From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966214AbdLSNHe (ORCPT ); Tue, 19 Dec 2017 08:07:34 -0500 Received: from galahad.ideasonboard.com ([185.26.127.97]:38380 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966188AbdLSNHc (ORCPT ); Tue, 19 Dec 2017 08:07:32 -0500 From: Laurent Pinchart To: jacopo mondi Cc: Jacopo Mondi , magnus.damm@gmail.com, geert@glider.be, mchehab@kernel.org, hverkuil@xs4all.nl, linux-renesas-soc@vger.kernel.org, linux-media@vger.kernel.org, linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, sakari.ailus@iki.fi Subject: Re: [PATCH v1 03/10] v4l: platform: Add Renesas CEU driver Date: Tue, 19 Dec 2017 15:07:41 +0200 Message-ID: <1605194.apxP3rZ1bD@avalon> Organization: Ideas on Board Oy In-Reply-To: <20171219115742.GB27115@w540> References: <1510743363-25798-1-git-send-email-jacopo+renesas@jmondi.org> <2710170.YbEgzp5Yxe@avalon> <20171219115742.GB27115@w540> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jacopo, (CC'ing Sakari) On Tuesday, 19 December 2017 13:57:42 EET jacopo mondi wrote: > On Mon, Dec 11, 2017 at 06:15:23PM +0200, Laurent Pinchart wrote: > > Hi Jacopo, > > > > Thank you for the patch. > > > > [snip] > > > >> +static int ceu_sensor_bound(struct v4l2_async_notifier *notifier, > >> + struct v4l2_subdev *v4l2_sd, > >> + struct v4l2_async_subdev *asd) > >> +{ > >> + struct v4l2_device *v4l2_dev = notifier->v4l2_dev; > >> + struct ceu_device *ceudev = v4l2_to_ceu(v4l2_dev); > >> + struct ceu_subdev *ceu_sd = to_ceu_subdev(asd); > >> + > >> + if (video_is_registered(&ceudev->vdev)) { > >> + v4l2_err(&ceudev->v4l2_dev, > >> + "Video device registered before this sub-device.\n"); > >> + return -EBUSY; > > > > Can this happen ? > > > >> + } > >> + > >> + /* Assign subdevices in the order they appear */ > >> + ceu_sd->v4l2_sd = v4l2_sd; > >> + ceudev->num_sd++; > >> + > >> + return 0; > >> +} > >> + > > > +static int ceu_sensor_complete(struct v4l2_async_notifier *notifier) > > > +{ > > > + struct v4l2_device *v4l2_dev = notifier->v4l2_dev; > > > + struct ceu_device *ceudev = v4l2_to_ceu(v4l2_dev); > > > + struct video_device *vdev = &ceudev->vdev; > > > + struct vb2_queue *q = &ceudev->vb2_vq; > > > + struct v4l2_subdev *v4l2_sd; > > > + int ret; > > > + > > > + /* Initialize vb2 queue */ > > > + q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE; > > > + q->io_modes = VB2_MMAP | VB2_USERPTR; > > > > No dmabuf ? > > > > > + q->drv_priv = ceudev; > > > + q->ops = &ceu_videobuf_ops; > > > + q->mem_ops = &vb2_dma_contig_memops; > > > + q->buf_struct_size = sizeof(struct ceu_buffer); > > > + q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC; > > > + q->lock = &ceudev->mlock; > > > + q->dev = ceudev->v4l2_dev.dev; > > > > [snip] > > > > > +static int ceu_probe(struct platform_device *pdev) > > > +{ > > > + struct device *dev = &pdev->dev; > > > + struct ceu_device *ceudev; > > > + struct resource *res; > > > + void __iomem *base; > > > + unsigned int irq; > > > + int num_sd; > > > + int ret; > > > + > > > + ceudev = kzalloc(sizeof(*ceudev), GFP_KERNEL); > > > > The memory is freed in ceu_vdev_release() as expected, but that will only > > work if the video device is registered. If the subdevs are never bound, > > the ceudev memory will be leaked if you unbind the CEU device from its > > driver. In my opinion this calls for registering the video device at > > probe time (although Hans disagrees). > > > > > + if (!ceudev) > > > + return -ENOMEM; > > > + > > > + platform_set_drvdata(pdev, ceudev); > > > + dev_set_drvdata(dev, ceudev); > > > > You don't need the second line, platform_set_drvdata() is a wrapper around > > dev_set_drvdata(). > > > > > + ceudev->dev = dev; > > > + > > > + INIT_LIST_HEAD(&ceudev->capture); > > > + spin_lock_init(&ceudev->lock); > > > + mutex_init(&ceudev->mlock); > > > + > > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > > + if (IS_ERR(res)) > > > + return PTR_ERR(res); > > > > No need for error handling here, devm_ioremap_resource() will check the > > res > > pointer. > > > > > + base = devm_ioremap_resource(dev, res); > > > > You can assign ceudev->base directly and remove the base local variable. > > > > > + if (IS_ERR(base)) > > > + return PTR_ERR(base); > > > + ceudev->base = base; > > > + > > > + ret = platform_get_irq(pdev, 0); > > > + if (ret < 0) { > > > + dev_err(dev, "failed to get irq: %d\n", ret); > > > + return ret; > > > + } > > > + irq = ret; > > > + > > > + ret = devm_request_irq(dev, irq, ceu_irq, > > > + 0, dev_name(dev), ceudev); > > > + if (ret) { > > > + dev_err(&pdev->dev, "Unable to register CEU interrupt.\n"); > > > + return ret; > > > + } > > > + > > > + pm_suspend_ignore_children(dev, true); > > > + pm_runtime_enable(dev); > > > + > > > + ret = v4l2_device_register(dev, &ceudev->v4l2_dev); > > > + if (ret) > > > + goto error_pm_disable; > > > + > > > + if (IS_ENABLED(CONFIG_OF) && dev->of_node) { > > > + num_sd = ceu_parse_dt(ceudev); > > > + } else if (dev->platform_data) { > > > + num_sd = ceu_parse_platform_data(ceudev, dev->platform_data); > > > + } else { > > > + dev_err(dev, "CEU platform data not set and no OF support\n"); > > > + ret = -EINVAL; > > > + goto error_v4l2_unregister; > > > + } > > > + > > > + if (num_sd < 0) { > > > + ret = num_sd; > > > + goto error_v4l2_unregister; > > > + } else if (num_sd == 0) > > > + return 0; > > > > You need braces around the second statement too. > > Ok, actually parse_dt() and parse_platform_data() behaves differently. > The former returns error if no subdevices are connected to CEU, the > latter returns 0. That's wrong. > > I wonder what's the correct behavior here. Other mainline drivers I > looked into (pxa_camera and atmel-isc) behaves differently from each > other, so I guess this is up to each platform to decide. No, what it means is that we've failed to standardize it, not that it shouldn't be standardized :-) > Also, the CEU can accept one single input (and I made it clear > in DT bindings documentation saying it accepts a single endpoint, > while I'm parsing all the available ones in driver, I will fix this) > but as it happens on Migo-R, there could be HW hacks to share the input > lines between multiple subdevices. Should I accept it from dts as well? > > So: > 1) Should we fail to probe if no subdevices are connected? While the CEU itself would be fully functional without a subdev, in practice it would be of no use. I would thus fail probing. > 2) Should we accept more than 1 subdevice from dts as it happens right > now for platform data? We need to support multiple connected devices, as some of the boards require that. What I'm not sure about is whether the multiplexer on the Migo-R board should be modeled as a subdevice. We could in theory connect multiple sensors to the CEU input signals without any multiplexer as long as all but one are in reset with their outputs in a high impedance state. As that wouldn' require a multiplexer we would need to support multiple endpoints in the CEU port. We could then support Migo-R the same way, making the multiplexer transparent. Sakari, what would you do here ? -- Regards, Laurent Pinchart