serial: max310x: Use devm_clk_get_optional() to get the input clock

[ Upstream commit 974e454d6f96da0c0ab1b4115b92587dd9406f6a ]

Simplify the code which fetches the input clock by using
devm_clk_get_optional(). If no input clock is present
devm_clk_get_optional() will return NULL instead of an error
which matches the behavior of the old code.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20201007084635.594991-2-andy.shevchenko@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 8afa6c6decea ("serial: max310x: fail probe if clock crystal is unstable")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 14537878f9855d6d2f3d782e11d7fd3937f0368d..8bf3c5ab5943120f7ac4871840c9b883ab135aa0 100644 (file)
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1265,7 +1265,6 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
                         struct regmap *regmap, int irq)
 {
        int i, ret, fmin, fmax, freq, uartclk;
-       struct clk *clk_osc, *clk_xtal;
        struct max310x_port *s;
        bool xtal = false;
 
@@ -1279,23 +1278,24 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
                return -ENOMEM;
        }
 
-       clk_osc = devm_clk_get(dev, "osc");
-       clk_xtal = devm_clk_get(dev, "xtal");
-       if (!IS_ERR(clk_osc)) {
-               s->clk = clk_osc;
+       s->clk = devm_clk_get_optional(dev, "osc");
+       if (IS_ERR(s->clk))
+               return PTR_ERR(s->clk);
+       if (s->clk) {
                fmin = 500000;
                fmax = 35000000;
-       } else if (!IS_ERR(clk_xtal)) {
-               s->clk = clk_xtal;
-               fmin = 1000000;
-               fmax = 4000000;
-               xtal = true;
-       } else if (PTR_ERR(clk_osc) == -EPROBE_DEFER ||
-                  PTR_ERR(clk_xtal) == -EPROBE_DEFER) {
-               return -EPROBE_DEFER;
        } else {
-               dev_err(dev, "Cannot get clock\n");
-               return -EINVAL;
+               s->clk = devm_clk_get_optional(dev, "xtal");
+               if (IS_ERR(s->clk))
+                       return PTR_ERR(s->clk);
+               if (s->clk) {
+                       fmin = 1000000;
+                       fmax = 4000000;
+                       xtal = true;
+               } else {
+                       dev_err(dev, "Cannot get clock\n");
+                       return -EINVAL;
+               }
        }
 
        ret = clk_prepare_enable(s->clk);