tn3399_openwrt/target/linux/bcm27xx/patches-5.15/950-0259-serial-8250-bcm2835aux-defer-if-clock-is-zero.patch
Álvaro Fernández Rojas 20ea6adbf1 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>
2022-05-17 15:11:22 +02:00

29 lines
983 B
Diff

From fa17971225e9c924238edf8657dc21a8687a0232 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Thu, 2 Jul 2020 13:53:20 +0100
Subject: [PATCH] serial: 8250: bcm2835aux - defer if clock is zero
See: https://github.com/raspberrypi/linux/issues/3700
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/tty/serial/8250/8250_bcm2835aux.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/drivers/tty/serial/8250/8250_bcm2835aux.c
+++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
@@ -148,6 +148,13 @@ static int bcm2835aux_serial_probe(struc
*/
up.port.uartclk = clk_get_rate(data->clk) * 2;
+ /* The clock is only queried at probe time, which means we get one shot
+ * at this. A zero clock is never going to work and is almost certainly
+ * due to a parent not being ready, so prefer to defer.
+ */
+ if (!up.port.uartclk)
+ return -EPROBE_DEFER;
+
/* register the port */
ret = serial8250_register_8250_port(&up);
if (ret < 0) {