[PATCH] earlycon: Initialize port->uartclk based on clock-frequency property
From: Michal Simek
Date: Tue Apr 10 2018 - 09:32:41 EST
On DT based platforms when current-speed property is present baudrate
is setup. Also port->uartclk is initialized to bogus BASE_BAUD * 16
value. Drivers like uartps/ns16550 contain logic when baudrate and
uartclk is used for baudrate calculation.
The patch is reading optional clock-frequency property to replace bogus
BASE_BAUD * 16 calculation to have proper baudrate calculation.
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
---
We should add documentation for current-speed, reg-offset, reg-shift,
big-endian, native-endian, reg-io-width and clock-frequency to any
generic location because they are all optional properties for all DT
earlycon drivers through of_setup_earlycon.
---
drivers/tty/serial/earlycon.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index a24278380fec..eb1f84258c44 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -279,6 +279,10 @@ int __init of_setup_earlycon(const struct earlycon_id *match,
if (val)
early_console_dev.baud = be32_to_cpu(*val);
+ val = of_get_flat_dt_prop(node, "clock-frequency", NULL);
+ if (val)
+ port->uartclk = be32_to_cpu(*val);
+
if (options) {
early_console_dev.baud = simple_strtoul(options, NULL, 0);
strlcpy(early_console_dev.options, options,
--
1.9.1