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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 18DC6C43461 for ; Wed, 14 Apr 2021 23:14:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB496611CC for ; Wed, 14 Apr 2021 23:14:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235079AbhDNXOq (ORCPT ); Wed, 14 Apr 2021 19:14:46 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:38788 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232201AbhDNXOm (ORCPT ); Wed, 14 Apr 2021 19:14:42 -0400 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id A92E951E; Thu, 15 Apr 2021 01:14:18 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1618442058; bh=8bq/OH4iT+lM6HDvwgt2xqwKGsOYhettA/liqKFhkNY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BxTf3nvS6XChHzkMYwkmG5cDVmUKrSQ8nE7zFcJC8iUuOqEKG1eagqO5niPjY98pc jFEojpzPbght/e45+/1xltTPrSzeHCQIWxrZxVyJKtfZDHI0KV4NslAc5/2rCry9VL pm4lfnCfDu5exrsi/tL4+CC5nWS25yTslriebNik= Date: Thu, 15 Apr 2021 02:14:17 +0300 From: Laurent Pinchart To: Jacopo Mondi Cc: kieran.bingham+renesas@ideasonboard.com, niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org, Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 11/17] media: i2c: rdacm20: Enable noise immunity Message-ID: References: <20210412093451.14198-1-jacopo+renesas@jmondi.org> <20210412093451.14198-12-jacopo+renesas@jmondi.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210412093451.14198-12-jacopo+renesas@jmondi.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jacopo, Thank you for the patch. On Mon, Apr 12, 2021 at 11:34:45AM +0200, Jacopo Mondi wrote: > Enable the noise immunity threshold at the end of the rdacm20 > initialization routine. > > The rdacm20 camera module has been so far tested with a startup > delay that allowed the embedded MCU to program the serializer. If > the initialization routine is run before the MCU programs the > serializer and the image sensor and their addresses gets changed > by the rdacm20 driver it is required to manually enable the noise > immunity threshold to make the communication on the control channel > more reliable. > > Reviewed-by: Kieran Bingham > Signed-off-by: Jacopo Mondi Reviewed-by: Laurent Pinchart > --- > drivers/media/i2c/rdacm20.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c > index c1a717153303..5e0314a2b1ca 100644 > --- a/drivers/media/i2c/rdacm20.c > +++ b/drivers/media/i2c/rdacm20.c > @@ -539,7 +539,19 @@ static int rdacm20_initialize(struct rdacm20_device *dev) > > dev_info(dev->dev, "Identified MAX9271 + OV10635 device\n"); > > - return 0; > + /* > + * Set reverse channel high threshold to increase noise immunity. > + * > + * This should be compensated by increasing the reverse channel > + * amplitude on the remote deserializer side. > + * > + * TODO Inspect the embedded MCU programming sequence to make sure > + * there are no conflicts with the configuration applied here. > + * > + * TODO Clarify the embedded MCU startup delay to avoid write > + * collisions on the I2C bus. > + */ > + return max9271_set_high_threshold(&dev->serializer, true); > } > > static int rdacm20_probe(struct i2c_client *client) -- Regards, Laurent Pinchart