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From: Stephen Warren <swarren@wwwdotorg.org>
To: Laxman Dewangan <ldewangan@nvidia.com>
Cc: linus.walleij@linaro.org, gnurou@gmail.com,
	thierry.reding@gmail.com, linux-gpio@vger.kernel.org,
	linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V3 4/4] gpio: tegra: Add support for gpio debounce
Date: Thu, 21 Apr 2016 12:35:54 -0600	[thread overview]
Message-ID: <57191D8A.9040704@wwwdotorg.org> (raw)
In-Reply-To: <1461159058-1439-5-git-send-email-ldewangan@nvidia.com>

On 04/20/2016 07:30 AM, Laxman Dewangan wrote:
> NVIDIA's Tegra210 support the HW debounce in the GPIO
> controller for all its GPIO pins.
>
> Add support for setting debounce timing by implementing the
> set_debounce callback of gpiochip.

> diff --git a/drivers/gpio/gpio-tegra.c b/drivers/gpio/gpio-tegra.c

> +static int tegra_gpio_set_debounce(struct gpio_chip *chip, unsigned int offset,

> +	/* There is only one debounce count register per port and hence
> +	 * set the maximum of current and requested debounce time.
> +	 */
> +	if (tgi->bank_info[bank].dbc_cnt[port] < debounce_ms) {
> +		tegra_gpio_writel(tgi, debounce_ms, GPIO_DBC_CNT(tgi, offset));
> +		tgi->bank_info[bank].dbc_cnt[port] = debounce_ms;
> +	}

Do we need any locking there? I imagine the GPIO core doesn't prevent 
different threads/drivers from manipulating different GPIOs in parallel 
on different cores.

  reply	other threads:[~2016-04-21 18:35 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-20 13:30 [PATCH V3 0/4] gpio: tegra: Cleanups and support fro debounce Laxman Dewangan
2016-04-20 13:30 ` [PATCH V3 1/4] gpio: tegra: Don't open code of_device_get_match_data() Laxman Dewangan
2016-04-20 13:30 ` [PATCH V3 2/4] gpio: tegra: Make of_device_id compatible data to constant Laxman Dewangan
2016-04-21 18:33   ` Stephen Warren
2016-04-20 13:30 ` [PATCH V3 3/4] gpio: tegra: Get rid of all file scoped global variables Laxman Dewangan
2016-04-21 18:33   ` Stephen Warren
2016-04-21 18:35     ` Laxman Dewangan
2016-04-21 19:34       ` Stephen Warren
2016-04-20 13:30 ` [PATCH V3 4/4] gpio: tegra: Add support for gpio debounce Laxman Dewangan
2016-04-21 18:35   ` Stephen Warren [this message]
2016-04-25  4:55   ` Alexandre Courbot
2016-04-25  8:29     ` Laxman Dewangan

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