[PATCH v3] phy: Track power-on and init counts in uclass

[Tom Rini]

On Thu, Dec 30, 2021 at 10:36:51PM +0300, Alper Nebi Yasak wrote:

> On boards using the RK3399 SoC, the USB OHCI and EHCI controllers share
> the same PHY device instance. While these controllers are being stopped
> they both attempt to power-off and deinitialize it, but trying to
> power-off the deinitialized PHY device results in a hang. This usually
> happens just before booting an OS, and can be explicitly triggered by
> running "usb start; usb stop" in the U-Boot shell.
> 
> Implement a uclass-wide counting mechanism for PHY initialization and
> power state change requests, so that we don't power-off/deinitialize a
> PHY instance until all of its users want it done. The Allwinner A10 USB
> PHY driver does this counting in-driver, remove those parts in favour of
> this in-uclass implementation.
> 
> The sandbox PHY operations test needs some changes since the uclass will
> no longer call into the drivers for actions matching its tracked state
> (e.g. powering-off a powered-off PHY). Update that test, and add a new
> one which simulates multiple users of a single PHY.
> 
> The major complication here is that PHY handles aren't deduplicated per
> instance, so the obvious idea of putting the counts in the PHY handles
> don't immediately work. It seems possible to bind a child udevice per
> PHY instance to the PHY provider and deduplicate the handles in each
> child's uclass-private areas, like in the CLK framework. An alternative
> approach could be to use those bound child udevices themselves as the
> PHY handles. Instead, to avoid the architectural changes those would
> require, this patch solves things by dynamically allocating a list of
> structs (one per instance) in the provider's uclass-private area.
> 
> Signed-off-by: Alper Nebi Yasak <alpernebiyasak at gmail.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> Tested-by: Peter Robinson <pbrobinson at gmail.com> - Rock960

Applied to u-boot/master, thanks!

-- 
Tom
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