| Message ID | 5123B719.2080300@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi eyerone, On 19.02.2013 18:32, Daniel Mack wrote: > On 19.02.2013 18:22, Mike Turquette wrote: >> > Quoting Daniel Mack (2013-02-19 01:53:18) >>> >> Hi Fabio, >>> >> Hi Afzal, >>> >> >>> >> On 19.02.2013 02:33, Fabio Estevam wrote: >>>> >>> On Mon, Feb 18, 2013 at 8:55 PM, Daniel Mack <zonque@gmail.com> wrote: >>>>> >>>> Hi, >>>>> >>>> >>>>> >>>> This might be a stupid question, but I'm somehow stuck here. I'm using a >>>>> >>>> driver with the following DTS sub-node: >>>>> >>>> >>>>> >>>> ref25: ref25M { >>>>> >>>> compatible = "fixed-clock"; >>>>> >>>> #clock-cells = <0>; >>>>> >>>> clock-frequency = <25000000>; >>>>> >>>> }; >>>>> >>>> >>>>> >>>> clock-generator@0 { >>>>> >>>> /* ... */ >>>>> >>>> #clock-cells = <1>; >>>>> >>>> clocks = <&ref25>; >>>>> >>>> } >>>>> >>>> >>>>> >>>> The device driver for clock-generator uses something like the following >>>>> >>>> call to get its clock: >>>>> >>>> >>>>> >>>> clk = of_clk_get(np, 0); >>>>> >>>> >>>>> >>>> but the return value is ERR_PTR(-ENOENT) and I also can't find this >>>>> >>>> clock in the clk debugfs tree. >>>>> >>>> >>>>> >>>> This is on a OMAP/AM33xx device with kernel 3.8-rc7 plus the -next tips >>>>> >>>> of arm-soc and omap, but with no other special clock options selected in >>>>> >>>> the config. Is there anything I'm missing to correctly instantiate the >>>>> >>>> dummy clock? >>>> >>> >>>> >>> Have you registered it with clk_register_fixed_rate() ? >>>> >>> >>>> >>> In imx we use imx_clk_fixed, which in turns call clk_register_fixed_rate(). >>>> >>> >>>> >>> Take a look at arch/arm/mach-imx/clk-imx51-imx53.c for a reference. >>> >> >>> >> Hmm no, I didn't do anything else than adding it to the DT in the first >>> >> place, hoping that a driver will pick it up and add the clock for me. >>> >> But it turns out that of_clk_init() is not called at all on my platform. >>> >> >>> >> I'm doing this now from omap_generic_init() and it works. If that's an >>> >> appropriate place to call it, I can provide a patch. >>> >> >> > >> > You can provide a patch, but your example above is for a dummy clock, >> > correct? > No, it's a real clock with a fixed frequency on the board, which feeds > another clock chip. I thought this is what fixed-clock is for, just like > what a fixed-regulator does? Or how would you describe such a thing in > DT, in order to use it as input to another device? > >> > It would be best to post your patch along with a real-world >> > use for calling of_clk_init(). > Not sure what you mean exactly, but the patch is attached. However, I > still think I lack some understanding here - the fact that compatible > strings have to be passed explicitly from generic code feels wrong. > > > Thanks, > Daniel > > > 0001-ARM-OMAP-generic-add-call-to-of_clk_init.patch > > > From 850120371830ffb5e2146aeb2d21c724d6ded09e Mon Sep 17 00:00:00 2001 > From: Daniel Mack <zonque@gmail.com> > Date: Tue, 19 Feb 2013 12:05:25 +0100 > Subject: [PATCH] ARM: OMAP: generic: add call to of_clk_init() > > This is needed to instanciate fixed clocks in the DT. > > Signed-off-by: Daniel Mack <zonque@gmail.com> > --- > arch/arm/mach-omap2/board-generic.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c > index 0274ff7..3580f16 100644 > --- a/arch/arm/mach-omap2/board-generic.c > +++ b/arch/arm/mach-omap2/board-generic.c > @@ -15,6 +15,7 @@ > #include <linux/of_irq.h> > #include <linux/of_platform.h> > #include <linux/irqdomain.h> > +#include <linux/clk-provider.h> > > #include <asm/mach/arch.h> > > @@ -35,6 +36,11 @@ static struct of_device_id omap_dt_match_table[] __initdata = { > { } > }; > > +static const __initconst struct of_device_id clk_match[] = { > + { .compatible = "fixed-clock", .data = of_fixed_clk_setup, }, > + {} > +}; > + > static void __init omap_generic_init(void) > { > omap_sdrc_init(NULL, NULL); > @@ -49,6 +55,7 @@ static void __init omap_generic_init(void) > omap4_panda_display_init_of(); > else if (of_machine_is_compatible("ti,omap4-sdp")) > omap_4430sdp_display_init_of(); > + of_clk_init(clk_match); > } > > #ifdef CONFIG_SOC_OMAP2420 Any opinion about this approach? Thanks, Daniel
From 850120371830ffb5e2146aeb2d21c724d6ded09e Mon Sep 17 00:00:00 2001 From: Daniel Mack <zonque@gmail.com> Date: Tue, 19 Feb 2013 12:05:25 +0100 Subject: [PATCH] ARM: OMAP: generic: add call to of_clk_init() This is needed to instanciate fixed clocks in the DT. Signed-off-by: Daniel Mack <zonque@gmail.com> --- arch/arm/mach-omap2/board-generic.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c index 0274ff7..3580f16 100644 --- a/arch/arm/mach-omap2/board-generic.c +++ b/arch/arm/mach-omap2/board-generic.c @@ -15,6 +15,7 @@ #include <linux/of_irq.h> #include <linux/of_platform.h> #include <linux/irqdomain.h> +#include <linux/clk-provider.h> #include <asm/mach/arch.h> @@ -35,6 +36,11 @@ static struct of_device_id omap_dt_match_table[] __initdata = { { } }; +static const __initconst struct of_device_id clk_match[] = { + { .compatible = "fixed-clock", .data = of_fixed_clk_setup, }, + {} +}; + static void __init omap_generic_init(void) { omap_sdrc_init(NULL, NULL); @@ -49,6 +55,7 @@ static void __init omap_generic_init(void) omap4_panda_display_init_of(); else if (of_machine_is_compatible("ti,omap4-sdp")) omap_4430sdp_display_init_of(); + of_clk_init(clk_match); } #ifdef CONFIG_SOC_OMAP2420 -- 1.8.1.2