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Tue, 4 Jun 2019 08:17:46 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DLEE107.ent.ti.com (157.170.170.37) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5 via Frontend Transport; Tue, 4 Jun 2019 08:17:46 -0500 Received: from a0393678ub.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id x54DGdGR098972; Tue, 4 Jun 2019 08:17:41 -0500 From: Kishon Vijay Abraham I To: Tom Joseph , Bjorn Helgaas , Rob Herring , Mark Rutland , Lorenzo Pieralisi , Arnd Bergmann , Gustavo Pimentel Subject: [RFC PATCH 11/30] PCI: cadence: Add support to drive PERST# line using GPIO Date: Tue, 4 Jun 2019 18:44:57 +0530 Message-ID: <20190604131516.13596-12-kishon@ti.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190604131516.13596-1-kishon@ti.com> References: <20190604131516.13596-1-kishon@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190604_141759_524756_A6DF9336 X-CRM114-Status: GOOD ( 16.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Jingoo Han , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Kishon Vijay Abraham I , linux-rockchip@lists.infradead.org, Greg Kroah-Hartman , linux-omap@vger.kernel.org, Frank Rowand , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP In platforms like TI's J721E EVM, the PERST# line is connected to a GPIO line and PERST# should be driven high to indicate the clocks are stable (As per Figure 2-10: Power Up of the PCIe CEM spec 3.0). Add support to make GPIO drive PERST# line. Signed-off-by: Kishon Vijay Abraham I --- drivers/pci/controller/pcie-cadence-host.c | 26 ++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/drivers/pci/controller/pcie-cadence-host.c b/drivers/pci/controller/pcie-cadence-host.c index 4ad8f2ece6e2..8b3b9827a8d6 100644 --- a/drivers/pci/controller/pcie-cadence-host.c +++ b/drivers/pci/controller/pcie-cadence-host.c @@ -3,6 +3,8 @@ // Cadence PCIe host controller driver. // Author: Cyrille Pitchen +#include +#include #include #include #include @@ -287,6 +289,7 @@ static int cdns_pcie_host_probe(struct platform_device *pdev) struct pci_host_bridge *bridge; struct list_head resources; struct cdns_pcie_rc *rc; + struct gpio_desc *gpiod; struct cdns_pcie *pcie; struct resource *res; int ret; @@ -349,13 +352,36 @@ static int cdns_pcie_host_probe(struct platform_device *pdev) dev_err(dev, "missing \"mem\"\n"); return -EINVAL; } + pcie->mem_res = res; + gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); + if (IS_ERR(gpiod)) { + ret = PTR_ERR(gpiod); + if (ret != -EPROBE_DEFER) + dev_err(dev, "Failed to get reset GPIO\n"); + return ret; + } + ret = cdns_pcie_init_phy(dev, pcie); if (ret) { dev_err(dev, "failed to init phy\n"); return ret; } + + /* + * "Power Sequencing and Reset Signal Timings" table in + * PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0 + * indicates PERST# should be deasserted after minimum of 100us + * once REFCLK is stable. The REFCLK to the connector in RC + * mode is selected while enabling the PHY. So deassert PERST# + * after 100 us. + */ + if (gpiod) { + usleep_range(100, 200); + gpiod_set_value_cansleep(gpiod, 1); + } + platform_set_drvdata(pdev, pcie); pm_runtime_enable(dev);