linux-kernel - Re: [PATCH] iio: adc: lpc18xx_adc: Reorder clk_get

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Date:   Mon, 25 Oct 2021 09:18:38 -0300
From:   André Gustavo Nakagomi Lopez <andregnl@....br>
To:     Vladimir Zapolskiy <vz@...ia.com>
Cc:     jic23@...nel.org, lars@...afoo.de, linux-iio@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: adc: lpc18xx_adc: Reorder clk_get_rate function call

On Sun, Oct 24, 2021 at 11:12:39PM +0300, Vladimir Zapolskiy wrote:
> Hi André,
> 
> On 10/24/21 10:43 PM, André Gustavo Nakagomi Lopez wrote:
> > clk_get_rate is not garanteed to work if called before clk_prepare_enable.
> 
> typo, s/garanteed/guaranteed/
> 
> > 
> > Reorder clk_get_rate, so it's called after clk_prepare_enable and
> > after devm_add_action_or_reset of lpc18xx_clk_disable.
> > 
> > Signed-off-by: André Gustavo Nakagomi Lopez <andregnl@....br>
> > ---
> >   drivers/iio/adc/lpc18xx_adc.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/lpc18xx_adc.c b/drivers/iio/adc/lpc18xx_adc.c
> > index ceefa4d793cf..ae9c9384f23e 100644
> > --- a/drivers/iio/adc/lpc18xx_adc.c
> > +++ b/drivers/iio/adc/lpc18xx_adc.c
> > @@ -157,9 +157,6 @@ static int lpc18xx_adc_probe(struct platform_device *pdev)
> >   		return dev_err_probe(&pdev->dev, PTR_ERR(adc->clk),
> >   				     "error getting clock\n");
> > -	rate = clk_get_rate(adc->clk);
> > -	clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
> > -
> >   	adc->vref = devm_regulator_get(&pdev->dev, "vref");
> >   	if (IS_ERR(adc->vref))
> >   		return dev_err_probe(&pdev->dev, PTR_ERR(adc->vref),
> > @@ -192,6 +189,9 @@ static int lpc18xx_adc_probe(struct platform_device *pdev)
> >   	if (ret)
> >   		return ret;
> > +	rate = clk_get_rate(adc->clk);
> > +	clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
> > +
> >   	adc->cr_reg = (clkdiv << LPC18XX_ADC_CR_CLKDIV_SHIFT) |
> >   			LPC18XX_ADC_CR_PDN;
> >   	writel(adc->cr_reg, adc->base + LPC18XX_ADC_CR);
> > 
> 
> Thank you for the change, per se this particular change is not needed on
> LPC18xx/43xx platform, however I don't object to it.
> 
> Suggested-by: Jonathan Cameron <jic23@...nel.org>
> Acked-by: Vladimir Zapolskiy <vz@...ia.com>
> 
> --
> Best wishes,
> Vladimir

Ok, thank you for the review. I will fix the typo and add the appropriate tags.