usb: core: add phy notify connect and disconnect

In Realtek SoC, the parameter of usb phy is designed to can dynamic
tuning base on port status. Therefore, add a notify callback of generic
phy driver when usb device connect and disconnect change.

The Realtek phy driver is designed to dynamically adjust disconnection
level and calibrate phy parameters. When the device connected bit changes
and when the disconnected bit changes, do connection change notification:

Check if portstatus is USB_PORT_STAT_CONNECTION and portchange is
USB_PORT_STAT_C_CONNECTION.
1. The device is connected, the driver lowers the disconnection level and
calibrates the phy parameters.
2. The device disconnects, the driver increases the disconnect level and
calibrates the phy parameters.

Generic phy driver in usb core framework does not support device connect
and disconnect notifications. Therefore, we add an api to notify phy
the connection changes.

Additionally, the generic phy only specifies primary_hcd in the original
design. Added specific "usb2-phy" on primary_hcd and "usb3-phy" on
shared_hcd.

Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
Link: https://lore.kernel.org/r/20231213031203.4911-4-stanley_chang@realtek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: core: phy: add support for PHY calibration

Some PHYs (for example Exynos5 USB3.0 DRD PHY) require calibration to be
done after every USB HCD reset. Generic PHY framework has been already
extended with phy_calibrate() function in commit 36914111e682 ("drivers:
phy: add calibrate method"). This patch adds support for it to generic
PHY handling code in USB HCD core.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Tested-by: Jochen Sprickerhof <jochen@sprickerhof.de>
Link: https://lore.kernel.org/r/20190829053028.32438-2-m.szyprowski@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: core: comply to PHY framework

Current implementation of the USB core does not take into account the
new PHY framework. Correct the situation by adding a call to
phy_set_mode() before phy_power_on().

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: core: phy: clean up return value check about devm_of_phy_get_by_index()

Use IS_ERR() instead of IS_ERR_OR_NULL() because devm_of_phy_get_by_index()
never return NULL value;
But still need ignore the error of -ENODEV, for more information, please
refer to:
[0] https://lkml.org/lkml/2018/4/19/88
[1] https://patchwork.kernel.org/patch/10160181/

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: core: phy: make it a no-op if CONFIG_GENERIC_PHY is disabled

If the generic PHY support is disabled the stub of devm_of_phy_get_by_index
returns ENOSYS. This corner case isn't handled properly by
usb_phy_roothub_add_phy and at least breaks USB support on Raspberry Pi
(bcm2835_defconfig):

dwc2 20980000.usb: dwc2_hcd_init() FAILED, returning -38
dwc2: probe of 20980000.usb failed with error -38

Let usb_phy_roothub_alloc() return in case CONFIG_GENERIC_PHY is
disabled to fix this issue (compilers might even be smart enough to
optimize away most of the code within usb_phy_roothub_alloc and
usb_phy_roothub_add_phy if CONFIG_GENERIC_PHY is disabled). All
existing usb_phy_roothub_* functions are already NULL-safe, so no
special handling is required there.

Fixes: 07dbff0ddbd8 ("usb: core: add a wrapper for the USB PHYs on the HCD")
Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: core: use phy_exit during suspend if wake up is not supported

If the USB controller can wake up the system (which is the case for
example with the Mediatek USB3 IP) then we must not call phy_exit during
suspend to ensure that the USB controller doesn't have to re-enumerate
the devices during resume.
However, if the USB controller cannot wake up the system (which is the
case for example on various TI platforms using a dwc3 controller) then
we must call phy_exit during suspend. Otherwise the PHY driver keeps the
clocks enabled, which prevents the system from reaching the lowest power
levels in the suspend state.

Solve this by introducing two new functions in the PHY wrapper which are
dedicated to the suspend and resume handling.
If the controller can wake up the system the new usb_phy_roothub_suspend
function will simply call usb_phy_roothub_power_off. However, if wake up
is not supported by the controller it will also call
usb_phy_roothub_exit.
The also new usb_phy_roothub_resume function takes care of calling
usb_phy_roothub_init (if the controller can't wake up the system) in
addition to usb_phy_roothub_power_on.

Fixes: 07dbff0ddbd86c ("usb: core: add a wrapper for the USB PHYs on the HCD")
Fixes: 178a0bce05cbc1 ("usb: core: hcd: integrate the PHY wrapper into the HCD core")
Reported-by: Roger Quadros <rogerq@ti.com>
Suggested-by: Roger Quadros <rogerq@ti.com>
Suggested-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Roger Quadros <rogerq@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: core: split usb_phy_roothub_{init,alloc}

Before this patch usb_phy_roothub_init served two purposes (from a
caller's point of view - like hcd.c):
- parsing the PHYs and allocating the list entries
- calling phy_init on each list entry

While this worked so far it has one disadvantage: if we need to call
phy_init for each PHY instance then the existing code cannot be re-used.
Solve this by splitting off usb_phy_roothub_alloc which only parses the
PHYs and allocates the list entries.
usb_phy_roothub_init then gets a struct usb_phy_roothub and only calls
phy_init on each PHY instance (along with the corresponding cleanup if
that failed somewhere).

This is a preparation step for adding proper suspend support for some
hardware that requires phy_exit to be called during suspend and phy_init
to be called during resume.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Roger Quadros <rogerq@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: core: phy: fix return value of usb_phy_roothub_exit()

usb_phy_roothub_exit() should return the error code from the phy_exit()
call if exiting the PHY failed.
However, since a wrong variable is used usb_phy_roothub_exit() currently
always returns 0, even if one of the phy_exit calls returned an error.
Clang also reports this bug:
kernel/drivers/usb/core/phy.c:114:8: warning: explicitly assigning value of
variable of type 'int' to itself [-Wself-assign] error, forbidden
warning: phy.c:114

Fix this by assigning the error code from phy_exit() to the "ret"
variable to propagate the error correctly.

Fixes: 07dbff0ddbd86c ("usb: core: add a wrapper for the USB PHYs on the HCD")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: core: add a wrapper for the USB PHYs on the HCD

Many SoC platforms have separate devices for the USB PHY which are
registered through the generic PHY framework. These PHYs have to be
enabled to make the USB controller actually work. They also have to be
disabled again on shutdown/suspend.

Currently (at least) the following HCI platform drivers are using custom
code to obtain all PHYs via devicetree for the roothub/controller and
disable/enable them when required:
- ehci-platform.c has ehci_platform_power_{on,off}
- xhci-mtk.c has xhci_mtk_phy_{init,exit,power_on,power_off}
- ohci-platform.c has ohci_platform_power_{on,off}

With this new wrapper the USB PHYs can be specified directly in the
USB controller's devicetree node (just like on the drivers listed
above). This allows SoCs like the Amlogic Meson GXL family to operate
correctly once this is wired up correctly. These SoCs use a dwc3
controller and require all USB PHYs to be initialized (if one of the USB
PHYs it not initialized then none of USB port works at all).

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Yixun Lan <yixun.lan@amlogic.com>
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Tested-by: Neil Armstrong <narmstrong@baylibre.con>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>