[PATCH v3 1/2] iio: mma8452: Fix probe failing when an i2c_device_id is used

[Hans de Goede <hdegoede@redhat.com>]

The mma8452_driver declares both of_match_table and i2c_driver.id_table
match-tables, but its probe() function only checked for of matches.

Add support for i2c_device_id matches. This fixes the driver not loading
on some x86 tablets (e.g. the Nextbook Ares 8) where the i2c_client is
instantiated by platform code using an i2c_device_id.

Fixes: c3cdd6e48e35 ("iio: mma8452: refactor for seperating chip specific data")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v3:
- Store name in struct mma_chip_info and use that to set indio_dev->name
- Switch to using device_get_match_data() for (potentially) adding ACPI
  enumeration support in the future

Changes in v2:
- Fix the following smatch warning:
  drivers/iio/accel/mma8452.c:1595 mma8452_probe() error: we previously assumed 'id' could be null (see line 1536)
  Reported-by: kernel test robot <lkp@intel.com>
  Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/iio/accel/mma8452.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 64b82b4503ad..0528717d9f44 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -176,6 +176,7 @@ static const struct mma8452_event_regs trans_ev_regs = {
  * @enabled_events:		event flags enabled and handled by this driver
  */
 struct mma_chip_info {
+	const char *name;
 	u8 chip_id;
 	const struct iio_chan_spec *channels;
 	int num_channels;
@@ -1301,6 +1302,7 @@ enum {
 
 static const struct mma_chip_info mma_chip_info_table[] = {
 	[mma8451] = {
+		.name = "mma8451",
 		.chip_id = MMA8451_DEVICE_ID,
 		.channels = mma8451_channels,
 		.num_channels = ARRAY_SIZE(mma8451_channels),
@@ -1325,6 +1327,7 @@ static const struct mma_chip_info mma_chip_info_table[] = {
 					MMA8452_INT_FF_MT,
 	},
 	[mma8452] = {
+		.name = "mma8452",
 		.chip_id = MMA8452_DEVICE_ID,
 		.channels = mma8452_channels,
 		.num_channels = ARRAY_SIZE(mma8452_channels),
@@ -1341,6 +1344,7 @@ static const struct mma_chip_info mma_chip_info_table[] = {
 					MMA8452_INT_FF_MT,
 	},
 	[mma8453] = {
+		.name = "mma8453",
 		.chip_id = MMA8453_DEVICE_ID,
 		.channels = mma8453_channels,
 		.num_channels = ARRAY_SIZE(mma8453_channels),
@@ -1357,6 +1361,7 @@ static const struct mma_chip_info mma_chip_info_table[] = {
 					MMA8452_INT_FF_MT,
 	},
 	[mma8652] = {
+		.name = "mma8652",
 		.chip_id = MMA8652_DEVICE_ID,
 		.channels = mma8652_channels,
 		.num_channels = ARRAY_SIZE(mma8652_channels),
@@ -1366,6 +1371,7 @@ static const struct mma_chip_info mma_chip_info_table[] = {
 		.enabled_events = MMA8452_INT_FF_MT,
 	},
 	[mma8653] = {
+		.name = "mma8653",
 		.chip_id = MMA8653_DEVICE_ID,
 		.channels = mma8653_channels,
 		.num_channels = ARRAY_SIZE(mma8653_channels),
@@ -1380,6 +1386,7 @@ static const struct mma_chip_info mma_chip_info_table[] = {
 		.enabled_events = MMA8452_INT_FF_MT,
 	},
 	[fxls8471] = {
+		.name = "fxls8471",
 		.chip_id = FXLS8471_DEVICE_ID,
 		.channels = mma8451_channels,
 		.num_channels = ARRAY_SIZE(mma8451_channels),
@@ -1522,13 +1529,6 @@ static int mma8452_probe(struct i2c_client *client,
 	struct mma8452_data *data;
 	struct iio_dev *indio_dev;
 	int ret;
-	const struct of_device_id *match;
-
-	match = of_match_device(mma8452_dt_ids, &client->dev);
-	if (!match) {
-		dev_err(&client->dev, "unknown device model\n");
-		return -ENODEV;
-	}
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
@@ -1537,7 +1537,14 @@ static int mma8452_probe(struct i2c_client *client,
 	data = iio_priv(indio_dev);
 	data->client = client;
 	mutex_init(&data->lock);
-	data->chip_info = match->data;
+
+	data->chip_info = device_get_match_data(&client->dev);
+	if (!data->chip_info && id) {
+		data->chip_info = &mma_chip_info_table[id->driver_data];
+	} else {
+		dev_err(&client->dev, "unknown device model\n");
+		return -ENODEV;
+	}
 
 	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
 	if (IS_ERR(data->vdd_reg))
@@ -1581,11 +1588,11 @@ static int mma8452_probe(struct i2c_client *client,
 	}
 
 	dev_info(&client->dev, "registering %s accelerometer; ID 0x%x\n",
-		 match->compatible, data->chip_info->chip_id);
+		 data->chip_info->name, data->chip_info->chip_id);
 
 	i2c_set_clientdata(client, indio_dev);
 	indio_dev->info = &mma8452_info;
-	indio_dev->name = id->name;
+	indio_dev->name = data->chip_info->name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = data->chip_info->channels;
 	indio_dev->num_channels = data->chip_info->num_channels;
-- 
2.33.1