[PATCH v2] phy: phy-imx8mq-usb: add vbus regulator support

[Tim Harvey]

On Mon, Jul 10, 2023 at 8:44 AM Marek Vasut <marex at denx.de> wrote:
>
> On 7/10/23 17:26, Tim Harvey wrote:
> > On Sat, Jul 8, 2023 at 1:55 PM Marek Vasut <marex at denx.de> wrote:
> >>
> >> On 6/9/23 19:28, Tim Harvey wrote:
> >>> Add support for enabling and disabling vbus-supply regulator found
> >>> on several imx8mp boards in the usb3_phy0 and usb3_phy1 nodes.
> >>>
> >>> Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> >>> Reviewed-by: Adam Ford <aford173 at gmail.com>
> >>> ---
> >>> v2:
> >>>    - protect ret with __maybe_unused in case CONFIG_CLK and
> >>>      CONFIG_DM_REGULATOR not defined
> >>>    - add error prints on failures
> >>>    - add Adam's rb tag
> >>> ---
> >>>    drivers/phy/phy-imx8mq-usb.c | 32 ++++++++++++++++++++++++++++++--
> >>>    1 file changed, 30 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/drivers/phy/phy-imx8mq-usb.c b/drivers/phy/phy-imx8mq-usb.c
> >>> index 69f01de55538..53099436b04b 100644
> >>> --- a/drivers/phy/phy-imx8mq-usb.c
> >>> +++ b/drivers/phy/phy-imx8mq-usb.c
> >>> @@ -14,6 +14,7 @@
> >>>    #include <linux/delay.h>
> >>>    #include <linux/err.h>
> >>>    #include <clk.h>
> >>> +#include <power/regulator.h>
> >>>
> >>>    #define PHY_CTRL0                   0x0
> >>>    #define PHY_CTRL0_REF_SSP_EN                BIT(2)
> >>> @@ -81,6 +82,7 @@ struct imx8mq_usb_phy {
> >>>    #endif
> >>>        void __iomem *base;
> >>>        enum imx8mpq_phy_type type;
> >>
> >> Shouldn't this be in #if CONFIG_IS_ENABLED(DM_REGULATOR) ?
> >>
> >>> +     struct udevice *vbus_supply;
> >
> > Hi Marek,
> >
> > No, the usage of it is within an 'if (CONFIG_IS_ENABLED(DM_REGULATOR)
> > && imx_phy->vbus_supply)' statement
>
> Except if this is not ifdef'd out, the structure is larger for no good
> reason if DM_REGULATOR is DISABLED.

ok, I see your point.

>
> >>>    };
> >>>
> >>>    static const struct udevice_id imx8mq_usb_phy_of_match[] = {
> >>> @@ -172,10 +174,10 @@ static int imx8mq_usb_phy_power_on(struct phy *usb_phy)
> >>>    {
> >>>        struct udevice *dev = usb_phy->dev;
> >>>        struct imx8mq_usb_phy *imx_phy = dev_get_priv(dev);
> >>> +     __maybe_unused int ret;
> >>>        u32 value;
> >>>
> >>>    #if CONFIG_IS_ENABLED(CLK)
> >>> -     int ret;
> >>>        ret = clk_enable(&imx_phy->phy_clk);
> >>>        if (ret) {
> >>>                printf("Failed to enable usb phy clock\n");
> >>> @@ -183,6 +185,14 @@ static int imx8mq_usb_phy_power_on(struct phy *usb_phy)
> >>>        }
> >>>    #endif
> >>>
> >>> +     if (CONFIG_IS_ENABLED(DM_REGULATOR) && imx_phy->vbus_supply) {
> >>> +             ret = regulator_set_enable(imx_phy->vbus_supply, true);
> >>> +             if (ret) {
> >>> +                     pr_err("Failed to enable VBUS regulator: %d\n", ret);
> >>
> >> You do need to disable clock enabled above.
> >
> > it does get disabled in imx8mq_usb_phy_power_off()
>
> If that called if power_on returns -ERRNO ?

sorry, I don't quite understand.

Are you asking me to add a regulator disable in a remove function to
make sure it's disabled if removed or are you saying that I shouldn't
return the error from regulator_set_enable from
imx8mq_usb_phy_power_on?

>
> >> This likely needs a fail path with "err: ... return ret;"
> >
> > there are no further conditional return paths in this function.
>
> I suspect there should be.

again, I don't understand. The only thing remaining in this function
is disable rx term override below so I don't see the point in adding a
goto around that if that is what you are suggesting.

I don't really know what 'rx term override' is either... perhaps the
regulator_set_enable should go after that?

best regards,

Tim
>
> >>> +                     return ret;
> >>> +             }
> >>> +     }
> >>> +
> >>>        /* Disable rx term override */
> >>>        value = readl(imx_phy->base + PHY_CTRL6);
> >>>        value &= ~PHY_CTRL6_RXTERM_OVERRIDE_SEL;
> >>> @@ -195,6 +205,7 @@ static int imx8mq_usb_phy_power_off(struct phy *usb_phy)
> >>>    {
> >>>        struct udevice *dev = usb_phy->dev;
> >>>        struct imx8mq_usb_phy *imx_phy = dev_get_priv(dev);
> >>> +     __maybe_unused int ret;
> >>>        u32 value;
> >>>
> >>>        /* Override rx term to be 0 */
> >>> @@ -206,6 +217,14 @@ static int imx8mq_usb_phy_power_off(struct phy *usb_phy)
> >>>        clk_disable(&imx_phy->phy_clk);
> >>>    #endif
> >>>
> >>> +     if (CONFIG_IS_ENABLED(DM_REGULATOR) && imx_phy->vbus_supply) {
> >>> +             ret = regulator_set_enable(imx_phy->vbus_supply, false);
> >>> +             if (ret) {
> >>> +                     pr_err("Failed to disable VBUS regulator: %d\n", ret);
> >>
> >> btw with DM, these can be dev_err() .
> >
> > Ok, I will send a v3 with that.
>
> Thanks !