Re: [PATCH V2 3/3] gpio: tegra: Add support for gpio debounce

[Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On 19/04/16 10:43, 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.
> 
> Signed-off-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> ---
> Changes from V1:
> - Write debounce count before enable.
> - Make sure the debounce count do not have any boot residuals.
> ---
>  drivers/gpio/gpio-tegra.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)

[snip]

> @@ -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));

If these registers are not valid on Tegra devices prior to Tegra210, I
don't think we should write to these locations on those devices (even if
we are writing back the values read).

> @@ -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];

Same here, not sure we should even bother reading these for Tegra's
before Tegra210.

Cheers
Jon