Re: [PATCH v4 11/22] phy: renesas: rcar-gen3-usb2: Use mux-state for phyrst management

Tommaso Merciai
2025-11-25T15:57:44Z

Hi Geert,
Thanks for your review!

On Tue, Nov 25, 2025 at 03:10:22PM +0100, Geert Uytterhoeven wrote:
> Hi Tommaso,
>
> On Fri, 21 Nov 2025 at 16:14, Tommaso Merciai
> <tommaso.merciai.xr@bp.renesas.com> wrote:
> > Add support for selecting the phyrst mux-state using the Linux mux
> > subsystem in the R-Car Gen3 USB2 PHY driver. This ensures correct hardware
> > initialization and integration with systems utilizing the mux-state device
> > tree property.
> >
> > A temporary wrapper for optional muxes is introduced until native support
> > is available in the multiplexer subsystem.
> >
> > Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
>
> Thanks for your patch!
>
> > --- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> > +++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> > @@ -938,11 +939,27 @@ static int rcar_gen3_phy_usb2_vbus_regulator_register(struct rcar_gen3_chan *cha
> > return rcar_gen3_phy_usb2_vbus_regulator_get_exclusive_enable(channel, enable);
> > }
> >
> > +/* Temporary wrapper until the multiplexer subsystem supports optional muxes */
> > +static inline struct mux_state *
> > +devm_mux_state_get_optional(struct device *dev, const char *mux_name)
> > +{
> > + if (!of_property_present(dev->of_node, "mux-states"))
> > + return NULL;
> > +
> > + return devm_mux_state_get(dev, mux_name);
> > +}
> > +
> > +static void rcar_gen3_phy_mux_state_deselect(void *data)
> > +{
> > + mux_state_deselect(data);
> > +}
> > +
> > static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
> > {
> > struct device *dev = &pdev->dev;
> > struct rcar_gen3_chan *channel;
> > struct phy_provider *provider;
> > + struct mux_state *mux_state;
> > int ret = 0, i, irq;
> >
> > if (!dev->of_node) {
> > @@ -1019,6 +1036,23 @@ static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
> > phy_set_drvdata(channel->rphys[i].phy, &channel->rphys[i]);
> > }
> >
> > + mux_state = devm_mux_state_get_optional(dev, NULL);
> > + if (IS_ERR(mux_state)) {
> > + if (PTR_ERR(mux_state) == -EPROBE_DEFER)
> > + return PTR_ERR(mux_state);
> > + mux_state = NULL;
>
> No need to set mux_state to NULL, as mux_state is not used below.
>
> However, shouldn't you propagate all errors up?
> If the mux is not present, mux_state should already be NULL,
> i.e. IS_ERR(mux_state) would be false.
>
> > + } else {
> > + ret = mux_state_select(mux_state);
>
> This causes a crash on R-Car Gen3 and RZ/Five, as mux_state_select()
> doesn't handle NULL pointers gracefully yet.
>
> Adding a check like
>
> - } else {
> + } else if (mux_state) {
>
> fixes the issue.

Thank you for checking this!

Ack :)
I will switch to:

mux_state = devm_mux_state_get_optional(dev, NULL);
if (IS_ERR(mux_state)) {
return PTR_ERR(mux_state);
} else if (mux_state) {
ret = mux_state_select(mux_state);
if (ret)
return dev_err_probe(dev, ret, "Failed to select USB mux\n");

ret = devm_add_action_or_reset(dev, rcar_gen3_phy_mux_state_deselect,
mux_state);
if (ret)
return dev_err_probe(dev, ret,
"Failed to register USB mux state deselect\n");
}

In v5.

Kind Regards,
Tommaso

>
> > + if (ret)
> > + return dev_err_probe(dev, ret, "Failed to select USB mux\n");
> > +
> > + ret = devm_add_action_or_reset(dev, rcar_gen3_phy_mux_state_deselect,
> > + mux_state);
> > + if (ret)
> > + return dev_err_probe(dev, ret,
> > + "Failed to register USB mux state deselect\n");
> > + }
> > +
> > if (channel->phy_data->no_adp_ctrl && channel->is_otg_channel) {
> > ret = rcar_gen3_phy_usb2_vbus_regulator_register(channel);
> > if (ret)
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
>