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 <s...@chromium.org>
---
Changes in v4:
- Add fdtdec function to return peripheral ID
Changes in v6:
- Move peripheral decode function into Tegra's clock.c
Changes in v7:
- Add belts and braces checking of device tree clock ID
Changes in v8:
- Only include clock_decode_periph_id() when CONFIG_OF_CONTROL defined
arch/arm/cpu/armv7/tegra2/clock.c | 58 ++++++++++++++++++++++++++++++
arch/arm/include/asm/arch-tegra2/clock.h | 13 +++++++
2 files changed, 71 insertions(+), 0 deletions(-)
diff --git a/arch/arm/cpu/armv7/tegra2/clock.c
b/arch/arm/cpu/armv7/tegra2/clock.c
index 11d2346..a94cf81 100644
--- 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 080ef18..6b12c76 100644
--- 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
*
--
1.7.7.3
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