Re: [Linux-stm32] [PATCH v3] pinctrl: stm32: Add check for clk_enable()

[Antonio Borneo <antonio.borneo@foss.st.com>]

On Fri, 2024-12-06 at 16:43 -0500, Mingwei Zheng wrote:
> Convert the driver to clk_bulk*() API.
> Add check for the return value of clk_bulk_enable() to catch
> the potential error.
> 
> Fixes: 05d8af449d93 ("pinctrl: stm32: Keep pinctrl block clock enabled when LEVEL IRQ requested")
> Signed-off-by: Mingwei Zheng <zmw12306@gmail.com>
> Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
> ---
> Changelog:
> 
> v2 -> v3:
> 
> 1. Convert clk_disable_unprepare to clk_bulk_disable
> and clk_bulk_unprepare.
> 
> v1 -> v2:
> 
> 1. Move int ret declaration into if block.
> ---
>  drivers/pinctrl/stm32/pinctrl-stm32.c | 28 +++++++++++++--------------
>  1 file changed, 13 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/pinctrl/stm32/pinctrl-stm32.c b/drivers/pinctrl/stm32/pinctrl-stm32.c
> index 5b7fa77c1184..0ef912e82736 100644
> --- a/drivers/pinctrl/stm32/pinctrl-stm32.c
> +++ b/drivers/pinctrl/stm32/pinctrl-stm32.c
> @@ -86,7 +86,6 @@ struct stm32_pinctrl_group {
>  
>  struct stm32_gpio_bank {
>         void __iomem *base;
> -       struct clk *clk;
>         struct reset_control *rstc;
>         spinlock_t lock;
>         struct gpio_chip gpio_chip;
> @@ -108,6 +107,7 @@ struct stm32_pinctrl {
>         unsigned ngroups;
>         const char **grp_names;
>         struct stm32_gpio_bank *banks;

Thanks for your patch!
While it's growing wider than your initial scope, it looks as a nice improvement.

> +       struct clk_bulk_data *clks;

Maybe I've missed it but, where does this array get allocated?
There exist clk_bulk_get_all() and devm_clk_bulk_get_all() that do the allocation for you, but they require all the clocks to be listed in the same "clocks" property, while this driver has a clock in
each DT subnode!
Some suggestion below.

>         unsigned nbanks;
>         const struct stm32_pinctrl_match_data *match_data;
>         struct irq_domain       *domain;
> @@ -1308,7 +1308,7 @@ static int stm32_gpiolib_register_bank(struct stm32_pinctrl *pctl, struct fwnode
>         if (IS_ERR(bank->base))
>                 return PTR_ERR(bank->base);
>  
> -       err = clk_prepare_enable(bank->clk);
> +       err = clk_prepare_enable(pctl->clks[pctl->nbanks].clk);
>         if (err) {
>                 dev_err(dev, "failed to prepare_enable clk (%d)\n", err);
>                 return err;
> @@ -1397,7 +1397,7 @@ static int stm32_gpiolib_register_bank(struct stm32_pinctrl *pctl, struct fwnode
>         return 0;
>  
>  err_clk:
> -       clk_disable_unprepare(bank->clk);
> +       clk_disable_unprepare(pctl->clks[pctl->nbanks].clk);
>         return err;
>  }
>  
> @@ -1631,11 +1631,10 @@ int stm32_pctl_probe(struct platform_device *pdev)
>                         fwnode_handle_put(child);
>                         return -EPROBE_DEFER;
>                 }
> -
> -               bank->clk = of_clk_get_by_name(np, NULL);
> -               if (IS_ERR(bank->clk)) {
> +               pctl->clks[i].clk = of_clk_get_by_name(np, NULL);

This is the first time the array is used, during stm32_pctl_probe(), so the array should be already allocated before this line.
The number of banks pctl->nbanks is computed few lines below, so it should be anticipated, or being replaced by a simpler
  pctl->nbanks = gpiochip_node_count(dev);

then allocation could be done with
  pctl->clks = devm_kmalloc_array(dev, pctl->nbanks, sizeof(*pctl->clks), GFP_KERNEL);

Also, you never assign `pctl->clks[i].id` which is then used by the error messages in, e.g., clk_bulk_enable().
We don't mandate the property "clock-names" in the DT subnodes, so no way to get a reasonable value from the DT.
I presume it's fine to set it to NULL... to be tested.

Regards,
Antonio


> +               if (IS_ERR(pctl->clks[i].clk)) {
>                         fwnode_handle_put(child);
> -                       return dev_err_probe(dev, PTR_ERR(bank->clk),
> +                       return dev_err_probe(dev, PTR_ERR(pctl->clks[i].clk),
>                                              "failed to get clk\n");
>                 }
>                 i++;
> @@ -1646,8 +1645,8 @@ int stm32_pctl_probe(struct platform_device *pdev)
>                 if (ret) {
>                         fwnode_handle_put(child);
>  
> -                       for (i = 0; i < pctl->nbanks; i++)
> -                               clk_disable_unprepare(pctl->banks[i].clk);
> +                       clk_bulk_disable(pctl->nbanks, pctl->clks);
> +                       clk_bulk_unprepare(pctl->nbanks, pctl->clks);
>  
>                         return ret;
>                 }
> @@ -1726,10 +1725,8 @@ static int __maybe_unused stm32_pinctrl_restore_gpio_regs(
>  int __maybe_unused stm32_pinctrl_suspend(struct device *dev)
>  {
>         struct stm32_pinctrl *pctl = dev_get_drvdata(dev);
> -       int i;
>  
> -       for (i = 0; i < pctl->nbanks; i++)
> -               clk_disable(pctl->banks[i].clk);
> +       clk_bulk_disable(pctl->nbanks, pctl->clks);
>  
>         return 0;
>  }
> @@ -1738,10 +1735,11 @@ int __maybe_unused stm32_pinctrl_resume(struct device *dev)
>  {
>         struct stm32_pinctrl *pctl = dev_get_drvdata(dev);
>         struct stm32_pinctrl_group *g = pctl->groups;
> -       int i;
> +       int i, ret;
>  
> -       for (i = 0; i < pctl->nbanks; i++)
> -               clk_enable(pctl->banks[i].clk);
> +       ret = clk_bulk_enable(pctl->nbanks, pctl->clks);
> +       if (ret)
> +               return ret;
>  
>         for (i = 0; i < pctl->ngroups; i++, g++)
>                 stm32_pinctrl_restore_gpio_regs(pctl, g->pin);