From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40501C433EF for ; Tue, 21 Dec 2021 22:53:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234467AbhLUWxc (ORCPT ); Tue, 21 Dec 2021 17:53:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229732AbhLUWxc (ORCPT ); Tue, 21 Dec 2021 17:53:32 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13A98C061574 for ; Tue, 21 Dec 2021 14:53:32 -0800 (PST) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 76ACD881; Tue, 21 Dec 2021 23:53:30 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1640127210; bh=8OLm1MYFAedFQostj1PlqAtoKGJqohAFQ1pTfl0I6gk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=q0zAvxaNh6WAgP3ppoP4N7bAiTydkBpQFxAQP0+kZ2zn1O/hLbVuwr6vphfZp4W70 kzjBBR/6Npgh0YbwP1WglBla3JuyQ6b7q9K5HSA8IgE6+jMS9LMhWABcbzp5zB+tsV ZqpVRUe+tx/xUh+vAfYTz12xFR065RacGS9MXnuQ= Date: Wed, 22 Dec 2021 00:53:27 +0200 From: Laurent Pinchart To: Sakari Ailus Cc: linux-media@vger.kernel.org, Manivannan Sadhasivam Subject: Re: [PATCH v2 2/2] media: i2c: IMX296 camera sensor driver Message-ID: References: <20211219220948.28953-1-laurent.pinchart@ideasonboard.com> <20211219220948.28953-3-laurent.pinchart@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Sakari, On Wed, Dec 22, 2021 at 12:41:08AM +0200, Sakari Ailus wrote: > On Tue, Dec 21, 2021 at 05:56:54PM +0200, Laurent Pinchart wrote: > > ,,, > > > > > +static int imx296_ctrls_init(struct imx296 *sensor) > > > > +{ > > > > + struct v4l2_fwnode_device_properties props; > > > > + unsigned int hblank; > > > > + int ret; > > > > + > > > > + ret = v4l2_fwnode_device_parse(sensor->dev, &props); > > > > + if (ret < 0) > > > > + return ret; > > > > + > > > > + v4l2_ctrl_handler_init(&sensor->ctrls, 9); > > > > + > > > > + v4l2_ctrl_new_std(&sensor->ctrls, &imx296_ctrl_ops, > > > > + V4L2_CID_EXPOSURE, 1, 1048575, 1, 1104); > > > > + v4l2_ctrl_new_std(&sensor->ctrls, &imx296_ctrl_ops, > > > > + V4L2_CID_ANALOGUE_GAIN, IMX296_GAIN_MIN, > > > > + IMX296_GAIN_MAX, 1, IMX296_GAIN_MIN); > > > > + > > > > + /* > > > > + * Horizontal blanking is controlled through the HMAX register, which > > > > + * contains a line length in INCK clock units. The INCK frequency is > > > > + * fixed to 74.25 MHz. The HMAX value is currently fixed to 1100, > > > > > > It seems the driver supports other values, too. Shouldn't this be the > > > actual frequency? > > > > That's not clear to me from the documentation I have access to :-( It's > > quite convoluted, there are a few examples from which I tried to infer > > what was going on, but no clear explanation. My board uses a fixed clock > > frequency of 37.125MHz so I can't test other values. > > > > Can we start with this and update it later if we can figure out more > > (assuming there's an issue, it may actually be correct already) ? > > Sounds reasonable. I was just wondering. > > > > > + * convert it to a number of pixels based on the nominal pixel rate. > > > > + */ > > > > + hblank = 1100 * 1188000000ULL / 10 / 74250000 > > > > + - IMX296_PIXEL_ARRAY_WIDTH; > > > > + sensor->hblank = v4l2_ctrl_new_std(&sensor->ctrls, &imx296_ctrl_ops, > > > > + V4L2_CID_HBLANK, hblank, hblank, 1, > > > > + hblank); > > > > + if (sensor->hblank) > > > > + sensor->hblank->flags |= V4L2_CTRL_FLAG_READ_ONLY; > > > > + > > > > + sensor->vblank = v4l2_ctrl_new_std(&sensor->ctrls, &imx296_ctrl_ops, > > > > + V4L2_CID_VBLANK, 30, > > > > + 1048575 - IMX296_PIXEL_ARRAY_HEIGHT, > > > > + 1, 30); > > > > + /* > > > > + * The sensor calculates the MIPI timings internally to achieve a bit > > > > + * rate between 1122 and 1198 Mbps. The exact value is unfortunately not > > > > + * reported, at least according to the documentation. Report a nominal > > > > + * rate of 1188 Mbps as that is used by the datasheet in multiple > > > > + * examples. > > > > + */ > > > > + v4l2_ctrl_new_std(&sensor->ctrls, NULL, V4L2_CID_PIXEL_RATE, > > > > + 1122000000 / 10, 1198000000 / 10, 1, 1188000000 / 10); > > > > > > What about the link frequency? > > > > > > Is this value constant for the sensor? Or should there be a list of > > > hardware supported link frequencies? > > > > It seems to be constant, but again the documentation is fairly unclear. > > Ack. > > ... > > > > > +static int __maybe_unused imx296_runtime_resume(struct device *dev) > > > > +{ > > > > + struct i2c_client *client = to_i2c_client(dev); > > > > + struct v4l2_subdev *subdev = i2c_get_clientdata(client); > > > > + struct imx296 *sensor = to_imx296(subdev); > > > > + > > > > + return imx296_power_on(sensor); > > > > +} > > > > + > > > > +static int __maybe_unused imx296_runtime_suspend(struct device *dev) > > > > +{ > > > > + struct i2c_client *client = to_i2c_client(dev); > > > > + struct v4l2_subdev *subdev = i2c_get_clientdata(client); > > > > + struct imx296 *sensor = to_imx296(subdev); > > > > + > > > > + imx296_power_off(sensor); > > > > + > > > > + return 0; > > > > > > I'd merge these two with imx296_power_o{n,ff}. > > > > That would require calling imx296_runtime_resume() and > > imx296_runtime_suspend() in probe() and remove(), which I don't really > > like. I'd prefer keeping the functions separate. > > You could keep calling the functions imx296_power_o{n,ff}. There's really > no need for two pairs of functions doing the same things. imx296_power_on() is called in probe() before the subdev is initialized, so the i2c_get_clientdata() call in imx296_runtime_resume() would fail. It may be possible to refactor the probe() function to fix this, but I think that explicit power on/off calls in probe() are clearer than calling the pm runtime resume and suspend handlers. > ... > > > > > + dev_warn(&adapter->dev, > > > > + "I2C-Adapter doesn't support I2C_FUNC_SMBUS_BYTE\n"); > > > > + return -EIO; > > > > + } > > > > + > > > > + sensor = devm_kzalloc(&client->dev, sizeof(*sensor), GFP_KERNEL); > > > > + if (!sensor) > > > > + return -ENOMEM; > > > > + > > > > + sensor->dev = &client->dev; > > > > + > > > > + mutex_init(&sensor->lock); > > > > > > You could simplify error handling a little by moving mutex init later. Up > > > to you. > > > > That's right, but if you don't mind I'd prefer keeping it here, to have > > ass the "static" initialization of "generic" members at the top. > > Sure. -- Regards, Laurent Pinchart