Add information wrt the USB host side of things for the Odroid-U2/U3 and the Odroid-X/X2
Signed-off-by: Suriyan Ramasami suriyan.r@gmail.com ---
Changes in v1: - Add USB host notes for the Odroid
doc/README.odroid | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+)
diff --git a/doc/README.odroid b/doc/README.odroid index 528bb95..0eaf3ff 100644 --- a/doc/README.odroid +++ b/doc/README.odroid @@ -141,3 +141,51 @@ And the boot sequence is: - boot_fit - if "Image.itb" exists - boot_zimg - if "zImage" exists - boot_uimg - if "uImage" exists + +11. USB host support +==================== +The Odroid-X/X2 have the below schematics wrt USB: + +Exynos USB_HOST1 -> USB3503 HUB ----> LAN9514 USB HUB -----> LAN9514 Ethernet + | | + | +-------Host1---------> USB port + | | + | +-------Host2---------> USB port + | | + | +-------Host3---------> USB port + | | + | +-------Host4---------> USB port + | + +-------------------------------------> USB port + | + +-------------------------------------> USB port + +The Odroid-U2/U3 have the below schematics wrt USB: + +Exynos HSIC1 -----------------------------------------------> LAN9514 Ethernet + +Exynos HSIC2 -----> USB3503A HUB ---------------Host1---------> USB port + | + +-----------------------Host2---------> USB port + | + +-----------------------HOst3---------> USB port (U3) + +The HSICs are used in the case of the Odroid-Us and the USB Host in the SoC +is used in the case of the Odroid-Xs. + +In drivers/usb/host/ehci-exynos.c, function names starting with exysno4412* +have been added to initialize the HSICs and the PHYs. + +In board/samsung/odroid/odroid.c, function board_usb_init() adds code to +initialize the USB3503 hub. +The initializing of the USB3503 hub is as defined in the USB3503A spec sheet. +Please refer to Figure 4.1 in the Datasheet. +a) Set the INT_N (X30) low (Odroid-Us) or high (Odroid-Xs). This is so that the +correct REFCLK frequency is selected. 24MHz for Odroid Us and 26MHz for Odroid +Xs. +b) Disconnect the HUB (Set HUB_CONNECT (X34) to 0) +c) Reset the HUB (Set RESET_N (X35) to 0 and then to 1) +d) HUB waits for REF_CLK (which we have set appropriately) +e) Timeout waiting for HUB configuration stage +f) Connect the HUB (Set HUB_CONNECT (X34) to 1) +g) Power recycle the LAN9730 which is connected to BUCK8 (Odroid Us)