Kevin,

I have now added clk_enable(), clk_disable to my driver. But I see the 
following logs randomly when the board is powered. I have 
CONFIG_DAVINCI_RESET_CLOCKS-y set. So this should get displayed always, right ? 

Clocks: disable unused uart1
Clocks: disable unused uart2
Clocks: disable unused ide
Clocks: disable unused asp0
Clocks: disable unused mmcsd
Clocks: disable unused spi
Clocks: disable unused usb
Clocks: disable unused vlynq
Clocks: disable unused pwm0
Clocks: disable unused pwm1
Clocks: disable unused pwm2
Clocks: disable unused timer1

Murali Karicheri
Software Design Engineer
Texas Instruments Inc.
Germantown, MD 20874
Phone : 301-515-3736
email: [email protected]

>-----Original Message-----
>From: Kevin Hilman [mailto:[email protected]]
>Sent: Wednesday, May 13, 2009 6:17 PM
>To: Karicheri, Muralidharan
>Cc: [email protected]
>Subject: Re: DM355 - No vpss register write happens in the latest kernel
>
>"Karicheri, Muralidharan" <[email protected]> writes:
>
>> We had figured that was the issue with the clock being disabled.
>>
>> I see vpss master, vpss slave and vpss dac clocks defined. Now vpss
>> clock is required for all the vpss modules (capture, display, h3a
>> etc). In VPSS we have registers for enabling clocks for each module,
>> but the above clock is applicable for more than one driver. How does
>> driver request clock in this case?
>
>Each driver that uses the clock should do a clk_get() and
>clk_enable().  The clock framework will track the usecounts and
>disable the hw clock when the usecount goes to zero, then re-enable
>the clock on the next clk_enable().
>
>> I believe this should be enabled from the evm board setup. Right now
>> I have set the flag to ALWAYS_ENABLED. Hope this is fine.
>
>No.
>
>You enable the clock by calling clk_get()/clk_enable().
>
>Kevin
>
>> Murali Karicheri
>> Software Design Engineer
>> Texas Instruments Inc.
>> Germantown, MD 20874
>> Phone : 301-515-3736
>> email: [email protected]
>>
>>>-----Original Message-----
>>>From: Kevin Hilman [mailto:[email protected]]
>>>Sent: Wednesday, May 13, 2009 5:35 PM
>>>To: Karicheri, Muralidharan
>>>Cc: [email protected]
>>>Subject: Re: DM355 - No vpss register write happens in the latest kernel
>>>
>>>"Karicheri, Muralidharan" <[email protected]> writes:
>>>
>>>
>>>> I have ported the video driver to the latest davinci git kernel and
>>>> I have built a single uImage for DM355 and DM6446. The driver works
>>>> fine on DM6446, but doesn't work on DM355. When I dumped the
>>>> registers, none of them were being written. I tried writing manually
>>>> using writel application and still I can't see the values in the
>>>> registers. The architecture code has changed recently quite a lot. I
>>>> have a version of the kernel that downloaded in March and this issue
>>>> was not seen there. This is blocking my driver work and any help
>>>> will be appreciated.
>>>
>>>My first guess would be that your driver doesn't enable all the
>>>relevant clocks for VPSS?
>>>
>>>You could try without the CONFIG_DAVINCI_RESET_CLOCKS=y in
>>>the config.
>>>
>>>If it works with that option disabled, then your driver has a bug in
>>>that it is not properly requesting clocks.
>>>
>>>Kevin
>>>

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