[PATCH 2/2] adc: stm32mp15: add support of generic channels binding

[Olivier Moysan]

Add support of generic IIO channels binding:
./devicetree/bindings/iio/adc/adc.yaml
Keep support of st,adc-channels for backward compatibility.

Signed-off-by: Olivier Moysan <olivier.moysan at foss.st.com>
---

 drivers/adc/stm32-adc.c | 51 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 6 deletions(-)

diff --git a/drivers/adc/stm32-adc.c b/drivers/adc/stm32-adc.c
index 1250385fbb92..85efc119dbf1 100644
--- a/drivers/adc/stm32-adc.c
+++ b/drivers/adc/stm32-adc.c
@@ -200,24 +200,63 @@ static int stm32_adc_legacy_chan_init(struct udevice *dev, unsigned int num_chan
 	return ret;
 }
 
+static int stm32_adc_generic_chan_init(struct udevice *dev, unsigned int num_channels)
+{
+	struct adc_uclass_plat *uc_pdata = dev_get_uclass_plat(dev);
+	struct stm32_adc *adc = dev_get_priv(dev);
+	ofnode child;
+	int val, ret;
+
+	ofnode_for_each_subnode(child, dev_ofnode(dev)) {
+		ret = ofnode_read_u32(child, "reg", &val);
+		if (ret) {
+			dev_err(dev, "Missing channel index %d\n", ret);
+			return ret;
+		}
+
+		if (val >= adc->cfg->max_channels) {
+			dev_err(dev, "Invalid channel %d\n", val);
+			return -EINVAL;
+		}
+
+		uc_pdata->channel_mask |= 1 << val;
+	}
+
+	return 0;
+}
+
 static int stm32_adc_chan_of_init(struct udevice *dev)
 {
 	struct adc_uclass_plat *uc_pdata = dev_get_uclass_plat(dev);
 	struct stm32_adc *adc = dev_get_priv(dev);
 	unsigned int num_channels;
 	int ret;
-
-	ret = stm32_adc_get_legacy_chan_count(dev);
-	if (ret < 0)
-		return ret;
-	num_channels = ret;
+	bool legacy = false;
+
+	num_channels = dev_get_child_count(dev);
+	/* If no channels have been found, fallback to channels legacy properties. */
+	if (!num_channels) {
+		legacy = true;
+
+		ret = stm32_adc_get_legacy_chan_count(dev);
+		if (!ret) {
+			dev_err(dev, "No channel found\n");
+			return -ENODATA;
+		} else if (ret < 0) {
+			return ret;
+		}
+		num_channels = ret;
+	}
 
 	if (num_channels > adc->cfg->max_channels) {
 		dev_err(dev, "too many st,adc-channels: %d\n", num_channels);
 		return -EINVAL;
 	}
 
-	ret = stm32_adc_legacy_chan_init(dev, num_channels);
+	if (legacy)
+		ret = stm32_adc_legacy_chan_init(dev, num_channels);
+	else
+		ret = stm32_adc_generic_chan_init(dev, num_channels);
 	if (ret < 0)
 		return ret;
 
-- 
2.25.1