2021-10-24 20:30:21

by André Gustavo Nakagomi Lopez

Subject: [PATCH] iio: adc: lpc18xx_adc: Reorder clk_get_rate function call

clk_get_rate is not garanteed to work if called before clk_prepare_enable.

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: Andr? Gustavo Nakagomi Lopez <[email protected]>
---
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);
--
2.33.0

2021-10-24 20:38:34

by Vladimir Zapolskiy

Subject: Re: [PATCH] iio: adc: lpc18xx_adc: Reorder clk_get_rate function call

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 <[email protected]>
> ---
> 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 <[email protected]>
Acked-by: Vladimir Zapolskiy <[email protected]>

--
Best wishes,
Vladimir

2021-10-25 12:21:21

by André Gustavo Nakagomi Lopez

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 Andr?,
>
> On 10/24/21 10:43 PM, Andr? 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: Andr? Gustavo Nakagomi Lopez <[email protected]>
> > ---
> > 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 <[email protected]>
> Acked-by: Vladimir Zapolskiy <[email protected]>
>
> --
> Best wishes,
> Vladimir

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