[PATCH 4/6] rtc: isl12022: drop redundant write to HR register

[Rasmus Villemoes]

There's nothing in the data sheet that says writing to one of the time
keeping registers is necessary to start the RTC. It does so at the
stop condition of the i2c transfer setting the WRTC bit:

  Upon initialization or power-up, the WRTC must be set to "1" to
  enable the RTC. Upon the completion of a valid write (STOP), the RTC
  starts counting.

Moreover, even if such a write to one of the timekeeping registers was
necessary, that's exactly what we do anyway just below when we
actually write the given struct rtc_time to the device.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
 drivers/rtc/rtc-isl12022.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/drivers/rtc/rtc-isl12022.c b/drivers/rtc/rtc-isl12022.c
index 234201ea2f7d..659f8e7f33f0 100644
--- a/drivers/rtc/rtc-isl12022.c
+++ b/drivers/rtc/rtc-isl12022.c
@@ -173,7 +173,7 @@ static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
 		/* Check if WRTC (write rtc enable) is set factory default is
 		 * 0 (not set) */
 		if (!(buf[0] & ISL12022_INT_WRTC)) {
-			dev_info(dev, "init write enable and 24 hour format\n");
+			dev_info(dev, "init write enable\n");
 
 			/* Set the write enable bit. */
 			ret = isl12022_write_reg(client,
@@ -181,20 +181,6 @@ static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
 						 buf[0] | ISL12022_INT_WRTC);
 			if (ret)
 				return ret;
-
-			/* Write to any RTC register to start RTC, we use the
-			 * HR register, setting the MIL bit to use the 24 hour
-			 * format. */
-			ret = isl12022_read_regs(client, ISL12022_REG_HR,
-						 buf, 1);
-			if (ret)
-				return ret;
-
-			ret = isl12022_write_reg(client,
-						 ISL12022_REG_HR,
-						 buf[0] | ISL12022_HR_MIL);
-			if (ret)
-				return ret;
 		}
 
 		isl12022->write_enabled = true;
-- 
2.37.2