linux-kernel - Re: [PATCH v4 4/4] media: i2c: imx274: Add IMX274 power on and off sequence

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Message-ID: <81747729-bd4c-adc5-5cac-608fd662e4fe@nvidia.com>
Date:   Mon, 31 Aug 2020 13:54:24 -0700
From:   Sowjanya Komatineni <skomatineni@...dia.com>
To:     Sakari Ailus <sakari.ailus@....fi>
CC:     <thierry.reding@...il.com>, <jonathanh@...dia.com>,
        <hverkuil@...all.nl>, <luca@...aceresoli.net>,
        <leonl@...pardimaging.com>, <robh+dt@...nel.org>,
        <lgirdwood@...il.com>, <broonie@...nel.org>,
        <linux-media@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 4/4] media: i2c: imx274: Add IMX274 power on and off
 sequence


On 8/31/20 1:48 PM, Sakari Ailus wrote:
> On Mon, Aug 31, 2020 at 01:46:00PM -0700, Sowjanya Komatineni wrote:
>> On 8/31/20 1:23 PM, Sakari Ailus wrote:
>>>> @@ -1968,19 +2087,45 @@ static int imx274_remove(struct i2c_client *client)
>>>>    	struct v4l2_subdev *sd = i2c_get_clientdata(client);
>>>>    	struct stimx274 *imx274 = to_imx274(sd);
>>>> +	pm_runtime_get_sync(&imx274->client->dev);
>>>> +
>>>>    	/* stop stream */
>>> This really shouldn't happen and the driver isn't expected to handle it
>>> either.
>> Do you mean to remove stop stream during remove()?
>>
>> Stop stream is not part of this change and as writes to sensor can't happen
>> when power off, added pm_runtime_get_sync
> Indeed.
>
> But there certainly isn't a need to power the sensor on to stream off, is
> there?

yeah not required. Will remove get_sync.

Will remove imx274 stop stream during remove() as separate patch as it 
was not introduced in this.

>>>>    	imx274_write_table(imx274, imx274_stop);
>>>>    	v4l2_async_unregister_subdev(sd);
>>>>    	v4l2_ctrl_handler_free(&imx274->ctrls.handler);
>>>> +
>>>> +	pm_runtime_put(&client->dev);
>>>> +	pm_runtime_disable(&client->dev);
>>>> +	pm_runtime_set_suspended(&client->dev);
>>>> +
>>>>    	media_entity_cleanup(&sd->entity);
>>>>    	mutex_destroy(&imx274->lock);
>>>>    	return 0;
>>>>    }