From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) (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 0CFD0170A2B; Tue, 13 Aug 2024 11:46:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.20 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723549582; cv=none; b=oNclDQS8R9JQFu4VehXDyBVC349RUNOyJuj3/Gh8lzu6/LcbXBrB+oCikptAl2uK0aZxjNHWkUvP23zxnr2aar6xnPL/j7jECH8z9IboDuIsXUDsjHRyJaqeJpQ3Qr2IzQS+JVKKAWDbYTxBBiETjG6Cq4//V1mIcfUFz++V1MA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723549582; c=relaxed/simple; bh=PEn3XtRW5tjHG4xl8Hpy2BfiNBLyF2Xe3sCNrstiv8Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I+IrYzl8RmJwvq44x+jQ/f6B3sCat5H9ogFMDvSEfeql18QckHEvpMw1o8uJVq9PWd9yjcxAgzmVVlN4aDxFNA/Qa5yPlq4FkkptLwQS9HU+M0suu8iIFgxtwKQiKimFDJiiGVC9Bu6AEzcXhSTgFUoYavcoAHwSvxcdKvmwAL8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=SIUmahaX; arc=none smtp.client-ip=198.175.65.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="SIUmahaX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1723549581; x=1755085581; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=PEn3XtRW5tjHG4xl8Hpy2BfiNBLyF2Xe3sCNrstiv8Y=; b=SIUmahaXxiR98Fc0tIM0nTtJqsKgfVOaiHlhBEWYTiLruyM5PTjlwLFN JmMm3ASDlRW2SXqvXZW7f7AAQ2oLjRBiOU9wZ4vLI49WVfqS8sH2Iiuu5 KBFgEgWJuLjrhMhSI7w5YH+ioO1Wjcd0/lgPyOOL9GbtJBWehwzTBklxt ibgUe4WYp14MqSYEUxOTzGv2bKiRv8j7m/RDB+kPZJdAj353eRE0QjgUP vya4LzYR35C8irQnxOtj0SMwcgPxz2XtiL5TWQYh0571U4g0ZqgcePXQY Un8qEBfZtBJyHkRvrT8UYa42bwX4Bs5c4UmK0fattNSU4vftZZuoD9lXo w==; X-CSE-ConnectionGUID: tfhQFx/VT42AZTsejq4kTA== X-CSE-MsgGUID: HvAJJ3y5SU6+4e2gy2J69A== X-IronPort-AV: E=McAfee;i="6700,10204,11162"; a="21523248" X-IronPort-AV: E=Sophos;i="6.09,285,1716274800"; d="scan'208";a="21523248" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Aug 2024 04:46:20 -0700 X-CSE-ConnectionGUID: PSIpAqcSTxuZeWGvCSvo1g== X-CSE-MsgGUID: P3hRk+ueTcOZ3cw0Qi3PVA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,285,1716274800"; d="scan'208";a="63037742" Received: from smile.fi.intel.com ([10.237.72.54]) by fmviesa005.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Aug 2024 04:46:16 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.98) (envelope-from ) id 1sdpyf-0000000EiFk-1s3a; Tue, 13 Aug 2024 14:46:13 +0300 Date: Tue, 13 Aug 2024 14:46:13 +0300 From: Andy Shevchenko To: Chen-Yu Tsai Cc: Rob Herring , Saravana Kannan , Matthias Brugger , AngeloGioacchino Del Regno , Wolfram Sang , Benson Leung , Tzung-Bi Shih , Mark Brown , Liam Girdwood , chrome-platform@lists.linux.dev, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, Douglas Anderson , Johan Hovold , Jiri Kosina , linux-i2c@vger.kernel.org Subject: Re: [PATCH v4 5/6] platform/chrome: Introduce device tree hardware prober Message-ID: References: <20240808095931.2649657-1-wenst@chromium.org> <20240808095931.2649657-6-wenst@chromium.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240808095931.2649657-6-wenst@chromium.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Thu, Aug 08, 2024 at 05:59:28PM +0800, Chen-Yu Tsai wrote: > Some devices are designed and manufactured with some components having > multiple drop-in replacement options. These components are often > connected to the mainboard via ribbon cables, having the same signals > and pin assignments across all options. These may include the display > panel and touchscreen on laptops and tablets, and the trackpad on > laptops. Sometimes which component option is used in a particular device > can be detected by some firmware provided identifier, other times that > information is not available, and the kernel has to try to probe each > device. > > This change attempts to make the "probe each device" case cleaner. The > current approach is to have all options added and enabled in the device > tree. The kernel would then bind each device and run each driver's probe > function. This works, but has been broken before due to the introduction > of asynchronous probing, causing multiple instances requesting "shared" > resources, such as pinmuxes, GPIO pins, interrupt lines, at the same > time, with only one instance succeeding. Work arounds for these include > moving the pinmux to the parent I2C controller, using GPIO hogs or > pinmux settings to keep the GPIO pins in some fixed configuration, and > requesting the interrupt line very late. Such configurations can be seen > on the MT8183 Krane Chromebook tablets, and the Qualcomm sc8280xp-based > Lenovo Thinkpad 13S. > > Instead of this delicate dance between drivers and device tree quirks, > this change introduces a simple I2C component prober. For any given > class of devices on the same I2C bus, it will go through all of them, > doing a simple I2C read transfer and see which one of them responds. > It will then enable the device that responds. > > This requires some minor modifications in the existing device tree. > The status for all the device nodes for the component options must be > set to "failed-needs-probe". This makes it clear that some mechanism is > needed to enable one of them, and also prevents the prober and device > drivers running at the same time. ... > + * Copyright (c) 2023 Google LLC At bare minimum we are in 2024 now. ... > +#include > +#include > +#include > +#include Why? > +#include ... > + for (size_t i = 0; i < ARRAY_SIZE(hw_prober_platforms); i++) { > + if (!of_machine_is_compatible(hw_prober_platforms[i].compatible)) > + continue; > + int ret; I didn't know we allow this kind of definition mix besides for-loop and __free()... Can you point me out where this style change was discussed? > + ret = hw_prober_platforms[i].prober(&pdev->dev, hw_prober_platforms[i].data); > + /* Ignore unrecoverable errors and keep going through other probers */ > + if (ret == -EPROBE_DEFER) > + return ret; > + } ... > +static void chromeos_of_hw_prober_driver_exit(void) > +{ > + if (!chromeos_of_hw_prober_pdev) > + return; First of all, this is dup for the next call, second, when may this conditional be true? > + platform_device_unregister(chromeos_of_hw_prober_pdev); > + platform_driver_unregister(&chromeos_of_hw_prober_driver); > +} > +module_exit(chromeos_of_hw_prober_driver_exit); -- With Best Regards, Andy Shevchenko