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 --- 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 *