On Wed, Jun 21, 2017 at 05:49:43PM +0300, Kirill Esipov wrote:
> DS3232/DS3234 has the temperature registers with a resolution of
> 0.25 degree celsius. This enables to get the value through hwmon.
>
> # cat /sys/class/hwmon/hwmon0/temp1_input
> 37250
>
> Signed-off-by: Kirill Esipov <yesi...@gmail.com>
> ---
> drivers/rtc/Kconfig | 9 ++++++
> drivers/rtc/rtc-ds3232.c | 84
> ++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 93 insertions(+)
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 8d3b95728326..b4a6a916d4df 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -791,6 +791,15 @@ config RTC_DRV_DS3232
> This driver can also be built as a module. If so, the module
> will be called rtc-ds3232.
>
> +config RTC_DRV_DS3232_HWMON
> + bool "HWMON support for Dallas/Maxim DS3232/DS3234"
> + depends on RTC_DRV_DS3232 && HWMON
> + depends on !(RTC_DRV_DS3232=y && HWMON=m)
> + default y
> + help
> + Say Y here if you want to expose temperature sensor data on
> + rtc-ds3232
> +
> config RTC_DRV_PCF2127
> tristate "NXP PCF2127"
> depends on RTC_I2C_AND_SPI
> diff --git a/drivers/rtc/rtc-ds3232.c b/drivers/rtc/rtc-ds3232.c
> index deff431a37c4..f94ff0685942 100644
> --- a/drivers/rtc/rtc-ds3232.c
> +++ b/drivers/rtc/rtc-ds3232.c
> @@ -22,6 +22,8 @@
> #include <linux/bcd.h>
> #include <linux/slab.h>
> #include <linux/regmap.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
>
> #define DS3232_REG_SECONDS 0x00
> #define DS3232_REG_MINUTES 0x01
> @@ -275,6 +277,86 @@ static int ds3232_update_alarm(struct device *dev,
> unsigned int enabled)
> return ret;
> }
>
> +/*----------------------------------------------------------------------*/
> +
> +#ifdef CONFIG_RTC_DRV_DS3232_HWMON
> +
> +/*
> + * Temperature sensor support for ds3232/ds3234 devices.
> + */
> +
> +#define DS3232_REG_TEMPERATURE 0x11
> +
> +/*
> + * A user-initiated temperature conversion is not started by this function,
> + * so the temperature is updated once every 64 seconds.
> + */
> +static int ds3232_hwmon_read_temp(struct device *dev, s32 *mC)
> +{
> + struct ds3232 *ds3232 = dev_get_drvdata(dev);
> + u8 temp_buf[2];
> + s16 temp;
> + int ret;
> +
> + ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_TEMPERATURE, temp_buf,
> + sizeof(temp_buf));
> +
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * Temperature is represented as a 10-bit code with a resolution of
> + * 0.25 degree celsius and encoded in two's complement format.
> + */
> + temp = (temp_buf[0] << 8) | temp_buf[1];
> + temp >>= 6;
> + *mC = temp * 250;
> +
> + return 0;
> +}
> +
> +static ssize_t ds3232_hwmon_show_temp(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + int ret;
> + s32 temp;
> +
> + ret = ds3232_hwmon_read_temp(dev, &temp);
> + if (ret < 0)
> + return ret;
> +
> + return sprintf(buf, "%d\n", temp);
> +}
> +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ds3232_hwmon_show_temp,
> + NULL, 0);
> +
> +static struct attribute *ds3232_hwmon_attrs[] = {
> + &sensor_dev_attr_temp1_input.dev_attr.attr,
> + NULL,
> +};
> +ATTRIBUTE_GROUPS(ds3232_hwmon);
> +
> +static void ds3232_hwmon_register(struct device *dev, const char *name)
> +{
> + struct ds3232 *ds3232 = dev_get_drvdata(dev);
> + struct device *hwmon_dev;
> +
> + hwmon_dev = devm_hwmon_device_register_with_groups(dev, name, ds3232,
> + ds3232_hwmon_groups);
Any reason for not using devm_hwmon_device_register_with_info() ?
Guenter
> + if (IS_ERR(hwmon_dev)) {
> + dev_warn(dev, "unable to register hwmon device %ld\n",
> + PTR_ERR(hwmon_dev));
> + }
> +}
> +
> +#else
> +
> +static void ds3232_hwmon_register(struct ds3232 *ds3232)
> +{
> +}
> +
> +#endif
> +
> static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
> {
> struct ds3232 *ds3232 = dev_get_drvdata(dev);
> @@ -366,6 +448,8 @@ static int ds3232_probe(struct device *dev, struct regmap
> *regmap, int irq,
> if (ds3232->irq > 0)
> device_init_wakeup(dev, 1);
>
> + ds3232_hwmon_register(dev, name);
> +
> ds3232->rtc = devm_rtc_device_register(dev, name, &ds3232_rtc_ops,
> THIS_MODULE);
> if (IS_ERR(ds3232->rtc))
