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,URIBL_BLOCKED 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 53490C433E1 for ; Sat, 20 Mar 2021 16:25:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F54061922 for ; Sat, 20 Mar 2021 16:25:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229761AbhCTQZN (ORCPT ); Sat, 20 Mar 2021 12:25:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229713AbhCTQYx (ORCPT ); Sat, 20 Mar 2021 12:24:53 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11B87C061574; Sat, 20 Mar 2021 09:24:53 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 25E098D3; Sat, 20 Mar 2021 17:24:49 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1616257489; bh=nInQQvrkhlkfJ8ZjNLVB5LPKoCqesSs+QiwQULKudDs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=s4st2l9ajDflvAxV+bB4+XZ3+Dc0Y6YiyDWU4uPb5zfvRq4t8hAQkTW5w/flqFFNq JKht7aMyT+sR0zun2zQNVpHKmefBQpURSe1G/5ZWKKE1PqSezXrX6rs0mikEEcpZue yXNOEj6rCfyFCd3mJ9zevBryUam9yaJbBvScmqbA= Date: Sat, 20 Mar 2021 18:24:09 +0200 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 v3 19/19] media: i2c: rdacm20: Re-work ov10635 reset Message-ID: References: <20210319164148.199192-1-jacopo+renesas@jmondi.org> <20210319164148.199192-20-jacopo+renesas@jmondi.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210319164148.199192-20-jacopo+renesas@jmondi.org> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Jacopo, Thank you for the patch. On Fri, Mar 19, 2021 at 05:41:48PM +0100, Jacopo Mondi wrote: > The OV10635 image sensor embedded in the camera module is currently > reset after the MAX9271 initialization with two long delays that were > most probably not correctly characterized. > > Re-work the image sensor reset procedure by holding the chip in reset > during the MAX9271 configuration, removing the long sleep delays and > only wait after the chip exits from reset for 350-500 microseconds > interval, which is larger than the minimum (2048 * (1 / XVCLK)) timeout > characterized in the chip manual. > > Reviewed-by: Kieran Bingham > Reviewed-by: Laurent Pinchart > Signed-off-by: Jacopo Mondi > --- > drivers/media/i2c/rdacm20.c | 29 +++++++++++++++++------------ > 1 file changed, 17 insertions(+), 12 deletions(-) > > diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c > index 7ed3866b5335..7ba2d0249da8 100644 > --- a/drivers/media/i2c/rdacm20.c > +++ b/drivers/media/i2c/rdacm20.c > @@ -454,6 +454,19 @@ static int rdacm20_init(struct v4l2_subdev *sd, unsigned int val) > if (ret) > return ret; > > + /* > + * Hold OV10635 in reset during max9271 configuration. The reset signal > + * has to be asserted for at least 200 microseconds. > + */ > + ret = max9271_enable_gpios(&dev->serializer, MAX9271_GPIO1OUT); > + if (ret) > + return ret; > + > + ret = max9271_clear_gpios(&dev->serializer, MAX9271_GPIO1OUT); enable and clear is very cnonfusing. How about mimicking the GPIO API, with direction_input(), direction_output() and set_value() functions ? It would also be nice if the polarity could be handled in a nicer way. There's no GPIO request API here, but maybe a max9271_gpio_set_flags() ? > + if (ret) > + return ret; > + usleep_range(200, 500); > + > ret = max9271_configure_gmsl_link(&dev->serializer); > if (ret) > return ret; > @@ -468,22 +481,14 @@ static int rdacm20_init(struct v4l2_subdev *sd, unsigned int val) > dev->serializer.client->addr = dev->addrs[0]; > > /* > - * Reset the sensor by cycling the OV10635 reset signal connected to the > - * MAX9271 GPIO1 and verify communication with the OV10635. > + * Release ov10635 from reset and initialize it. The image sensor > + * requires at least 2048 XVCLK cycles (85 micro-seconds at 24MHz) > + * before being available. Stay safe and wait up to 500 micro-seconds. > */ > - ret = max9271_enable_gpios(&dev->serializer, MAX9271_GPIO1OUT); > - if (ret) > - return ret; > - > - ret = max9271_clear_gpios(&dev->serializer, MAX9271_GPIO1OUT); > - if (ret) > - return ret; > - usleep_range(10000, 15000); > - > ret = max9271_set_gpios(&dev->serializer, MAX9271_GPIO1OUT); > if (ret) > return ret; > - usleep_range(10000, 15000); > + usleep_range(100, 500); > > for (i = 0; i < OV10635_PID_TIMEOUT; ++i) { > ret = ov10635_read16(dev, OV10635_PID); -- Regards, Laurent Pinchart