From 418319026ca3e7b7b8964fed8dbe7ba464c1d95a Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Mon, 26 Aug 2019 15:29:29 +0800 Subject: [PATCH] serial: sprd: keep console alive even if missing the 'enable' clock The sprd serial console can work with only 26M fixed clock, but the probe() is returning fail if the clock "enable" is not configured in device tree. This patch will fix the problem to let the uart device which is used for console can be initialized even missing "enable" clock configured in devicetree. We should make sure the debug function as available as we can. Signed-off-by: Chunyan Zhang Signed-off-by: Chunyan Zhang Reviewed-by: Baolin Wang Tested-by: Baolin Wang Link: https://lore.kernel.org/r/20190826072929.7696-4-zhang.lyra@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sprd_serial.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c index 6b9000f7adca..f8db5c8e4e39 100644 --- a/drivers/tty/serial/sprd_serial.c +++ b/drivers/tty/serial/sprd_serial.c @@ -1111,6 +1111,16 @@ static int sprd_remove(struct platform_device *dev) return 0; } +static bool sprd_uart_is_console(struct uart_port *uport) +{ + struct console *cons = sprd_uart_driver.cons; + + if (cons && cons->index >= 0 && cons->index == uport->line) + return true; + + return false; +} + static int sprd_clk_init(struct uart_port *uport) { struct clk *clk_uart, *clk_parent; @@ -1137,10 +1147,17 @@ static int sprd_clk_init(struct uart_port *uport) u->clk = devm_clk_get(uport->dev, "enable"); if (IS_ERR(u->clk)) { - if (PTR_ERR(u->clk) != -EPROBE_DEFER) - dev_err(uport->dev, "uart%d can't get enable clock\n", - uport->line); - return PTR_ERR(u->clk); + if (PTR_ERR(u->clk) == -EPROBE_DEFER) + return -EPROBE_DEFER; + + dev_warn(uport->dev, "uart%d can't get enable clock\n", + uport->line); + + /* To keep console alive even if the error occurred */ + if (!sprd_uart_is_console(uport)) + return PTR_ERR(u->clk); + + u->clk = NULL; } return 0;