Hi Benoit,
On 11/16/2012 12:30 PM, Benoit Cousson wrote:
> Hi Roger,
>
> On 11/15/2012 03:56 PM, Roger Quadros wrote:
>> Provides a means for the OMAP USB host subsystem to be initialized
>> from Device tree. This is a first step for device tree migration where
>> we specify only the board specific stuff. Things like I/O address space
>> and interrupts are not yet specified in the device tree but can be
>> done as a next step.
>>
>> This patch will allow boards to be booted with our without device tree
>> and have USB host functional.
>>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> ---
>> .../devicetree/bindings/arm/omap/usb-host.txt | 60 +++++++++++++++++
>> arch/arm/mach-omap2/board-generic.c | 1 +
>> arch/arm/mach-omap2/common.h | 2 +
>> arch/arm/mach-omap2/usb-host.c | 71 ++++++++++++++++++++
>> 4 files changed, 134 insertions(+), 0 deletions(-)
>> create mode 100644 Documentation/devicetree/bindings/arm/omap/usb-host.txt
>>
>> diff --git a/Documentation/devicetree/bindings/arm/omap/usb-host.txt b/Documentation/devicetree/bindings/arm/omap/usb-host.txt
>> new file mode 100644
>> index 0000000..f25cfa4
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/omap/usb-host.txt
>> @@ -0,0 +1,60 @@
>> +* usb-host - OMAP USB Host Subsystem
>> +
>> +The OMAP USB host subsystem consists of the following modules
>> +1) USBTLL (Tranceiverless interface)
>> +2) USBHOST (Host Controller module) which includes both EHCI and OHCI controllers
>> +
>> +THe USB Host subsystem can be connected to the external world using 3 PORTs that could
>> +be configured in various modes like UTMI+ for external PHY, ULPI transceiverless link (TLL),
>> +Serial TLL, High-speed interchip (HSIC), etc.
>> +
>> +Required proprties:
>> +- compatible: Must be "ti,usb-host";
>> +- num_ports: Number of physical ports available
>> +
>> +Optional properties:
>> +- 1 child node for each available port. These child nodes are usually supplied by the
>> + board support device tree as they are specific to how the ports are wired on the board
>> +
>> + - mode: Integer specifying the mode in which the port is used
>> + * OMAP_USBHS_PORT_MODE_UNUSED = 0,
>> + * OMAP_EHCI_PORT_MODE_PHY = 1,
>> + * OMAP_EHCI_PORT_MODE_TLL = 2,
>> + * OMAP_EHCI_PORT_MODE_HSIC = 3,
>> + * OMAP_OHCI_PORT_MODE_PHY_6PIN_DATSE0 = 4,
>> + * OMAP_OHCI_PORT_MODE_PHY_6PIN_DPDM = 5,
>> + * OMAP_OHCI_PORT_MODE_PHY_3PIN_DATSE0 = 6,
>> + * OMAP_OHCI_PORT_MODE_PHY_4PIN_DPDM = 7,
>> + * OMAP_OHCI_PORT_MODE_TLL_6PIN_DATSE0 = 8,
>> + * OMAP_OHCI_PORT_MODE_TLL_6PIN_DPDM = 9,
>> + * OMAP_OHCI_PORT_MODE_TLL_3PIN_DATSE0 = 10,
>> + * OMAP_OHCI_PORT_MODE_TLL_4PIN_DPDM = 11,
>> + * OMAP_OHCI_PORT_MODE_TLL_2PIN_DATSE0 = 12,
>> + * OMAP_OHCI_PORT_MODE_TLL_2PIN_DPDM = 13,
>> + - clk: Name of the clock that needs to be active when using the port
>> + - clkrate: Frequency at which the above clk needs to be run at
>> +
>> +
>> +Example:
>> +
>> +/* In the OMAP Core tree */
>> +usbhost: usb-host {
>> + compatible = "ti,usb-host";
>> + num_ports = <3>;
>> +};
>> +
>> +/* In the Board tree */
>> +&usbhost {
>> + port@0 {
>> + mode = <1>;
>> + clk = "auxclk3_ck";
>> + clkrate = <19200000>;
>> + };
>> + port@1 {
>> + mode = <0>;
>> + };
>> + port@2 {
>> + mode = <0>;
>> + };
>> +};
>> +
>> diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c
>> index 601ecdf..4e53b62 100644
>> --- a/arch/arm/mach-omap2/board-generic.c
>> +++ b/arch/arm/mach-omap2/board-generic.c
>> @@ -40,6 +40,7 @@ static void __init omap_generic_init(void)
>> omap_sdrc_init(NULL, NULL);
>>
>> of_platform_populate(NULL, omap_dt_match_table, NULL, NULL);
>> + usbhost_init_of();
>
> You should never have to add that kind of hacks in generic board file.
> Why do you need that during board init?
>
> In theory, the of_platform_populate will create all the devices, and
> during the driver probe you will create the sub nodes.
>
OK. I was thinking of this as a temporary fix till the USB host drivers
support OF nodes natively. Maybe I should work on fixing up the host
drivers instead.
But I'm not sure how the PM runtime calls map to omap_device/hwmod
framework when device tree boot is used. I can see that the device tree
node can specify "ti,hwmods = " parameter. Just can't seem to figure out
how all this adds up :P
cheers,
-roger
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