[PATCH AUTOSEL for 4.9 192/281] Fix serial console on SNI RM400 machines

[Sasha Levin]

From: Thomas Bogendoerfer <tsbog...@alpha.franken.de>

[ Upstream commit e279e6d98e0cf2c2fe008b3c29042b92f0e17b1d ]

sccnxp driver doesn't get the correct uart clock rate, if CONFIG_HAVE_CLOCK
is disabled. Correct usage of clk API to make it work with/without it.

Fixes: 90efa75f7ab0 (serial: sccnxp: Using CLK API for getting UART clock)

Suggested-by: Russell King - ARM Linux <li...@armlinux.org.uk>
Signed-off-by: Thomas Bogendoerfer <tsbog...@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 drivers/tty/serial/sccnxp.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c
index fcf803ffad19..cdd2f942317c 100644
--- a/drivers/tty/serial/sccnxp.c
+++ b/drivers/tty/serial/sccnxp.c
@@ -884,14 +884,19 @@ static int sccnxp_probe(struct platform_device *pdev)
 
        clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(clk)) {
-               if (PTR_ERR(clk) == -EPROBE_DEFER) {
-                       ret = -EPROBE_DEFER;
+               ret = PTR_ERR(clk);
+               if (ret == -EPROBE_DEFER)
                        goto err_out;
-               }
+               uartclk = 0;
+       } else {
+               clk_prepare_enable(clk);
+               uartclk = clk_get_rate(clk);
+       }
+
+       if (!uartclk) {
                dev_notice(&pdev->dev, "Using default clock frequency\n");
                uartclk = s->chip->freq_std;
-       } else
-               uartclk = clk_get_rate(clk);
+       }
 
        /* Check input frequency */
        if ((uartclk < s->chip->freq_min) || (uartclk > s->chip->freq_max)) {
-- 
2.14.1