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 4B0DDC433E1 for ; Fri, 26 Mar 2021 11:11:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AB7F61A44 for ; Fri, 26 Mar 2021 11:11:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229914AbhCZLKx (ORCPT ); Fri, 26 Mar 2021 07:10:53 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:60947 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229826AbhCZLKi (ORCPT ); Fri, 26 Mar 2021 07:10:38 -0400 Received: from uno.localdomain (93-34-118-233.ip49.fastwebnet.it [93.34.118.233]) (Authenticated sender: jacopo@jmondi.org) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 41CA820000A; Fri, 26 Mar 2021 11:10:30 +0000 (UTC) Date: Fri, 26 Mar 2021 12:11:03 +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 v3 19/19] media: i2c: rdacm20: Re-work ov10635 reset Message-ID: <20210326111103.uaiqtmodwqpm4acb@uno.localdomain> 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: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Laurent, On Sat, Mar 20, 2021 at 06:24:09PM +0200, Laurent Pinchart wrote: > 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() ? > Probably, that's an unrelated rework that could go on top unrelated to this patch > > + 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