[PATCH RFC] tango4 clk rewrite

[Mason <slash.tmp@free.fr>]

Hello,

I'd like to hear your comments on this rewrite of the clk driver
for tango4. The main changes are:

1) Flag unsupported setups (to make assumptions explicit)
2) Drop LEGACY_DIV method
3) Support two additional clocks (usb and sdio)

For the extract method, what is the preferred way:
A macro or an inline function?
(Too bad you guys don't like the bit-field approach)


 drivers/clk/clk-tango4.c | 64 ++++++++++++++++++++++++++++++++----------------
 1 file changed, 43 insertions(+), 21 deletions(-)

diff --git a/drivers/clk/clk-tango4.c b/drivers/clk/clk-tango4.c
index 004ab7dfcfe3..f8fa3955f9ee 100644
--- a/drivers/clk/clk-tango4.c
+++ b/drivers/clk/clk-tango4.c
@@ -4,17 +4,26 @@
 #include <linux/init.h>
 #include <linux/io.h>
 
-static struct clk *out[2];
-static struct clk_onecell_data clk_data = { out, 2 };
+#define SYSCLK_DIV	0x20
+#define CPUCLK_DIV	0x24
 
-#define SYSCLK_CTRL	0x20
-#define CPUCLK_CTRL	0x24
-#define LEGACY_DIV	0x3c
+#define FATAL(cond) if (cond) panic("Unsupported clkgen setup!\n")
 
-#define PLL_N(val)	(((val) >>  0) & 0x7f)
-#define PLL_K(val)	(((val) >> 13) & 0x7)
-#define PLL_M(val)	(((val) >> 16) & 0x7)
-#define DIV_INDEX(val)	(((val) >>  8) & 0xf)
+#define CLK_COUNT 4 /* cpu_clk, sys_clk, usb_clk, sdio_clk */
+static struct clk *out[CLK_COUNT];
+static struct clk_onecell_data clk_data = { out, CLK_COUNT };
+
+#define EXTRACT(v,o,w) (((v) >> (o)) & ((1u << (w)) - 1))
+
+static inline u32 extract(u32 val, int offset, int width) {
+	return (val >> offset) & ((1u << width) - 1);
+}
+
+/*** CLKGEN_PLL ***/
+#define PLL_N(v)	extract(v,  0, 7)
+#define PLL_K(v)	extract(v, 13, 3)
+#define PLL_M(v)	extract(v, 16, 3)
+#define PLL_ISEL(v)	extract(v, 24, 3)
 
 static void __init make_pll(int idx, const char *parent, void __iomem *base)
 {
@@ -26,36 +35,49 @@ static void __init make_pll(int idx, const char *parent, void __iomem *base)
 	mul =  PLL_N(val) + 1;
 	div = (PLL_M(val) + 1) << PLL_K(val);
 	clk_register_fixed_factor(NULL, name, parent, 0, mul, div);
+	FATAL(PLL_ISEL(val) != 1);
 }
 
-static int __init get_div(void __iomem *base)
+static void __init make_cd(int idx, void __iomem *base)
 {
-	u8 sysclk_tab[16] = { 2, 4, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4 };
-	int idx = DIV_INDEX(readl_relaxed(base + LEGACY_DIV));
+	char name[8];
+	u32 mul, div;
 
-	return sysclk_tab[idx];
+	sprintf(name, "cd%d", idx);
+	mul =  1 << 27;
+	div = (1 << 28) + readl_relaxed(base + idx*8);
+	clk_register_fixed_factor(NULL, name, "pll2", 0, mul, div);
 }
 
 static void __init tango4_clkgen_setup(struct device_node *np)
 {
-	int div, ret;
+	int i, err;
 	void __iomem *base = of_iomap(np, 0);
 	const char *parent = of_clk_get_parent_name(np, 0);
 
 	if (!base)
 		panic("%s: invalid address\n", np->full_name);
 
+	FATAL(readl_relaxed(base + CPUCLK_DIV) & BIT(23));
+	FATAL(readl_relaxed(base + SYSCLK_DIV) & BIT(23));
+
 	make_pll(0, parent, base);
 	make_pll(1, parent, base);
+	make_pll(2, parent, base);
+	make_cd(2, base + 0x80);
+	make_cd(6, base + 0x80);
+
+	out[0] = clk_register_divider(NULL, "cpu_clk", "pll0", 0,
+			base + CPUCLK_DIV, 8, 8, CLK_DIVIDER_ONE_BASED, NULL);
+	out[1] = clk_register_fixed_factor(NULL, "sys_clk", "pll1", 0, 1, 4);
+	out[2] = clk_register_fixed_factor(NULL,  "usb_clk", "cd2", 0, 1, 2);
+	out[3] = clk_register_fixed_factor(NULL, "sdio_clk", "cd6", 0, 1, 2);
 
-	out[0] = clk_register_divider(NULL, "cpuclk", "pll0", 0,
-			base + CPUCLK_CTRL, 8, 8, CLK_DIVIDER_ONE_BASED, NULL);
+	err = of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
 
-	div = readl_relaxed(base + SYSCLK_CTRL) & BIT(23) ? get_div(base) : 4;
-	out[1] = clk_register_fixed_factor(NULL, "sysclk", "pll1", 0, 1, div);
+	for (i = 0; i < CLK_COUNT; ++i)
+		if (IS_ERR(out[i])) err = 1;
 
-	ret = of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
-	if (IS_ERR(out[0]) || IS_ERR(out[1]) || ret < 0)
-		panic("%s: clk registration failed\n", np->full_name);
+	if (err) panic("%s: clk registration failed\n", np->full_name);
 }
 CLK_OF_DECLARE(tango4_clkgen, "sigma,tango4-clkgen", tango4_clkgen_setup);