[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CACRpkdb=pvDEA88bNPhEMp2RUgKX=i_N-gwWA7gRwSG13L7=Fw@mail.gmail.com>
Date: Wed, 26 Aug 2015 09:49:34 +0200
From: Linus Walleij <linus.walleij@...aro.org>
To: Grygorii Strashko <grygorii.strashko@...com>
Cc: Alexandre Courbot <gnurou@...il.com>,
Santosh Shilimkar <ssantosh@...nel.org>,
Kevin Hilman <khilman@...prootsystems.com>,
Tony Lindgren <tony@...mide.com>,
Javier Martinez Canillas <javier@...hile0.org>,
Linux-OMAP <linux-omap@...r.kernel.org>,
"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/7] gpio: omap: fix omap2_set_gpio_debounce
On Tue, Aug 18, 2015 at 1:10 PM, Grygorii Strashko
<grygorii.strashko@...com> wrote:
> According to TRMs:
>
> Required input line stable =
> (the value of the GPIO_DEBOUNCINGTIME[7:0].DEBOUNCETIME + 1) × 31,
> where the value of the GPIO_DEBOUNCINGTIME[7:0].DEBOUNCETIME bit field
> is from 0 to 255.
>
> But now omap2_set_gpio_debounce() will calculate debounce time and
> behave incorrectly in the following cases:
> 1) requested debounce time is !0 and <32
> calculated DEBOUNCETIME = 0x1 == 62 us;
> expected value of DEBOUNCETIME = 0x0 == 31us
> 2) requested debounce time is 0
> calculated DEBOUNCETIME = 0x1 == 62 us;
> expected: disable debounce and DEBOUNCETIME = 0x0
> 3) requested debounce time is >32 and <63
> calculated DEBOUNCETIME = 0x0 and debounce will be disabled;
> expected: enable debounce and DEBOUNCETIME = 0x1 == 62 us
>
> Hence, rework omap2_set_gpio_debounce() to fix above cases:
> 1) introduce local variable "enable" and use it to identify
> when debounce need to be enabled or disabled. Disable debounce
> if requested debounce time is 0.
> 2) use below formula for debounce time calculation:
> debounce = (DIV_ROUND_UP(debounce, 31) - 1) & 0xFF;
>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
Very hightech. Patch applied.
Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists