Re: [PATCH] clk: Add device tree binding to clk-fixed-factor

Gregory CLEMENT
2013-04-10T15:56:33Z

Hi Christian,

On 04/10/2013 05:40 PM, Christian Ruppert wrote:
> This patch adds a device tree binding for the simple fixed factor clock
> divider/multiplier of the common clock tree binding.

This patch remind me of something :
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-August/116405.html

Do you have a use case for it, this time?

My version have been hold off waiting for an user for it.
Will you need it for a driver?

Regards,

>
> Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>
> ---
> .../bindings/clock/fixed-factor-clkdiv.txt | 24 +++++++++++++++
> drivers/clk/clk-fixed-factor.c | 32 ++++++++++++++++++++
> include/linux/clk-provider.h | 1 +
> 3 files changed, 57 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/clock/fixed-factor-clkdiv.txt
>
> diff --git a/Documentation/devicetree/bindings/clock/fixed-factor-clkdiv.txt b/Documentation/devicetree/bindings/clock/fixed-factor-clkdiv.txt
> new file mode 100644
> index 0000000..352bac4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/fixed-factor-clkdiv.txt
> @@ -0,0 +1,24 @@
> +Device Tree Clock bindings for plat-tb10x
> +
> +This binding uses the common clock binding[1].
> +
> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
> +
> +Required properties:
> +- compatible : shall be "fixed-factor-clkdiv"
> +- #clock-cells: from common clock binding; shall be set to 0
> +- clocks: shall be the input parent clock phandle for the clock.
> +- clock-mult: defines the multiplication factor of the output clock frequency
> + wrt. the input clock frequency.
> +- clock-div: defines the division factor of the output clock frequency wrt.
> + the input clock frequency.
> +
> +Example:
> +cpu_clk: clkdiv_cpu { /* CPU clock derived from pll0. 1/2 of pll frequency */
> + compatible = "fixed-factor-clkdiv";
> + #clock-cells = <0>;
> + clocks = <&pll0>;
> + clock-mult = <1>;
> + clock-div = <2>;
> + clock-output-names = "cpu_clk";
> +};
> diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
> index 1ef271e..85e45f1 100644
> --- a/drivers/clk/clk-fixed-factor.c
> +++ b/drivers/clk/clk-fixed-factor.c
> @@ -11,6 +11,7 @@
> #include <linux/clk-provider.h>
> #include <linux/slab.h>
> #include <linux/err.h>
> +#include <linux/of.h>
>
> /*
> * DOC: basic fixed multiplier and divider clock that cannot gate
> @@ -96,3 +97,34 @@ struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
>
> return clk;
> }
> +
> +#ifdef CONFIG_OF
> +/**
> + * of_fixed_factor_clkdiv_setup() - Set up simple fixed factor clock divider
> + */
> +void of_fixed_factor_clkdiv_setup(struct device_node *node)
> +{
> + struct clk *clk;
> + const char *clk_name = node->name;
> + const char *parent_name;
> + u32 mult, div;
> +
> + if (of_property_read_u32(node, "clock-mult", &mult))
> + return;
> +
> + if (of_property_read_u32(node, "clock-div", &div))
> + return;
> +
> + parent_name = of_clk_get_parent_name(node, 0);
> +
> + of_property_read_string(node, "clock-output-names", &clk_name);
> +
> + clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
> + mult, div);
> + if (!IS_ERR(clk))
> + of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +}
> +EXPORT_SYMBOL_GPL(of_fixed_factor_clkdiv_setup);
> +CLK_OF_DECLARE(fixed_clkdiv, "fixed-factor-clkdiv",
> + of_fixed_factor_clkdiv_setup);
> +#endif
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 7f197d7..d4937cf 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -184,6 +184,7 @@ struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
> unsigned long fixed_rate);
>
> void of_fixed_clk_setup(struct device_node *np);
> +void of_fixed_factor_clkdiv_setup(struct device_node *node);
>
> /**
> * struct clk_gate - gating clock
>

--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.