[PATCH 8/9] phy: exynos5-usbdrd: subscribe to orientation notifier if required

[André Draszik]

Hi Vinod,

Thanks for your review.

On Wed, 2024-12-04 at 19:40 +0530, Vinod Koul wrote:
> On 27-11-24, 10:58, André Draszik wrote:
> > gs101's SS phy needs to be configured differently based on the
> > connector orientation, as the SS link can only be established if the
> > mux is configured correctly.
> > 
> > The code to handle programming of the mux is in place already, this commit
> > now adds the missing pieces to subscribe to the Type-C orientation
> > switch event.
> > 
> > Note that for this all to work we rely on the USB controller
> > re-initialising us. It should invoke our .exit() upon cable unplug, and
> > during cable plug we'll receive the orientation event after which we
> > expect our .init() to be called.
> > 
> > Above reinitialisation happens if the DWC3 controller can enter runtime
> > suspend automatically. For the DWC3 driver, this is an opt-in:
> >     echo auto > /sys/devices/.../11110000.usb/power/control
> > Once done, things work as long as the UDC is not bound as otherwise it
> > stays busy because it doesn't cancel / stop outstanding TRBs. For now
> > we have to manually unbind the UDC in that case:
> >      echo "" > sys/kernel/config/usb_gadget/.../UDC
> > 
> > Signed-off-by: André Draszik <andre.draszik at linaro.org>
> > ---
> >  drivers/phy/samsung/Kconfig              |  1 +
> >  drivers/phy/samsung/phy-exynos5-usbdrd.c | 60 ++++++++++++++++++++++++++++++++
> >  2 files changed, 61 insertions(+)
> > 
> > diff --git a/drivers/phy/samsung/Kconfig b/drivers/phy/samsung/Kconfig
> > index f10afa3d7ff5..fc7bd1088576 100644
> > --- a/drivers/phy/samsung/Kconfig
> > +++ b/drivers/phy/samsung/Kconfig
> > @@ -80,6 +80,7 @@ config PHY_EXYNOS5_USBDRD
> >  	tristate "Exynos5 SoC series USB DRD PHY driver"
> >  	depends on (ARCH_EXYNOS && OF) || COMPILE_TEST
> >  	depends on HAS_IOMEM
> > +	depends on TYPEC || (TYPEC=n && COMPILE_TEST)
> >  	depends on USB_DWC3_EXYNOS
> >  	select GENERIC_PHY
> >  	select MFD_SYSCON
> > diff --git a/drivers/phy/samsung/phy-exynos5-usbdrd.c b/drivers/phy/samsung/phy-exynos5-usbdrd.c
> > index 1a34e9b4618a..2010d25ee817 100644
> > --- a/drivers/phy/samsung/phy-exynos5-usbdrd.c
> > +++ b/drivers/phy/samsung/phy-exynos5-usbdrd.c
> > @@ -394,6 +394,7 @@ struct exynos5_usbdrd_phy_drvdata {
> >   * @extrefclk: frequency select settings when using 'separate
> >   *	       reference clocks' for SS and HS operations
> >   * @regulators: regulators for phy
> > + * @sw: TypeC orientation switch handle
> >   * @orientation: TypeC connector orientation - normal or flipped
> >   */
> >  struct exynos5_usbdrd_phy {
> > @@ -415,6 +416,7 @@ struct exynos5_usbdrd_phy {
> >  	u32 extrefclk;
> >  	struct regulator_bulk_data *regulators;
> >  
> > +	struct typec_switch_dev *sw;
> >  	enum typec_orientation orientation;
> >  };
> >  
> > @@ -1400,6 +1402,60 @@ static int exynos5_usbdrd_phy_clk_handle(struct exynos5_usbdrd_phy *phy_drd)
> >  	return 0;
> >  }
> >  
> > +#if IS_ENABLED(CONFIG_TYPEC)
> > +static int exynos5_usbdrd_orien_sw_set(struct typec_switch_dev *sw,
> > +				       enum typec_orientation orientation)
> > +{
> > +	struct exynos5_usbdrd_phy *phy_drd = typec_switch_get_drvdata(sw);
> > +
> > +	scoped_guard(mutex, &phy_drd->phy_mutex)
> > +		phy_drd->orientation = orientation;
> > +
> > +	return 0;
> > +}
> > +
> > +static void exynos5_usbdrd_orien_switch_unregister(void *data)
> > +{
> > +	struct exynos5_usbdrd_phy *phy_drd = data;
> > +
> > +	typec_switch_unregister(phy_drd->sw);
> > +}
> > +
> > +static int exynos5_usbdrd_setup_notifiers(struct exynos5_usbdrd_phy *phy_drd)
> > +{
> > +	int ret;
> > +
> > +	phy_drd->orientation = (enum typec_orientation)-1;
> 
> Should this be TYPEC_ORIENTATION_NONE?

It's -1 so that exynos5_usbdrd_orien_sw_set() (patch 9) can
check against the current value after driver load.

That said, it should probably be moved into patch 9 where it
actually matters, or even be removed altogether, in combination
with that check in exynos5_usbdrd_orien_sw_set() from patch 9.

I had added the check because some (not all) other phy drivers
do that, but looking further at that, I believe it's not
actually necessary, exynos5_usbdrd_orien_sw_set() can execute
unconditionally.

Will remove this and related code in next version.

Cheers,
Andre'