Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on

From	Peter De Schrijver <pdeschrijver@nvidia.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on
Date	2017-03-13 11:50 +0100
Message-ID	<tkvI6-7IV-21@gated-at.bofh.it> (permalink)
References	(1 earlier) <tgGsq-852-23@gated-at.bofh.it> <thWls-5tJ-17@gated-at.bofh.it> <thXKy-6FK-19@gated-at.bofh.it> <ti1XQ-146-39@gated-at.bofh.it> <ti49j-2x3-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Mon, Mar 06, 2017 at 04:53:48PM +0100, Geert Uytterhoeven wrote:
> Hi Peter,
> 
> On Mon, Mar 6, 2017 at 3:28 PM, Peter De Schrijver
> <pdeschrijver@nvidia.com> wrote:
> > On Mon, Mar 06, 2017 at 09:58:29AM +0000, Jon Hunter wrote:
> >> On 06/03/17 08:38, Peter De Schrijver wrote:
> >> > On Thu, Mar 02, 2017 at 05:56:49PM +0000, Jon Hunter wrote:
> >> >> On 28/02/17 15:19, Peter De Schrijver wrote:
> >> >>> This is needed to make the JTAG debugging interface work.
> >> >>>
> >> >>> Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
> >> >>> ---
> >> >>>  drivers/clk/tegra/clk-tegra210.c | 1 +
> >> >>>  1 file changed, 1 insertion(+)
> >> >>>
> >> >>> diff --git a/drivers/clk/tegra/clk-tegra210.c b/drivers/clk/tegra/clk-tegra210.c
> >> >>> index 9a2512a..708f5f1 100644
> >> >>> --- a/drivers/clk/tegra/clk-tegra210.c
> >> >>> +++ b/drivers/clk/tegra/clk-tegra210.c
> >> >>> @@ -2680,6 +2680,7 @@ static void tegra210_cpu_clock_resume(void)
> >> >>>   { TEGRA210_CLK_EMC, TEGRA210_CLK_CLK_MAX, 0, 1 },
> >> >>>   { TEGRA210_CLK_MSELECT, TEGRA210_CLK_CLK_MAX, 0, 1 },
> >> >>>   { TEGRA210_CLK_CSITE, TEGRA210_CLK_CLK_MAX, 0, 1 },
> >> >>> + { TEGRA210_CLK_DBGAPB, TEGRA210_CLK_CLK_MAX, 0, 1 },
> >> >>>   { TEGRA210_CLK_TSENSOR, TEGRA210_CLK_CLK_M, 400000, 0 },
> >> >>>   { TEGRA210_CLK_I2C1, TEGRA210_CLK_PLL_P, 0, 0 },
> >> >>>   { TEGRA210_CLK_I2C2, TEGRA210_CLK_PLL_P, 0, 0 },
> >> >>
> >> >> Should there be some dependency on say CONFIG_DEBUG_KERNEL? I am not
> >> >> sure we always want this on for all cases.
> >> >
> >> > Why would you not want it to be always on?
> >>
> >> Purely for power reasons. I do not know how much power keeping this
> >
> > I don't expect it to be significant but I don't have any numbers.
> >
> >> clock running consumes, but I don't like the idea of clocks running all
> >> the time when they are not needed.
> >
> > Problem is that in this case there is no easy way to determine if the clock
> > needs to be on.
> 
> I had a similar issue with SH-Mobile AG5, where the power domain containing
> the JTAG interface is powered down.
> 
> [DEBUG] ARM: dts: sh73a0: Add minimal device node for Coresight-ETM
> https://patchwork.kernel.org/patch/8151511/
> 
> Want to debug? Apply patch. I know it's not ideal...
> 

Don't you always want to debug? :-)

Peter.

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Jon Hunter <jonathanh@nvidia.com> - 2017-03-02 22:30 +0100
  Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Peter De Schrijver <pdeschrijver@nvidia.com> - 2017-03-06 09:40 +0100
    Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Jon Hunter <jonathanh@nvidia.com> - 2017-03-06 11:10 +0100
      Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Peter De Schrijver <pdeschrijver@nvidia.com> - 2017-03-06 15:40 +0100
        Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Jon Hunter <jonathanh@nvidia.com> - 2017-03-06 17:00 +0100
        Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Geert Uytterhoeven <geert@linux-m68k.org> - 2017-03-06 18:00 +0100
          Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Jon Hunter <jonathanh@nvidia.com> - 2017-03-07 21:30 +0100
            Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Geert Uytterhoeven <geert@linux-m68k.org> - 2017-03-08 11:20 +0100
          Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Jon Hunter <jonathanh@nvidia.com> - 2017-03-08 12:30 +0100
            Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Geert Uytterhoeven <geert@linux-m68k.org> - 2017-03-08 12:50 +0100
              Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Jon Hunter <jonathanh@nvidia.com> - 2017-03-08 13:20 +0100
                Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Peter De Schrijver <pdeschrijver@nvidia.com> - 2017-03-13 11:50 +0100
                Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Jon Hunter <jonathanh@nvidia.com> - 2017-03-13 12:10 +0100
                Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Peter De Schrijver <pdeschrijver@nvidia.com> - 2017-03-13 15:20 +0100
          Re: [PATCH] clk: tegra: mark TEGRA210_CLK_DBGAPB as always on Peter De Schrijver <pdeschrijver@nvidia.com> - 2017-03-13 11:50 +0100

csiph-web