tegra20: add clock_set_pllout function

Common practice on Tegra 2 boards is to use the pllp_out4 FO
to generate the ULPI reference clock. For this to work we have
to override the default hardware generated output divider.

This function adds a clean way to do so.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Tom Warren <twarren@nvidia.com>

2 files changed, 21 insertions, 2 deletions

diff --git a/arch/arm/include/asm/arch-tegra/clk_rst.h b/arch/arm/include/asm/arch-tegra/clk_rst.h
index 8c3be91514..7b548c2298 100644
--- a/arch/arm/include/asm/arch-tegra/clk_rst.h
+++ b/arch/arm/include/asm/arch-tegra/clk_rst.h
@@ -27,8 +27,7 @@
 /* PLL registers - there are several PLLs in the clock controller */
 struct clk_pll {
 	uint pll_base;		/* the control register */
-	uint pll_out;		/* output control */
-	uint reserved;
+	uint pll_out[2];	/* output control */
 	uint pll_misc;		/* other misc things */
 };
 
@@ -112,6 +111,14 @@ struct clk_rst_ctlr {
 #define PLL_DIVM_SHIFT		0
 #define PLL_DIVM_MASK		(0x1f << PLL_DIVM_SHIFT)
 
+/* CLK_RST_CONTROLLER_PLLx_OUTx_0 */
+#define PLL_OUT_RSTN		(1 << 0)
+#define PLL_OUT_CLKEN		(1 << 1)
+#define PLL_OUT_OVRRIDE		(1 << 2)
+
+#define PLL_OUT_RATIO_SHIFT	8
+#define PLL_OUT_RATIO_MASK	(0xffU << PLL_OUT_RATIO_SHIFT)
+
 /* CLK_RST_CONTROLLER_PLLx_MISC_0 */
 #define PLL_CPCON_SHIFT		8
 #define PLL_CPCON_MASK		(15U << PLL_CPCON_SHIFT)
diff --git a/arch/arm/include/asm/arch-tegra/clock.h b/arch/arm/include/asm/arch-tegra/clock.h
index 3eff163e85..eac1dc2662 100644
--- a/arch/arm/include/asm/arch-tegra/clock.h
+++ b/arch/arm/include/asm/arch-tegra/clock.h
@@ -58,6 +58,18 @@ unsigned long clock_start_pll(enum clock_id id, u32 divm, u32 divn,
 		u32 divp, u32 cpcon, u32 lfcon);
 
 /**
+ * Set PLL output frequency
+ *
+ * @param clkid	clock id
+ * @param pllout	pll output id
+ * @param rate		desired output rate
+ *
+ * @return 0 if ok, -1 on error (invalid clock id or no suitable divider)
+ */
+int clock_set_pllout(enum clock_id clkid, enum pll_out_id pllout,
+		unsigned rate);
+
+/**
  * Read low-level parameters of a PLL.
  *
  * @param id	clock id to read (note: USB is not supported)