Add a method which can locate a clock for a device, given its index. This uses the normal device tree bindings to return the clock device and the first argument which is normally used as a peripheral ID in U-Boot.

Signed-off-by: Simon Glass sjg@chromium.org ---

Changes in v3: - Use CONFIG_IS_ENABLED(OF_CONTROL) in C and header file

Changes in v2: - Make the peripheral ID a return value - Add an assert for clk_devp - Make the function dependent on OF_CONTROL

drivers/clk/clk-uclass.c | 28 ++++++++++++++++++++++++++++ include/clk.h | 17 +++++++++++++++++ 2 files changed, 45 insertions(+)

diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c index f2eb73c..18ded9c 100644 --- a/drivers/clk/clk-uclass.c +++ b/drivers/clk/clk-uclass.c @@ -12,6 +12,8 @@ #include <dm/lists.h> #include <dm/root.h>

+DECLARE_GLOBAL_DATA_PTR; + ulong clk_get_rate(struct udevice *dev) { struct clk_ops *ops = clk_get_ops(dev); @@ -72,6 +74,32 @@ int clk_get_id(struct udevice *dev, int args_count, uint32_t *args) return ops->get_id(dev, args_count, args); }

+#if CONFIG_IS_ENABLED(OF_CONTROL) +int clk_get_by_index(struct udevice *dev, int index, struct udevice **clk_devp) +{ + struct fdtdec_phandle_args args; + int ret; + + assert(*clk_devp); + ret = fdtdec_parse_phandle_with_args(gd->fdt_blob, dev->of_offset, + "clocks", "#clock-cells", 0, index, + &args); + if (ret) { + debug("%s: fdtdec_parse_phandle_with_args failed: err=%d\n", + __func__, ret); + return ret; + } + + ret = uclass_get_device_by_of_offset(UCLASS_CLK, args.node, clk_devp); + if (ret) { + debug("%s: uclass_get_device_by_of_offset failed: err=%d\n", + __func__, ret); + return ret; + } + return args.args_count > 0 ? args.args[0] : 0; +} +#endif + UCLASS_DRIVER(clk) = { .id = UCLASS_CLK, .name = "clk", diff --git a/include/clk.h b/include/clk.h index 1e334ed..aea1c41 100644 --- a/include/clk.h +++ b/include/clk.h @@ -159,4 +159,21 @@ static inline int fdt_clk_get(const void *fdt, int nodeoffset, int index, } #endif

+#if CONFIG_IS_ENABLED(OF_CONTROL) +/** + * clk_get_by_index() - look up a clock referenced by a device + * + * Parse a device's 'clocks' list, returning information on the indexed clock, + * ensuring that it is activated. + * + * @dev: Device containing the clock reference + * @index: Clock index to return (0 = first) + * @clk_devp: Returns clock device + * @return: Peripheral ID for the device to control. This is the first + * argument after the clock node phandle. If there is no arguemnt, + * returns 0. Return -ve error code on any error + */ +int clk_get_by_index(struct udevice *dev, int index, struct udevice **clk_devp); +#endif + #endif /* _CLK_H_ */