Re: [PATCH -next 1/4] iio: adc: at91_adc: Use devm_clk_get_enabled() helper function

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 25 Aug 2023 18:57:43 +0800
Jinjie Ruan <ruanjinjie@huawei.com> wrote:

> The devm_clk_get_enabled() helper:
>     - calls devm_clk_get()
>     - calls clk_prepare_enable() and registers what is needed in order to
>       call clk_disable_unprepare() when needed, as a managed resource.
> 
> This simplifies the code.
> 
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>

This looks good, but should ideally be proceeded by a separate patch moving to
devm_request_irq() as then the exit paths will become much simpler and you
can also move to return dev_err_probe() save a few pointless lines of code
and give the benefit of debug info for deferred return codes.




> ---
>  drivers/iio/adc/at91_adc.c | 38 ++++++++++----------------------------
>  1 file changed, 10 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index de6650f9c4b1..318e33ce22fb 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -1087,32 +1087,20 @@ static int at91_adc_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	st->clk = devm_clk_get(&pdev->dev, "adc_clk");
> +	st->clk = devm_clk_get_enabled(&pdev->dev, "adc_clk");
>  	if (IS_ERR(st->clk)) {
> -		dev_err(&pdev->dev, "Failed to get the clock.\n");
> -		ret = PTR_ERR(st->clk);
> -		goto error_free_irq;
> -	}
> -
> -	ret = clk_prepare_enable(st->clk);
> -	if (ret) {
>  		dev_err(&pdev->dev,
>  			"Could not prepare or enable the clock.\n");
> +		ret = PTR_ERR(st->clk);
>  		goto error_free_irq;
>  	}
>  
> -	st->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk");
> +	st->adc_clk = devm_clk_get_enabled(&pdev->dev, "adc_op_clk");
>  	if (IS_ERR(st->adc_clk)) {
> -		dev_err(&pdev->dev, "Failed to get the ADC clock.\n");
> -		ret = PTR_ERR(st->adc_clk);
> -		goto error_disable_clk;
> -	}
> -
> -	ret = clk_prepare_enable(st->adc_clk);
> -	if (ret) {
>  		dev_err(&pdev->dev,
>  			"Could not prepare or enable the ADC clock.\n");
> -		goto error_disable_clk;
> +		ret = PTR_ERR(st->adc_clk);
> +		goto error_free_irq;
>  	}
>  
>  	/*
> @@ -1132,7 +1120,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	if (!st->startup_time) {
>  		dev_err(&pdev->dev, "No startup time available.\n");
>  		ret = -EINVAL;
> -		goto error_disable_adc_clk;
> +		goto error_free_irq;
>  	}
>  	ticks = (*st->caps->calc_startup_ticks)(st->startup_time, adc_clk_khz);
>  
> @@ -1160,7 +1148,7 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	ret = at91_adc_channel_init(idev);
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "Couldn't initialize the channels.\n");
> -		goto error_disable_adc_clk;
> +		goto error_free_irq;
>  	}
>  
>  	init_waitqueue_head(&st->wq_data_avail);
> @@ -1175,19 +1163,19 @@ static int at91_adc_probe(struct platform_device *pdev)
>  		ret = at91_adc_buffer_init(idev);
>  		if (ret < 0) {
>  			dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
> -			goto error_disable_adc_clk;
> +			goto error_free_irq;
>  		}
>  
>  		ret = at91_adc_trigger_init(idev);
>  		if (ret < 0) {
>  			dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
>  			at91_adc_buffer_remove(idev);
> -			goto error_disable_adc_clk;
> +			goto error_free_irq;
>  		}
>  	} else {
>  		ret = at91_ts_register(idev, pdev);
>  		if (ret)
> -			goto error_disable_adc_clk;
> +			goto error_free_irq;
>  
>  		at91_ts_hw_init(idev, adc_clk_khz);
>  	}
> @@ -1207,10 +1195,6 @@ static int at91_adc_probe(struct platform_device *pdev)
>  	} else {
>  		at91_ts_unregister(st);
>  	}
> -error_disable_adc_clk:
> -	clk_disable_unprepare(st->adc_clk);
> -error_disable_clk:
> -	clk_disable_unprepare(st->clk);
>  error_free_irq:
>  	free_irq(st->irq, idev);
>  	return ret;
> @@ -1228,8 +1212,6 @@ static int at91_adc_remove(struct platform_device *pdev)
>  	} else {
>  		at91_ts_unregister(st);
>  	}
> -	clk_disable_unprepare(st->adc_clk);
> -	clk_disable_unprepare(st->clk);
>  	free_irq(st->irq, idev);
>  
>  	return 0;


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