I am ok if you prefer ADC128_VOLTAGE_CHANNEL with a second parameter
as real_bits.
> > +
> > static const struct iio_chan_spec adc128s052_channels[] = {
> > ADC128_VOLTAGE_CHANNEL(0),
> > ADC128_VOLTAGE_CHANNEL(1),
> > @@ -124,26 +137,30 @@ static const struct iio_chan_spec adc124s021_channels[] = {
> >
> > static const char * const bd79104_regulators[] = { "iovdd" };
> >
> > -static const struct adc128_configuration adc128_config[] = {
> > - {
> > - .channels = adc128s052_channels,
> > - .num_channels = ARRAY_SIZE(adc128s052_channels),
> > - .refname = "vref",
> > - }, {
> > - .channels = adc122s021_channels,
> > - .num_channels = ARRAY_SIZE(adc122s021_channels),
> > - .refname = "vref",
> > - }, {
> > - .channels = adc124s021_channels,
> > - .num_channels = ARRAY_SIZE(adc124s021_channels),
> > - .refname = "vref",
> > - }, {
> > - .channels = adc128s052_channels,
> > - .num_channels = ARRAY_SIZE(adc128s052_channels),
> > - .refname = "vdd",
> > - .other_regulators = &bd79104_regulators,
> > - .num_other_regulators = 1,
> > - },
> > +static const struct adc128_configuration adc122s021_config = {
> > + .channels = adc122s021_channels,
> > + .num_channels = ARRAY_SIZE(adc122s021_channels),
> > + .refname = "vref",
> > +};
>
> Ideal would be to have this as a precursor patch rather than adding complexity
> to this one which is focused on the bits related stuff.
>
> It's a good change to have but does make it harder to spot the main
> content in here.
>
>
I will split this in v5.
> > +
> > +static const struct adc128_configuration adc124s021_config = {
> > + .channels = adc124s021_channels,
> > + .num_channels = ARRAY_SIZE(adc124s021_channels),
> > + .refname = "vref",
> > +};
>
On Sat, 28 Jun 2025 13:01:53 -0700
> > > + .type = IIO_VOLTAGE, \
> > > + .indexed = 1, \
> > > + .channel = (num), \
> > > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> > > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> > > + .scan_index = (num), \
> > > + .scan_type = { \
> > > + .sign = 'u', \
> > > + .realbits = (real_bits), \
> > > + .storagebits = 16, \
> > > + .shift = (12 - real_bits), \
> > > + }, \
> > > }
> > >
> > > +#define ADC128_VOLTAGE_CHANNEL(num) _ADC128_VOLTAGE_CHANNEL(num, 12)
> >
> > I wonder if it would be clearer to just have the 12 explicit in each entry
> > and skip this two levels of macro thing?
> >
> Do you mean to pass realbits to
> ADC128_VOLTAGE_CHANNEL/_ADC128_VOLTAGE_CHANNEL as e.g.,
>
> static const struct iio_chan_spec adc122s021_channels[] = {
> ADC128_VOLTAGE_CHANNEL(0, 12),
> ADC128_VOLTAGE_CHANNEL(1, 12),
> };
>
> I think we added 2nd level macros as ADC082_VOLTAGE_CHANNEL,
> ADC102_VOLTAGE_CHANNEL, etc., to have a visual distinction for a different
> part nos.
I think as we can have lots of parts with each resolution that will
end up confusing.
> But I am ok if you prefer ADC128_VOLTAGE_CHANNEL with a second parameter
> as real_bits.
I think that's going to be easier to follow.
Jonathan
On Sun, Jun 29, 2025 at 05:26:55PM +0100, Jonathan Cameron wrote:
> On Sat, 28 Jun 2025 13:01:53 -0700
>
> > > > + .type = IIO_VOLTAGE, \
> > > > + .indexed = 1, \
> > > > + .channel = (num), \
> > > > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> > > > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> > > > + .scan_index = (num), \
> > > > + .scan_type = { \
> > > > + .sign = 'u', \
> > > > + .realbits = (real_bits), \
> > > > + .storagebits = 16, \
> > > > + .shift = (12 - real_bits), \
> > > > + }, \
> > > > }
> > > >
> > > > +#define ADC128_VOLTAGE_CHANNEL(num) _ADC128_VOLTAGE_CHANNEL(num, 12)
> > >
> > > I wonder if it would be clearer to just have the 12 explicit in each entry
> > > and skip this two levels of macro thing?
> > >
> > Do you mean to pass realbits to
> > ADC128_VOLTAGE_CHANNEL/_ADC128_VOLTAGE_CHANNEL as e.g.,
> >
> > static const struct iio_chan_spec adc122s021_channels[] = {
> > ADC128_VOLTAGE_CHANNEL(0, 12),
> > ADC128_VOLTAGE_CHANNEL(1, 12),
> > };
> >
> > I think we added 2nd level macros as ADC082_VOLTAGE_CHANNEL,
> > ADC102_VOLTAGE_CHANNEL, etc., to have a visual distinction for a different
> > part nos.
>
> I think as we can have lots of parts with each resolution that will
> end up confusing.
>
> > But I am ok if you prefer ADC128_VOLTAGE_CHANNEL with a second parameter
> > as real_bits.
>
> I think that's going to be easier to follow.
>
Ok, I will change it in v5.
> Jonathan
>
© 2016 - 2026 Red Hat, Inc.