[PATCH 5/8] rtc: isl12022: implement RTC_VL_READ and RTC_VL_CLR ioctls

[Rasmus Villemoes]

Hook up support for reading the values of the SR_LBAT85 and SR_LBAT75
bits. Translate the former to "battery low", and the latter to
"battery empty or not-present".

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
 drivers/rtc/rtc-isl12022.c | 41 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/rtc/rtc-isl12022.c b/drivers/rtc/rtc-isl12022.c
index cb8f1d92e116..1b6659a9b33a 100644
--- a/drivers/rtc/rtc-isl12022.c
+++ b/drivers/rtc/rtc-isl12022.c
@@ -203,7 +203,48 @@ static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	return regmap_bulk_write(regmap, ISL12022_REG_SC, buf, sizeof(buf));
 }
 
+static int isl12022_read_sr(struct regmap *regmap)
+{
+	int ret;
+	u32 val;
+
+	ret = regmap_read(regmap, ISL12022_REG_SR, &val);
+	if (ret < 0)
+		return ret;
+	return val;
+}
+
+static int isl12022_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+	struct regmap *regmap = dev_get_drvdata(dev);
+	u32 user = 0;
+	int ret;
+
+	switch (cmd) {
+	case RTC_VL_READ:
+		ret = isl12022_read_sr(regmap);
+		if (ret < 0)
+			return ret;
+
+		if (ret & ISL12022_SR_LBAT85)
+			user |= RTC_VL_BACKUP_LOW;
+
+		if (ret & ISL12022_SR_LBAT75)
+			user |= RTC_VL_BACKUP_EMPTY;
+
+		return put_user(user, (u32 __user *)arg);
+
+	case RTC_VL_CLR:
+		return regmap_clear_bits(regmap, ISL12022_REG_SR,
+					 ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75);
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
 static const struct rtc_class_ops isl12022_rtc_ops = {
+	.ioctl		= isl12022_rtc_ioctl,
 	.read_time	= isl12022_rtc_read_time,
 	.set_time	= isl12022_rtc_set_time,
 };
-- 
2.37.2