tegra: fdt: Add function to return peripheral/clock ID

A common requirement is to find the clock ID for a peripheral. This is the
second cell of the 'clocks' property (the first being the phandle itself).

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

diff --git a/arch/arm/cpu/armv7/tegra2/clock.c b/arch/arm/cpu/armv7/tegra2/clock.c
index 11d2346d83b0fda80052b79f68ac3583779ba990..a94cf817e57dea47fc794e0e133e4526d6ca5195 100644 (file)
--- a/arch/arm/cpu/armv7/tegra2/clock.c
+++ b/arch/arm/cpu/armv7/tegra2/clock.c
@@ -28,6 +28,7 @@
 #include <asm/arch/tegra2.h>
 #include <common.h>
 #include <div64.h>
+#include <fdtdec.h>
 
 /*
  * This is our record of the current clock rate of each clock. We don't
@@ -918,6 +919,63 @@ void clock_ll_start_uart(enum periph_id periph_id)
        reset_set_enable(periph_id, 0);
 }
 
+#ifdef CONFIG_OF_CONTROL
+/*
+ * Convert a device tree clock ID to our peripheral ID. They are mostly
+ * the same but we are very cautious so we check that a valid clock ID is
+ * provided.
+ *
+ * @param clk_id       Clock ID according to tegra2 device tree binding
+ * @return peripheral ID, or PERIPH_ID_NONE if the clock ID is invalid
+ */
+static enum periph_id clk_id_to_periph_id(int clk_id)
+{
+       if (clk_id > 95)
+               return PERIPH_ID_NONE;
+
+       switch (clk_id) {
+       case 1:
+       case 2:
+       case 7:
+       case 10:
+       case 20:
+       case 30:
+       case 35:
+       case 49:
+       case 56:
+       case 74:
+       case 76:
+       case 77:
+       case 78:
+       case 79:
+       case 80:
+       case 81:
+       case 82:
+       case 83:
+       case 91:
+       case 95:
+               return PERIPH_ID_NONE;
+       default:
+               return clk_id;
+       }
+}
+
+int clock_decode_periph_id(const void *blob, int node)
+{
+       enum periph_id id;
+       u32 cell[2];
+       int err;
+
+       err = fdtdec_get_int_array(blob, node, "clocks", cell,
+                                  ARRAY_SIZE(cell));
+       if (err)
+               return -1;
+       id = clk_id_to_periph_id(cell[1]);
+       assert(clock_periph_id_isvalid(id));
+       return id;
+}
+#endif /* CONFIG_OF_CONTROL */
+
 int clock_verify(void)
 {
        struct clk_pll *pll = get_pll(CLOCK_ID_PERIPH);

diff --git a/arch/arm/include/asm/arch-tegra2/clock.h b/arch/arm/include/asm/arch-tegra2/clock.h
index 080ef18e81dec2602f031ad10f4745cfdbe3c4f0..6b12c76e8d5383df41ea0a94c87e0d638b5b4340 100644 (file)
--- a/arch/arm/include/asm/arch-tegra2/clock.h
+++ b/arch/arm/include/asm/arch-tegra2/clock.h
@@ -177,6 +177,7 @@ enum periph_id {
        PERIPH_ID_CRAM2,
 
        PERIPH_ID_COUNT,
+       PERIPH_ID_NONE = -1,
 };
 
 /* Converts a clock number to a clock register: 0=L, 1=H, 2=U */
@@ -355,6 +356,18 @@ unsigned clock_get_rate(enum clock_id clkid);
  */
 void clock_ll_start_uart(enum periph_id periph_id);
 
+/**
+ * Decode a peripheral ID from a device tree node.
+ *
+ * This works by looking up the peripheral's 'clocks' node and reading out
+ * the second cell, which is the clock number / peripheral ID.
+ *
+ * @param blob         FDT blob to use
+ * @param node         Node to look at
+ * @return peripheral ID, or PERIPH_ID_NONE if none
+ */
+enum periph_id clock_decode_periph_id(const void *blob, int node);
+
 /*
  * Checks that clocks are valid and prints a warning if not
  *