linux-kernel - [PATCH v4 06/13] iio: dac: ds4424: use device match data for chip info

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Message-ID: <20260203093434.2548978-7-o.rempel@pengutronix.de>
Date: Tue,  3 Feb 2026 10:34:26 +0100
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Jonathan Cameron <jic23@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>
Cc: Oleksij Rempel <o.rempel@...gutronix.de>,
	kernel@...gutronix.de,
	linux-kernel@...r.kernel.org,
	linux-iio@...r.kernel.org,
	devicetree@...r.kernel.org,
	Andy Shevchenko <andy@...nel.org>,
	David Lechner <dlechner@...libre.com>,
	Nuno Sá <nuno.sa@...log.com>,
	David Jander <david@...tonic.nl>
Subject: [PATCH v4 06/13] iio: dac: ds4424: use device match data for chip info

Refactor the driver to use device match data instead of checking ID enums
in a switch statement.

Define a `ds4424_chip_info` structure to hold variant-specific attributes
(currently just the channel count) and attach it directly to the I2C and
OF device ID tables.

Use `client->name` instead of `id->name` to decouple the probe function
from the legacy `i2c_device_id` structure.

This simplifies the probe function and makes it easier to add support for
new variants like DS4402/DS4404.

Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
---
changes v4:
- New patch
---
 drivers/iio/dac/ds4424.c | 44 +++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 23 deletions(-)

diff --git a/drivers/iio/dac/ds4424.c b/drivers/iio/dac/ds4424.c
index 3385f39521d9..5709d8a39d7b 100644
--- a/drivers/iio/dac/ds4424.c
+++ b/drivers/iio/dac/ds4424.c
@@ -34,9 +34,16 @@
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 }
 
-enum ds4424_device_ids {
-	ID_DS4422,
-	ID_DS4424,
+struct ds4424_chip_info {
+	u8 num_channels;
+};
+
+static const struct ds4424_chip_info ds4422_info = {
+	.num_channels = DS4422_MAX_DAC_CHANNELS,
+};
+
+static const struct ds4424_chip_info ds4424_info = {
+	.num_channels = DS4424_MAX_DAC_CHANNELS,
 };
 
 struct ds4424_data {
@@ -204,11 +211,15 @@ static const struct iio_info ds4424_iio_info = {
 
 static int ds4424_probe(struct i2c_client *client)
 {
-	const struct i2c_device_id *id = i2c_client_get_device_id(client);
+	const struct ds4424_chip_info *chip_info;
 	struct ds4424_data *data;
 	struct iio_dev *indio_dev;
 	int ret;
 
+	chip_info = i2c_get_match_data(client);
+	if (!chip_info)
+		return -ENODEV;
+
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;
@@ -216,7 +227,6 @@ static int ds4424_probe(struct i2c_client *client)
 	data = iio_priv(indio_dev);
 	i2c_set_clientdata(client, indio_dev);
 	data->client = client;
-	indio_dev->name = id->name;
 
 	data->vcc_reg = devm_regulator_get(&client->dev, "vcc");
 	if (IS_ERR(data->vcc_reg))
@@ -236,20 +246,8 @@ static int ds4424_probe(struct i2c_client *client)
 	if (ret < 0)
 		goto fail;
 
-	switch (id->driver_data) {
-	case ID_DS4422:
-		indio_dev->num_channels = DS4422_MAX_DAC_CHANNELS;
-		break;
-	case ID_DS4424:
-		indio_dev->num_channels = DS4424_MAX_DAC_CHANNELS;
-		break;
-	default:
-		dev_err(&client->dev,
-				"ds4424: Invalid chip id.\n");
-		ret = -ENXIO;
-		goto fail;
-	}
-
+	indio_dev->name = client->name;
+	indio_dev->num_channels = chip_info->num_channels;
 	indio_dev->channels = ds4424_channels;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &ds4424_iio_info;
@@ -278,16 +276,16 @@ static void ds4424_remove(struct i2c_client *client)
 }
 
 static const struct i2c_device_id ds4424_id[] = {
-	{ "ds4422", ID_DS4422 },
-	{ "ds4424", ID_DS4424 },
+	{ "ds4422", (kernel_ulong_t)&ds4422_info },
+	{ "ds4424", (kernel_ulong_t)&ds4424_info },
 	{ }
 };
 
 MODULE_DEVICE_TABLE(i2c, ds4424_id);
 
 static const struct of_device_id ds4424_of_match[] = {
-	{ .compatible = "maxim,ds4422" },
-	{ .compatible = "maxim,ds4424" },
+	{ .compatible = "maxim,ds4422", .data = &ds4422_info },
+	{ .compatible = "maxim,ds4424", .data = &ds4424_info },
 	{ }
 };
 
-- 
2.47.3