Re: [PATCH 02/16] media: qcom: camss: csiphy-3ph: Remove redundant PHY init sequence control loop

[Depeng Shao]

Hi Bryan,

On 12/11/2024 11:38 PM, Bryan O'Donoghue wrote:
> On 11/12/2024 14:07, Depeng Shao wrote:
> > From: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> >
> > Adding a new CSIPHY init sequence using downstream as a reference 
> > prompted
> > me to look at why we are splitting up the init sequence into chunks.
> >
> > Right now we declare CSI PHY init sequences as an array of five equally
> > sized writes with a hard-coded control loop to iterate through each of 
> > the
> > five indexes. One bug in this model is that if you don't have an even
> > number of writes, you can't init the PHY as you wish.
> >
> > In downstream the original code has something of the character
> > phy_init_seq[MAX_LANES][MAX_PARAMS] which in upstream we have translated
> > into phy_init_seq[5][SOME_NUMBER_OF_EQUAL_WRITES];
> >
> > What the code does is take a pointer to the first index of the
> > r = &phy_init_seq[0][0]; and then literally does write(r, value); r++;
> >
> > The controlling loop that hard-codes '5' in-lieu of MAX_LANES does no
> > special sleep, fabric-coherence sync or even a printk() to justify its
> > existence. Our compilers are optimising all of this away anyway so lets
> > drop.
> >
> > Reduce the array declaration down to one flat aggregate init and let the
> > code just step through. As a happy side-effect we can then also handle
> > odd-number writes as the number of elements in the init sequence will no
> > longer have to be evenly divisible.
> >
> > Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> > Signed-off-by: Depeng Shao <quic_depengs@xxxxxxxxxxx>
> > Reviewed-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
> > Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@xxxxxxxxxx>
> > ---
>
> A new version of this patch is required to ensure 7280 is handled
>
> https://git.codelinaro.org/bryan.odonoghue/kernel/-/ 
> commit/4c831fd58aa7629f994b5f4d8533b154a74d35cc

Sure, I will pick the latest version.

Thanks,
Depeng