The Tegra EHCI driver directly calls various functions in the Tegra USB
PHY driver. The reverse is also true; the PHY driver calls into the EHCI
driver. This is problematic when the two are built as modules.

The calls from the PHY to EHCI driver were originally added in commit
bbdabdb "usb: add APIs to access host registers from Tegra PHY", for the
following reasons:

1) The register being touched is an EHCI register, so logically only the
   EHCI driver should touch it.
2) (1) implies that some locking may be needed to correctly implement the
   r/m/w access to this shared register.
3) We were expecting to pass only the PHY register space to the Tegra PHY
   driver, and hence it would not have access to touch the shared
   registers.

To solve this, that commit added functions in the EHCI driver to touch the
shared register on behalf of the PHY driver.

In practice, we ended up not having any locking in the implementaiton of
those functions, and I've been led to believe this is safe. Equally, (3)
did not happen either. Hence, it is possible for the PHY driver to touch
the shared register directly.

Given that, this patch moves the code to touch the shared register back
into the PHY driver, to eliminate the module problems. If we actually
need locking or co-ordination in the future, I propose we put the lock
support into some pre-existing core module, or into a third separate
module, in order to avoid the circular dependencies.

I apologize for my contribution to code churn here.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Registered Tegra USB PHY as a separate platform driver.

To synchronize host controller and PHY initialization, used deferred
probe mechanism. As PHY should be initialized before EHCI starts running,
deferred probe of Tegra EHCI driver till PHY probe gets completed.

Got rid of instance number based handling in host driver.

Made use of DT params to get the PHY Pad registers.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

As GPIO information is avail through DT, used it to get Tegra ULPI
reset GPIO number. Added a new member to tegra_usb_phy structure to
store this number.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Added a new PHY mode to support OTG.
Obtained Tegra USB PHY mode using DT property.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Both phy-tegra-usb.c and ehci-tegra.c export symbols used by the other one,
which does not work if one of them or both are loadable modules, resulting
in an error like:

drivers/built-in.o: In function `utmi_phy_clk_disable':
drivers/usb/phy/phy-tegra-usb.c:302: undefined reference to `tegra_ehci_set_phcd'
drivers/built-in.o: In function `utmi_phy_clk_enable':
drivers/usb/phy/phy-tegra-usb.c:324: undefined reference to `tegra_ehci_set_phcd'
drivers/built-in.o: In function `utmi_phy_power_on':
drivers/usb/phy/phy-tegra-usb.c:447: undefined reference to `tegra_ehci_set_pts'

This turns the interface into a one-way dependency by letting the tegra ehci
driver pass two function pointers for callbacks that need to be called by
the phy driver.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Venu Byravarasu <vbyravarasu@nvidia.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

As pointer to PHY structure can be stored in struct usb_hcd
making use of it, to call Tegra PHY APIs.

Call to usb_phy_shutdown() is moved up in tegra_ehci_remove(),
so that to avoid dereferencing of hcd after its freed up.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

As Tegra PHY driver needs to access one of the host registers,
added few APIs.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
[swarren: moved assignment of phy->is_ulpi_phy to previous patch.]
Signed-off-by: Stephen Warren <swarren@nvidia.com>

Tegra20 USB has 3 PHY instances:
Instance 1 and 3 are UTMI. Instance 2 is ULPI.

As instance number was used to differentiate ULPI from UTMI,
used DT param to get this info and processed accordingly.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Acked-by: Felipe Balbi <balbi@ti.com>
[swarren: moved assignment of phy->is_ulpi_phy into this patch out
of next patch.]
Signed-off-by: Stephen Warren <swarren@nvidia.com>

Tegra20 USB has 3 PHY instances. Instance 0 is based on
legacy PHY interface and other two are standard interfaces.

As instance number was used to differentiate legacy from
standard interfaces, used DT param to get this info and
processed accordingly.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

As tegra_usb_phy_clk_disable/enable() are not being
used, removing them.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>