[PATCH] iio: afe: iio-rescale: Add platform IDs

[PATCH] iio: afe: iio-rescale: Add platform IDs

[Fabio Forni via B4 Relay]

From: Fabio Forni <development@redaril.me>

When a rescaler is probed starting from a `struct swnode`,
device_get_match_data() will always set rescale->cfg to NULL,
because device_get_match_data() is unimplemented for software nodes.

This commit makes the probe function fall back to platform IDs when
it couldn't fetch the rescaler configuration from the match table.

Signed-off-by: Fabio Forni <development@redaril.me>
---
 drivers/iio/afe/iio-rescale.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
index 3a6a09ffa526..fcdeeacedbe8 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -517,12 +517,28 @@ static const struct of_device_id rescale_match[] = {
 };
 MODULE_DEVICE_TABLE(of, rescale_match);
 
+static const struct platform_device_id rescale_platform_ids[] = {
+	{ .name = "current-sense-amplifier",
+	  .driver_data = CURRENT_SENSE_AMPLIFIER, },
+	{ .name = "current-sense-shunt",
+	  .driver_data = CURRENT_SENSE_SHUNT, },
+	{ .name = "voltage-divider",
+	  .driver_data = VOLTAGE_DIVIDER, },
+	{ .name = "temperature-sense-rtd",
+	  .driver_data = TEMP_SENSE_RTD, },
+	{ .name = "temperature-transducer",
+	  .driver_data = TEMP_TRANSDUCER, },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, rescale_platform_ids);
+
 static int rescale_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct iio_dev *indio_dev;
 	struct iio_channel *source;
 	struct rescale *rescale;
+	const struct platform_device_id *id;
 	int sizeof_ext_info;
 	int sizeof_priv;
 	int i;
@@ -548,6 +564,15 @@ static int rescale_probe(struct platform_device *pdev)
 	rescale = iio_priv(indio_dev);
 
 	rescale->cfg = device_get_match_data(dev);
+	if (!rescale->cfg) {
+		id = platform_get_device_id(pdev);
+		if (!id)
+			return dev_err_probe(dev,
+					     -EINVAL,
+					     "missing or invalid device configuration");
+
+		rescale->cfg = &rescale_cfg[id->driver_data];
+	}
 	rescale->numerator = 1;
 	rescale->denominator = 1;
 	rescale->offset = 0;
@@ -602,6 +627,7 @@ static struct platform_driver rescale_driver = {
 		.name = "iio-rescale",
 		.of_match_table = rescale_match,
 	},
+	.id_table = rescale_platform_ids,
 };
 module_platform_driver(rescale_driver);
 

---
base-commit: 6c377d19d4a5116d9bec5203aa3c6c11523e7898
change-id: 20261008-iio_rescale_platform_ids-0d2a7dac974a

Best regards,
-- 
Fabio Forni <development@redaril.me>

Re: [PATCH] iio: afe: iio-rescale: Add platform IDs

[Andy Shevchenko]

On Thu, Oct 08, 2026 at 11:27:59PM +0200, Fabio Forni via B4 Relay wrote:

> When a rescaler is probed starting from a `struct swnode`,

How? Pure platform devices can't be probed from struct swnode.

> device_get_match_data() will always set rescale->cfg to NULL,
> because device_get_match_data() is unimplemented for software nodes.
> 
> This commit makes the probe function fall back to platform IDs when

Read Submitting Patches documentation on imperative mode (search for
'This patch').

> it couldn't fetch the rescaler configuration from the match table.

...

> +static const struct platform_device_id rescale_platform_ids[] = {
> +	{ .name = "current-sense-amplifier",
> +	  .driver_data = CURRENT_SENSE_AMPLIFIER, },

Drop trailing inner commas and make these one-liners (yes, long ones).

	{ .name = "current-sense-amplifier", .driver_data = CURRENT_SENSE_AMPLIFIER },

> +	{ .name = "current-sense-shunt",
> +	  .driver_data = CURRENT_SENSE_SHUNT, },
> +	{ .name = "voltage-divider",
> +	  .driver_data = VOLTAGE_DIVIDER, },
> +	{ .name = "temperature-sense-rtd",
> +	  .driver_data = TEMP_SENSE_RTD, },
> +	{ .name = "temperature-transducer",
> +	  .driver_data = TEMP_TRANSDUCER, },
> +	{ }
> +};


>  static int rescale_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct iio_dev *indio_dev;
>  	struct iio_channel *source;
>  	struct rescale *rescale;
> +	const struct platform_device_id *id;

Keep reversed xmas tree order, please.

>  	int sizeof_ext_info;
>  	int sizeof_priv;
>  	int i;

...

>  	rescale->cfg = device_get_match_data(dev);
> +	if (!rescale->cfg) {
> +		id = platform_get_device_id(pdev);
> +		if (!id)
> +			return dev_err_probe(dev,
> +					     -EINVAL,

ENODATA

> +					     "missing or invalid device configuration");
> +
> +		rescale->cfg = &rescale_cfg[id->driver_data];
> +	}

And it's better to make it a helper, actually we have drivers [1] that do
something similar, I would recommend you considering adding that helper
directly into platform driver core. But at least local one is a good start.

[1] for example, drivers/pinctrl/intel/pinctrl-intel.c.

-- 
With Best Regards,
Andy Shevchenko