Commit Graph

3 Commits

Author SHA1 Message Date
Martin Blumenstingl
bc4a0241d4 phy: amlogic: phy-meson-gxl-usb2: support the clock and reset line
The Meson GXL USB2 PHYs require an additional clock (USB) which has to
be enabled. If that clock is disabled then all PHY registers read 0x0.
Luckily for us that clock is always enabled (either by harddware
defaults, the bootrom, or any of the bootloaders before u-boot/BL3-3).

The OTG capable USB2 PHY additionally has a reset line (USB_OTG, which
is shared with other components, such as the USB3 PHY for example).

Extend the driver so it handles this clock and the shared reset line.
We only trigger the reset during the .init phase since it's a shared
reset line, so triggering it during the driver's .reset implementation
would effectively also only trigger it once anyways.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
2018-03-08 13:56:27 +05:30
Martin Blumenstingl
cba1372812 phy: amlogic: phy-meson-gxl-usb2: don't log an error on -EPROBE_DEFER
devm_phy_create can return -EPROBE_DEFER if the phy-supply is not ready
yet. Silence this warning as the driver framework will re-attempt
registering the PHY - this second try works without any errors. So only
log actual errors to keep the kernel log free of misleading error
messages.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
2018-03-08 13:56:26 +05:30
Martin Blumenstingl
697b373c6d phy: meson: add USB2 PHY support for Meson GXL and GXM
This adds a new driver for the USB2 PHYs found on Meson GXL and GXM SoCs
(both SoCs are using the same USB PHY register layout).

The USB2 PHY is a simple PHY which only has a few registers to configure
the mode (host/device) and a reset register (to enable/disable the PHY).

Unfortunately there are no datasheets available for this PHY. The driver
was written by reading the code from Amlogic's GPL kernel sources and
by analyzing the registers on an actual GXL and GXM device running the
kernel that was shipped on the boards I have.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
2017-06-06 14:49:47 +05:30