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X-CSE-ConnectionGUID: LrOoh5HaQFelrZD0oE/hbg== X-CSE-MsgGUID: 5eexzdSHS1CdcqZM67MQsA== X-IronPort-AV: E=McAfee;i="6800,10657,11557"; a="71978628" X-IronPort-AV: E=Sophos;i="6.18,277,1751266800"; d="scan'208";a="71978628" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2025 23:18:08 -0700 X-CSE-ConnectionGUID: w9Myn/mvTEi4V2WfCcL8aQ== X-CSE-MsgGUID: VA6/VX+CTgac/s8lyjtaLA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,277,1751266800"; d="scan'208";a="180013732" Received: from abityuts-desk.ger.corp.intel.com (HELO kekkonen.fi.intel.com) ([10.245.245.105]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2025 23:18:07 -0700 Received: from kekkonen.localdomain (localhost [IPv6:::1]) by kekkonen.fi.intel.com (Postfix) with ESMTP id 46E2211FC22; Fri, 19 Sep 2025 09:18:03 +0300 (EEST) Date: Fri, 19 Sep 2025 09:18:03 +0300 Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo From: Sakari Ailus To: =?iso-8859-1?Q?Andr=E9?= Apitzsch Cc: Val Packett , Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , devicetree@vger.kernel.org, Daniel Scally , ~postmarketos/upstreaming@lists.sr.ht, phone-devel@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 7/7] media: i2c: dw9719: Fix power on/off sequence Message-ID: References: <20250817-dw9719-v1-0-426f46c69a5a@apitzsch.eu> <20250817-dw9719-v1-7-426f46c69a5a@apitzsch.eu> <550f28a9aa82a28beb35fd3490dbe08928ba9eed.camel@apitzsch.eu> <048dd9a2d3257ddea4e4223b023bde9747469083.camel@apitzsch.eu> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <048dd9a2d3257ddea4e4223b023bde9747469083.camel@apitzsch.eu> On Thu, Sep 18, 2025 at 11:31:18PM +0200, André Apitzsch wrote: > Hi Sakari, > > Am Mittwoch, dem 17.09.2025 um 13:10 +0300 schrieb Sakari Ailus: > > Hi André, Val, > > > > On Tue, Sep 16, 2025 at 05:08:44PM -0300, Val Packett wrote: > > > > > > On 9/15/25 5:48 PM, André Apitzsch wrote: > > > > Hi Sakari, > > > > > > > > @Val, please see below. > > > > > > > > Am Montag, dem 18.08.2025 um 07:44 +0000 schrieb Sakari Ailus: > > > > > Hi André, > > > > > > > > > > On Sun, Aug 17, 2025 at 07:09:26PM +0200, André Apitzsch via B4 > > > > > Relay wrote: > > > > > >    u64 val; > > > > > >    int ret; > > > > > >    int err; > > > > > > @@ -109,13 +116,15 @@ static int dw9719_power_up(struct > > > > > > dw9719_device *dw9719, bool detect) > > > > > >    if (ret) > > > > > >    return ret; > > > > > > - /* Jiggle SCL pin to wake up device */ > > > > > > - reg_pwr = (dw9719->model == DW9718S) ? DW9718S_PD : > > > > > > DW9719_CONTROL; > > > > > > - cci_write(dw9719->regmap, reg_pwr, DW9719_SHUTDOWN, > > > > > > &ret); > > > > > > - fsleep(100); > > > > > > + /* > > > > > > + * Need 100us to transition from SHUTDOWN to > > > > > > STANDBY. > > > > > > + * Jiggle the SCL pin to wake up the device (even > > > > > > when the > > > > > > regulator > > > > > > + * is shared) and wait double the time to be sure, > > > > > > then > > > > > > retry the write. > > > > > Why double? Isn't the datasheet correct when it comes to the > > > > > power-on sequence? > > > > > > > > > I haven't noticed any problems during power-up of DW9761. > > > > However, according to the commit message, there seems be an issue > > > > with DW9718S. But I don't own the device and cannot test it. > > > > > > > > Maybe Val can provided some additional information. > > > > > > I haven't had access to the datasheet for the DW9718S, so this was > > > all deduced experimentally. By "to be sure" I meant that I > > > literally raised the timeout "just in case", not based on actual > > > issues. > > > > > > The actually important change was expecting the failure on the > > > write and not erroring out. > > > > Ack. > > > > André: could you add this information to the comment as well? > > Could you clarify which information. What you now have in the commit message. It's relevant for the driver. -- Sakari Ailus