On Wed, 8 Sep 2021 17:54:49 +0200
Olivier Moysan <olivier.moysan at foss.st.com> wrote:
> Add support of generic IIO channel binding:
> ./devicetree/bindings/iio/adc/adc.yaml
> Keep support of st,adc-channels and st,adc-diff-channels
> for backward compatibility.
>
> Signed-off-by: Olivier Moysan <olivier.moysan at foss.st.com>
Hi Olivier,
A few minor things inline.
Thanks,
Jonathan
> ---
> drivers/iio/adc/stm32-adc.c | 99 +++++++++++++++++++++++++++++++++----
> 1 file changed, 90 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 2f137d14f141..ae4a314854f7 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -35,7 +35,7 @@
> #define STM32H7_BOOST_CLKRATE 20000000UL
>
> #define STM32_ADC_CH_MAX 20 /* max number of channels */
> -#define STM32_ADC_CH_SZ 10 /* max channel name size */
> +#define STM32_ADC_CH_SZ 16 /* max channel name size */
> #define STM32_ADC_MAX_SQ 16 /* SQ1..SQ16 */
> #define STM32_ADC_MAX_SMP 7 /* SMPx range is [0..7] */
> #define STM32_ADC_TIMEOUT_US 100000
> @@ -1732,6 +1732,11 @@ static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm
> num_channels += ret;
> }
>
> + if (!num_channels) {
> + dev_err(indio_dev->dev.parent, "No channel found\n");
> + return -ENODATA;
I'd return 0 and handle this at the caller. Both because it makes this
patch more readable and because a count of 0 isn't an error of the function
reading how many they are, but rather at a higher level.
> + }
> +
> return num_channels;
> }
>
> @@ -1792,6 +1797,73 @@ static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
> return scan_index;
> }
>
> +static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
> + struct stm32_adc *adc,
> + struct iio_chan_spec *channels)
> +{
> + struct device_node *node = indio_dev->dev.of_node;
> + const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
> + struct device_node *child;
> + const char *name;
> + int val, scan_index = 0, ret;
> + bool differential;
> + u32 vin[2];
> +
> + for_each_available_child_of_node(node, child) {
> + ret = of_property_read_u32(child, "reg", &val);
> + if (ret) {
> + dev_err(&indio_dev->dev, "Missing channel index %d\n", ret);
> + goto err;
> + }
> +
> + ret = of_property_read_string(child, "label", &name);
> + /* label is optional */
> + if (!ret) {
> + if (strlen(name) >= STM32_ADC_CH_SZ) {
> + dev_err(&indio_dev->dev, "Label %s exceeds %d characters\n",
> + name, STM32_ADC_CH_SZ);
> + return -EINVAL;
> + }
> + strncpy(adc->chan_name[val], name, STM32_ADC_CH_SZ);
> + } else if (ret != -EINVAL) {
> + dev_err(&indio_dev->dev, "Invalid label %d\n", ret);
> + goto err;
> + }
> +
> + if (val >= adc_info->max_channels) {
> + dev_err(&indio_dev->dev, "Invalid channel %d\n", val);
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + differential = false;
> + ret = of_property_read_u32_array(child, "diff-channels", vin, 2);
> + /* diff-channels is optional */
> + if (!ret) {
> + differential = true;
> + if (vin[0] != val || vin[1] >= adc_info->max_channels) {
> + dev_err(&indio_dev->dev, "Invalid channel in%d-in%d\n",
> + vin[0], vin[1]);
> + goto err;
> + }
> + } else if (ret != -EINVAL) {
> + dev_err(&indio_dev->dev, "Invalid diff-channels property %d\n", ret);
> + goto err;
> + }
> +
> + stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
> + vin[1], scan_index, differential);
> + scan_index++;
> + }
> +
> + return scan_index;
> +
> +err:
> + of_node_put(child);
> +
> + return ret;
> +}
> +
> static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
> {
> struct device_node *node = indio_dev->dev.of_node;
> @@ -1800,15 +1872,21 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
> struct iio_chan_spec *channels;
> int scan_index = 0, num_channels = 0, ret, i;
> u32 smp = 0;
> + bool legacy = false;
>
> - ret = stm32_adc_get_legacy_chan_count(indio_dev, adc);
> - if (ret < 0)
> - return ret;
> - num_channels = ret;
> -
> + num_channels = of_get_available_child_count(node);
> + /*
> + * If no channels have been found, fallback to channels legacy properties.
> + * Legacy channel properties will be ignored, if some channels are
drop the ,
Legacy channel properties will be ignored if some channels...
> + * already defined using the standard binding.
> + */
> if (!num_channels) {
> - dev_err(&indio_dev->dev, "No channels configured\n");
> - return -ENODATA;
> + ret = stm32_adc_get_legacy_chan_count(indio_dev, adc);
> + if (ret < 0)
> + return ret;
> +
> + legacy = true;
Trivial but I would set legacy at top of this if block so it is nearer the comment.
> + num_channels = ret;
> }
>
> if (num_channels > adc_info->max_channels) {
> @@ -1832,7 +1910,10 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
> if (!channels)
> return -ENOMEM;
>
> - ret = stm32_adc_legacy_chan_init(indio_dev, adc, channels);
> + if (legacy)
> + ret = stm32_adc_legacy_chan_init(indio_dev, adc, channels);
> + else
> + ret = stm32_adc_generic_chan_init(indio_dev, adc, channels);
> if (ret < 0)
> return ret;
> scan_index = ret;