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rtc-pcf8523: add low battery voltage support 

Implement reading of the battery voltage low signal for rtc-pcf8523.

The bit is read-only and cannot be cleared by software, so no
clear function is implemented.

[akpm@linux-foundation.org: omit pcf8563_rtc_ioctl() if CONFIG_RTC_INTF_DEV=n]
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jesper Nilsson 2013-02-21 16:44:27 -08:00 committed by Linus Torvalds
parent fca1dd031a
commit f32bc70d5f
1 changed files with 31 additions and 0 deletions
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31
drivers/rtc/rtc-pcf8523.c
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@ -23,6 +23,7 @@
#define REG_CONTROL3_PM_VDD (1 << 6) /* switch-over disabled */
#define REG_CONTROL3_PM_DSM (1 << 5) /* direct switching mode */
#define REG_CONTROL3_PM_MASK 0xe0
#define REG_CONTROL3_BLF (1 << 2) /* battery low bit, read-only */
#define REG_SECONDS 0x03
#define REG_SECONDS_OS (1 << 7)
@ -250,9 +251,39 @@ static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
return pcf8523_start_rtc(client);
}
#ifdef CONFIG_RTC_INTF_DEV
static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
unsigned long arg)
{
struct i2c_client *client = to_i2c_client(dev);
u8 value;
int ret = 0, err;
switch (cmd) {
case RTC_VL_READ:
err = pcf8523_read(client, REG_CONTROL3, &value);
if (err < 0)
return err;
if (value & REG_CONTROL3_BLF)
ret = 1;
if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
return -EFAULT;
return 0;
default:
return -ENOIOCTLCMD;
}
}
#else
#define pcf8523_rtc_ioctl NULL
#endif
static const struct rtc_class_ops pcf8523_rtc_ops = {
.read_time = pcf8523_rtc_read_time,
.set_time = pcf8523_rtc_set_time,
.ioctl = pcf8523_rtc_ioctl,
};
static int pcf8523_probe(struct i2c_client *client,