ARM: SAMSUNG: Add a workaround for get_clock() for serial driver

Serial drivers call get_clock() very early, before platform bus
has been set up, this requires a special check to let them get
a proper clock. Without this patch, a serial console is broken
on S5PV310 and S5PC210 boards.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[kgene.kim@samsung.com: fix coding-style]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>

1 files changed, 26 insertions, 1 deletions

diff --git a/arch/arm/plat-samsung/clock.c b/arch/arm/plat-samsung/clock.c
index 90a20512d68d..e8d20b0bc50e 100644
--- a/arch/arm/plat-samsung/clock.c
+++ b/arch/arm/plat-samsung/clock.c
@@ -48,6 +48,9 @@
 #include <plat/clock.h>
 #include <plat/cpu.h>
 
+#include <linux/serial_core.h>
+#include <plat/regs-serial.h> /* for s3c24xx_uart_devs */
+
 /* clock information */
 
 static LIST_HEAD(clocks);
@@ -65,6 +68,28 @@ static int clk_null_enable(struct clk *clk, int enable)
         return 0;
 }
 
+static int dev_is_s3c_uart(struct device *dev)
+{
+        struct platform_device **pdev = s3c24xx_uart_devs;
+        int i;
+        for (i = 0; i < ARRAY_SIZE(s3c24xx_uart_devs); i++, pdev++)
+                if (*pdev && dev == &(*pdev)->dev)
+                        return 1;
+        return 0;
+}
+
+/*
+ * Serial drivers call get_clock() very early, before platform bus
+ * has been set up, this requires a special check to let them get
+ * a proper clock
+ */
+
+static int dev_is_platform_device(struct device *dev)
+{
+        return dev->bus == &platform_bus_type ||
+               (dev->bus == NULL && dev_is_s3c_uart(dev));
+}
+
 /* Clock API calls */
 
 struct clk *clk_get(struct device *dev, const char *id)
@@ -73,7 +98,7 @@ struct clk *clk_get(struct device *dev, const char *id)
         struct clk *clk = ERR_PTR(-ENOENT);
         int idno;
 
-        if (dev == NULL || dev->bus != &platform_bus_type)
+        if (dev == NULL || !dev_is_platform_device(dev))
                 idno = -1;
         else
                 idno = to_platform_device(dev)->id;