Messages in this thread | | | Subject | Re: [PATCH v6 00/41] ARM: davinci: convert to common cloc k framework | From | David Lechner <> | Date | Thu, 25 Jan 2018 10:18:19 -0600 |
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On 01/25/2018 06:53 AM, Sekhar Nori wrote: > On Wednesday 24 January 2018 01:33 PM, Bartosz Golaszewski wrote: >> 2018-01-23 21:23 GMT+01:00 David Lechner <david@lechnology.com>: >>> On 01/23/2018 02:05 PM, David Lechner wrote: >>>> >>>> On 01/23/2018 02:01 PM, David Lechner wrote: >>>>> >>>>> On 01/23/2018 01:53 PM, Bartosz Golaszewski wrote: >>>>>> >>>>>> >>>>>> In the mdio case - the problem is that devm_clk_get() doesn't fail, >>>>>> but somehow the clock doesn't end up in the list of the device's >>>>>> clocks - which is why it's not enabled by pm_runtime_get_sync(). >>>>>> >>>>> >>>>> >>>>> Right. This is because devm_clk_get() now finds the clock via device >>>>> tree instead of a clkdev lookup entry. However, I think that the PM >>>>> notifier registered in arch/arm/mach-davinci/pm_domain.c only uses >>>>> the clkdev lookup to match the con_id and does not use device tree. >>>>> The same thing is happing in mdio, emac and lcdc. >>>>> >>>> >>>> Minor correction: It looks like emac doesn't do this because it doesn't >>>> have a con_id of "fck". But, the same clock is shared by emac and mdio, so >>>> since mdio enables the clock, emac doesn't notice or care that it did >>>> not enable the clock itself. >>> >>> >>> How about using pm_clk_add_clk() in these drivers to explicitly use the >>> clocks for power management instead of relying on pm_clk_add_notifier() >>> to do this implicitly? >> >> Yes, this sounds good. > > Looking at how pm_clk_notify() in clock_ops.c uses con_id[] list, right > now pm_runtime() will work only for clocks which have con_id (from the > list above) mentioned in DT. Since clk_find() mandates con_id match when > its available, NULL con_id does not match. > > For simple devices like DaVinci which uses just one clock for power > management per device (multiple devices might share a clock, but not > other way around as far as I recall, anyway I will double check this > assertion), the attached patch should make EMAC work. > > That still leaves why lcdc does not work. One difference is it uses > PSC1. Are there other devices in PSC1 which work (just to rule out any > thing wrong with PSC1 handling). > > Thanks, > Sekhar > > ---8<--- > diff --git a/arch/arm/mach-davinci/pm_domain.c b/arch/arm/mach-davinci/pm_domain.c > index 78eac2c0c146..0dce7397856d 100644 > --- a/arch/arm/mach-davinci/pm_domain.c > +++ b/arch/arm/mach-davinci/pm_domain.c > @@ -23,7 +23,6 @@ static struct dev_pm_domain davinci_pm_domain = { > > static struct pm_clk_notifier_block platform_bus_notifier = { > .pm_domain = &davinci_pm_domain, > - .con_ids = { "fck", "master", "slave", NULL }, > }; > > static int __init davinci_pm_runtime_init(void) > >
Won't this cause *all* clocks, not just PSC clocks, to be used for power management?
Some examples of devices with more than just the PSC clock are SATA and the USB PHY.
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