Re: [PATCH 04/12] clk: qcom: gcc-mdm9607: Fix BIMC PLL definition

[Konrad Dybcio]

On 6/10/26 7:58 PM, Stephan Gerhold wrote:
> On Wed, Jun 10, 2026 at 10:43:12PM +0530, Taniya Das wrote:
>> On 6/9/2026 7:44 PM, Stephan Gerhold wrote:
>>> The gcc-mdm9607 driver was originally based on gcc-msm8916, but a closer
>>> match nowadays is gcc-msm8909. Looking at the differences between
>>> gcc-mdm9607 and gcc-msm8909, there is quite some confusion around the
>>> definitions for the BIMC PLL.
>>>
>>> It turns out the BIMC PLL on MDM9607 is actually an Alpha PLL just like on
>>> MSM8909. We can vote for it using BIT(2), which explains why BIT(3) was
>>> used for GPLL2.
>>
>> BIMC PLL is never controlled from High Level OS (APSS). These are
>> controlled by other subsystems and voting should be via the ICC for BW
>> requirements.
>>
> 
> The driver doesn't really control the BIMC PLL here, the PLL is defined
> with fixed/shared/read-only ops so it mostly just exists to model the
> clock tree properly and have the clock rate readable for the PLL itself
> and any downstream consumers.
> 
> There are multiple drivers that do it like this (e.g. gcc-msm8916,
> gcc-msm8939), is there a reason why we should drop this?

My fear is that the kernel may have stale data at any point.. perhaps
unless we set CLK_GET_RATE_NOCACHE?

Konrad