linux-kernel - Re: [PATCH V4 4/4] video: simplefb: switch to use clk

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Message-ID: <66eb6870-3674-0fdb-f5fb-4915a76191f6@redhat.com>
Date:   Wed, 29 Aug 2018 15:00:39 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Dong Aisheng <aisheng.dong@....com>, linux-clk@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        sboyd@...nel.org, mturquette@...libre.com, shawnguo@...nel.org,
        thor.thayer@...ux.intel.com, linux-imx@....com,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-fbdev@...r.kernel.org,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Stephen Boyd <sboyd@...eaurora.org>
Subject: Re: [PATCH V4 4/4] video: simplefb: switch to use clk_bulk API to
 simplify clock operations

Hi,

On 29-08-18 14:51, Dong Aisheng wrote:
> Switching to use clk_bulk API to simplify clock operations.
> 
> Cc: Hans de Goede <hdegoede@...hat.com>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> Cc: linux-fbdev@...r.kernel.org
> Cc: Masahiro Yamada <yamada.masahiro@...ionext.com>
> Cc: Stephen Boyd <sboyd@...eaurora.org>
> Tested-by: Thor Thayer <thor.thayer@...ux.intel.com>
> Signed-off-by: Dong Aisheng <aisheng.dong@....com>
> ---
> 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 | 66 ++++++++----------------------------------
>   1 file changed, 12 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
> index 9a9d748..ed9a4c8 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;
>   
>   	return 0;
>   }
> @@ -252,39 +228,21 @@ 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;
> +
> +	ret = clk_bulk_prepare_enable(par->clk_count, par->clks);
> +	if (ret)
> +		dev_warn(&pdev->dev, "failed to enable clocks\n");

If clk_bulk_prepare_enable() fails, it leaves all clocks disabled,
so you should not set par->clks_enabled = true; then.

Otherwise this patch looks good.

Regards,

Hans



>   
> -	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;
> -			}
> -		}
> -	}
>   	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);
>   }
>   #else
>   static int simplefb_clocks_get(struct simplefb_par *par,
>