Add device tree binding support for the clock uclass. This allows clock consumers to get the peripheral ID based on the "clocks" property in the device tree.
Usage: Assume the following device tree:
clk: myclock { compatible = "myclocktype"; #clock-cells = <1>; };
uart { compatible = "myuart"; clocks = <&clk 3>; };
i2c { compatible = "myi2c"; clocks = <&clk 5>; };
The UART, I2C driver can get the peripheral ID 3, 5, respectively by calling fdt_clk_get(). The clock provider should set its get_id callback to clk_get_id_simple. This should be enough for most cases although more complicated DT-PeripheralID translation would be possible by a specific get_id callback.
Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com ---
drivers/clk/Makefile | 1 + drivers/clk/clk-fdt.c | 37 +++++++++++++++++++++++++++++++++++++ include/clk.h | 20 ++++++++++++++++++++ 3 files changed, 58 insertions(+) create mode 100644 drivers/clk/clk-fdt.c
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 4a6a4a8..5fcdf39 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -6,6 +6,7 @@ #
obj-$(CONFIG_CLK) += clk-uclass.o +obj-$(CONFIG_$(SPL_)OF_CONTROL) += clk-fdt.o obj-$(CONFIG_ROCKCHIP_RK3036) += clk_rk3036.o obj-$(CONFIG_ROCKCHIP_RK3288) += clk_rk3288.o obj-$(CONFIG_SANDBOX) += clk_sandbox.o diff --git a/drivers/clk/clk-fdt.c b/drivers/clk/clk-fdt.c new file mode 100644 index 0000000..fc53157 --- /dev/null +++ b/drivers/clk/clk-fdt.c @@ -0,0 +1,37 @@ +/* + * Copyright (C) 2015 Masahiro Yamada yamada.masahiro@socionext.com + * + * Device Tree support for clk uclass + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <clk.h> +#include <dm/uclass.h> +#include <fdtdec.h> + +int fdt_clk_get(const void *fdt, int nodeoffset, int index, + struct udevice **dev) +{ + struct fdtdec_phandle_args clkspec; + struct udevice *clkdev; + int rc; + + rc = fdtdec_parse_phandle_with_args(fdt, nodeoffset, "clocks", + "#clock-cells", 0, index, &clkspec); + if (rc) + return rc; + + rc = uclass_get_device_by_of_offset(UCLASS_CLK, clkspec.node, &clkdev); + if (rc) + return rc; + + rc = clk_get_id(clkdev, clkspec.args_count, clkspec.args); + if (rc < 0) + return rc; + + if (dev) + *dev = clkdev; + + return rc; +} diff --git a/include/clk.h b/include/clk.h index 1efbaf2..518cb47 100644 --- a/include/clk.h +++ b/include/clk.h @@ -121,4 +121,24 @@ static inline int clk_get_id_simple(struct udevice *dev, int args_count, return args_count > 0 ? args[0] : 0; }
+#if CONFIG_IS_ENABLED(OF_CONTROL) +/** + * fdt_clk_get() - Get peripheral ID from device tree + * + * @fdt: FDT blob + * @periph: Offset of clock consumer node + * @index: index of a phandle to parse out in "clocks" property + * @dev: if not NULL, filled with pointer of clock provider + * @return peripheral ID, or -ve error code + */ +int fdt_clk_get(const void *fdt, int nodeoffset, int index, + struct udevice **dev); +#else +static inline int fdt_clk_get(const void *fdt, int nodeoffset, int index, + struct udevice **dev); +{ + return -ENOSYS; +} +#endif + #endif /* _CLK_H_ */