# \[PATCH V5 4/4\] video: simplefb: switch to use clk\_bulk API to simplify clock operations

- From: Hans de Goede \<hidden\>
- Date: 2018-08-29 15:22:03 
- List: linux-arm-kernel
- Page: https://ratatoskr.run/linux-arm-kernel/2018/08/8772406
- Thread: https://ratatoskr.run/linux-arm-kernel/2018/08/8772391/t.md

```text
Hi,

On 29-08-18 16:41, Dong Aisheng wrote:
> Switching to use clk_bulk API to simplify clock operations.
> 
> Cc: Hans de Goede <redacted>
> Cc: Bartlomiej Zolnierkiewicz <redacted>
> Cc: linux-fbdev at vger.kernel.org
> Cc: Masahiro Yamada <redacted>
> Cc: Stephen Boyd <redacted>
> Tested-by: Thor Thayer <redacted>
> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
> ---
> v4->v5:
>   * fix wrong setting of par->clks_enabled
> v3->v4:
>   * no changes
> v2->v3:
>   * fix a build warning on x86 platform due to a wrong
>     of the prototype of simplefb_clocks_enable
> v1->v2:
>   * switch to clk_bulk_get_all from of_clk_bulk_get_all
> ---
>   drivers/video/fbdev/simplefb.c | 68 +++++++++---------------------------------
>   1 file changed, 14 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
> index 9a9d748..8d1fbd6 100644
> --- a/drivers/video/fbdev/simplefb.c
> +++ b/drivers/video/fbdev/simplefb.c
> @@ -182,7 +182,7 @@ struct simplefb_par {
>   #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
>   	bool clks_enabled;
>   	unsigned int clk_count;
> -	struct clk **clks;
> +	struct clk_bulk_data *clks;
>   #endif
>   #if defined CONFIG_OF && defined CONFIG_REGULATOR
>   	bool regulators_enabled;
> @@ -214,37 +214,13 @@ static int simplefb_clocks_get(struct simplefb_par *par,
>   			       struct platform_device *pdev)
>   {
>   	struct device_node *np = pdev->dev.of_node;
> -	struct clk *clock;
> -	int i;
>   
>   	if (dev_get_platdata(&pdev->dev) || !np)
>   		return 0;
>   
> -	par->clk_count = of_clk_get_parent_count(np);
> -	if (!par->clk_count)
> -		return 0;
> -
> -	par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
> -	if (!par->clks)
> -		return -ENOMEM;
> -
> -	for (i = 0; i < par->clk_count; i++) {
> -		clock = of_clk_get(np, i);
> -		if (IS_ERR(clock)) {
> -			if (PTR_ERR(clock) == -EPROBE_DEFER) {
> -				while (--i >= 0) {
> -					if (par->clks[i])
> -						clk_put(par->clks[i]);
> -				}
> -				kfree(par->clks);
> -				return -EPROBE_DEFER;
> -			}
> -			dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
> -				__func__, i, PTR_ERR(clock));
> -			continue;
> -		}
> -		par->clks[i] = clock;
> -	}
> +	par->clk_count = clk_bulk_get_all(&pdev->dev, &par->clks);
> +	if ((par->clk_count < 0) && (par->clk_count == -EPROBE_DEFER))
> +		return -EPROBE_DEFER;

I just noticed this now, but clk_count is unsigned so it will never
be < 0, please make it signed.

Also there is no need to check for < 0 just (par->clk_count == -EPROBE_DEFER)
is enough (if that is true < 0 also always is true).

>   
>   	return 0;
>   }
> @@ -252,39 +228,23 @@ static int simplefb_clocks_get(struct simplefb_par *par,
>   static void simplefb_clocks_enable(struct simplefb_par *par,
>   				   struct platform_device *pdev)
>   {
> -	int i, ret;
> +	int ret;
>   
> -	for (i = 0; i < par->clk_count; i++) {
> -		if (par->clks[i]) {
> -			ret = clk_prepare_enable(par->clks[i]);
> -			if (ret) {
> -				dev_err(&pdev->dev,
> -					"%s: failed to enable clock %d: %d\n",
> -					__func__, i, ret);
> -				clk_put(par->clks[i]);
> -				par->clks[i] = NULL;
> -			}
> -		}
> +	ret = clk_bulk_prepare_enable(par->clk_count, par->clks);

Hmm, what happens if par->clk_count < 0 (another <0 value then
-EPROBEDEFER) ?

> +	if (ret) {
> +		par->clks_enabled = false;

No need to set false here.

> +		dev_warn(&pdev->dev, "failed to enable clocks\n");
> +	} else {
> +		par->clks_enabled = true;
>   	}
> -	par->clks_enabled = true;
>   }
>   
>   static void simplefb_clocks_destroy(struct simplefb_par *par)
>   {
> -	int i;
> -
> -	if (!par->clks)
> -		return;
> -
> -	for (i = 0; i < par->clk_count; i++) {
> -		if (par->clks[i]) {
> -			if (par->clks_enabled)
> -				clk_disable_unprepare(par->clks[i]);
> -			clk_put(par->clks[i]);
> -		}
> -	}
> +	if (par->clks_enabled)
> +		clk_bulk_disable_unprepare(par->clk_count, par->clks);
>   
> -	kfree(par->clks);
> +	clk_bulk_put_all(par->clk_count, par->clks);

Again what about par->clk_count < 0 ?

Regards,

Hans
```