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
