linux-kernel - Re: [PATCH 5/7] memory: pl172: simplify with devm_clk_get

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Message-ID: <20240823125155.00002c2f@Huawei.com>
Date: Fri, 23 Aug 2024 12:51:55 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
CC: Santosh Shilimkar <ssantosh@...nel.org>, Krzysztof Kozlowski
	<krzk@...nel.org>, Roger Quadros <rogerq@...nel.org>, Tony Lindgren
	<tony@...mide.com>, Vladimir Zapolskiy <vz@...ia.com>, Miquel Raynal
	<miquel.raynal@...tlin.com>, Michal Simek <michal.simek@....com>,
	<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 5/7] memory: pl172: simplify with devm_clk_get_enabled()

On Fri, 23 Aug 2024 12:16:00 +0200
Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> wrote:

> Use devm_clk_get_enabled() to drop clock prepare/unprepare parts and
> make code simpler.  Change to dev_err_probe() in handling clk_get_rate()
> error to make it even simpler.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Follow up suggestion inline + I'd use dev_err_probe() one more
time.

Anyhow fine either way
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

> ---
>  drivers/memory/pl172.c | 23 +++++------------------
>  1 file changed, 5 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/memory/pl172.c b/drivers/memory/pl172.c
> index 390012401f64..db5fbee34077 100644
> --- a/drivers/memory/pl172.c
> +++ b/drivers/memory/pl172.c
> @@ -216,28 +216,20 @@ static int pl172_probe(struct amba_device *adev, const struct amba_id *id)
>  	if (!pl172)
>  		return -ENOMEM;
>  
> -	pl172->clk = devm_clk_get(dev, "mpmcclk");
> +	pl172->clk = devm_clk_get_enabled(dev, "mpmcclk");
>  	if (IS_ERR(pl172->clk))
>  		return dev_err_probe(dev, PTR_ERR(pl172->clk),
>  				     "no mpmcclk provided clock\n");
>  
> -	ret = clk_prepare_enable(pl172->clk);
> -	if (ret) {
> -		dev_err(dev, "unable to mpmcclk enable clock\n");
> -		return ret;
> -	}
> -
>  	pl172->rate = clk_get_rate(pl172->clk) / MSEC_PER_SEC;
> -	if (!pl172->rate) {
> -		dev_err(dev, "unable to get mpmcclk clock rate\n");
> -		ret = -EINVAL;
> -		goto err_clk_enable;
> -	}
> +	if (!pl172->rate)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "unable to get mpmcclk clock rate\n");
>  
>  	ret = amba_request_regions(adev, NULL);
Seeing as you are here an obvious follow up...

Use a devm_add_action_or_reset() and a local cleanup callback
or spin up a devm_amba_request_regions() and apply that here
and probably in other similar locations (a quick look suggested
this would be generally useful).

Then can drop remove entirely which is always nice to see + return
directly in the remaining error path.

>  	if (ret) {
>  		dev_err(dev, "unable to request AMBA regions\n");
> -		goto err_clk_enable;
> +		return ret;
I'd make this a return dev_err_probe() as well.

>  	}
>  
>  	pl172->base = devm_ioremap(dev, adev->res.start,
> @@ -267,16 +259,11 @@ static int pl172_probe(struct amba_device *adev, const struct amba_id *id)
>  
>  err_no_ioremap:
>  	amba_release_regions(adev);
> -err_clk_enable:
> -	clk_disable_unprepare(pl172->clk);
>  	return ret;
>  }
>  
>  static void pl172_remove(struct amba_device *adev)
>  {
> -	struct pl172_data *pl172 = amba_get_drvdata(adev);
> -
> -	clk_disable_unprepare(pl172->clk);
>  	amba_release_regions(adev);
>  }
>  
>