From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA24037881D; Tue, 21 Jul 2026 15:12:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784646746; cv=none; b=B/i/PAw4JPxhNcw482b8wwcYsQmF6NlukScGGm5V4ROa++WQfoSyvxxAoVGWnLJM8RTyC9xX8ZEoVolIktSYkS35KKktsIU/GOFuiTlV+cXfae4kXEVWub8hDwMq8OAbpFQ6qfMHUmQz7rJmA2kcxBTGtX5ryOjBFPiKgvz0hnI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784646746; c=relaxed/simple; bh=WrcaDKB2Ri9OMrVab+Ec/tqUSpaEs4nKG8J8TsX4CjA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JV4tPBQChrRu/6xyVJWwtKdrNeyUKPEJOTS59qFbaC6aCW4ljMioLJYQFos9q8cVMdqVkqfyfCoCxv6tQBO5ll/fxuFsK/7OTgvnNX8X9MdAi7cFx3HY9835yrUX2TgRPS/WpnqwqdR6kg67PKl62LTNSprgpDG2X1t7wKaRTG8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=fRTFro0y; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="fRTFro0y" Received: from killaraus.ideasonboard.com (2001-14ba-70f3-e800--a06.rev.dnainternet.fi [IPv6:2001:14ba:70f3:e800::a06]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 4507CC1; Tue, 21 Jul 2026 17:11:23 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1784646683; bh=WrcaDKB2Ri9OMrVab+Ec/tqUSpaEs4nKG8J8TsX4CjA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fRTFro0yNk3Xckmx78zzH+JUBlO7gBKu/NH0XQ4O2jLin0TAuJm42ONP/nsJUF7W+ ToVyWhsljzwn98l6/SolYSBFH0EwaVamP7rGgeC8uTteTZB8/iemDJG2/3kdFTe7w/ fAsmsHTfUheRXHlRp+E0O3QHIGIPYJBqHAnqDi/c= Date: Tue, 21 Jul 2026 18:12:21 +0300 From: Laurent Pinchart To: Alexander Stein Cc: Mauro Carvalho Chehab , Sakari Ailus , Dave Stevenson , Richard Leitner , Hans de Goede , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] media: ov9282: enable single-read I2C transactions Message-ID: <20260721151221.GM50424@killaraus.ideasonboard.com> References: <20260721-cci-single-v1-0-8485171e1393@linux.dev> <20260721-cci-single-v1-2-8485171e1393@linux.dev> <2422477.ElGaqSPkdT@steina-w> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <2422477.ElGaqSPkdT@steina-w> On Tue, Jul 21, 2026 at 03:38:26PM +0200, Alexander Stein wrote: > Hi Richard, > > thanks for addressing this long-standing issue. > > Am Dienstag, 21. Juli 2026, 15:25:29 CEST schrieb Richard Leitner: > > Some OV9282 camera modules, such as those from Vision Components, fail > > multi-byte register reads with the default CCI I2C regmap access pattern > > and only work when single-register read transactions are used. This > > results in the driver being unable to probe due to a chip id mismatch. > > > > As the driver has no reliable way to identify affected modules enable > > use_single_read for OV9282 unconditionally when creating the CCI regmap. > > What about a property in the DT instead? In DT it should be clear if a > Vision Components camera is used. Yes, this should not be done by default, or we'll have to do the same for all sensors used in any module from Vision Components. > > Tested on an i.M8MP system with OV9282 modules from Vision Components. > > > > Signed-off-by: Richard Leitner > > --- > > drivers/media/i2c/ov9282.c | 7 ++++++- > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c > > index 5b6f897a74fcd..8267a0a9c6f2d 100644 > > --- a/drivers/media/i2c/ov9282.c > > +++ b/drivers/media/i2c/ov9282.c > > @@ -1283,6 +1283,11 @@ static int ov9282_probe(struct i2c_client *client) > > struct ov9282 *ov9282; > > int ret; > > > > + const struct cci_regmap_config config = { > > + .reg_addr_bits = 16, > > + .use_single_read = true, > > + }; > > + > > ov9282 = devm_kzalloc(&client->dev, sizeof(*ov9282), GFP_KERNEL); > > if (!ov9282) > > return -ENOMEM; > > @@ -1301,7 +1306,7 @@ static int ov9282_probe(struct i2c_client *client) > > return ret; > > } > > > > - ov9282->regmap = devm_cci_regmap_init_i2c(client, 16); > > + ov9282->regmap = devm_cci_regmap_init_i2c_cfg(client, &config); > > if (IS_ERR(ov9282->regmap)) > > return dev_err_probe(ov9282->dev, PTR_ERR(ov9282->regmap), > > "Failed to init CCI\n"); -- Regards, Laurent Pinchart