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SubjectRe: [PATCH 17/22] phy: qcom-qmp-combo: merge USB and DP configurations
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On 14/11/2022 11:54, Johan Hovold wrote:
> On Sat, Nov 12, 2022 at 10:43:14AM +0300, Dmitry Baryshkov wrote:
>> On 11/11/2022 11:56, Johan Hovold wrote:
>>> It does not really make any sense to keep separate configuration
>>> structures for the USB and DP parts of the same PHY so merge them.
>>>
>>> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
>>> ---
>>> drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 182 +++++++---------------
>>> 1 file changed, 57 insertions(+), 125 deletions(-)
>>>
>>> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
>>> index b27d1821116c..249912b75964 100644
>>> --- a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
>>> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
>>> @@ -798,10 +798,7 @@ static const u8 qmp_dp_v5_voltage_swing_hbr_rbr[4][4] = {
>>>
>>> struct qmp_phy;
>>>
>>> -/* struct qmp_phy_cfg - per-PHY initialization config */
>>> struct qmp_phy_cfg {
>>> - /* phy-type - PCIE/UFS/USB */
>>> - unsigned int type;
>>> int lanes;
>>
>> int lanes doesn't really make sense here in my opinion. It should be
>> usb_lanes and dp_lanes.
>
> It doesn't make much less sense than having it here currently do.
>
> All of these USB-C PHYs are dual lane for bi-directional SS USB and
> quad lane for uni-directional DP (even if only CC1 orientation and lanes
> 2 and 3 are currently supported).

I was under impression that sdm845 has just a single lane for each of
USB and DP. After rechecking the phy/next, I see that it was my mistake
(quite logical, SS is two lanes, so the compliant PHY must have two
lanes too).

I wander how/if 4-lane DP works. The only thing that we do is
programming of the QSERDES_DP_PHY_PD_CTL register, however judging e.g.
your 4-lane PCIe changes, one should probably also program the other two
lanes. Maybe it is handled automatically inside the hardware.

> I should probably just drop the lanes parameter completely, either as a
> preparatory clean up or as follow-on one (e.g. also a bit depending on
> if there are other reasons for respinning a v2).

I think a follow up is enough, but let's get it. Having a single lanes=2
field looks... strange.

--
With best wishes
Dmitry

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