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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 899AAC4332D for ; Tue, 16 Mar 2021 12:57:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5C58365050 for ; Tue, 16 Mar 2021 12:57:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234204AbhCPM4y (ORCPT ); Tue, 16 Mar 2021 08:56:54 -0400 Received: from relay10.mail.gandi.net ([217.70.178.230]:51805 "EHLO relay10.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233865AbhCPMzm (ORCPT ); Tue, 16 Mar 2021 08:55:42 -0400 Received: from uno.localdomain (host-79-22-58-175.retail.telecomitalia.it [79.22.58.175]) (Authenticated sender: jacopo@jmondi.org) by relay10.mail.gandi.net (Postfix) with ESMTPSA id 9A26524000B; Tue, 16 Mar 2021 12:55:36 +0000 (UTC) Date: Tue, 16 Mar 2021 13:56:07 +0100 From: Jacopo Mondi To: Laurent Pinchart Cc: Jacopo Mondi , 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 v2 02/18] media: i2c: rdacm20: Enable noise immunity Message-ID: <20210316125607.lxhrgzahxvxfy6ll@uno.localdomain> References: <20210315131512.133720-1-jacopo+renesas@jmondi.org> <20210315131512.133720-3-jacopo+renesas@jmondi.org> 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-kernel@vger.kernel.org Hi Laurent, On Mon, Mar 15, 2021 at 11:37:26PM +0200, Laurent Pinchart wrote: > Hi Jacopo, > > Thank you for the patch. > > On Mon, Mar 15, 2021 at 02:14:56PM +0100, 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. > > I'm still worried by the race with the MCU. Any update on dumping the > MCU configuration to check what it initializes ? > Not yet, you're right ... I mainly focused on testing with rdacm21, what if I strip the rdacm20 changes out from this series ? I will have to keep the init() operation introduction to maintain compatibility with max9286 changes, and in case of no regressions, we can keep the 8 seconds delay in the .dtsi. However it will break upstream support on Eagle for rdacm20 as we don't have a regulator where to insert the startup delay there, and a downstream patch that waits for 8 seconds in the deserializer driver should be used instead... > > Reviewed-by: Kieran Bingham > > Signed-off-by: Jacopo Mondi > > --- > > drivers/media/i2c/rdacm20.c | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c > > index 90eb73f0e6e9..f7fd5ae955d0 100644 > > --- a/drivers/media/i2c/rdacm20.c > > +++ b/drivers/media/i2c/rdacm20.c > > @@ -541,7 +541,13 @@ 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. > > + */ > > + return max9271_set_high_threshold(&dev->serializer, true); > > } > > > > static int rdacm20_probe(struct i2c_client *client) > > -- > Regards, > > Laurent Pinchart