Now that the upstream Type-C PHY code is getting broader test coverage we
got reports of USB devices plugged in during boot or those plugged in for
the first time after boot occasionally not working correctly.
This is partially caused by the USB2 parts of the PHY being left in an
unknown state by the previous boot stages. We reset all other parts during
probe but forgot about the USB2 PHY so let's fix that and actually reset
and power off the USB2 PHY as well.
Reported-by: James Calligeros <jcalligeros99@gmail.com>
Reported-by: Janne Grunau <j@jannau.net>
Fixes: 8e98ca1e74 ("phy: apple: Add Apple Type-C PHY")
Signed-off-by: Sven Peter <sven@kernel.org>
Reviewed-by: Janne Grunau <j@jannau.net>
Tested-by: Janne Grunau <j@jannau.net>
Link: https://patch.msgid.link/20260108-atcphy-coldboot-fix-v1-1-01c41c6e84f2@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The Apple Type-C PHY (ATCPHY) is a PHY for USB 2.0, USB 3.x,
USB4/Thunderbolt, and DisplayPort connectivity found in Apple Silicon SoCs.
The PHY handles muxing between these different protocols and also provides
the reset controller for the attached dwc3 USB controller.
There is no documentation available for this PHY and the entire sequence
of MMIO pokes has been figured out by tracing all MMIO access of Apple's
driver under a thin hypervisor and correlating the register reads/writes
to their kernel's debug output to find their names. Deviations from this
sequence generally results in the port not working or, especially when
the mode is switched to USB4 or Thunderbolt, to some watchdog resetting
the entire SoC.
This initial commit already introduces support for Display Port and
USB4/Thunderbolt but the drivers for these are not ready. We cannot
control the alternate mode negotiation and are stuck with whatever Apple's
firmware decides such that any DisplayPort or USB4/Thunderbolt device will
result in a correctly setup PHY but not be usable until the other drivers
are upstreamed as well.
Co-developed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Janne Grunau <j@jannau.net>
Co-developed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> # for reset controller
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Sven Peter <sven@kernel.org>
Link: https://patch.msgid.link/20251214-b4-atcphy-v3-3-ba82b20e9459@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
