2009-05-22 04:12:56     some question ablout sl811 on bf527

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2009-05-22 04:12:56     some question ablout sl811 on bf527

liang wang (CHINA)

Message: 74434   

 

Dear sir:

 

I don't understand the two function

 

one is defined in arch/blackfin/mach-bf527/board/ezkit.c

 

void sl811_port_power(struct device *dev, int is_on)

{

    gpio_request(CONFIG_USB_SL811_BFIN_GPIO_VBUS, "usb:SL811_VBUS");

    gpio_direction_output(CONFIG_USB_SL811_BFIN_GPIO_VBUS, is_on);

}

 

another one is:

 

/drivers/usb/host/sl811hs-hcd.c

 

port_power()

 

I wonder two funtion .what is the purpose of this tow funtion? Can anyone introduce it to me?

 

thanks

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2009-05-25 04:30:20     some question ablout sl811 on bf527

Michael Hennerich (GERMANY)

Message: 74529    >I wonder two funtion .what is the purpose of this tow funtion? Can anyone introduce it to me?

 

They care used to control Power Supply to the USB VBUS Pin.

-Michael

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2009-05-26 01:31:16     Re: some question ablout sl811 on bf527

liang wang (CHINA)

Message: 74560   

 

Dear Michael:

 

thank you for you reply!

 

Is there any document introduce how to write a usb host controller driver?

 

Or the document about linux USB stack?

 

best regards!

 

                                                                         wangl

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2009-05-26 02:42:02     Re: some question ablout sl811 on bf527

Mike Frysinger (UNITED STATES)

Message: 74563   

 

writing a host controller is a huge undertaking and shouldnt be taken lightly.  simply buy one that's already out there and working fine.

 

otherwise, you should ask your questions on the Linux USB lists as we really dont have any insight into this matter.

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2009-05-26 03:01:29     Re: some question ablout sl811 on bf527

liang wang (CHINA)

Message: 74565   

 

Thank you Mike!

 

Our usb host is CH375 ,there is no linux driver provided by the IC productor.Just like the audio codec we use SPI codec VS1053,so I  see the  code of SL811 to learn how to write one!Any how ,thank you  very much !

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2009-06-22 04:15:28     Re: some question ablout sl811 on bf527

liang wang (CHINA)

Message: 76105   

 

Dear Mike:

 

There is a  timer list in SL811-hcd .c ,the timer handler function is: sl811h_timer(unsigned long _sl811),

 

However,there is a timer list in   struct usb_hcd

 

struct usb_hcd {

 

    struct usb_bus        self;        /* hcd is-a bus */

    struct kref        kref;        /* reference counter */

 

    const char        *product_desc;    /* product/vendor string */

    char            irq_descr[24];    /* driver + bus # */

 

    struct timer_list    rh_timer;    /* drives root-hub polling */

 

}.This timer is used to poll the hub state,Why need to implment another timerlist in SL811?

 

What is the purpose of this timer?

 

Thank you !        

 

Best regards

 

                                                                                    Liang

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2009-06-22 08:01:43     Re: some question ablout sl811 on bf527

Robin Getz (UNITED STATES)

Message: 76121   

 

Liang:

 

Ask the people who wrote the driver - it was not us.

 

From the top of the file:

 

* Copyright (C) 2004 Psion Teklogix (for NetBook PRO)

* Copyright (C) 2004-2005 David Brownell

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