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Date:   Wed, 1 Nov 2023 14:13:14 +0000
From:   Sakari Ailus <sakari.ailus@linux.intel.com>
To:     Tommaso Merciai <tomm.merciai@gmail.com>
Cc:     Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        martin.hecht@avnet.eu, michael.roeder@avnet.eu, mhecht73@gmail.com,
        linuxfancy@googlegroups.com,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>,
        Marco Felsch <m.felsch@pengutronix.de>,
        Gerald Loacker <gerald.loacker@wolfvision.net>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Daniel Scally <djrscally@gmail.com>,
        Shawn Tu <shawnx.tu@intel.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        linux-kernel@vger.kernel.org,
        Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [PATCH v10 3/3] media: i2c: Add support for alvium camera
Message-ID: <ZUJc-p_i4JjqkM9i@kekkonen.localdomain>
References: <20231020141354.2500602-1-tomm.merciai@gmail.com>
 <20231020141354.2500602-4-tomm.merciai@gmail.com>
 <a98bca80-944c-493b-9872-75b94cd24eea@wanadoo.fr>
 <ZUDpAR3ZyBVrUyat@tom-HP-ZBook-Fury-15-G7-Mobile-Workstation>
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In-Reply-To: <ZUDpAR3ZyBVrUyat@tom-HP-ZBook-Fury-15-G7-Mobile-Workstation>
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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.

> }
> 
> 
> 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! :)

-- 
Regards,

Sakari Ailus