openwrtv4/target/linux/sunxi/patches-3.13/124-clk-sunxi-muxable-ahb-clock.patch

From 9490107c16c8eaa35b07794e19d5d2eddea8e44b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20L=C3=B3pez?= <emilio@elopez.com.ar>
Date: Sat, 14 Sep 2013 20:48:40 -0300
Subject: [PATCH] clk: sunxi: Implement muxable AHB clock
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sun5i and sun7i have a mux to change the AHB clock parent, this commit
adds support for it on the driver.

Signed-off-by: Emilio López <emilio@elopez.com.ar>
---
 Documentation/devicetree/bindings/clock/sunxi.txt |  1 +
 drivers/clk/sunxi/clk-sunxi.c                     | 37 +++++++++++++++++++++++
 2 files changed, 38 insertions(+)

--- a/Documentation/devicetree/bindings/clock/sunxi.txt
+++ b/Documentation/devicetree/bindings/clock/sunxi.txt
@@ -15,6 +15,7 @@ Required properties:
 	"allwinner,sun4i-axi-clk" - for the AXI clock
 	"allwinner,sun4i-axi-gates-clk" - for the AXI gates
 	"allwinner,sun4i-ahb-clk" - for the AHB clock
+	"allwinner,sun5i-a13-ahb-clk" - for the AHB clock on A13
 	"allwinner,sun4i-ahb-gates-clk" - for the AHB gates on A10
 	"allwinner,sun5i-a13-ahb-gates-clk" - for the AHB gates on A13
 	"allwinner,sun5i-a10s-ahb-gates-clk" - for the AHB gates on A10s
--- a/drivers/clk/sunxi/clk-sunxi.c
+++ b/drivers/clk/sunxi/clk-sunxi.c
@@ -249,7 +249,32 @@ static void sun4i_get_pll5_factors(u32 *
 	*n = DIV_ROUND_UP(div, (*k+1));
 }
 
+/**
+ * sun5i_get_ahb_factors() - calculates p factor for AHB
+ * AHB rate is calculated as follows
+ * rate = parent_rate >> p
+ */
+
+static void sun5i_a13_get_ahb_factors(u32 *freq, u32 parent_rate,
+				      u8 *n, u8 *k, u8 *m, u8 *p)
+{
+	u8 div;
+
+	/* This clock can only divide, so we will never achieve a higher
+	 * rate than the parent's */
+	if (*freq > parent_rate)
+		*freq = parent_rate;
+
+	/* Normalize value to a parent multiple */
+	div = *freq / parent_rate;
+	*freq = parent_rate * div;
+
+	/* we were called to round the frequency, we can now return */
+	if (n == NULL)
+		return;
 
+	*p = div;
+}
 
 /**
  * sun4i_get_apb1_factors() - calculates m, p factors for APB1
@@ -375,6 +400,11 @@ static struct clk_factors_config sun4i_p
 	.kwidth = 2,
 };
 
+static struct clk_factors_config sun5i_a13_ahb_config = {
+	.pshift = 4,
+	.pwidth = 2,
+};
+
 static struct clk_factors_config sun4i_apb1_config = {
 	.mshift = 0,
 	.mwidth = 5,
@@ -408,6 +438,12 @@ static const struct factors_data sun4i_p
 	.getter = sun4i_get_pll5_factors,
 };
 
+static const struct factors_data sun5i_a13_ahb_data __initconst = {
+	.mux = 6,
+	.table = &sun5i_a13_ahb_config,
+	.getter = sun5i_a13_get_ahb_factors,
+};
+
 static const struct factors_data sun4i_apb1_data __initconst = {
 	.table = &sun4i_apb1_config,
 	.getter = sun4i_get_apb1_factors,
@@ -916,6 +952,7 @@ free_clkdata:
 static const struct of_device_id clk_factors_match[] __initconst = {
 	{.compatible = "allwinner,sun4i-pll1-clk", .data = &sun4i_pll1_data,},
 	{.compatible = "allwinner,sun6i-a31-pll1-clk", .data = &sun6i_a31_pll1_data,},
+	{.compatible = "allwinner,sun5i-a13-ahb-clk", .data = &sun5i_a13_ahb_data,},
 	{.compatible = "allwinner,sun4i-apb1-clk", .data = &sun4i_apb1_data,},
 	{.compatible = "allwinner,sun4i-mod0-clk", .data = &sun4i_mod0_data,},
 	{}