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    SubjectRe: [PATCH 6/6] rtc: isl12022: add support for temperature sensor
    On 30/08/2022 12:01:52+0200, Rasmus Villemoes wrote:
    > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
    > ---
    > drivers/rtc/rtc-isl12022.c | 81 ++++++++++++++++++++++++++++++++++++++
    > 1 file changed, 81 insertions(+)
    >
    > diff --git a/drivers/rtc/rtc-isl12022.c b/drivers/rtc/rtc-isl12022.c
    > index b295ec92ee17..1bd72f436318 100644
    > --- a/drivers/rtc/rtc-isl12022.c
    > +++ b/drivers/rtc/rtc-isl12022.c
    > @@ -17,6 +17,8 @@
    > #include <linux/of.h>
    > #include <linux/of_device.h>
    > #include <linux/regmap.h>
    > +#include <linux/hwmon.h>
    > +#include <linux/hwmon-sysfs.h>

    You should keep that list ordered

    >
    > /* ISL register offsets */
    > #define ISL12022_REG_SC 0x00
    > @@ -30,6 +32,9 @@
    > #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 +43,7 @@
    >
    > #define ISL12022_INT_WRTC (1 << 6)
    >
    > +#define ISL12022_BETA_TSE (1 << 7)
    >
    > static struct i2c_driver isl12022_driver;
    >
    > @@ -48,6 +54,79 @@ struct isl12022 {
    > bool write_enabled; /* true if write enable is set */
    > };
    >
    > +/*
    > + * 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, s32 *mC)
    > +{
    > + struct isl12022 *isl12022 = dev_get_drvdata(dev);
    > + struct regmap *regmap = isl12022->regmap;
    > + u8 temp_buf[2];
    > + s32 temp;
    > + int 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 ssize_t
    > +isl12022_hwmon_show_temp(struct device *dev, struct device_attribute *attr, char *buf)
    > +{
    > + int ret;
    > + s32 temp;
    > +
    > + ret = isl12022_hwmon_read_temp(dev, &temp);
    > + if (ret)
    > + return ret;
    > +
    > + return sprintf(buf, "%d\n", temp);
    > +}
    > +static SENSOR_DEVICE_ATTR(temp1_input, 0444, isl12022_hwmon_show_temp,
    > + NULL, 0);
    > +
    > +static struct attribute *isl12022_hwmon_attrs[] = {
    > + &sensor_dev_attr_temp1_input.dev_attr.attr,
    > + NULL,
    > +};
    > +ATTRIBUTE_GROUPS(isl12022_hwmon);
    > +
    > +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_groups(dev, "isl12022", isl12022,
    > + isl12022_hwmon_groups);
    > + 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.
    > @@ -179,6 +258,8 @@ 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);
    > --
    > 2.37.2
    >

    --
    Alexandre Belloni, co-owner and COO, Bootlin
    Embedded Linux and Kernel engineering
    https://bootlin.com

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