usb: ulpi: Add omap-ulpi-view port support

Based on discussion from this thread [1].
Adding omap-view port that helps us in using the generic ulpi
framework for any ulpi phy ops using the INSNREG05_ULPI viewport
reg available on omap platform.

Currently ehci ports are available on omap3/4 platforms so enable the same
for beagle and panda, patch is tested on the same boards.

Thanks to Igor Grinberg <grinberg@compulab.co.il> for reviewing the
omap-ehci patches and suggesting this approach.

[1]: http://www.mail-archive.com/u-boot@lists.denx.de/msg76076.html

Tested-by: Stefano Babic <sbabic@denx.de>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Govindraj.R <govindraj.raja@ti.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/doc/README.omap-ulpi-viewport b/doc/README.omap-ulpi-viewport
new file mode 100644
index 0000000..a5240b9
--- /dev/null
+++ b/doc/README.omap-ulpi-viewport
@@ -0,0 +1,27 @@
+Reference code ""drivers/usb/ulpi/omap-ulpi-viewport.c"
+
+Contains the ulpi read write api's to perform
+any ulpi phy port access on omap platform.
+
+On omap ehci reg map contains INSNREG05_ULPI
+register which offers the ulpi phy access so
+any ulpi phy commands should be passsed using this
+register.
+
+omap-ulpi-viewport.c is a low level function
+implementation of "drivers/usb/ulpi/ulpi.c"
+
+To enable and use omap-ulpi-viewport.c
+we require CONFIG_USB_ULPI_VIEWPORT_OMAP and
+CONFIG_USB_ULPI be enabled in config file.
+
+Any ulpi ops request can be done with ulpi.c
+and soc specific binding and usage is done with
+omap-ulpi-viewport implementation.
+
+Ex: scenario:
+omap-ehci driver code requests for ulpi phy reset if
+ehci is used in phy mode, which will call ulpi phy reset
+the ulpi phy reset does ulpi_read/write from viewport
+implementation which will do ulpi reset using the
+INSNREG05_ULPI register.