msm8916-openwrt/target/linux/bcm27xx/patches-6.6/950-0323-rtc-pcf8523-Fix-oscillator-stop-bit-handling.patch
Álvaro Fernández Rojas 8c405cdccc bcm27xx: add 6.6 kernel patches
The patches were generated from the RPi repo with the following command:
git format-patch v6.6.34..rpi-6.1.y

Some patches needed rebasing and, as usual, the applied and reverted, wireless
drivers, Github workflows, READMEs and defconfigs patches were removed.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
2024-06-18 18:52:49 +02:00

57 lines
1.7 KiB
Diff

From 0729d7f79a0c2296a095ffa980b89068638c1645 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Mon, 29 Oct 2018 14:45:45 +0000
Subject: [PATCH 0323/1085] rtc: pcf8523: Fix oscillator stop bit handling
See: https://github.com/raspberrypi/firmware/issues/1065
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/rtc/rtc-pcf8523.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -100,6 +100,7 @@ static int pcf8523_rtc_read_time(struct
{
struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
u8 regs[10];
+ u32 value;
int err;
err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs,
@@ -110,6 +111,33 @@ static int pcf8523_rtc_read_time(struct
if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS))
return -EINVAL;
+ if (regs[0] & PCF8523_SECONDS_OS) {
+ /*
+ * If the oscillator was stopped, try to clear the flag. Upon
+ * power-up the flag is always set, but if we cannot clear it
+ * the oscillator isn't running properly for some reason. The
+ * sensible thing therefore is to return an error, signalling
+ * that the clock cannot be assumed to be correct.
+ */
+
+ regs[0] &= ~PCF8523_SECONDS_OS;
+
+ err = regmap_write(pcf8523->regmap, PCF8523_REG_SECONDS,
+ regs[0]);
+ if (err < 0)
+ return err;
+
+ err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS,
+ &value);
+ if (err < 0)
+ return err;
+
+ if (value & PCF8523_SECONDS_OS)
+ return -EAGAIN;
+
+ regs[0] = value;
+ }
+
tm->tm_sec = bcd2bin(regs[3] & 0x7f);
tm->tm_min = bcd2bin(regs[4] & 0x7f);
tm->tm_hour = bcd2bin(regs[5] & 0x3f);