On Fri, 8 Mar 2024 at 12:47, Satya Priya Kakitapalli (Temp)
<quic_skakitap@xxxxxxxxxxx> wrote:
>
>
> On 3/6/2024 7:25 PM, Bryan O'Donoghue wrote:
> > On 06/03/2024 08:30, Satya Priya Kakitapalli (Temp) wrote:
> >>>
> >>> Anyway I suspect the right thing to do is to define a
> >>> titan_top_gdsc_clk with shared ops to "park" the GDSC clock to 19.2
> >>> MHz instead of turning it off.
> >>>
> >>> You can get rid of the hard-coded always-on and indeed represent the
> >>> clock in /sysfs - which is preferable IMO to just whacking registers
> >>> to keep clocks always-on in probe anyway.
> >>>
> >>> Please try to define the titan_top_gdsc_clk as a shared_ops clock
> >>> instead of hard coding to always on.
> >>>
> >>
> >> Defining the gdsc clk allows consumers to control it, we do not want
> >> this clock to be disabled/controlled from consumers. Hence it is
> >> better to not model this clock and just keep it always on from probe.
> >
> > Not if you mark it critical
> >
>
> Marking the clock as critical keeps the associated power domain
> always-on which impacts power. For this reason we are not using
> CLK_IS_CRITICAL and instead making them always on from probe.
Please consider using pm_clk instead. This is a cleaner solution
compared to keeping the clocks always on.
> > static struct clk_branch cam_cc_gdsc_clk = {
> > .halt_reg = 0xc1e4,
> > .halt_check = BRANCH_HALT,
> > .clkr = {
> > .enable_reg = 0xc1e4,
> > .enable_mask = BIT(0),
> > .hw.init = &(struct clk_init_data){
> > .name = "cam_cc_gdsc_clk",
> > .parent_hws = (const struct clk_hw*[]){
> > &cam_cc_xo_clk_src.clkr.hw
> > },
> > .num_parents = 1,
> > .flags = CLK_IS_CRITICAL | CLK_SET_RATE_PARENT,
> > .ops = &clk_branch2_ops,
> > },
> > },
> > };
> >
> > and then add this to your camss clocks
> >
> > <&clock_camcc CAM_CC_GDSC_CLK>;
> >
> > The practice we have of just whacking clocks always-on in the probe()
> > of the clock driver feels lazy to me, leaving the broken cleanups we
> > have aside.
> >
> > As a user of the system I'd rather see correct/complete data in
> > /sys/kernel/debug/clk/clk_summary
> >
> > Anyway I'm fine with setting the clock always on, I can always send
> > out a series to address this bug-bear myself.
> >
> > So yeah just fix the cleanup and then please feel free to add my
> >
> > Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
>
--
With best wishes
Dmitry
