[PATCH] ARM: 2847/1: S3C24XX - Documentation for USB OHCI host

Patch from Ben Dooks

Documentation for the in-built OHCI host controller
and the support for it in Linux.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 93 insertions, 0 deletions

diff --git a/Documentation/arm/Samsung-S3C24XX/USB-Host.txt b/Documentation/arm/Samsung-S3C24XX/USB-Host.txt
new file mode 100644
index 000000000000..b93b68e2b143
--- /dev/null
+++ b/Documentation/arm/Samsung-S3C24XX/USB-Host.txt
@@ -0,0 +1,93 @@
+                        S3C24XX USB Host support
+                        ========================
+
+
+
+Introduction
+------------
+
+  This document details the S3C2410/S3C2440 in-built OHCI USB host support.
+
+Configuration
+-------------
+
+  Enable at least the following kernel options:
+
+  menuconfig:
+
+   Device Drivers  --->
+     USB support  --->
+       <*> Support for Host-side USB
+       <*>   OHCI HCD support
+
+
+  .config:
+    CONFIG_USB
+    CONFIG_USB_OHCI_HCD
+
+
+  Once these options are configured, the standard set of USB device
+  drivers can be configured and used.
+
+
+Board Support
+-------------
+
+  The driver attaches to a platform device, which will need to be
+  added by the board specific support file in linux/arch/arm/mach-s3c2410,
+  such as mach-bast.c or mach-smdk2410.c
+
+  The platform device's platform_data field is only needed if the
+  board implements extra power control or over-current monitoring.
+
+  The OHCI driver does not ensure the state of the S3C2410's MISCCTRL
+  register, so if both ports are to be used for the host, then it is
+  the board support file's responsibility to ensure that the second
+  port is configured to be connected to the OHCI core.
+
+
+Platform Data
+-------------
+
+  See linux/include/asm-arm/arch-s3c2410/usb-control.h for the
+  descriptions of the platform device data. An implementation
+  can be found in linux/arch/arm/mach-s3c2410/usb-simtec.c .
+
+  The `struct s3c2410_hcd_info` contains a pair of functions
+  that get called to enable over-current detection, and to
+  control the port power status.
+
+  The ports are numbered 0 and 1.
+
+  power_control:
+
+    Called to enable or disable the power on the port.
+
+  enable_oc:
+
+    Called to enable or disable the over-current monitoring.
+    This should claim or release the resources being used to
+    check the power condition on the port, such as an IRQ.
+
+  report_oc:
+
+    The OHCI driver fills this field in for the over-current code
+    to call when there is a change to the over-current state on
+    an port. The ports argument is a bitmask of 1 bit per port,
+    with bit X being 1 for an over-current on port X.
+
+    The function s3c2410_usb_report_oc() has been provided to
+    ensure this is called correctly.
+
+  port[x]:
+
+    This is struct describes each port, 0 or 1. The platform driver
+    should set the flags field of each port to S3C_HCDFLG_USED if
+    the port is enabled.
+
+
+
+Document Author
+---------------
+
+Ben Dooks, (c) 2005 Simtec Electronics