From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5533E17D8B2 for ; Tue, 25 Jun 2024 20:50:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719348652; cv=none; b=RNCPFAcP0WdXZThn4smP7fLWSnJ4Y09aPI7vNnjG0TbsODS4Sd3+bVi1AEj0ca9Hw+15sSU4epiohqP0q1C9pebaSDzLPdMed1FbvpDbE7f6INqkIv2wP086jn4MtK8Hk2yXv19EHjaqUCCqrIeOXlNk7d3y5p52+OCIn/yJxPc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719348652; c=relaxed/simple; bh=Ogjj5Y0GInxX7wH4alxoCYfsIpG12FTyThgwrjywxFk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LizY8yFNOUXPowJ29wJs4YvUeU6AxFcB3T0A2i12zuBVvW+0eh5TV0z+5vBPj+9N1UvHUnKMIQMLTw3rMAgqNebw29qzp8Uv4pcBnP/tcvNXzrN8CGl1uoF329S+berB+SEsuWMYDRYo0yJwuim6w6uHXrSTw7npKoK0Q5Oa33A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=ViIICWdQ; arc=none smtp.client-ip=209.85.214.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ViIICWdQ" Received: by mail-pl1-f179.google.com with SMTP id d9443c01a7336-1fa0f143b85so26352595ad.3 for ; Tue, 25 Jun 2024 13:50:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1719348650; x=1719953450; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=x6GQ6rOvbBTY6MyXxNlEdQ9tXnIS+mQmwp3XvJBUVR8=; b=ViIICWdQYrYsYugtkF51SRl/Lx/ltBTN19eh5canSrNEzU8PH4LOCxzTQzWdTW7Ydo JVzWduP+vXdjLSAv2dhQyAdUFnpYaxN9/1VUywYox3UlK64zFpbZ/dv4MvyrJOZUOdVf Jf/Ot72lYbHmMZ82O6Kpp/gCqHqXSWCN5ES7xxRhEzMQvtuR5zrlInKqyF6wiq884Gqe iOwXzP6GyqKoLvPz/MMPwYA2A58/UKbLjCEMzbAI3XG9iwvG7o+G6MyEW0C+gNYgFZVx 0qVoRjP7nY+rvKefG+ZE6RxdV5Qo/NN36xFG1UBt3bRgBwFwVwJvGa5lVyoaIDRVlQEU Kz3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719348650; x=1719953450; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=x6GQ6rOvbBTY6MyXxNlEdQ9tXnIS+mQmwp3XvJBUVR8=; b=Sf99DpmCfx5LdveIEm1EB3ZrAs1uBVFXlH7f5+UHz/6ruY/x6AOuBvpb95BHZoSm9M OEfJqTkpmLvmn498aQZZXjCAQvKteVgNGwD13nP6YJ7KYSfWqm0mvYhE2jej+0t72q5H lvAdvWppJluysD6MB/t7A+rhAAnNEnwU5Rvf4wmeSrzVj+nBngnyx729x9vkJc3AJ5WN cXFh2zjzHhHA054cv7aw1lvs83BRHPQF5856OekpK6EAgJu/hY5uUXKOc0eNPmE6fsGn 02LVzJc8XCqp3o97T35ap1JsiBlyvl+znyLT5Yy50y+0RcQL4wgEzxmQPJAanO95r1/d mDtA== X-Gm-Message-State: AOJu0YxgHKp8LVwlGKrrmy4KBDum0ZMAPWaww86YGEdKwHeWMXsPu5Oh euyoi700SHbB+Ah7A8ewf2BeHYIrZgWNgnrKS9phPbVAekqPmdcF X-Google-Smtp-Source: AGHT+IF+njpMbFN3tDaGAQW+eWZZC4xDKS0IwvHQHda6wsVP5qAd5E/gEHQxepJ/eRXxs6Hyy8xmLg== X-Received: by 2002:a17:902:bd07:b0:1f7:23d9:f530 with SMTP id d9443c01a7336-1fa23f8df23mr69726525ad.66.1719348650428; Tue, 25 Jun 2024 13:50:50 -0700 (PDT) Received: from google.com ([2620:15c:9d:2:ff4:b46e:2948:c244]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f9eb3c5ed2sm86069205ad.155.2024.06.25.13.50.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Jun 2024 13:50:50 -0700 (PDT) Date: Tue, 25 Jun 2024 13:50:47 -0700 From: Dmitry Torokhov To: Marek Vasut Cc: linux-input@vger.kernel.org, Arnd Bergmann , Greg Kroah-Hartman , Linus Walleij , kernel@dh-electronics.com Subject: Re: [PATCH] Input: ads7846 - add dummy command register clearing cycle Message-ID: References: <20240320072533.170029-1-marex@denx.de> Precedence: bulk X-Mailing-List: linux-input@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: On Sun, Jun 23, 2024 at 08:21:00PM +0200, Marek Vasut wrote: > On 3/20/24 8:23 AM, Marek Vasut wrote: > > On STM32MP135F with XPT2046 touch controller attached to SPI bus, it has > > been observed that the touch controller locks up after Linux kernel has > > finished booting. Adding a dummy cycle on the SPI bus seems to mitigate > > the lock up. > > > > The XPTEK XPT2046 controller seems to be an identical clone of TI TSC2046, > > the datasheet seems to be a clone of the TI part as well, text seem to be > > word to word identical, except all the pictures have been drawn again. > > > > This touch controller is present e.g. on WaveShare 3.2inch RPi LCD (B) > > panel, the DTO provided by WaveShare uses 50 kHz SPI clock for this > > touch controller, which is unusually low and possibly might have been > > used as some sort of workaround for an issue. The SPI LCD on the same > > bus uses 16 MHz clock. > > > > SPI bus DT properties spi-cs-setup-delay-ns, spi-cs-hold-delay-ns, > > spi-cs-inactive-delay-ns, spi-rx-delay-us, spi-tx-delay-us set to > > range of 500ns..5us seem to have no impact on the behavior of the > > touch controller, the lock up always occurs. The STM32MP13xx SPI > > controller users GPIO control for the nCS pins. > > > > Since the dummy cycle happens after the controller has been put into > > power down mode and both ADC and REF regulators have been disabled, > > the cycle should have no impact on the configuration of the controller, > > i.e. it should be a NOP. > > > > It is unclear whether this problem is specific to this cloned XPT2046 > > controller, or whether this is also present on TSC2046. A test on > > either TSC2046 or ADS7846 would be very welcome. > > Hi, > > Are there still any open topics with this patch ? I am concerned that we are putting workaroud for a single controller into common function. Can we quirk it based on compatible? If not then I would like someone to run tests on other controllers. Unfortunately I do not have such hardware. Linus, do you have devices with ads7846 or tsc2046 by chance? Spitz? Thanks. -- Dmitry