On Thu, Oct 14, 2021 at 03:01:28PM +0200, Krzysztof Adamski wrote:
> 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 <krzysztof.adamski@xxxxxxxxx>
Applied, after "s/^ / /"
Guenter
> ---
> drivers/hwmon/tmp421.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
> index af08bc985a13..606914f20910 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
>
> @@ -310,6 +311,7 @@ static int 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);
> @@ -329,6 +331,22 @@ static int tmp421_probe_child_from_dt(struct i2c_client *client,
>
> data->channel[i].enabled = of_device_is_available(child);
>
> + err = of_property_read_s32(child, "ti,n-factor", &val);
> + if (!err) {
> + if (i == 0) {
> + dev_err(dev, "n-factor can't be set for internal channel\n");
> + return -EINVAL;
> + }
> +
> + if (val > 127 || val < -128) {
> + dev_err(dev, "n-factor for channel %d invalid (%d)\n",
> + i, val);
> + return -EINVAL;
> + }
> + i2c_smbus_write_byte_data(client, TMP421_N_FACTOR_REG_1 + i - 1,
> + val);
> + }
> +
> return 0;
> }
>
