Re: [PATCH v1 1/3] gpio: rockchip: make gpio work without cru module

[Peter Geis <pgwipeout@xxxxxxxxx>]

On Wed, Aug 31, 2022 at 9:30 PM Jianqun Xu <jay.xu@xxxxxxxxxxxxxx> wrote:
>
> In some case the system may has no builtin cru module, the gpio driver
> will fail to get periph clock and debounce clock.
>
> On rockchip SoCs, the pclk and dbg clk are default to be enabled and
> ungated, the gpio possible to work without cru module.
>
> This patch makes gpio work fine without cru module.

What happens if the cru probes later and these clocks become available
but aren't claimed so clk_disable_unused shuts them down?

>
> Signed-off-by: Jianqun Xu <jay.xu@xxxxxxxxxxxxxx>
> ---
>  drivers/gpio/gpio-rockchip.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpio/gpio-rockchip.c b/drivers/gpio/gpio-rockchip.c
> index a4c4e4584f5b..1da0324445cc 100644
> --- a/drivers/gpio/gpio-rockchip.c
> +++ b/drivers/gpio/gpio-rockchip.c
> @@ -195,6 +195,9 @@ static int rockchip_gpio_set_debounce(struct gpio_chip *gc,
>         unsigned int cur_div_reg;
>         u64 div;
>
> +       if (!bank->db_clk)
> +               return -ENOENT;
> +
>         if (bank->gpio_type == GPIO_TYPE_V2 && !IS_ERR(bank->db_clk)) {
>                 div_debounce_support = true;
>                 freq = clk_get_rate(bank->db_clk);
> @@ -654,8 +657,10 @@ static int rockchip_get_bank_data(struct rockchip_pin_bank *bank)
>                 return -EINVAL;
>
>         bank->clk = of_clk_get(bank->of_node, 0);
> -       if (IS_ERR(bank->clk))
> -               return PTR_ERR(bank->clk);
> +       if (IS_ERR(bank->clk)) {
> +               bank->clk = NULL;
> +               dev_warn(bank->dev, "works without clk pm\n");
> +       }
>
>         clk_prepare_enable(bank->clk);
>         id = readl(bank->reg_base + gpio_regs_v2.version_id);
> @@ -666,9 +671,8 @@ static int rockchip_get_bank_data(struct rockchip_pin_bank *bank)
>                 bank->gpio_type = GPIO_TYPE_V2;
>                 bank->db_clk = of_clk_get(bank->of_node, 1);
>                 if (IS_ERR(bank->db_clk)) {
> -                       dev_err(bank->dev, "cannot find debounce clk\n");
> -                       clk_disable_unprepare(bank->clk);
> -                       return -EINVAL;
> +                       bank->db_clk = NULL;
> +                       dev_warn(bank->dev, "works without debounce clk pm\n");
>                 }
>         } else {
>                 bank->gpio_regs = &gpio_regs_v1;
> --
> 2.25.1
>
>
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