Re: [PATCH v2 3/3] media: camss: Link CAMSS power domain

Bryan O'Donoghue
2023-05-26T21:17:13Z

On 26/05/2023 21:57, Konrad Dybcio wrote:
> This code contains a whole bunch of hacky counting logic that should have
> been substituted with _byname, but now we're stuck with indices to keep
> compatibility with old DTs :/
>
> If CAMSS_GDSC (talking about pre-TITAN hw) was a parent of all the other
> CAMSS-related GDSCs, we could make it their parent in the clock driver
> and call it a day.

I mean, it wouldn't make much sense from a hw design POV if that weren't
the case..

Hmm looks like its already there.

static struct gdsc vfe0_gdsc = {
.gdscr = 0x3664,
.cxcs = (unsigned int []){ 0x36a8 },
.cxc_count = 1,
.pd = {
.name = "vfe0",
},
.parent = &camss_gdsc.pd,
.pwrsts = PWRSTS_OFF_ON,
};

static struct gdsc vfe1_gdsc = {
.gdscr = 0x3674,
.cxcs = (unsigned int []){ 0x36ac },
.cxc_count = 1,
.pd = {
.name = "vfe1",
},
.parent = &camss_gdsc.pd,
.pwrsts = PWRSTS_OFF_ON,
};

I feel this is probably a problem in the description of dependencies for
the CSIPHY in the dts for the 8996..

I.e. the CSIPHY requires some clocks and power-rails to be switched on ah..

static const struct resources csiphy_res_8x96[] = {
/* CSIPHY0 */
{
.regulators = {},
.clock = { "top_ahb", "ispif_ahb", "ahb",
"csiphy0_timer" },

should probably look something like

static const struct resources csiphy_res_8x96[] = {
/* CSIPHY0 */
{
.regulators = {},
.clock = { "top_ahb", "ispif_ahb", "ahb",
"csiphy0_timer", "vfe0"},

But basically yeah, we haven't modeled the dependency to the CAMSS_GDSC
via the VFEx

Hmm wait - why haven't we included the CAMSS_GDSC in the dtsi for the 8996 ?

git diff
diff --git a/arch/arm64/boot/dts/qcom/msm8996.dtsi
b/arch/arm64/boot/dts/qcom/msm8996.dtsi
index 30257c07e1279..60e5d3f5336d4 100644
--- a/arch/arm64/boot/dts/qcom/msm8996.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8996.dtsi
@@ -2120,7 +2120,8 @@ camss: camss@a00000 {
"vfe0",
"vfe1";
power-domains = <&mmcc VFE0_GDSC>,
- <&mmcc VFE1_GDSC>;
+ <&mmcc VFE1_GDSC>,
+ <&mmcc CAMSS_GDSC>;

Either of those approaches should mitigate this patch.

---
bod