bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0026-Revert-rtc-pcf8523-properly-handle-oscillator-stop-b.patch b/target/linux/bcm27xx/patches-5.15/950-0026-Revert-rtc-pcf8523-properly-handle-oscillator-stop-b.patch
new file mode 100644
index 0000000000..32a58221d0
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0026-Revert-rtc-pcf8523-properly-handle-oscillator-stop-b.patch
@@ -0,0 +1,48 @@
+From 39869587dac09c9e738960ccdf01e1dc62a906f7 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Mon, 29 Oct 2018 14:45:45 +0000
+Subject: [PATCH] Revert "rtc: pcf8523: properly handle oscillator stop
+ bit"
+
+This reverts commit ede44c908d44b166a5b6bd7caacd105c2ff5a70f.
+
+See: https://github.com/raspberrypi/firmware/issues/1065
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.org>
+---
+ drivers/rtc/rtc-pcf8523.c | 24 ++++++++++++++++++++++--
+ 1 file changed, 22 insertions(+), 2 deletions(-)
+
+--- a/drivers/rtc/rtc-pcf8523.c
++++ b/drivers/rtc/rtc-pcf8523.c
+@@ -242,8 +242,28 @@ static int pcf8523_rtc_read_time(struct
+ 	if (err < 0)
+ 		return err;
+ 
+-	if (regs[0] & 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 = pcf8523_write(client, PCF8523_REG_SECONDS, regs[0]);
++		if (err < 0)
++			return err;
++
++		err = pcf8523_read(client, PCF8523_REG_SECONDS, &regs[0]);
++		if (err < 0)
++			return err;
++
++		if (regs[0] & PCF8523_SECONDS_OS)
++			return -EAGAIN;
++	}
+ 
+ 	tm->tm_sec = bcd2bin(regs[0] & 0x7f);
+ 	tm->tm_min = bcd2bin(regs[1] & 0x7f);