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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 157F9C433FF for ; Tue, 13 Aug 2019 11:52:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E4CBC20844 for ; Tue, 13 Aug 2019 11:52:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727470AbfHMLwO (ORCPT ); Tue, 13 Aug 2019 07:52:14 -0400 Received: from retiisi.org.uk ([95.216.213.190]:53200 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725981AbfHMLwO (ORCPT ); Tue, 13 Aug 2019 07:52:14 -0400 Received: from valkosipuli.localdomain (valkosipuli.retiisi.org.uk [IPv6:2a01:4f9:c010:4572::80:2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by hillosipuli.retiisi.org.uk (Postfix) with ESMTPS id 58F8C634C89; Tue, 13 Aug 2019 14:52:05 +0300 (EEST) Received: from sailus by valkosipuli.localdomain with local (Exim 4.92) (envelope-from ) id 1hxVLQ-0000fI-OT; Tue, 13 Aug 2019 14:52:04 +0300 Date: Tue, 13 Aug 2019 14:52:04 +0300 From: Sakari Ailus To: Russell King - ARM Linux admin Cc: Manivannan Sadhasivam , mchehab@kernel.org, robh+dt@kernel.org, devicetree@vger.kernel.org, c.barrett@framos.com, linux-kernel@vger.kernel.org, a.brela@framos.com, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Subject: Re: [PATCH v2 1/3] dt-bindings: media: i2c: Add IMX290 CMOS sensor binding Message-ID: <20190813115204.GB2527@valkosipuli.retiisi.org.uk> References: <20190806130938.19916-1-manivannan.sadhasivam@linaro.org> <20190806130938.19916-2-manivannan.sadhasivam@linaro.org> <20190813113846.GG13294@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190813113846.GG13294@shell.armlinux.org.uk> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Russell, On Tue, Aug 13, 2019 at 12:38:46PM +0100, Russell King - ARM Linux admin wrote: > On Tue, Aug 06, 2019 at 06:39:36PM +0530, Manivannan Sadhasivam wrote: > > +Required Properties: > > +- compatible: Should be "sony,imx290" > > +- reg: I2C bus address of the device > > +- clocks: Reference to the xclk clock. > > +- clock-names: Should be "xclk". > > +- clock-frequency: Frequency of the xclk clock. > > Driver code: > > + ret = of_property_read_u32(dev->of_node, "clock-frequency", &xclk_freq);+ if (ret) { > + dev_err(dev, "Could not get xclk frequency\n"); > + return ret; > + } > + > + /* external clock must be 37.125 MHz */ > + if (xclk_freq != 37125000) { > + dev_err(dev, "External clock frequency %u is not supported\n", > + xclk_freq); > + return -EINVAL; > + } > > So, only 37125000 is supported - is that not worth mentioning in this > description? Is this a hard requirement of the sensor? If so, why > does it need to be mentioned in the DT binding? The driver only supports a particular frequency, but the sensor is not limited to that. Unfortunately this is not uncommon for camera sensors, for the vendors often provide register settings for a given configuration only (external clock frequency, number of CSI-2 lanes, CSI-2 bus frequency, image cropping, binning etc.). That still doesn't mean there are no alternative configurations for different external clock frequencies, or that there could not be a driver that was able to configure the sensor to use a given frequency. -- Regards, Sakari Ailus