Re: [PATCH v4 6/7] phy: exynos5-usbdrd: subscribe to orientation notifier if required

Hi Krzysztof,

On Sat, 2025-02-15 at 11:07 +0100, Krzysztof Kozlowski wrote:

On 14/02/2025 20:30, Marek Szyprowski wrote:

quoted

On 06.12.2024 17:31, André Draszik wrote:

quoted

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

Note that if the orientation-switch property is missing from the DT,
the code will behave as before this commit (meaning for gs101 it will
work in SS mode in one orientation only). Other platforms are not
affected either way.

Signed-off-by: André Draszik <andre.draszik@linaro.org>

---
v3:
* drop init to -1 of phy_drd->orientation (Vinod)
* avoid #ifdef and switch to normal conditional IS_ENABLED() for
   CONFIG_TYPEC

v2:
* move #include typec_mux.h from parent patch into this one (Peter)
---
  drivers/phy/samsung/Kconfig              |  1 +
  drivers/phy/samsung/phy-exynos5-usbdrd.c | 56 ++++++++++++++++++++++++++++++++
  2 files changed, 57 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)

BTW, this syntax never made any sense - it did not work. The optional
dependency is expressed as:
	depends on TYPEC || !TYPEC

The depends is required to get it to link. PHY_EXYNOS5_USBDRD
defaults to Y, while TYPEC defaults to M in the arm64 defconfig.
Using this expression, PHY_EXYNOS5_USBDRD changes to M.

Otherwise it won't link.

but what it epxressed is that it is possible to build it without typec
only for compile test, which is odd if this was meant to be optional.
And further code:
	if (!IS_ENABLED(CONFIG_TYPEC))

clearly suggests this should be optional.

Yes, it's meant to be optional.

Cheers,
Andre'