linux-kernel - Re: [PATCH 03/14] iio: adc: rzg2l_adc: Simplify the runtime PM code

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Message-ID: <9fbf057c-164b-4451-85a8-cf4d5807b4c1@bp.renesas.com>
Date: Tue, 3 Dec 2024 12:53:23 +0000
From: Paul Barker <paul.barker.ct@...renesas.com>
To: Claudiu <claudiu.beznea@...on.dev>,
 prabhakar.mahadev-lad.rj@...renesas.com, jic23@...nel.org, lars@...afoo.de,
 robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
 geert+renesas@...der.be, magnus.damm@...il.com, mturquette@...libre.com,
 sboyd@...nel.org, p.zabel@...gutronix.de
Cc: linux-iio@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-clk@...r.kernel.org, Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH 03/14] iio: adc: rzg2l_adc: Simplify the runtime PM code

Hi Claudiu,

On 03/12/2024 11:13, Claudiu wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> 
> All Renesas SoCs using the rzg2l_adc driver manage ADC clocks through PM
> domains. Calling pm_runtime_{resume_and_get, put_sync}() implicitly sets
> the state of the clocks. As a result, the code in the rzg2l_adc driver that
> explicitly manages ADC clocks can be removed, leading to simpler and
> cleaner implementation.
> 
> Additionally, replace the use of rzg2l_adc_set_power() with direct PM
> runtime API calls to further simplify and clean up the code.
> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> ---
>  drivers/iio/adc/rzg2l_adc.c | 100 ++++++++----------------------------
>  1 file changed, 20 insertions(+), 80 deletions(-)
> 
> diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
> index 7039949a7554..a17690ecbdc3 100644
> --- a/drivers/iio/adc/rzg2l_adc.c
> +++ b/drivers/iio/adc/rzg2l_adc.c
> @@ -8,7 +8,6 @@
>   */
>  
>  #include <linux/bitfield.h>
> -#include <linux/clk.h>
>  #include <linux/completion.h>
>  #include <linux/delay.h>
>  #include <linux/iio/iio.h>
> @@ -69,8 +68,6 @@ struct rzg2l_adc_data {
>  
>  struct rzg2l_adc {
>  	void __iomem *base;
> -	struct clk *pclk;
> -	struct clk *adclk;
>  	struct reset_control *presetn;
>  	struct reset_control *adrstn;
>  	struct completion completion;
> @@ -188,29 +185,18 @@ static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
>  	return 0;
>  }
>  
> -static int rzg2l_adc_set_power(struct iio_dev *indio_dev, bool on)
> -{
> -	struct device *dev = indio_dev->dev.parent;
> -
> -	if (on)
> -		return pm_runtime_resume_and_get(dev);
> -
> -	return pm_runtime_put_sync(dev);
> -}
> -
>  static int rzg2l_adc_conversion(struct iio_dev *indio_dev, struct rzg2l_adc *adc, u8 ch)
>  {
> +	struct device *dev = indio_dev->dev.parent;
>  	int ret;
>  
> -	ret = rzg2l_adc_set_power(indio_dev, true);
> +	ret = pm_runtime_resume_and_get(dev);
>  	if (ret)
>  		return ret;

Should we check (ret < 0) here instead of just (ret)? According to the
docs [1], pm_runtime_resume_and_get() can return 1 if the device is
already active.

[1]: https://docs.kernel.org/power/runtime_pm.html#runtime-pm-device-helper-functions

Thanks,

-- 
Paul Barker
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