From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Grinberg Subject: Re: [PATCH 5/5] Input: ads7846: set proper debounce time in driver level Date: Tue, 12 Jun 2012 10:53:58 +0300 Message-ID: <4FD6F596.6050905@compulab.co.il> References: <1339423216-1323-1-git-send-email-zumeng.chen@gmail.com> <1339423216-1323-6-git-send-email-zumeng.chen@gmail.com> <4FD602AD.1060304@compulab.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Zumeng Chen Cc: khilman@ti.com, tony@atomide.com, Dmitry Torokhov , Vaibhav Hiremath , ajay.gupta@ti.com, khasim@ti.com, "linux-input@vger.kernel.org" , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: linux-input@vger.kernel.org On 06/12/12 05:49, Zumeng Chen wrote: > > > 2012/6/11 Igor Grinberg > > > Hi, > > This is input subsystem, add Dmitry and linux-input. > > On 06/11/12 17:00, Zumeng Chen wrote: > > 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. > > What about other non-OMAP platforms? > > Good point, I thought it should be the same situation, and I have no other boards > to validate it :) Then I'll fall back on my original patch to bracket them with OMAP3EVM This isn't a good solution either... > > > NULL pointer for board_pdata, only means that the default pdata is used. > Please, see the common-board-devices.c file more closely. > > Yes, I just went through again, two points: > > 1 ) get_pendown_state is not set for OMAP3 boards, and the state You can supply your own pdata and provide the get_pendown_state() callback. > will be get by gpio_get_value(gpio-omap.c) > The second path will be available in the ads7846_setup_pendown > if (pdata->get_pendown_state) { > ts->get_pendown_state = pdata->get_pendown_state; > } else if (gpio_is_valid(pdata->gpio_pendown)) { > > 2 ) All omap3 boards set gpio_pendown for pdata. > So it had better we set_debounce in driver level after gpio_request_one > having done > I'll remove DEBOUNCE_TIME in V2 and change into like following: > > +#ifdef CONFIG_MACH_OMAP3EVM > + /* 310 means 10 microsecond for omap3 */ > + gpio_set_debounce(pdata->gpio_pendown, 310); > +#endif I don't think this kind of fix is acceptable... > > > > > > This patch has been validated on 3530evm. > > > > Signed-off-by: Zumeng Chen > > > Signed-off-by: Syed Mohammed Khasim > > > Signed-off-by: Tony Lindgren > > > --- > > drivers/input/touchscreen/ads7846.c | 2 ++ > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c > > index f02028e..a82a5fb 100644 > > --- a/drivers/input/touchscreen/ads7846.c > > +++ b/drivers/input/touchscreen/ads7846.c > > @@ -61,6 +61,7 @@ > > > > /* this driver doesn't aim at the peak continuous sample rate */ > > #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */) > > +#define DEBOUNCE_TIME 310 /* About 10 ms */ > > I think hard coding this value is wrong. > > Yes, me too. > > Can't it be derived from the pdata->debounce_* fields? > > Yes, I agreed this way, and to be honest, my first choice > is to find if there is a member for debounce, but no. And > there is no more sense to derive it from debounce_max, > although which is the right value for us. It makes sense to me... Why do you think there is no sense? -- Regards, Igor.