Re: [PATCH 05/13] iio: adc: lpc18xx: Benefit from devm_clk_get_enabled() to simplify

[Jonathan Cameron <jic23@kernel.org>]

On Mon,  8 Aug 2022 22:47:32 +0200
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:

> Make use of devm_clk_get_enabled() to replace some code that effectively
> open codes this new function.
> 
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
This makes me very slightly nervous because it juggles the order of
clock enabling and powering up the device (potentially anyway).
It's always possible that will cause problems - though I think it
is unlikely (and would cause all sorts of problems if someone
used a fixed regulator or clock) to I'm applying this anyway.

> ---
>  drivers/iio/adc/lpc18xx_adc.c | 18 +-----------------
>  1 file changed, 1 insertion(+), 17 deletions(-)
> 
> diff --git a/drivers/iio/adc/lpc18xx_adc.c b/drivers/iio/adc/lpc18xx_adc.c
> index ae9c9384f23e..8bbc18aaa474 100644
> --- a/drivers/iio/adc/lpc18xx_adc.c
> +++ b/drivers/iio/adc/lpc18xx_adc.c
> @@ -122,11 +122,6 @@ static void lpc18xx_clear_cr_reg(void *data)
>  	writel(0, adc->base + LPC18XX_ADC_CR);
>  }
>  
> -static void lpc18xx_clk_disable(void *clk)
> -{
> -	clk_disable_unprepare(clk);
> -}
> -
>  static void lpc18xx_regulator_disable(void *vref)
>  {
>  	regulator_disable(vref);
> @@ -152,7 +147,7 @@ static int lpc18xx_adc_probe(struct platform_device *pdev)
>  	if (IS_ERR(adc->base))
>  		return PTR_ERR(adc->base);
>  
> -	adc->clk = devm_clk_get(&pdev->dev, NULL);
> +	adc->clk = devm_clk_get_enabled(&pdev->dev, NULL);
>  	if (IS_ERR(adc->clk))
>  		return dev_err_probe(&pdev->dev, PTR_ERR(adc->clk),
>  				     "error getting clock\n");
> @@ -178,17 +173,6 @@ static int lpc18xx_adc_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	ret = clk_prepare_enable(adc->clk);
> -	if (ret) {
> -		dev_err(&pdev->dev, "unable to enable clock\n");
> -		return ret;
> -	}
> -
> -	ret = devm_add_action_or_reset(&pdev->dev, lpc18xx_clk_disable,
> -				       adc->clk);
> -	if (ret)
> -		return ret;
> -
>  	rate = clk_get_rate(adc->clk);
>  	clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
>