From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (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 C0AD1745C7 for ; Thu, 21 Dec 2023 20:13:04 +0000 (UTC) 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="nw9Wlkhk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1703189584; x=1734725584; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=PA2txARed54R/QQdGqV9jJaFmaCK/sHZ44SJ0NakNgg=; b=nw9WlkhkYc2EKtRkXNVclQKUpieKPr7nb8poRuri2AFRu7TOqZk4sNt3 0AzB1mIK4LGQXtklJ5r1DNi79LGORcCFf5kPHHAM/fTdseBQ0ra/aaDc9 M1/ckuBKxPlI7OxRLm0JAJ7lzglchwnFzeJYYJjaLQLteA8ckQyHb3q7T rCZvEfCypPw5sgM4VG57DqYGotwACEzelyTuzXWKieHr6X7IK9sxjMXrY BlYauTnKV77Wg25G/L3m7xkUPE2FMR9wVb0e6o2CmzH7YGUXMQvqHJVZa 0Ri0S/iun189KZ8n+ovgfEwJAilhGqooVGeqcVEN/60xnb58cPszOs7SW w==; X-IronPort-AV: E=McAfee;i="6600,9927,10931"; a="3265594" X-IronPort-AV: E=Sophos;i="6.04,294,1695711600"; d="scan'208";a="3265594" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Dec 2023 12:13:04 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10931"; a="1023979772" X-IronPort-AV: E=Sophos;i="6.04,294,1695711600"; d="scan'208";a="1023979772" Received: from smile.fi.intel.com ([10.237.72.54]) by fmsmga006.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Dec 2023 12:13:02 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.97) (envelope-from ) id 1rGPPg-00000007xji-0ZBE; Thu, 21 Dec 2023 22:13:00 +0200 Date: Thu, 21 Dec 2023 22:12:59 +0200 From: Andy Shevchenko To: Aleksandrs Vinarskis Cc: Lee Jones , linux-kernel@vger.kernel.org, Hans de Goede Subject: Re: [PATCH v4 0/2] Fix LPSS clock divider for XPS 9530 Message-ID: References: <20231221185142.9224-1-alex.vinarskis@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20231221185142.9224-1-alex.vinarskis@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Thu, Dec 21, 2023 at 07:51:40PM +0100, Aleksandrs Vinarskis wrote: > Dell XPS 9530 (2023) uses spi-pxa2xx with clock-divider enabled from > intel-lpss with the ratio of 1:32767 (Dell's firmware bug). This caps SPI > controller's speed at very low value of 3051Hz, which makes the interface > practically unusable. Since either spi-pxa2xx or intel-lpss should have > clock divider enabled, not both, and SPI controller can have higher speed > than requested by the device, it is preffered to disable intel-lpss > clock-divider, and let SPI controller handle it. > > Fixing this issue directly in Dell firmware by setting lpss divider to 1:1 > would've been the ideal solution, but is unlikely to ever happen. > > Particular driver already implements customized solution for handling buggy > ACPI tables for select Microsoft devices. This patch series converts it to > a more generic quirk table, and adds a new quirk QUIRK_CLOCK_DIVIDER_UNITY > which forces clock divider to be set to 1:1. In the future, devices with > similar bug (if any) can be easily added to the same pci id lookup table. LGTM now, Reviewed-by: Andy Shevchenko -- With Best Regards, Andy Shevchenko