[PATCH v7 3/4] hwmon: (sht3x) Add devicetree support

[Zaixiang Xu]

Add an of_device_id table to support devicetree based instantiation
of the supported sensors.

The devicetree binding models all higher accuracy parts with a
fallback to the base part of their group, so only the two base
compatibles need to be listed. The match data distinguishes the
humidity and temperature parts (SHT3x) from the temperature-only
parts (STS3x), which require different configuration.

Start enum sht3x_chips at 1: with sht3x equal to 0, the OF match
data for the SHT devices would be NULL, causing i2c_get_match_data()
to fall back to i2c_device_id name matching, which fails for
devicetree names. The devices would then only work because the
resulting chip id 0 happens to equal sht3x. Non-zero match data
avoids relying on that coincidence.

Signed-off-by: Zaixiang Xu <zaixiang.xu.dev@xxxxxxxxx>
---
 drivers/hwmon/sht3x.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/sht3x.c b/drivers/hwmon/sht3x.c
index c2f6b73aa7f3..6d47cfd340f8 100644
--- a/drivers/hwmon/sht3x.c
+++ b/drivers/hwmon/sht3x.c
@@ -61,7 +61,7 @@ static const unsigned char sht3x_cmd_read_serial_number[]      = { 0x37, 0x80 };
 #define SHT3X_MAX_HUMIDITY     100000
 
 enum sht3x_chips {
-	sht3x,
+	sht3x = 1,
 	sts3x,
 };
 
@@ -939,8 +939,19 @@ static const struct i2c_device_id sht3x_ids[] = {
 
 MODULE_DEVICE_TABLE(i2c, sht3x_ids);
 
+static const struct of_device_id sht3x_of_match[] = {
+	{ .compatible = "sensirion,sht30", .data = (void *)(uintptr_t)sht3x },
+	{ .compatible = "sensirion,sts30", .data = (void *)(uintptr_t)sts3x },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, sht3x_of_match);
+
 static struct i2c_driver sht3x_i2c_driver = {
-	.driver.name = "sht3x",
+	.driver = {
+		.name = "sht3x",
+		.of_match_table = sht3x_of_match,
+	},
 	.probe       = sht3x_probe,
 	.id_table    = sht3x_ids,
 };
-- 
2.34.1