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, USER_AGENT_SANE_1 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 48D78C4332E for ; Mon, 15 Mar 2021 17:21:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 103D064EBD for ; Mon, 15 Mar 2021 17:21:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232080AbhCORUj (ORCPT ); Mon, 15 Mar 2021 13:20:39 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:38946 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230502AbhCORUU (ORCPT ); Mon, 15 Mar 2021 13:20:20 -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 BDE93316; Mon, 15 Mar 2021 18:20:18 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1615828819; bh=EfmuDX1Homi+ciII042TtgOrjGfPcOAsZFWHSi2vgdg=; h=Reply-To:Subject:To:Cc:References:From:Date:In-Reply-To:From; b=XwALossDYbr2SBUlo68kqmYc9RdL1vRHiN95l19MQ/tNXIOeoa/trHKfOC5x6x9pu j9wooIgQyrZgAZN0LchHYVXDIq3Dmdo4vaBf9uHxJmdWVgbU9KZqXvwmEYOmItnynk pu9g3mQV3sav4dKaBs+yPX97/hSEacg4lH+ly96U= Reply-To: kieran.bingham+renesas@ideasonboard.com Subject: Re: [PATCH v2 11/18] media: i2c: rdacm21: Fix OV10640 powerdown 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: <20210315131512.133720-1-jacopo+renesas@jmondi.org> <20210315131512.133720-12-jacopo+renesas@jmondi.org> From: Kieran Bingham Organization: Ideas on Board Message-ID: <76196b54-304f-f17f-04af-67bcacd9d923@ideasonboard.com> Date: Mon, 15 Mar 2021 17:20:16 +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: <20210315131512.133720-12-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-kernel@vger.kernel.org Hi Jacopo, On 15/03/2021 13:15, Jacopo Mondi wrote: > The OV10640 image sensor powerdown signal is controlled by the first > line of the OV490 GPIO pad #1, but the pad #0 identifier > OV490_GPIO_OUTPUT_VALUE0 was erroneously used. As a result the image > sensor powerdown signal was never asserted but was kept high by an > internal pull-up resistor, causing sporadic failures during the > image sensor startup phase. > > Fix this by using the correct GPIO pad identifier. > > While at it also fix the GPIO signal handling sequence, as the reset > line was released before the powerdown one, and introduce the correct > delays in between the two operations. > > Wait the mandatory 1 millisecond delay after the powerup lane is Technically you wait 1.5 milliseconds below - but I think that's fine here ;-) > asserted. The reset delay is not characterized in the chip manual if > not as "255 XVCLK + initialization". Wait for at least 3 milliseconds > to guarantee the SCCB bus is available. > > This commit fixes a sporadic start-up error triggered by a failure to > read the OV10640 chip ID: > rdacm21 8-0054: OV10640 ID mismatch: (0x01) > > Fixes: a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module") > Signed-off-by: Jacopo Mondi Sometime it might be nice to see this look more like the GPIO interfaces, but I think this is fine for now. Reviewed-by: Kieran Bingham > --- > drivers/media/i2c/rdacm21.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c > index 7bce55adfd7c..50a9b0d8255d 100644 > --- a/drivers/media/i2c/rdacm21.c > +++ b/drivers/media/i2c/rdacm21.c > @@ -333,13 +333,15 @@ static int ov10640_initialize(struct rdacm21_device *dev) > { > u8 val; > > - /* Power-up OV10640 by setting RESETB and PWDNB pins high. */ > + /* Power-up OV10640 by setting PWDNB and RESETB pins high. */ > ov490_write_reg(dev, OV490_GPIO_SEL0, OV490_GPIO0); > ov490_write_reg(dev, OV490_GPIO_SEL1, OV490_SPWDN0); > ov490_write_reg(dev, OV490_GPIO_DIRECTION0, OV490_GPIO0); > ov490_write_reg(dev, OV490_GPIO_DIRECTION1, OV490_SPWDN0); > + > + ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE1, OV490_SPWDN0); > + usleep_range(1500, 3000); > ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_GPIO0); > - ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_SPWDN0); > usleep_range(3000, 5000); > > /* Read OV10640 ID to test communications. */ >