Re: [PATCH 4/5] clk: qcom: Add camera clock controller driver for SM8150

[Bryan O'Donoghue]

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

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>