From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Warren <swarren@wwwdotorg.org>
Subject: Re: [PATCH V2 3/3] gpio: tegra: Add support for gpio debounce
Date: Tue, 19 Apr 2016 10:11:58 -0600
Message-ID: <571658CE.1040306@wwwdotorg.org>
References: <1461059020-25373-1-git-send-email-ldewangan@nvidia.com>
 <1461059020-25373-3-git-send-email-ldewangan@nvidia.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <1461059020-25373-3-git-send-email-ldewangan@nvidia.com>
Sender: linux-kernel-owner@vger.kernel.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
List-Id: linux-tegra@vger.kernel.org

On 04/19/2016 03:43 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

> @@ -327,6 +360,9 @@ static int tegra_gpio_resume(struct device *dev)
>   			tegra_gpio_writel(bank->oe[p], GPIO_OE(gpio));
>   			tegra_gpio_writel(bank->int_lvl[p], GPIO_INT_LVL(gpio));
>   			tegra_gpio_writel(bank->int_enb[p], GPIO_INT_ENB(gpio));
> +			tegra_gpio_writel(bank->dbc_cnt[p], GPIO_DBC_CNT(gpio));
> +			tegra_gpio_writel(bank->dbc_enb[p],
> +					  GPIO_MSK_DBC_EN(gpio));

Why not just write to the "regular" register rather than the mask 
register here...

> @@ -351,6 +387,10 @@ static int tegra_gpio_suspend(struct device *dev)
>   			bank->oe[p] = tegra_gpio_readl(GPIO_OE(gpio));
>   			bank->int_enb[p] = tegra_gpio_readl(GPIO_INT_ENB(gpio));
>   			bank->int_lvl[p] = tegra_gpio_readl(GPIO_INT_LVL(gpio));
> +			bank->dbc_enb[p] = tegra_gpio_readl(
> +							GPIO_MSK_DBC_EN(gpio));
> +			bank->dbc_enb[p] = (bank->dbc_enb[p] << 8) ||
> +						bank->dbc_enb[p];

... since that would avoid having to or in the mask value in the saved 
register value here; you could just save/restore the regular register in 
the same way as any other register.