Re: [PATCH v7 00/21] Move PMC clocks into Tegra PMC driver

[Sameer Pujar]

On 1/10/2020 10:06 AM, Sowjanya Komatineni wrote:
> On 1/9/20 7:32 PM, Sowjanya Komatineni wrote:
> > On 1/9/20 7:24 PM, Sowjanya Komatineni wrote:
> > > On 1/9/20 5:39 PM, Sowjanya Komatineni wrote:
> > > > On 1/9/20 11:44 AM, Dmitry Osipenko wrote:
> > > > > External email: Use caution opening links or attachments
> > > > >
> > > > >
> > > > > 08.01.2020 07:24, Sowjanya Komatineni ÐÐÑÐÑ:
> > > > > > This patch series moves Tegra PMC clocks from clock driver to pmc 
> > > > > > driver
> > > > > > along with the device trees changes and audio driver which uses 
> > > > > > one of
> > > > > > the pmc clock for audio mclk.
> > > > > >
> > > > > > Tegra PMC has clk_out_1, clk_out_2, clk_out_3 and blink controls 
> > > > > > which
> > > > > > are currently registered by Tegra clock driver using 
> > > > > > clk_regiser_mux and
> > > > > > clk_register_gate which performs direct Tegra PMC register access.
> > > > > >
> > > > > > When Tegra PMC is in secure mode, any access from non-secure 
> > > > > > world will
> > > > > > not go through.
> > > > > >
> > > > > > This patch series adds these Tegra PMC clocks and blink controls 
> > > > > > to Tegra
> > > > > > PMC driver with PMC as clock provider and removes them from Tegra 
> > > > > > clock
> > > > > > driver.
> > > > > >
> > > > > > PMC clock clk_out_1 is dedicated for audio mclk from Tegra30 thru 
> > > > > > Tegra210
> > > > > > and clock driver does inital parent configuration for it and 
> > > > > > enables them.
> > > > > > But this clock should be taken care by audio driver as there is 
> > > > > > no need
> > > > > > to have this clock pre enabled.
> > > > > >
> > > > > > So, this series also includes patch that updates ASoC driver to take
> > > > > > care of parent configuration for mclk if device tree don't specify
> > > > > > initial parent configuration using assigned-clock-parents and 
> > > > > > controls
> > > > > > audio mclk enable/disable during ASoC machine startup and shutdown.
> > > > > >
> > > > > > DTs are also updated to use clk_out_1 as audio mclk rather than 
> > > > > > extern1.
> > > > > >
> > > > > > This series also includes a patch for mclk fallback to extern1 when
> > > > > > retrieving mclk fails to have this backward compatible of new DT 
> > > > > > with
> > > > > > old kernels.
> > > > > Suspend-resume doesn't work anymore, reverting this series helps. I
> > > > > don't have any other information yet, please take a look.
> > > > Thanks Dmitry. Will test suspend resume and check..
> > >
> > > I see if we leave audio mclk (cdev1) enabled during 
> > > tegra_asoc_utils_init, suspend resume works.
> > >
> > > Without audio mclk enabled during tegra_asoc_utils_init, somehow it 
> > > prevents entry to suspend on Tegra30 platform.
> > >
> > > Will look in detail..
> > audio mclk is only needed for audio and werid that having it not 
> > enabled all the time like in current clock driver prevents suspend 
> > entry on Tegra30
> >
> > Looks like this issue is masked earlier with having mclk enabled all 
> > the time by clock driver.
> On linux-next without this patch series, I just disabled mclk to be 
> enabled all the time (removed set_rate from utils_init) and also 
> disabled default enable from clock driver.
>
> So somehow disabling mclk is preventing suspend entry.

This is strange.

> Probably debugging suspend issue on Tegra30 when audio mclk is 
> disabled can be done separately and will keep audio mclk enabled in 
> asoc_utils_init with comment mentioning this issue and fix as TBD to 
> move on with PMC clock fixes.

Sounds fine with me as the suspend/resume issue is not introduced in the 
current series. It can be addressed separately.

>