Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753474Ab3HBOFp (ORCPT ); Fri, 2 Aug 2013 10:05:45 -0400 Received: from hqemgate16.nvidia.com ([216.228.121.65]:15075 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752869Ab3HBOFn (ORCPT ); Fri, 2 Aug 2013 10:05:43 -0400 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Fri, 02 Aug 2013 07:04:12 -0700 Message-ID: <51FBBCB1.9060906@nvidia.com> Date: Fri, 2 Aug 2013 17:05:37 +0300 From: Tuomas Tynkkynen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130330 Thunderbird/17.0.5 MIME-Version: 1.0 Newsgroups: gmane.linux.kernel,gmane.linux.ports.tegra,gmane.linux.usb.general To: Stephen Warren CC: , , , , , Subject: Re: [PATCH 4/6] usb: phy: tegra: Program new PHY parameters References: <1375292522-7855-1-git-send-email-ttynkkynen@nvidia.com> <1375292522-7855-5-git-send-email-ttynkkynen@nvidia.com> <51FAD020.8090306@wwwdotorg.org> In-Reply-To: <51FAD020.8090306@wwwdotorg.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1615 Lines: 33 On 08/02/2013 12:16 AM, Stephen Warren wrote: > On 07/31/2013 11:42 AM, Tuomas Tynkkynen wrote: >> The Tegra30 TRM recommends configuration of certain PHY parameters for >> optimal quality. Program the following registers based on device tree >> parameters: >> >> - UTMIP_XCVR_HSSLEW: HS slew rate control. >> - UTMIP_HSSQUELCH_LEVEL: HS squelch detector level >> - UTMIP_HSDISCON_LEVEL: HS disconnect detector level. >> >> These registers exist in Tegra20, but programming them hasn't been >> necessary, so these parameters won't be set on Tegra20 to keep the >> device trees backward compatible. >> >> Additionally, the UTMIP_XCVR_SETUP parameter can be set from fuses >> instead of a software-programmed value, as the optimal value can >> vary between invidual boards. The boolean property >> nvidia,xcvr-setup-use-fuses can be used to enable this behaviour. > >> diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c > Those two chunks end up clearing some fields in the register now even on > earlier chips, whereas before their values were maintained when doing > the read/modify/write. Yet, the commit description says the new fields > aren't changed on Tegra20. Do the changes above need to be guarded by if > (requires_extra_tuning_parameters)? Oops, you are right. I overlooked that some of those fields have non-zero reset values. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/