rtc: ds1307: add temperature sensor support for ds3231 (445c0207) · Commits · 戴 / test

drivers/rtc/Kconfig

+9 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/rtc/rtc-ds1307.c

+88 −0

Original line number	Diff line number	Diff line
		@@ -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:

Admin message