Re: [PATCH v4 3/6] media: qcom: camss: csiphy-3ph: Add Gen2 v1.1 two-phase MIPI CSI-2 DPHY init

[Bryan O'Donoghue]

On 09/11/2023 13:55, Konrad Dybcio wrote:
> On 11/9/23 12:30, Bryan O'Donoghue wrote:
> > Add a PHY configuration sequence for the sc8280xp which uses a Qualcomm
> > Gen 2 version 1.1 CSI-2 PHY.
> >
> > The PHY can be configured as two phase or three phase in C-PHY or D-PHY
> > mode. This configuration supports two-phase D-PHY mode.
> >
> > Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> > ---
> Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
>
> Aside from initialization, looks like the reset seq should be more
> complex:
>
> https://git.codelinaro.org/clo/la/platform/vendor/opensource/camera-kernel/-/blob/LA.AU.1.3.7-02900-gen3_gvmgh.0/drivers/cam_sensor_module/cam_csiphy/include/cam_csiphy_1_1_hwreg.h?ref_type=tags#L39-45
>
> https://git.codelinaro.org/clo/la/platform/vendor/opensource/camera-kernel/-/blob/LA.AU.1.3.7-02900-gen3_gvmgh.0/drivers/cam_sensor_module/cam_csiphy/cam_csiphy_core.c#L133-154
>
> similarly for the "common regs" that seem to extend the init seq
>
> https://git.codelinaro.org/clo/la/platform/vendor/opensource/camera-kernel/-/blob/LA.AU.1.3.7-02900-gen3_gvmgh.0/drivers/cam_sensor_module/cam_csiphy/cam_csiphy_core.c#L491-527
>
> Konrad

So..

https://git.codelinaro.org/clo/la/platform/vendor/opensource/camera-kernel/-/blob/LA.AU.1.3.7-02900-gen3_gvmgh.0/drivers/cam_sensor_module/cam_csiphy/include/cam_csiphy_1_1_hwreg.h?ref_type=tags#L39

static struct csiphy_reg_t csiphy_reset_reg_1_1[] = {
	{0x0814, 0x00, 0x05, CSIPHY_LANE_ENABLE}, // this is interesting
                                                  // powers off lanemask
                                                  // seems like a good
                                                  // idea to me
	{0x0818, 0x00, 0x00, CSIPHY_DEFAULT_PARAMS}, [1]
	{0x081C, 0x00, 0x00, CSIPHY_DEFAULT_PARAMS}, [2]
	{0x0800, 0x01, 0x01, CSIPHY_DEFAULT_PARAMS}, // this we already
	{0x0800, 0x00, 0x00, CSIPHY_DEFAULT_PARAMS}, // do right now
};

[1] [2] I don't see why you need that and I'd imagine the reset drives 
these values to zero anyway.. it should as I read the reg docs, I'd 
guess this is a reset sequence that comes out of a Si test bench.

The 0x814 warrants an investigation - i.e. can we add it across 
platforms without breaking existing setups.

I'll kick that to a separate - one LOC "series", so we can take our time 
validating if it has any unexpected side-effects across our various 
platforms.

---
bod