From: Camel Guo <redacted>

In order to make it possible to get battery voltage status, this commit
adds RTC_VL_READ, RTC_VL_CLR ioctl commands to rtc-rs5c372.

Signed-off-by: Camel Guo <redacted>
---

v2: Set RTC_VL_BACKUP_LOW if VDET is set. Do not clear PON, XSTP in
RTC_VL_CLR ioctl

  drivers/rtc/rtc-rs5c372.c | 60 +++++++++++++++++++++++++++++++++++++++
  1 file changed, 60 insertions(+)

diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
index 80980414890c..4ab8718d9360 100644
--- a/drivers/rtc/rtc-rs5c372.c
+++ b/drivers/rtc/rtc-rs5c372.c

@@ -485,6 +485,65 @@ static int rs5c372_rtc_proc(struct device *dev, 

struct seq_file *seq)
  #define rs5c372_rtc_proc        NULL
  #endif

+#ifdef CONFIG_RTC_INTF_DEV
+static int rs5c372_ioctl(struct device *dev, unsigned int cmd, unsigned 
long arg)
+{
+       struct rs5c372  *rs5c = i2c_get_clientdata(to_i2c_client(dev));
+       unsigned char   ctrl2;
+       int             addr;
+       unsigned int    flags;
+
+       dev_dbg(dev, "%s: cmd=%x\n", __func__, cmd);
+
+       addr = RS5C_ADDR(RS5C_REG_CTRL2);
+       ctrl2 = i2c_smbus_read_byte_data(rs5c->client, addr);
+
+       switch (cmd) {
+       case RTC_VL_READ:
+               flags = 0;
+
+               switch (rs5c->type) {
+               case rtc_r2025sd:
+               case rtc_r2221tl:
+                       if ((rs5c->type == rtc_r2025sd && !(ctrl2 & 
R2x2x_CTRL2_XSTP)) ||
+                               (rs5c->type == rtc_r2221tl &&  (ctrl2 & 
R2x2x_CTRL2_XSTP))) {
+                               flags |= RTC_VL_DATA_INVALID;
+                       }
+                       if (ctrl2 & R2x2x_CTRL2_VDET)
+                               flags |= RTC_VL_BACKUP_LOW;
+                       break;
+               default:
+                       if (ctrl2 & RS5C_CTRL2_XSTP)
+                               flags |= RTC_VL_DATA_INVALID;
+                       break;
+               }
+
+               return put_user(flags, (unsigned int __user *)arg);
+       case RTC_VL_CLR:
+               /* clear VDET bit */
+               switch (rs5c->type) {
+               case rtc_r2025sd:
+               case rtc_r2221tl:
+                       ctrl2 &= ~R2x2x_CTRL2_VDET;
+               default:
+                       break;
+               }
+
+               if (i2c_smbus_write_byte_data(rs5c->client, addr, ctrl2) 
< 0) {
+                       dev_dbg(&rs5c->client->dev, "%s: write error in 
line %i\n",
+                                       __func__, __LINE__);
+                       return -EIO;
+               }
+               return 0;
+       default:
+               return -ENOIOCTLCMD;
+       }
+       return 0;
+}
+#else
+#define rs5c372_ioctl  NULL
+#endif
+
  static const struct rtc_class_ops rs5c372_rtc_ops = {
          .proc           = rs5c372_rtc_proc,
          .read_time      = rs5c372_rtc_read_time,

@@ -492,6 +551,7 @@ static const struct rtc_class_ops rs5c372_rtc_ops = {
          .read_alarm     = rs5c_read_alarm,
          .set_alarm      = rs5c_set_alarm,
          .alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
+       .ioctl          = rs5c372_ioctl,
  };

  #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)

-- 
2.20.1