sh: clkfwk: setup clock parent from current register value

Some clocks can select its parent clock by CPG register.
But it might have been modified by boot-loader or something.
This patch removed fixed initial parent clock,
and setup it from their current register settings.
It works on div6 reparent clocks for now.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Author: morimoto

arch/arm/mach-shmobile/clock-sh7372.c

@@ -411,11 +411,11 @@ static struct clk *fsibckcr_parent[] = {
 };
 
 static struct clk div6_reparent_clks[DIV6_REPARENT_NR] = {
-	[DIV6_HDMI] = SH_CLK_DIV6_EXT(&pllc1_div2_clk, HDMICKCR, 0,
+	[DIV6_HDMI] = SH_CLK_DIV6_EXT(HDMICKCR, 0,
 				      hdmi_parent, ARRAY_SIZE(hdmi_parent), 6, 2),
-	[DIV6_FSIA] = SH_CLK_DIV6_EXT(&pllc1_div2_clk, FSIACKCR, 0,
+	[DIV6_FSIA] = SH_CLK_DIV6_EXT(FSIACKCR, 0,
 				      fsiackcr_parent, ARRAY_SIZE(fsiackcr_parent), 6, 2),
-	[DIV6_FSIB] = SH_CLK_DIV6_EXT(&pllc1_div2_clk, FSIBCKCR, 0,
+	[DIV6_FSIB] = SH_CLK_DIV6_EXT(FSIBCKCR, 0,
 				      fsibckcr_parent, ARRAY_SIZE(fsibckcr_parent), 6, 2),
 };
 

arch/sh/kernel/cpu/sh4a/clock-sh7724.c

@@ -189,9 +189,9 @@ static struct clk *fclkbcr_parent[] = {
 };
 
 static struct clk div6_reparent_clks[DIV6_REPARENT_NR] = {
-	[DIV6_FA] = SH_CLK_DIV6_EXT(&div3_clk, FCLKACR, 0,
+	[DIV6_FA] = SH_CLK_DIV6_EXT(FCLKACR, 0,
 				      fclkacr_parent, ARRAY_SIZE(fclkacr_parent), 6, 2),
-	[DIV6_FB] = SH_CLK_DIV6_EXT(&div3_clk, FCLKBCR, 0,
+	[DIV6_FB] = SH_CLK_DIV6_EXT(FCLKBCR, 0,
 				      fclkbcr_parent, ARRAY_SIZE(fclkbcr_parent), 6, 2),
 };
 

drivers/sh/clk/cpg.c

@@ -167,6 +167,38 @@ static struct clk_ops sh_clk_div6_reparent_clk_ops = {
 	.set_parent	= sh_clk_div6_set_parent,
 };
 
+static int __init sh_clk_init_parent(struct clk *clk)
+{
+	u32 val;
+
+	if (clk->parent)
+		return 0;
+
+	if (!clk->parent_table || !clk->parent_num)
+		return 0;
+
+	if (!clk->src_width) {
+		pr_err("sh_clk_init_parent: cannot select parent clock\n");
+		return -EINVAL;
+	}
+
+	val  = (__raw_readl(clk->enable_reg) >> clk->src_shift);
+	val &= (1 << clk->src_width) - 1;
+
+	if (val >= clk->parent_num) {
+		pr_err("sh_clk_init_parent: parent table size failed\n");
+		return -EINVAL;
+	}
+
+	clk->parent = clk->parent_table[val];
+	if (!clk->parent) {
+		pr_err("sh_clk_init_parent: unable to set parent");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int __init sh_clk_div6_register_ops(struct clk *clks, int nr,
 					   struct clk_ops *ops)
 {
@@ -190,6 +222,9 @@ static int __init sh_clk_div6_register_ops(struct clk *clks, int nr,
 		clkp->ops = ops;
 		clkp->freq_table = freq_table + (k * freq_table_size);
 		clkp->freq_table[nr_divs].frequency = CPUFREQ_TABLE_END;
+		ret = sh_clk_init_parent(clkp);
+		if (ret < 0)
+			break;
 
 		ret = clk_register(clkp);
 	}

include/linux/sh_clk.h

@@ -131,10 +131,9 @@ int sh_clk_div4_enable_register(struct clk *clks, int nr,
 int sh_clk_div4_reparent_register(struct clk *clks, int nr,
 			 struct clk_div4_table *table);
 
-#define SH_CLK_DIV6_EXT(_parent, _reg, _flags, _parents,	\
+#define SH_CLK_DIV6_EXT(_reg, _flags, _parents,			\
 			_num_parents, _src_shift, _src_width)	\
 {								\
-	.parent = _parent,					\
 	.enable_reg = (void __iomem *)_reg,			\
 	.flags = _flags,					\
 	.parent_table = _parents,				\
@@ -144,7 +143,11 @@ int sh_clk_div4_reparent_register(struct clk *clks, int nr,
 }
 
 #define SH_CLK_DIV6(_parent, _reg, _flags)			\
-	SH_CLK_DIV6_EXT(_parent, _reg, _flags, NULL, 0, 0, 0)
+{								\
+	.parent		= _parent,				\
+	.enable_reg	= (void __iomem *)_reg,			\
+	.flags		= _flags,				\
+}
 
 int sh_clk_div6_register(struct clk *clks, int nr);
 int sh_clk_div6_reparent_register(struct clk *clks, int nr);