[PATCH 6/8] hwmon: (tmp421) support specifying n-factor via DT
From: Krzysztof Adamski <hidden>
Date: 2021-09-07 13:45:45
Also in:
linux-hwmon
Subsystem:
hardware monitoring, the rest · Maintainers:
Guenter Roeck, Linus Torvalds
Previous patches added a way to specify some channel specific parameters in DT and n-factor is definitely one of them. This calibration mechanism is board specific as its value depends on the diodes/transistors being connected to the sensor and thus the DT seems like a right fit for that information. It is very similar to the value of shunt resistor that some drivers allows specifying in DT. This patch adds a possibility to set n-factor for each channel via "n-factor" DT property in each channel subnode. Signed-off-by: Krzysztof Adamski <redacted> --- drivers/hwmon/tmp421.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
index a41d7935acb9..90c6b094785e 100644
--- a/drivers/hwmon/tmp421.c
+++ b/drivers/hwmon/tmp421.c@@ -34,6 +34,7 @@ enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 }; #define TMP421_STATUS_REG 0x08 #define TMP421_CONFIG_REG_1 0x09 #define TMP421_CONVERSION_RATE_REG 0x0B +#define TMP421_N_FACTOR_REG_1 0x21 #define TMP421_MANUFACTURER_ID_REG 0xFE #define TMP421_DEVICE_ID_REG 0xFF
@@ -302,6 +303,7 @@ void tmp421_probe_child_from_dt(struct i2c_client *client, { struct device *dev = &client->dev; u32 i; + s32 val; int err; err = of_property_read_u32(child, "reg", &i);
@@ -321,6 +323,21 @@ void tmp421_probe_child_from_dt(struct i2c_client *client, data->channel[i].disabled = true; return; } + + if (i == 0) + return; /* input 0 is internal channel */ + + err = of_property_read_s32(child, "n-factor", &val); + if (!err) { + if (val > 127 || val < -128) + dev_err(dev, "n-factor for channel %d invalid (%d)\n", + i, val); + else + i2c_smbus_write_byte_data(client, + TMP421_N_FACTOR_REG_1 + i - 1, + val); + } + } void tmp421_probe_from_dt(struct i2c_client *client, struct tmp421_data *data)
--
2.31.1