From patchwork Fri Mar 25 13:32:35 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Krzysztof_Ha=C5=82asa?= X-Patchwork-Id: 601986 Return-Path: X-Original-To: incoming-imx@patchwork.ozlabs.org Delivered-To: patchwork-incoming-imx@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3qWkn82kxzz9s9Z for ; Sat, 26 Mar 2016 00:34:52 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ajRrN-0007nA-Mv; Fri, 25 Mar 2016 13:33:05 +0000 Received: from ni.piap.pl ([195.187.100.4]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ajRrJ-0007O1-N5 for linux-arm-kernel@lists.infradead.org; Fri, 25 Mar 2016 13:33:03 +0000 Received: from t19.piap.pl (OSB1819.piap.pl [10.0.9.19]) by ni.piap.pl (Postfix) with ESMTP id A8AD44413ED; Fri, 25 Mar 2016 14:32:35 +0100 (CET) From: khalasa@piap.pl (Krzysztof =?utf-8?Q?Ha=C5=82asa?=) To: Petr =?utf-8?Q?=C5=A0tetiar?= , Richard Zhu , Lucas Stach , Bjorn Helgaas , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity Date: Fri, 25 Mar 2016 14:32:35 +0100 Message-ID: MIME-Version: 1.0 X-KLMS-Rule-ID: 1 X-KLMS-Message-Action: clean X-KLMS-AntiSpam-Lua-Profiles: 93578 [Mar 25 2016] X-KLMS-AntiSpam-Version: 5.5.9.33 X-KLMS-AntiSpam-Envelope-From: khalasa@piap.pl X-KLMS-AntiSpam-Rate: 0 X-KLMS-AntiSpam-Status: not_detected X-KLMS-AntiSpam-Method: none X-KLMS-AntiSpam-Moebius-Timestamps: 4033847, 4033871, 4033855 X-KLMS-AntiSpam-Info: LuaCore: 415 415 56d27afa4611b5fc17406ce7708f83a66d615280, Auth:dkim=none X-KLMS-AntiSpam-Interceptor-Info: scan successful X-KLMS-AntiPhishing: Clean, 2016/03/24 15:12:18 X-KLMS-AntiVirus: Kaspersky Security 8.0 for Linux Mail Server, version 8.0.1.721, bases: 2016/03/25 05:36:00 #7328597 X-KLMS-AntiVirus-Status: Clean, skipped X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160325_063302_108687_559CCEB6 X-CRM114-Status: GOOD ( 10.46 ) X-Spam-Score: -2.9 (--) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-2.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [195.187.100.4 listed in list.dnswl.org] -1.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+incoming-imx=patchwork.ozlabs.org@lists.infradead.org List-Id: linux-imx-kernel.lists.patchwork.ozlabs.org A recent commit 5c5fb40de8f14391a1238db05cef88754faf9229 stated: Follows: linus/v4.4-rc2 Precedes: linus/v4.5-rc1 PCI: imx6: Add support for active-low reset GPIO We previously used of_get_named_gpio(), which ignores the OF flags cell, so the reset GPIO defaulted to "active high." This doesn't work on the Toradex Apalis SoM with Ixora base board, which has an active-low reset GPIO. Use devm_gpiod_get_optional() instead so we pay attention to the active high/low flag. This also adds support for GPIOs described via ACPI. The (now replaced) code doesn't support the above: @@ -287,10 +287,10 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) usleep_range(200, 500); /* Some boards don't have PCIe reset GPIO. */ - if (gpio_is_valid(imx6_pcie->reset_gpio)) { - gpio_set_value_cansleep(imx6_pcie->reset_gpio, 0); + if (imx6_pcie->reset_gpio) { + gpiod_set_value_cansleep(imx6_pcie->reset_gpio, 0); msleep(100); - gpio_set_value_cansleep(imx6_pcie->reset_gpio, 1); + gpiod_set_value_cansleep(imx6_pcie->reset_gpio, 1); } return 0; If the reset_gpio setup code had ignored the flags (haven't checked that), then clearly the resets were active-low (most reset lines are, because they can be then driven with open-drain/collector output). The gpiod_set_value*(0) activates reset, gpiod_set_value(1) - deactivates. Now we're told the setup code is now level-aware, but the above sequence thus _deactivates_ reset for 100 ms, then _activates_ it again. It has no chance to work, unless a board has a broken DTS file. A quick grep shows that about half the IMX6 boards specify an active-low PCIe reset, 4 ask for active-high, and another 4 don't bother. I wonder if all boards (except maybe that Toradex set) use an active-low PCIe reset and are now broken. Perhaps Toradex uses active-high and thus works. I'm not fixing individual DTS files because I don't really know, though perhaps we should change them all to "active-low", since it would work the same as before the 5c5fb40de8f14391a1238db05cef88754faf9229 change. Confirmed to fix Gateworks Laguna GW54xx. Without the patch, the following happens (as expected): PCI host bridge /soc/pcie@0x01000000 ranges: No bus range found for /soc/pcie@0x01000000, using [bus 00-ff] IO 0x01f80000..0x01f8ffff -> 0x00000000 MEM 0x01000000..0x01efffff -> 0x01000000 imx6q-pcie 1ffc000.pcie: phy link never came up Signed-off-by: Krzysztof Hałasa Reviewed-by: Fabio Estevam diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index fe60096..f17fb02 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -288,9 +288,9 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp) /* Some boards don't have PCIe reset GPIO. */ if (imx6_pcie->reset_gpio) { - gpiod_set_value_cansleep(imx6_pcie->reset_gpio, 0); - msleep(100); gpiod_set_value_cansleep(imx6_pcie->reset_gpio, 1); + msleep(100); + gpiod_set_value_cansleep(imx6_pcie->reset_gpio, 0); } return 0;