Re: [PATCH v7 5/5] iio: adc: ad7405: add ad7405 driver

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 10 Jun 2025 12:09:22 +0000
"Ioan-daniel, Pop" <Pop.Ioan-daniel@analog.com> wrote:

> > 
> > Why do we need this .channel element if all instances use the same one?  If you
> > are are shortly going to add support for more devices where this will change
> > then this is ok.  If not, just have one static const channel and use that without
> > looking it up via these chip_info structures.
> >  
> 
> Hi! I'm not aware of any other parts that use different channel types. It's true that all parts use the same .channel.
> Should I submit a new patch version with the requested change?

No need - it's an easy tweak (hopefully).  I fixed up the owner thing Nuno noticed
and applied this diff whilst picking this up.


diff --git a/drivers/iio/adc/ad7405.c b/drivers/iio/adc/ad7405.c
index 487d661f9050..9adf85a732ce 100644
--- a/drivers/iio/adc/ad7405.c
+++ b/drivers/iio/adc/ad7405.c
@@ -25,7 +25,6 @@ static const unsigned int ad7405_dec_rates_range[] = {
 
 struct ad7405_chip_info {
        const char *name;
-       struct iio_chan_spec channel;
        const unsigned int full_scale_mv;
 };
 
@@ -69,7 +68,7 @@ static int ad7405_read_raw(struct iio_dev *indio_dev,
        switch (info) {
        case IIO_CHAN_INFO_SCALE:
                *val = st->info->full_scale_mv;
-               *val2 = st->info->channel.scan_type.realbits - 1;
+               *val2 = indio_dev->channels[0].scan_type.realbits - 1;
                return IIO_VAL_FRACTIONAL_LOG2;
        case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
                *val = st->dec_rate;
@@ -78,7 +77,7 @@ static int ad7405_read_raw(struct iio_dev *indio_dev,
                *val = DIV_ROUND_CLOSEST_ULL(st->ref_frequency, st->dec_rate);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_OFFSET:
-               *val = -(1 << (st->info->channel.scan_type.realbits - 1));
+               *val = -(1 << (indio_dev->channels[0].scan_type.realbits - 1));
                return IIO_VAL_INT;
        default:
                return -EINVAL;
@@ -120,48 +119,44 @@ static const struct iio_info ad7405_iio_info = {
        .read_avail = &ad7405_read_avail,
 };
 
-#define AD7405_IIO_CHANNEL {                                   \
-       .type = IIO_VOLTAGE,                                    \
-       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
-                       BIT(IIO_CHAN_INFO_OFFSET),              \
-       .info_mask_shared_by_all = IIO_CHAN_INFO_SAMP_FREQ |    \
-                       BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),  \
-       .info_mask_shared_by_all_available =                    \
-                       BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),  \
-       .indexed = 1,                                           \
-       .channel = 0,                                           \
-       .channel2 = 1,                                          \
-       .differential = 1,                                      \
-       .scan_index = 0,                                        \
-       .scan_type = {                                          \
-               .sign = 'u',                                    \
-               .realbits = 16,                                 \
-               .storagebits = 16,                              \
-       },                                                      \
-}
+static const struct iio_chan_spec ad7405_channel = {
+       .type = IIO_VOLTAGE,
+       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
+                       BIT(IIO_CHAN_INFO_OFFSET),
+       .info_mask_shared_by_all = IIO_CHAN_INFO_SAMP_FREQ |
+                       BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+       .info_mask_shared_by_all_available =
+                       BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+       .indexed = 1,
+       .channel = 0,
+       .channel2 = 1,
+       .differential = 1,
+       .scan_index = 0,
+       .scan_type = {
+               .sign = 'u',
+               .realbits = 16,
+               .storagebits = 16,
+       },
+};
 
 static const struct ad7405_chip_info ad7405_chip_info = {
        .name = "ad7405",
        .full_scale_mv = 320,
-       .channel = AD7405_IIO_CHANNEL,
 };
 
 static const struct ad7405_chip_info adum7701_chip_info = {
        .name = "adum7701",
        .full_scale_mv = 320,
-       .channel = AD7405_IIO_CHANNEL,
 };
 
 static const struct ad7405_chip_info adum7702_chip_info = {
        .name = "adum7702",
        .full_scale_mv = 64,
-       .channel = AD7405_IIO_CHANNEL,
 };
 
 static const struct ad7405_chip_info adum7703_chip_info = {
        .name = "adum7703",
        .full_scale_mv = 320,
-       .channel = AD7405_IIO_CHANNEL,
 };
 
 static const char * const ad7405_power_supplies[] = {
@@ -200,7 +195,7 @@ static int ad7405_probe(struct platform_device *pdev)
                return -EINVAL;
 
        indio_dev->name = st->info->name;
-       indio_dev->channels = &st->info->channel;
+       indio_dev->channels = &ad7405_channel;
        indio_dev->num_channels = 1;
        indio_dev->info = &ad7405_iio_info;
 
Let me know if I messed it up.  Pushed out as testing for now.

Thanks,

Jonathan