[PATCH V2 5/5] Input: ads7846: set proper debounce time in driver level

Zumeng Chen zumeng.chen at windriver.com
Thu Jun 14 02:59:28 EDT 2012

于 2012年06月14日 14:31, Hiremath, Vaibhav 写道:
> On Thu, Jun 14, 2012 at 10:16:55, Zumeng Chen wrote:
>> 于 2012年06月13日 20:18, Hiremath, Vaibhav 写道:
>>> On Wed, Jun 13, 2012 at 07:14:10, Zumeng Chen wrote:
>>>> From: Zumeng Chen<zumeng.chen at windriver.com>
>>>> If we don't set proper debouce time for ads7846, then there are
>>>> flooded interrupt counters of ads7846 responding to one time
>>>> touch on screen, so the driver couldn't work well.
>>>> And since most OMAP3 series boards pass NULL pointer of board_pdata
>>>> to omap_ads7846_init, so it's more proper to set it in driver level
>>>> after having gpio_request done.
>>>> This patch has been validated on 3530evm.
>>>> Signed-off-by: Zumeng Chen<zumeng.chen at windriver.com>
>>>> Signed-off-by: Syed Mohammed Khasim<khasim at ti.com>
>>>> ---
>>>>   drivers/input/touchscreen/ads7846.c |    4 ++++
>>>>   1 files changed, 4 insertions(+), 0 deletions(-)
>>>> diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
>>>> index f02028e..459ff29 100644
>>>> --- a/drivers/input/touchscreen/ads7846.c
>>>> +++ b/drivers/input/touchscreen/ads7846.c
>>>> @@ -980,6 +980,10 @@ static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads784
>>>>   		}
>>>>   		ts->gpio_pendown = pdata->gpio_pendown;
>>>> +#ifdef CONFIG_ARCH_OMAP3
>>>> +		/* 310 means about 10 microsecond for omap3 */
>>>> +		gpio_set_debounce(pdata->gpio_pendown, 310);
>>>> +#endif
>>> Zumeng,
>>> With my sign-off you are changing the original code, that too
>>> without my sign-off and ack.
>>> I wouldn't mind you to submit patches from my tree, but the expectation is
>>> if you are changing the original code, it should be under your sign-off.
>> Thanks, good to learn. I'll remove in next time.
>>> Coming to the patch, #ifdef in driver is not recommended, and this 10msec
>>> delay is specific to OMAP GPIO and driver should not be aware of this,
>>> that's where you will find the original patch handling it in board file.
>> According to the git blame of the board-omap3evm.c I think
>> 96974a24 did a good thing to all the related codes for omap3
>> boards. So I think we can call board and driver as BSP level :-)
>> If #ifdef in driver can save many codes, I guess it's deserved.
> No, not really.
> In the same commit, the debounce time is already handled as an argument to 
> the function omap_ads7846_init(), and that’s the way it should be.
That means you'd like to implement the same get_pendown_state for every
omap3 board? Currently, board_pdata is NULL.

And actually, the reason why I agree 96974a24 is that get_pendown_state
for all omap3 boards is the common chip level gpio operations. so I think
we should set debounce for them in one common point.

But since Igor and you don't like them, I have created and tested the
patch, and I'd like Mike to check if convenience too
But obviously there are more codes than mine before :-)

> So no need for #ifdefs in driver...
> Thanks,
> Vaibhav

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