linux-kernel - Re: [PATCH v2 2/5] media: i2c: ov5645: Use runtime PM

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Message-ID: <Y1pphVPw0J97AmW4@paasikivi.fi.intel.com>
Date:   Thu, 27 Oct 2022 11:20:37 +0000
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Prabhakar <prabhakar.csengg@...il.com>
Cc:     Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hverkuil@...all.nl>,
        Shawn Tu <shawnx.tu@...el.com>,
        Jacopo Mondi <jacopo@...ndi.org>, linux-media@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org,
        Biju Das <biju.das.jz@...renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v2 2/5] media: i2c: ov5645: Use runtime PM

Hi Prabhakar,

One more comment.

On Fri, Oct 14, 2022 at 07:34:56PM +0100, Prabhakar wrote:
> @@ -1209,12 +1190,16 @@ static int ov5645_probe(struct i2c_client *client)
>  
>  	dev_info(dev, "OV5645 detected at address 0x%02x\n", client->addr);
>  
> +	pm_runtime_set_active(dev);
> +	pm_runtime_get_noresume(dev);
> +	pm_runtime_enable(dev);

You won't gain anything by eanbling runtime PM here. Just move it to the
end of the function before the rest of the calls. Error handling becomes
more simple.

> +
>  	ret = ov5645_read_reg(ov5645, OV5645_AEC_PK_MANUAL,
>  			      &ov5645->aec_pk_manual);
>  	if (ret < 0) {
>  		dev_err(dev, "could not read AEC/AGC mode\n");
>  		ret = -ENODEV;
> -		goto power_down;
> +		goto err_pm_runtime;
>  	}
>  
>  	ret = ov5645_read_reg(ov5645, OV5645_TIMING_TC_REG20,
> @@ -1222,7 +1207,7 @@ static int ov5645_probe(struct i2c_client *client)
>  	if (ret < 0) {
>  		dev_err(dev, "could not read vflip value\n");
>  		ret = -ENODEV;
> -		goto power_down;
> +		goto err_pm_runtime;
>  	}
>  
>  	ret = ov5645_read_reg(ov5645, OV5645_TIMING_TC_REG21,
> @@ -1230,23 +1215,30 @@ static int ov5645_probe(struct i2c_client *client)
>  	if (ret < 0) {
>  		dev_err(dev, "could not read hflip value\n");
>  		ret = -ENODEV;
> -		goto power_down;
> +		goto err_pm_runtime;
>  	}
>  
> -	ov5645_s_power(&ov5645->sd, false);
> -
>  	ret = v4l2_async_register_subdev(&ov5645->sd);
>  	if (ret < 0) {
>  		dev_err(dev, "could not register v4l2 device\n");
> +		pm_runtime_disable(dev);
> +		pm_runtime_set_suspended(dev);
>  		goto free_entity;
>  	}
>  
> +	pm_runtime_set_autosuspend_delay(dev, 1000);
> +	pm_runtime_use_autosuspend(dev);
> +	pm_runtime_put_autosuspend(dev);
> +
>  	ov5645_entity_init_cfg(&ov5645->sd, NULL);
>  
>  	return 0;
>  
> +err_pm_runtime:
> +	pm_runtime_disable(dev);
> +	pm_runtime_put_noidle(dev);
>  power_down:
> -	ov5645_s_power(&ov5645->sd, false);
> +	ov5645_set_power_off(dev);
>  free_entity:
>  	media_entity_cleanup(&ov5645->sd.entity);
>  free_ctrl:

-- 
Kind regards,

Sakari Ailus