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

Jon Hunter
2016-04-19T10:43:34Z

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@nvidia.com>
>
> ---
> 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