clk: exynos: add function for Samsung CMU ops->request

The request function performs a simple check if the clock with the
provided ID is present or not. This is done with a simple call to
clk_get_by_id(). A non-zero return value indicates that the requested
clock is not available.

In some cases, clk->dev points to the clock bank device instead of
the clock device. This pointer is therefore overwritten in order to
reference to the correct device instance.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

drivers/clk/exynos/clk.c

@@ -10,6 +10,19 @@
 #include <dm.h>
 #include "clk.h"
 
+int samsung_clk_request(struct clk *clk)
+{
+	struct clk *c;
+	int ret;
+
+	ret = clk_get_by_id(clk->id, &c);
+	if (ret)
+		return ret;
+
+	clk->dev = c->dev;
+	return 0;
+}
+
 static void
 samsung_clk_register_fixed_rate(struct udevice *dev, void __iomem *base,
 				unsigned int cmu_id,

drivers/clk/exynos/clk.h

@@ -9,10 +9,13 @@
 #ifndef __EXYNOS_CLK_H
 #define __EXYNOS_CLK_H
 
+#include <clk.h>
 #include <errno.h>
 #include <linux/clk-provider.h>
 #include "clk-pll.h"
 
+int samsung_clk_request(struct clk *clk);
+
 #define _SAMSUNG_CLK_OPS(_name, _cmu)					\
 static int _name##_of_xlate(struct clk *clk,				\
 			    struct ofnode_phandle_args *args)		\
@@ -37,6 +40,7 @@ static const struct clk_ops _name##_clk_ops = {				\
 	.enable = ccf_clk_enable,					\
 	.disable = ccf_clk_disable,					\
 	.of_xlate = _name##_of_xlate,					\
+	.request = samsung_clk_request,					\
 }
 
 /**