Linux-PHY Archive on lore.kernel.org

* Re: [PATCH 3/3] phy: qcom: edp: Add eDP phy mode switch support
From: Yongxing Mou @ 2026-02-25  8:00 UTC (permalink / raw)
  To: Konrad Dybcio, Vinod Koul, Neil Armstrong
  Cc: linux-arm-msm, linux-phy, linux-kernel
In-Reply-To: <f7fed0cc-0c59-4a75-b045-a83df924113d@oss.qualcomm.com>

On 2/13/2026 7:06 PM, Konrad Dybcio wrote:
> On 2/10/26 11:29 AM, Yongxing Mou wrote:
>>
>>
>> On 2/6/2026 7:02 PM, Konrad Dybcio wrote:
>>> On 2/5/26 10:20 AM, Yongxing Mou wrote:
>>>> Add DP/eDP switch support by splitting the PHY swing/pre-emphasis tables
>>>> into separate DP and eDP configurations. This allows the driver to select
>>>> the correct table based on the is_edp flag.
>>>>
>>>> Add a dedicated table for the SC7280/glymur platforms, as they are not
>>>> compatible with the others.
>>>>
>>>> Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
>>>> ---
>>>
>>> [...]
>>>
>>>> +static const u8 edp_swing_hbr2_hbr3_v3[4][4] = {
>>>> +    { 0x0b, 0x11, 0x16, 0x1b },
>>>> +    { 0x0b, 0x19, 0x1f, 0xff },
>>>> +    { 0x18, 0x1f, 0xff, 0xff },
>>>> +    { 0x1f, 0xff, 0xff, 0xff }
>>>> +};
>>>> +
>>>> +static const u8 edp_pre_emp_hbr2_hbr3_v3[4][4] = {
>>>> +    { 0x0c, 0x15, 0x19, 0x1e },
>>>> +    { 0x09, 0x14, 0x19, 0xff },
>>>> +    { 0x0f, 0x14, 0xff, 0xff },
>>>> +    { 0x0d, 0xff, 0xff, 0xff }
>>>> +};
>>>
>>> This is not quite in line with docs for kodiak. Now, if you have
>>> better/newer sequences than the HPG, I'm not objecting, but please
>>> cross-check
>>>
>>> the rest of this patch I think looks fine
>>>
>>> Konrad
>> Thanks for point that..
>>>> +static const u8 edp_swing_hbr2_hbr3_v3[4][4] = {
>>>> +    { 0x0b, 0x11, 0x16, 0x1b },
>> here should be { 0x06, 0x11, 0x16, 0x1b }, arr[0][1]: 0x0b->0x06
>> does this looks fine? will check tables again..
> 
> For kodiak I see:
> 
> eDP HBR23 / low vdiff:
> 
> swing
> 0x0b, 0x11, 0x17, 0x1c
> 0x10, 0x19, 0x1f
> 0x19, 0x1f
> 0x1f
> 
> preemp
> 0x0c, 0x15, 0x19, 0x1e
> 0x08, 0x15, 0x19
> 0x0e, 0x14
> 0x0d
> 
> (notice how that mostly differs by the lowest bit being (not)set vs
> your proposal)
> 
> eDP HBR23 / high vdiff:
> 
> swing
> 0x0a, 0x11, 0x17, 0x1f
> 0x0c, 0x14, 0x1d
> 0x15, 0x1f
> 0x17
> 
> preemp
> 
> 0x08, 0x11, 0x17, 0x1b
> 0x00, 0x0c, 0x13
> 0x05, 0x10,
> 0x00
> 
> Konrad
Hi, this is different from what I saw. what i saw
from kodiak HPG:
eDP low vdiff (High HBR):
  0x06, 0x11, 0x16, 0x1B
  0x0B, 0x19, 0x1f
  0x18, 0x1f
  0x1f

  preemp
  0x0c, 0x15, 0x19, 0x1e
  0x09, 0x14, 0x19
  0x0f, 0x14
  0x0d

eDP high vdiff (High HBR):
  swing
  0x0a, 0x11, 0x17, 0x1f
  0x0c, 0x14, 0x1d
  0x15, 0x1f
  0x17

  preemp

  0x08, 0x11, 0x16, 0x1b
  0x00, 0x0c, 0x13
  0x05, 0x10,
  0x00
The set of values you provided looks more like data from LeMans / 
SC8280xp / glymur (low vidff). I’ll follow up by email later to confirm 
whether this is due to us using different HPGs.

thanks.

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