On 16.07.2024 6:46 PM, Dmitry Baryshkov wrote:
> On Tue, Jul 16, 2024 at 03:46:24PM GMT, neil.armstrong@xxxxxxxxxx wrote:
>> On 16/07/2024 15:44, Dmitry Baryshkov wrote:
>>> On Tue, 16 Jul 2024 at 15:32, Neil Armstrong <neil.armstrong@xxxxxxxxxx> wrote:
>>>>
>>>> On 16/07/2024 13:20, Dmitry Baryshkov wrote:
>>>>> On Tue, Jul 16, 2024 at 11:05:22AM GMT, Neil Armstrong wrote:
>>>>>> Add the missing CLK_SET_RATE_PARENT for the byte0_div_clk_src
>>>>>> and byte1_div_clk_src, the clock rate should propagate to
>>>>>> the corresponding _clk_src.
>>>>>>
>>>>>> Fixes: 9e939f008338 ("clk: qcom: add the SM8650 Display Clock Controller driver")
>>>>>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
>>>>>> Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
>>>>>> ---
>>>>>> drivers/clk/qcom/dispcc-sm8650.c | 2 ++
>>>>>> 1 file changed, 2 insertions(+)
>>>>>
>>>>> This doesn't seem correct, the byte1_div_clk_src is a divisor, so the
>>>>> rate should not be propagated. Other platforms don't set this flag.
>>>>>
>>>>
>>>> Why not ? the disp_cc_mdss_byte1_clk_src has CLK_SET_RATE_PARENT and a div_table,
>>>> and we only pass DISP_CC_MDSS_BYTE1_CLK to the dsi controller.
>>>
>>> Yes, the driver sets byte_clk with the proper rate, then it sets
>>> byte_intf_clk, which results in a proper divisor.
>>> If we have CLK_SET_RATE_PARENT for byte1_div_clk_src, then setting
>>> byte_intf_clk rate will also result in a rate change for the byte_clk
>>> rate.
>>>
>>> Note, all other platforms don't set that flag for this reason (I think
>>> I had to remove it during sm8450 development for this reason).
>>>
>>
>> Ack, I think this deserves a comment explaining this, I'll add it.
>
> But where to place it? This applies to _all_ dispcc controllers.
Commit message
Konrad
