diff options
| -rw-r--r-- | drivers/rtc/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/rtc/rtc-ds1307.c | 88 |
2 files changed, 97 insertions, 0 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 27f6ac46c596..d47ad96132bf 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -212,6 +212,15 @@ config RTC_DRV_DS1307 This driver can also be built as a module. If so, the module will be called rtc-ds1307. +config RTC_DRV_DS1307_HWMON + bool "HWMON support for rtc-ds1307" + depends on RTC_DRV_DS1307 && HWMON + depends on !(RTC_DRV_DS1307=y && HWMON=m) + default y + help + Say Y here if you want to expose temperature sensor data on + rtc-ds1307 (only DS3231) + config RTC_DRV_DS1374 tristate "Dallas/Maxim DS1374" help diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index bfedeb543bfd..2462d5a53a53 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -19,6 +19,8 @@ #include <linux/rtc.h> #include <linux/slab.h> #include <linux/string.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> /* * We can't determine type by probing, but if we expect pre-Linux code @@ -842,6 +844,90 @@ out: return; } +/*----------------------------------------------------------------------*/ + +#ifdef CONFIG_RTC_DRV_DS1307_HWMON + +/* + * Temperature sensor support for ds3231 devices. + */ + +#define DS3231_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 ds3231_hwmon_read_temp(struct device *dev, s16 *mC) +{ + struct ds1307 *ds1307 = dev_get_drvdata(dev); + u8 temp_buf[2]; + s16 temp; + int ret; + + ret = ds1307->read_block_data(ds1307->client, DS3231_REG_TEMPERATURE, + sizeof(temp_buf), temp_buf); + if (ret < 0) + return ret; + if (ret != sizeof(temp_buf)) + return -EIO; + + /* + * 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 ds3231_hwmon_show_temp(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int ret; + s16 temp; + + ret = ds3231_hwmon_read_temp(dev, &temp); + if (ret) + return ret; + + return sprintf(buf, "%d\n", temp); +} +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ds3231_hwmon_show_temp, + NULL, 0); + +static struct attribute *ds3231_hwmon_attrs[] = { + &sensor_dev_attr_temp1_input.dev_attr.attr, + NULL, +}; +ATTRIBUTE_GROUPS(ds3231_hwmon); + +static void ds1307_hwmon_register(struct ds1307 *ds1307) +{ + struct device *dev; + + if (ds1307->type != ds_3231) + return; + + dev = devm_hwmon_device_register_with_groups(&ds1307->client->dev, + ds1307->client->name, + ds1307, ds3231_hwmon_groups); + if (IS_ERR(dev)) { + dev_warn(&ds1307->client->dev, + "unable to register hwmon device %ld\n", PTR_ERR(dev)); + } +} + +#else + +static void ds1307_hwmon_register(struct ds1307 *ds1307) +{ +} + +#endif + static int ds1307_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -1207,6 +1293,8 @@ read_rtc: } } + ds1307_hwmon_register(ds1307); + return 0; exit: |