linux-kernel - Re: [PATCH v2 04/12] i2c: riic: Use pm_runtime_resume_and

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Message-ID: <2wm6vd4dib7tqpdq2eusjhyvfl3sofyvy65w6axvdjbkmgm5cn@bjltpbwwilc2>
Date: Fri, 5 Jul 2024 00:42:41 +0200
From: Andi Shyti <andi.shyti@...nel.org>
To: Claudiu <claudiu.beznea@...on.dev>
Cc: chris.brandt@...esas.com, 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, 
	wsa+renesas@...g-engineering.com, linux-renesas-soc@...r.kernel.org, linux-i2c@...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 v2 04/12] i2c: riic: Use pm_runtime_resume_and_get()

Hi Claudiu,

> diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
> index 83e4d5e14ab6..002b11b020fa 100644
> --- a/drivers/i2c/busses/i2c-riic.c
> +++ b/drivers/i2c/busses/i2c-riic.c
> @@ -113,6 +113,8 @@ struct riic_irq_desc {
>  	char *name;
>  };
>  
> +static const char * const riic_rpm_err_msg = "Failed to runtime resume";

Please, don't do this. Much clearer to write the message
explicitly.

> +
>  static inline void riic_writeb(struct riic_dev *riic, u8 val, u8 offset)
>  {
>  	writeb(val, riic->base + riic->info->regs[offset]);
> @@ -133,10 +135,14 @@ static int riic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>  	struct riic_dev *riic = i2c_get_adapdata(adap);
>  	struct device *dev = adap->dev.parent;
>  	unsigned long time_left;
> -	int i;
> +	int i, ret;
>  	u8 start_bit;
>  
> -	pm_runtime_get_sync(dev);
> +	ret = pm_runtime_resume_and_get(dev);

In principle I like the error message to be always checked and I
will always approve it. Whenever there is a return value, even
when we are sure it's always '0', it needs to be checked.

I had lots of discussions in the past about this topic but I
haven't always found support. I'd love to have the ack from a
renesas maintainer here.

> +	if (ret) {
> +		dev_err(dev, riic_rpm_err_msg);
> +		return ret;
> +	}
>  
>  	if (riic_readb(riic, RIIC_ICCR2) & ICCR2_BBSY) {
>  		riic->err = -EBUSY;

...

> @@ -498,11 +509,18 @@ static void riic_i2c_remove(struct platform_device *pdev)
>  {
>  	struct riic_dev *riic = platform_get_drvdata(pdev);
>  	struct device *dev = &pdev->dev;
> +	int ret;
>  
> -	pm_runtime_get_sync(dev);
> -	riic_writeb(riic, 0, RIIC_ICIER);
> -	pm_runtime_put(dev);
>  	i2c_del_adapter(&riic->adapter);

You swapped the position of this. Please put the
i2c_del_adapter() at the end.

Thanks,
Andi

> +
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret) {
> +		dev_err(dev, riic_rpm_err_msg);
> +	} else {
> +		riic_writeb(riic, 0, RIIC_ICIER);
> +		pm_runtime_put(dev);
> +	}
> +
>  	pm_runtime_disable(dev);
>  }
>  
> -- 
> 2.39.2
>