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=-17.3 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,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 88CDBC433DB for ; Fri, 19 Mar 2021 16:50:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CBBF61963 for ; Fri, 19 Mar 2021 16:50:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230129AbhCSQuS (ORCPT ); Fri, 19 Mar 2021 12:50:18 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:35150 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230267AbhCSQt4 (ORCPT ); Fri, 19 Mar 2021 12:49:56 -0400 Received: from [192.168.0.20] (cpc89244-aztw30-2-0-cust3082.18-1.cable.virginm.net [86.31.172.11]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 053D18EF; Fri, 19 Mar 2021 17:49:47 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1616172588; bh=EIbEVZoJtQcPzgY11TiM0Rs8F4dkdFCSO7Skdg6wC0A=; h=Reply-To:Subject:To:Cc:References:From:Date:In-Reply-To:From; b=i9P4488dZZ9tqEIQKMUizkjDVLg1XVrH1DhhAXm6cQO9QhH/5wjNDbJeaz4iGE5m7 I6rNSjtjS23d7JaD7bQHyDBYT6j92hLos4xC7kUO0peV4C3Tow+tcVOGT/ZknxhE2+ 7dlkjVpMXwCi1NYM7468NvUbnt0bNruZtolZtBvE= Reply-To: kieran.bingham+renesas@ideasonboard.com Subject: Re: [PATCH v3 11/19] media: i2c: rdacm21: Add dealy after OV490 reset To: Jacopo Mondi , laurent.pinchart+renesas@ideasonboard.com, niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org Cc: Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210319164148.199192-1-jacopo+renesas@jmondi.org> <20210319164148.199192-12-jacopo+renesas@jmondi.org> From: Kieran Bingham Organization: Ideas on Board Message-ID: <99971a13-4d02-2255-6653-569915da181d@ideasonboard.com> Date: Fri, 19 Mar 2021 16:49:44 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210319164148.199192-12-jacopo+renesas@jmondi.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Jacopo, s/dealy/delay/ in $SUBJECT On 19/03/2021 16:41, Jacopo Mondi wrote: > Add a delay after the OV490 chip is put in reset state. The reset > signal shall be held for at least 250 useconds. > > Signed-off-by: Jacopo Mondi > --- > drivers/media/i2c/rdacm21.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c > index babd14b21252..875bec9f7904 100644 > --- a/drivers/media/i2c/rdacm21.c > +++ b/drivers/media/i2c/rdacm21.c > @@ -448,7 +448,10 @@ static int rdacm21_init(struct v4l2_subdev *sd, unsigned int val) > if (ret) > return ret; > > - /* Enable GPIO1 and hold OV490 in reset during max9271 configuration. */ > + /* > + * Enable GPIO1 and hold OV490 in reset during max9271 configuration. > + * The reset signal has to be asserted for at least 250 useconds. > + */ > ret = max9271_enable_gpios(&dev->serializer, MAX9271_GPIO1OUT); > if (ret) > return ret; > @@ -456,6 +459,7 @@ static int rdacm21_init(struct v4l2_subdev *sd, unsigned int val) > ret = max9271_clear_gpios(&dev->serializer, MAX9271_GPIO1OUT); > if (ret) > return ret; > + usleep_range(250, 500); Aha, for a second there I thought the comment meant it had to be asserted for 250 uS before clearing it again. But it's 250 uS before using the OV490. Perhaps possible to update the comment a little, but nothing that matters. Reviewed-by: Kieran Bingham > ret = max9271_configure_gmsl_link(&dev->serializer); > if (ret) >