[PATCH] iio: adc: sun20i-gpadc: support non-contiguous channel lookups

[Michal Piekos]

Using consumer driver like iio-hwmon which resolve channels thorugh
io-channels phandles will fail for sparse channels because IIO core
threats phandle argument as index into channel array.
        eg. <&gpadc 1> will fail if there is only channel at 1 specified

Add fwnode_xlate which maps DT phandle to the registered channel whose
chan->channel matches the hardware channel number. It allows sparse
channel maps to be consumed by drivers like iio-hwmon.

Tested on Radxa Cubie A5E.

Signed-off-by: Michal Piekos <michal.piekos at mmpsystems.pl>
---
 drivers/iio/adc/sun20i-gpadc-iio.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/iio/adc/sun20i-gpadc-iio.c b/drivers/iio/adc/sun20i-gpadc-iio.c
index 861c14da75ad..95f34a352158 100644
--- a/drivers/iio/adc/sun20i-gpadc-iio.c
+++ b/drivers/iio/adc/sun20i-gpadc-iio.c
@@ -139,8 +139,21 @@ static irqreturn_t sun20i_gpadc_irq_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static int sun20i_gpadc_fwnode_xlate(struct iio_dev *indio_dev,
+		const struct fwnode_reference_args *iiospec)
+{
+	int i;
+
+	for (i = 0; i < indio_dev->num_channels; i++)
+		if (indio_dev->channels[i].channel == iiospec->args[0])
+			return i;
+
+	return -EINVAL;
+}
+
 static const struct iio_info sun20i_gpadc_iio_info = {
 	.read_raw = sun20i_gpadc_read_raw,
+	.fwnode_xlate = sun20i_gpadc_fwnode_xlate,
 };
 
 static void sun20i_gpadc_reset_assert(void *data)

---
base-commit: 1d5dcaa3bd65f2e8c9baa14a393d3a2dc5db7524
change-id: 20260513-fix-sunxi-gpadc-sparse-channels-2b6b2063bd49

Best regards,
--  
Michal Piekos <michal.piekos at mmpsystems.pl>