linux-kernel - [PATCH 1/2] rtc: hym8563: try multiple times to init device

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Message-Id: <20220608161150.58919-2-linux@fw-web.de>
Date:   Wed,  8 Jun 2022 18:11:48 +0200
From:   Frank Wunderlich <linux@...web.de>
To:     linux-rockchip@...ts.infradead.org
Cc:     Frank Wunderlich <frank-w@...lic-files.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Heiko Stuebner <heiko@...ech.de>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-rtc@...r.kernel.org,
        Peter Geis <pgwipeout@...il.com>
Subject: [PATCH 1/2] rtc: hym8563: try multiple times to init device

From: Peter Geis <pgwipeout@...il.com>

RTC sometimes does not respond the first time in init.
Try multiple times to get a response.

Signed-off-by: Peter Geis <pgwipeout@...il.com>
Signed-off-by: Frank Wunderlich <frank-w@...lic-files.de>
---
 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;
 
-- 
2.34.1