On 2022-06-08 17:11, Frank Wunderlich wrote:
From: Peter Geis <pgwipeout@xxxxxxxxx>
RTC sometimes does not respond the first time in init.
Try multiple times to get a response.
FWIW, given that HYM8563 is fairly common on RK3288 boards - I can't say
I've ever noticed an issue with mine, for instance - it seems dubious
that this would be a general issue of the chip itself. Are you sure it's
not a SoC or board-level issue with the I2C bus being in a funny initial
state, timings being marginal, or suchlike?
Robin.
Signed-off-by: Peter Geis <pgwipeout@xxxxxxxxx>
Signed-off-by: Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx>
---
drivers/rtc/rtc-hym8563.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/rtc/rtc-hym8563.c b/drivers/rtc/rtc-hym8563.c
index 90e602e99d03..9adcedaa4613 100644
--- a/drivers/rtc/rtc-hym8563.c
+++ b/drivers/rtc/rtc-hym8563.c
@@ -13,6 +13,7 @@
#include <linux/clk-provider.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
+#include <linux/delay.h>
#include <linux/rtc.h>
#define HYM8563_CTL1 0x00
@@ -438,10 +439,16 @@ static irqreturn_t hym8563_irq(int irq, void *dev_id)
static int hym8563_init_device(struct i2c_client *client)
{
- int ret;
+ int ret, i;
/* Clear stop flag if present */
- ret = i2c_smbus_write_byte_data(client, HYM8563_CTL1, 0);
+ for (i = 0; i < 3; i++) {
+ ret = i2c_smbus_write_byte_data(client, HYM8563_CTL1, 0);
+ if (ret == 0)
+ break;
+ msleep(20);
+ }
+
if (ret < 0)
return ret;
