Kevin,
Could you give a small tutorial on how to use the clock API?
I have hard time getting it to work. I did the following....
dm355.c
static struct clk vpfe_capture_clk = {
.name = "vpfe-capture", // not sure if this can be any name
.parent = &vpss_master_clk, // cause vpfe capture requires vpss clock
};
....
CLK("vpfe-capture.0", "vpfe-capture", &vpfe_capture_clk),
CLK(NULL, NULL, NULL),
};
in my driver I call,
struct clk *vpfe_clk;
vpfe_clk = clk_get(&pdev->dev, "vpfe-capture")
clk_enable(vpfe_clk);
To clean up
clk_disable(vpfe_clk);
clk_put(vpfe_clk);
But this enables VPSS clock. But registers are still not writeable.
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: Thursday, May 14, 2009 1:22 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 now added clk_enable(), clk_disable to my driver. But I see
>> the following logs randomly when the board is powered.
>
>randomly? The disabled clocks will be dumped on every boot.
>
>> I have CONFIG_DAVINCI_RESET_CLOCKS-y set. So this should get
>> displayed always, right ?
>
>Yes. Since I don't see VPSS clock being disabled, you must
>be either getting/enabling the clocks very early in boot, or
>building your driver into the kernel and getting the clocks
>in the probe method.
>
>I suggest you also test by building your driver as a module
>and loading it after the kernel boots. This will test that
>the kernel can disable the clocks during boot, but your driver
>can re-enable them later.
>
>Kevin
>
>> 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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