On 11/16/2012 11:55 AM, Roger Quadros wrote:
> 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.
Well, yeah, that's clearly better.
> 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
It is done auto-magically in the omap_device code. As soon as you add
the "ti,hwmods: attribute, an omap_device will be created instead of a
regular platform_device. A custom PM domain is added to handle the
pm_runtime callback for OMAP IPs. And every omap_device belongs to that
PM domain.
Regards,
Benoit
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