linux-kernel - Re: [PATCH v10 3/3] media: i2c: Add support for alvium camera

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Message-ID: <ZUKwtifkbq0d8Eqt@tom-HP-ZBook-Fury-15-G7-Mobile-Workstation>
Date:   Wed, 1 Nov 2023 21:10:30 +0100
From:   Tommaso Merciai <tomm.merciai@...il.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     Sakari Ailus <sakari.ailus@...ux.intel.com>, martin.hecht@...et.eu,
        michael.roeder@...et.eu, mhecht73@...il.com,
        linuxfancy@...glegroups.com,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
        Marco Felsch <m.felsch@...gutronix.de>,
        Gerald Loacker <gerald.loacker@...fvision.net>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Daniel Scally <djrscally@...il.com>,
        Shawn Tu <shawnx.tu@...el.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-kernel@...r.kernel.org,
        Linux Media Mailing List <linux-media@...r.kernel.org>
Subject: Re: [PATCH v10 3/3] media: i2c: Add support for alvium camera

Hi Cristophe, Sakari,

On Wed, Nov 01, 2023 at 06:16:55PM +0100, Tommaso Merciai wrote:
> Hi Cristophe,
> 
> On Wed, Nov 01, 2023 at 03:22:18PM +0100, Christophe JAILLET wrote:
> > Le 01/11/2023 à 15:13, Sakari Ailus a écrit :
> > > Hi Tommaso,
> > > 
> > > On Tue, Oct 31, 2023 at 12:46:09PM +0100, Tommaso Merciai wrote:
> > > > > > +static int alvium_get_dt_data(struct alvium_dev *alvium)
> > > > > > +{
> > > > > > +	struct device *dev = &alvium->i2c_client->dev;
> > > > > > +	struct fwnode_handle *fwnode = dev_fwnode(dev);
> > > > > > +	struct fwnode_handle *endpoint;
> > > > > > +	int ret = -EINVAL;
> > > > > > +
> > > > > > +	if (!fwnode)
> > > > > > +		return -EINVAL;
> > > > > > +
> > > > > > +	/* Only CSI2 is supported for now: */
> > > > > > +	alvium->ep.bus_type = V4L2_MBUS_CSI2_DPHY;
> > > > > > +
> > > > > > +	endpoint = fwnode_graph_get_endpoint_by_id(fwnode, 0, 0, 0);
> > > > > > +	if (!endpoint) {
> > > > > > +		dev_err(dev, "endpoint node not found\n");
> > > > > > +		return -EINVAL;
> > > > > > +	}
> > > > > > +
> > > > > > +	if (v4l2_fwnode_endpoint_alloc_parse(endpoint, &alvium->ep)) {
> > > > > > +		dev_err(dev, "could not parse endpoint\n");
> > > > > > +		goto error_out;
> > > > > 
> > > > > This could go to another label to be less confusing, but
> > > > > v4l2_fwnode_endpoint_free() looks to be a no-op here, so good enough.
> > > > 
> > > > Thanks for the comment.
> > > > To be honest right now this is clear to me
> > > > I prefere to stay on the following :)
> > > > Prefer to keep just only one path.
> > > 
> > > You can safely call v4l2_fwnode_endpoint_free() on an unparsed endpoint (or
> > > on and endpoint the parsing of which failed). I prefer this too.
> > > 
> > > > > > +		ret = -ENODEV;
> > > > > > +		goto err_powerdown;
> > > > > > +	}
> > > > > > +
> > > > > > +	ret = alvium_get_hw_info(alvium);
> > > > > > +	if (ret) {
> > > > > > +		dev_err(dev, "get_hw_info fail %d\n", ret);
> > > > > > +		goto err_powerdown;
> > > > > > +	}
> > > > > > +
> > > > > > +	ret = alvium_hw_init(alvium);
> > > > > > +	if (ret) {
> > > > > > +		dev_err(dev, "hw_init fail %d\n", ret);
> > > > > > +		goto err_powerdown;
> > > > > > +	}
> > > > > > +
> > > > > > +	ret = alvium_setup_mipi_fmt(alvium);
> > > > > > +	if (ret) {
> > > > > > +		dev_err(dev, "setup_mipi_fmt fail %d\n", ret);
> > > > > > +		goto err_powerdown;
> > > > > > +	}
> > > > > > +
> > > > > > +	/*
> > > > > > +	 * Enable runtime PM without autosuspend:
> > > > > > +	 *
> > > > > > +	 * Don't use pm autosuspend (alvium have ~7s boot time).
> > > > > > +	 * Alvium has been powered manually:
> > > > > > +	 *  - mark it as active
> > > > > > +	 *  - increase the usage count without resuming the device.
> > > > > > +	 */
> > > > > > +	pm_runtime_set_active(dev);
> > > > > > +	pm_runtime_get_noresume(dev);
> > > > > > +	pm_runtime_enable(dev);
> > > > > > +
> > > > > > +	/* Initialize the V4L2 subdev. */
> > > > > > +	ret = alvium_subdev_init(alvium);
> > > > > > +	if (ret)
> > > > > > +		goto err_pm;
> > > > > > +
> > > > > > +	ret = v4l2_async_register_subdev(&alvium->sd);
> > > > > > +	if (ret < 0) {
> > > > > > +		dev_err(dev, "Could not register v4l2 device\n");
> > > > > > +		goto err_subdev;
> > > > > > +	}
> > > > > > +
> > > > > > +	return 0;
> > > > > > +
> > > > > > +err_subdev:
> > > > > > +	alvium_subdev_cleanup(alvium);
> > > > > 
> > > > > Should this also be called by the remove function?
> > > > > Or is it already handled by an un-register mechanism?
> > > > 
> > > > Right, I miss this.
> > > > Thanks.
> > > > I put this to remove function like:
> > > > 
> > > > static void alvium_remove(struct i2c_client *client)
> > > > {
> > > > 	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > > > 	struct alvium_dev *alvium = sd_to_alvium(sd);
> > > > 	struct device *dev = &alvium->i2c_client->dev;
> > > > 
> > > > 	/*
> > > > 	 * Disable runtime PM. In case runtime PM is disabled in the kernel,
> > > > 	 * make sure to turn power off manually.
> > > > 	 */
> > > > 	pm_runtime_disable(dev);
> > > > 	if (!pm_runtime_status_suspended(dev))
> > > > 		alvium_power_on(alvium, false);
> > > > 	pm_runtime_set_suspended(dev);
> > > > 
> > > > 	alvium_subdev_cleanup(alvium);
> > > > 	i2c_unregister_device(alvium->i2c_client);
> > > 
> > > This doesn't belong here (as you didn't register it). It was missed in the
> > > review earlier.
> > 
> > Should be v4l2_async_unregister_subdev()?
> 
> Mmmm good point.
> I think actually I'm missing this.
> You are completely right. Thanks.

Checking imx219.c/imx290.c as reference
I think the right remove function would be:

static void alvium_remove(struct i2c_client *client)
{
	struct v4l2_subdev *sd = i2c_get_clientdata(client);
	struct alvium_dev *alvium = sd_to_alvium(sd);
	struct device *dev = &alvium->i2c_client->dev;

	v4l2_async_unregister_subdev(sd);
	alvium_subdev_cleanup(alvium);
	/*
	 * Disable runtime PM. In case runtime PM is disabled in the kernel,
	 * make sure to turn power off manually.
	 */
	pm_runtime_disable(dev);
	if (!pm_runtime_status_suspended(dev))
		alvium_power_on(alvium, false);
	pm_runtime_set_suspended(dev);
}

Regards,
Tommaso

> 
> Regards,
> Tommaso
> 
> > 
> > CJ
> > 
> > > 
> > > > }
> > > > 
> > > > 
> > > > If for you Cristophe, Sakari, Laurent,
> > > > it's ok I prefer to skip v11 that I sent this morning too early.
> > > > I collected hints from Cristophe right now and I plan to send v12
> > > > this afternoon/evening if for you all is ok.
> > > > 
> > > > https://github.com/avs-sas/linux/blob/tm/media_stage/v6.6.0-rc3/alvium_drv/v12/drivers/media/i2c/alvium-csi2.c
> > > > 
> > > > Please let me know.
> > > > 
> > > > Thanks again to all! :)
> > > 
> >