On 04/11/2013 11:19 AM, Christian Ruppert wrote: > Hi Gregory, > > Since there doesn't seem to be anyone opposing this feature I just > checked your patch and after adding the CLK_OF_DECLARE macro in the end > it works well for us. Tell me if you would like to rebase and resubmit > your patch or if I should follow up on our own. I can rebase and resubmit my patch, it's pretty straightforward. The problem was the lack of user in the kernel. And by user I mean a driver using these functions. Usually a new function enter in the kernel only if there are users for it inside the kernel so if you plan to submit a driver using this piece of code, then I see no reason to not get it. > > Greetings, > Christian > > On Wed, Apr 10, 2013 at 06:27:47PM +0200, christian ruppert wrote: >> Hi Gregory, >> >> We use derived clocks with fixed ratios for our TB10x platform. I >> originally had this in the platform code but Vineet (the platform >> maintainer) rightly pointed out that the common clock framework would >> be the correct place for it. >> Is there any reason not to support this functionality? After all, the >> generic fixed rate clock also has a device tree binding and I'd guess >> we're not the only ones statically deriving one clock from another in >> our SOCs. >> >> Greetings, >> Christian >> >> On Wed, Apr 10, 2013 at 05:56:25PM +0200, Gregory CLEMENT wrote: >>> 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@xxxxxxxxxx> >>>> --- >>>> .../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. >>> http://free-electrons.com >> >> -- >> Christian Ruppert , <christian.ruppert@xxxxxxxxxx> >> /| >> Tel: +41/(0)22 816 19-42 //| 3, Chemin du Pré-Fleuri >> _// | bilis Systems CH-1228 Plan-les-Ouates > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
