[PATCH AUTOSEL 4.19 011/191] serial: samsung: Enable baud clock for UART reset procedure in resume

Sasha Levin
2019-11-10T03:16:54Z

From: Marek Szyprowski <m.szyprowski@samsung.com>

[ Upstream commit 1ff3652bc7111df26b5807037f624be294cf69d5 ]

Ensure that the baud clock is also enabled for UART register writes in
driver resume. On Exynos5433 SoC this is needed to avoid external abort
issue.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/samsung.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index c6058b52d5d59..2a49b6d876b87 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1944,7 +1944,11 @@ static int s3c24xx_serial_resume(struct device *dev)

if (port) {
clk_prepare_enable(ourport->clk);
+ if (!IS_ERR(ourport->baudclk))
+ clk_prepare_enable(ourport->baudclk);
s3c24xx_serial_resetport(port, s3c24xx_port_to_cfg(port));
+ if (!IS_ERR(ourport->baudclk))
+ clk_disable_unprepare(ourport->baudclk);
clk_disable_unprepare(ourport->clk);

uart_resume_port(&s3c24xx_uart_drv, port);
@@ -1967,7 +1971,11 @@ static int s3c24xx_serial_resume_noirq(struct device *dev)
if (rx_enabled(port))
uintm &= ~S3C64XX_UINTM_RXD_MSK;
clk_prepare_enable(ourport->clk);
+ if (!IS_ERR(ourport->baudclk))
+ clk_prepare_enable(ourport->baudclk);
wr_regl(port, S3C64XX_UINTM, uintm);
+ if (!IS_ERR(ourport->baudclk))
+ clk_disable_unprepare(ourport->baudclk);
clk_disable_unprepare(ourport->clk);
}
}
--
2.20.1