Re: [PATCH v2 4/4] phy: qcom: phy-qcom-snps-eusb2: Add extra register write for Milos

["Luca Weiss" <luca.weiss@fairphone.com>]

On Thu Jul 10, 2025 at 2:29 PM CEST, Konrad Dybcio wrote:
> On 7/10/25 2:25 PM, Luca Weiss wrote:
>> On Thu Jul 10, 2025 at 2:10 PM CEST, Konrad Dybcio wrote:
>>> On 7/9/25 11:18 AM, Luca Weiss wrote:
>>>> As per the downstream devicetree for Milos, add a register write for
>>>> QCOM_USB_PHY_CFG_CTRL_1 as per the "eUSB2 HPG version 1.0.2 update".
>>>>
>>>> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
>>>> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
>>>> ---
>>>> The downstream driver supports an arbitrary extra init sequence via
>>>> qcom,param-override-seq.
>>>>
>>>> volcano-usb.dtsi has the following which is implemented in this patch:
>>>>
>>>>     /* eUSB2 HPG version 1.0.2 update */
>>>>     qcom,param-override-seq =
>>>>             <0x00 0x58>;
>>>> ---
>>>>  drivers/phy/phy-snps-eusb2.c | 6 ++++++
>>>>  1 file changed, 6 insertions(+)
>>>>
>>>> diff --git a/drivers/phy/phy-snps-eusb2.c b/drivers/phy/phy-snps-eusb2.c
>>>> index e232b8b4d29100b8fee9e913e2124788af09f2aa..87fc086424ba4d9fb3ce870aa7f7971a51d4a567 100644
>>>> --- a/drivers/phy/phy-snps-eusb2.c
>>>> +++ b/drivers/phy/phy-snps-eusb2.c
>>>> @@ -420,6 +420,12 @@ static int qcom_snps_eusb2_hsphy_init(struct phy *p)
>>>>  	/* set default parameters */
>>>>  	qcom_eusb2_default_parameters(phy);
>>>>  
>>>> +	if (of_device_is_compatible(p->dev.of_node, "qcom,milos-snps-eusb2-phy")) {
>>>> +		/* eUSB2 HPG version 1.0.2 update */
>>>> +		writel_relaxed(0x0, phy->base + QCOM_USB_PHY_CFG_CTRL_1);
>>>> +		readl_relaxed(phy->base + QCOM_USB_PHY_CFG_CTRL_1);
>>>
>>> Said HPG asks to clear bits [7:1] on all targets
>> 
>> Okay, so make this unconditional and only update those bits instead of
>> writing the full register?
>
> Yes
>
>> 
>> Keep the write at this location, or move the code somewhere else in the
>> function?
> Let's simply do this instead:
>
> diff --git a/drivers/phy/phy-snps-eusb2.c b/drivers/phy/phy-snps-eusb2.c
> index 87f323e758d6..6c44d0366f34 100644
> --- a/drivers/phy/phy-snps-eusb2.c
> +++ b/drivers/phy/phy-snps-eusb2.c
> @@ -392,7 +392,7 @@ static int qcom_snps_eusb2_hsphy_init(struct phy *p)
>  
>         snps_eusb2_hsphy_write_mask(phy->base, QCOM_USB_PHY_CFG_CTRL_1,
>                                     PHY_CFG_PLL_CPBIAS_CNTRL_MASK,
> -                                   FIELD_PREP(PHY_CFG_PLL_CPBIAS_CNTRL_MASK, 0x1));
> +                                   FIELD_PREP(PHY_CFG_PLL_CPBIAS_CNTRL_MASK, 0x0));
>  
>         snps_eusb2_hsphy_write_mask(phy->base, QCOM_USB_PHY_CFG_CTRL_4,
>                                     PHY_CFG_PLL_INT_CNTRL_MASK

Sounds reasonable, if the HPG suggests that...

Just asking myself why this wasn't updated in the driver but only added
via the qcom,param-override-seq for some SoCs. But downstream is still
downstream I guess.

Regards
Luca

>
>
> Konrad