On Wed, 19 Dec 2012 17:00:33 +0100
Jesper Nilsson <[email protected]> wrote:
> This patch implements 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.
>
> ...
>
> --- a/drivers/rtc/rtc-pcf8523.c
> +++ b/drivers/rtc/rtc-pcf8523.c
> @@ -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 +252,35 @@ static int pcf8523_rtc_set_time(struct device *dev,
> struct rtc_time *tm)
> return pcf8523_start_rtc(client);
> }
>
> +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;
> + }
> +}
> +
> 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,
> };
Other drivers make the ioctl conditional on CONFIG_RTC_INTF_DEV,
presumably to avoid bloat.
--- a/drivers/rtc/rtc-pcf8523.c~rtc-pcf8523-add-low-battery-voltage-support-fix
+++ a/drivers/rtc/rtc-pcf8523.c
@@ -251,6 +251,7 @@ static int pcf8523_rtc_set_time(struct d
return pcf8523_start_rtc(client);
}
+#ifdef CONFIG_RTC_INTF_DEV
static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
unsigned long arg)
{
@@ -275,6 +276,9 @@ static int pcf8523_rtc_ioctl(struct devi
return -ENOIOCTLCMD;
}
}
+#else
+#define pcf8523_rtc_ioctl NULL
+#endif
static const struct rtc_class_ops pcf8523_rtc_ops = {
.read_time = pcf8523_rtc_read_time,
_
--
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