| Message ID | 1461654582-668-3-git-send-email-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | Stephen Boyd |
| Headers | show |
On 26 April 2016 at 09:09, Geert Uytterhoeven <geert+renesas@glider.be> wrote: > As a pure Clock Domain does not have the concept of powering the domain > itself, the CPG/MSTP driver does not provide power_off() and power_on() > callbacks. > However, the genpd core may still perform a dummy power down, causing > /sys/kernel/debug/pm_genpd/pm_genpd_summary to report the domain's > status being "off-0". > > Use the always-on governor to make sure the domain is never powered > down, and always shows up as "on" in pm_genpd_summary. Hmm. Hypothetically, what if the clock domain would be a subdomain, where its master is able to power down? Using the always on governor would prevent the master from power off as well. I am wondering whether we should introduce some similar as pm_runtime_no_callbacks() but for the generic PM domain instead. What do you think? > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- > drivers/clk/renesas/clk-mstp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/clk/renesas/clk-mstp.c b/drivers/clk/renesas/clk-mstp.c > index 969fbb61ab07b9b8..5093a250650dad6d 100644 > --- a/drivers/clk/renesas/clk-mstp.c > +++ b/drivers/clk/renesas/clk-mstp.c > @@ -319,7 +319,7 @@ void __init cpg_mstp_add_clk_domain(struct device_node *np) > pd->flags = GENPD_FLAG_PM_CLK; > pd->attach_dev = cpg_mstp_attach_dev; > pd->detach_dev = cpg_mstp_detach_dev; > - pm_genpd_init(pd, &simple_qos_governor, false); > + pm_genpd_init(pd, &pm_domain_always_on_gov, false); > > of_genpd_add_provider_simple(np, pd); > } > -- > 1.9.1 > Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Ulf, On Wed, Apr 27, 2016 at 3:59 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote: > On 26 April 2016 at 09:09, Geert Uytterhoeven <geert+renesas@glider.be> wrote: >> As a pure Clock Domain does not have the concept of powering the domain >> itself, the CPG/MSTP driver does not provide power_off() and power_on() >> callbacks. >> However, the genpd core may still perform a dummy power down, causing >> /sys/kernel/debug/pm_genpd/pm_genpd_summary to report the domain's >> status being "off-0". >> >> Use the always-on governor to make sure the domain is never powered >> down, and always shows up as "on" in pm_genpd_summary. > > Hmm. > > Hypothetically, what if the clock domain would be a subdomain, where > its master is able to power down? Using the always on governor would > prevent the master from power off as well. That's correct. However, on R-Mobile/R-Car SoCs, this is not the case, so it doesn't matter here. > I am wondering whether we should introduce some similar as > pm_runtime_no_callbacks() but for the generic PM domain instead. > > What do you think? In my case, the domain is not managed by its parent, to there's no such analogy. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 27 April 2016 at 16:04, Geert Uytterhoeven <geert@linux-m68k.org> wrote: > Hi Ulf, > > On Wed, Apr 27, 2016 at 3:59 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote: >> On 26 April 2016 at 09:09, Geert Uytterhoeven <geert+renesas@glider.be> wrote: >>> As a pure Clock Domain does not have the concept of powering the domain >>> itself, the CPG/MSTP driver does not provide power_off() and power_on() >>> callbacks. >>> However, the genpd core may still perform a dummy power down, causing >>> /sys/kernel/debug/pm_genpd/pm_genpd_summary to report the domain's >>> status being "off-0". >>> >>> Use the always-on governor to make sure the domain is never powered >>> down, and always shows up as "on" in pm_genpd_summary. >> >> Hmm. >> >> Hypothetically, what if the clock domain would be a subdomain, where >> its master is able to power down? Using the always on governor would >> prevent the master from power off as well. > > That's correct. However, on R-Mobile/R-Car SoCs, this is not the case, so it > doesn't matter here. > >> I am wondering whether we should introduce some similar as >> pm_runtime_no_callbacks() but for the generic PM domain instead. >> >> What do you think? > > In my case, the domain is not managed by its parent, to there's no such > analogy. Ok, fair enough. This looks good to me! Kind regards Uffe > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/clk/renesas/clk-mstp.c b/drivers/clk/renesas/clk-mstp.c index 969fbb61ab07b9b8..5093a250650dad6d 100644 --- a/drivers/clk/renesas/clk-mstp.c +++ b/drivers/clk/renesas/clk-mstp.c @@ -319,7 +319,7 @@ void __init cpg_mstp_add_clk_domain(struct device_node *np) pd->flags = GENPD_FLAG_PM_CLK; pd->attach_dev = cpg_mstp_attach_dev; pd->detach_dev = cpg_mstp_detach_dev; - pm_genpd_init(pd, &simple_qos_governor, false); + pm_genpd_init(pd, &pm_domain_always_on_gov, false); of_genpd_add_provider_simple(np, pd); }
As a pure Clock Domain does not have the concept of powering the domain itself, the CPG/MSTP driver does not provide power_off() and power_on() callbacks. However, the genpd core may still perform a dummy power down, causing /sys/kernel/debug/pm_genpd/pm_genpd_summary to report the domain's status being "off-0". Use the always-on governor to make sure the domain is never powered down, and always shows up as "on" in pm_genpd_summary. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- drivers/clk/renesas/clk-mstp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)