Re: [PATCH v3 9/9] rtc: isl12022: add support for temperature sensor

Guenter Roeck
2022-10-26T14:46:21Z

On 10/26/22 06:38, Rasmus Villemoes wrote:
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>

There should be some description above. Other than that,

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> v3: drop 0444 update_interval property.
>
> v2 of patches 1-8 are already upstream (b1a1baa657c7 and parents).
>
> drivers/rtc/rtc-isl12022.c | 94 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 94 insertions(+)
>
> diff --git a/drivers/rtc/rtc-isl12022.c b/drivers/rtc/rtc-isl12022.c
> index ca677c4265e6..a3b0de3393f5 100644
> --- a/drivers/rtc/rtc-isl12022.c
> +++ b/drivers/rtc/rtc-isl12022.c
> @@ -17,6 +17,7 @@
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/regmap.h>
> +#include <linux/hwmon.h>
>
> /* ISL register offsets */
> #define ISL12022_REG_SC 0x00
> @@ -30,6 +31,9 @@
> #define ISL12022_REG_SR 0x07
> #define ISL12022_REG_INT 0x08
>
> +#define ISL12022_REG_BETA 0x0d
> +#define ISL12022_REG_TEMP_L 0x28
> +
> /* ISL register bits */
> #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
>
> @@ -38,6 +42,7 @@
>
> #define ISL12022_INT_WRTC (1 << 6)
>
> +#define ISL12022_BETA_TSE (1 << 7)
>
> static struct i2c_driver isl12022_driver;
>
> @@ -46,6 +51,93 @@ struct isl12022 {
> struct regmap *regmap;
> };
>
> +static umode_t isl12022_hwmon_is_visible(const void *data,
> + enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + if (type == hwmon_temp && attr == hwmon_temp_input)
> + return 0444;
> +
> + return 0;
> +}
> +
> +/*
> + * A user-initiated temperature conversion is not started by this function,
> + * so the temperature is updated once every ~60 seconds.
> + */
> +static int isl12022_hwmon_read_temp(struct device *dev, long *mC)
> +{
> + struct isl12022 *isl12022 = dev_get_drvdata(dev);
> + struct regmap *regmap = isl12022->regmap;
> + u8 temp_buf[2];
> + int temp, ret;
> +
> + ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L,
> + temp_buf, sizeof(temp_buf));
> + if (ret)
> + return ret;
> + /*
> + * Temperature is represented as a 10-bit number, unit half-Kelvins.
> + */
> + temp = (temp_buf[1] << 8) | temp_buf[0];
> + temp *= 500;
> + temp -= 273000;
> +
> + *mC = temp;
> +
> + return 0;
> +}
> +
> +static int isl12022_hwmon_read(struct device *dev,
> + enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + if (type == hwmon_temp && attr == hwmon_temp_input)
> + return isl12022_hwmon_read_temp(dev, val);
> +
> + return -EOPNOTSUPP;
> +}
> +
> +static const struct hwmon_channel_info *isl12022_hwmon_info[] = {
> + HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
> + NULL
> +};
> +
> +static const struct hwmon_ops isl12022_hwmon_ops = {
> + .is_visible = isl12022_hwmon_is_visible,
> + .read = isl12022_hwmon_read,
> +};
> +
> +static const struct hwmon_chip_info isl12022_hwmon_chip_info = {
> + .ops = &isl12022_hwmon_ops,
> + .info = isl12022_hwmon_info,
> +};
> +
> +static void isl12022_hwmon_register(struct device *dev)
> +{
> + struct isl12022 *isl12022;
> + struct device *hwmon;
> + int ret;
> +
> + if (!IS_REACHABLE(CONFIG_HWMON))
> + return;
> +
> + isl12022 = dev_get_drvdata(dev);
> +
> + ret = regmap_update_bits(isl12022->regmap, ISL12022_REG_BETA,
> + ISL12022_BETA_TSE, ISL12022_BETA_TSE);
> + if (ret) {
> + dev_warn(dev, "unable to enable temperature sensor\n");
> + return;
> + }
> +
> + hwmon = devm_hwmon_device_register_with_info(dev, "isl12022", isl12022,
> + &isl12022_hwmon_chip_info,
> + NULL);
> + if (IS_ERR(hwmon))
> + dev_warn(dev, "unable to register hwmon device: %pe\n", hwmon);
> +}
> +
> /*
> * In the routines that deal directly with the isl12022 hardware, we use
> * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
> @@ -160,6 +252,8 @@ static int isl12022_probe(struct i2c_client *client)
> return PTR_ERR(isl12022->regmap);
> }
>
> + isl12022_hwmon_register(&client->dev);
> +
> isl12022->rtc = devm_rtc_allocate_device(&client->dev);
> if (IS_ERR(isl12022->rtc))
> return PTR_ERR(isl12022->rtc);