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 5E0F4C433F5 for ; Wed, 22 Dec 2021 09:31:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243929AbhLVJbK (ORCPT ); Wed, 22 Dec 2021 04:31:10 -0500 Received: from mga14.intel.com ([192.55.52.115]:60298 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231653AbhLVJbJ (ORCPT ); Wed, 22 Dec 2021 04:31:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1640165469; x=1671701469; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=rQ/Cai9x0R34onPyQIivWXgGskbH+Wuk+cpaqorNtU4=; b=QcKN9ueXhVRDgwn0/T73PoxNqUpRMOPhLx+DvjdVdcCziyhTI3r4IERc nx9zMsaD9hgcLPSyeli2esbspxeRzrh4KhFQ02zhs2uxP2rflYOXPWGjw YVq+SvXA+sapIxePTdWGpuIeP0ANpdDECahrQZPdKtSJhJfhuOYYlp8Y7 Ymb4AaGGZctSKrbLXU9vAXFNy1OLGFJxHrRojfYgGHrAbBWruIFtYitZ5 TDOiG//WOYSzSHqqc/i9kJvs+gdowMboLiRY2t4RjVqHDPkcMkU1qMNn4 mSvNB6Bqyw3m++DShh0+O8WCAwIBkHHx12sBlvSyssj0Ue/0kNm71bDZE w==; X-IronPort-AV: E=McAfee;i="6200,9189,10205"; a="240809227" X-IronPort-AV: E=Sophos;i="5.88,226,1635231600"; d="scan'208";a="240809227" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2021 01:31:09 -0800 X-IronPort-AV: E=Sophos;i="5.88,226,1635231600"; d="scan'208";a="664223439" Received: from paasikivi.fi.intel.com ([10.237.72.42]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2021 01:31:08 -0800 Received: from paasikivi.fi.intel.com (localhost [127.0.0.1]) by paasikivi.fi.intel.com (Postfix) with SMTP id 42B72201AA; Wed, 22 Dec 2021 11:31:06 +0200 (EET) Date: Wed, 22 Dec 2021 11:31:06 +0200 From: Sakari Ailus To: Laurent Pinchart 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=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Laurent, On Wed, Dec 22, 2021 at 12:53:27AM +0200, Laurent Pinchart wrote: > 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. They're doing exactly the same things, powering the device on and off. The fact that it's used as a runtime PM callback as well as called directly doesn't change its nature. Most other drivers do it this way actually. What it'd take is a call to v4l2_i2c_subdev_init() before powering the sensor on. -- Kind regards, Sakari Ailus