From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: [PATCH] PCI: tegra: Fix support for GPIO based PERST# Date: Fri, 5 Jul 2019 09:48:50 +0100 Message-ID: <20190705084850.30777-1-jonathanh@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Sender: linux-kernel-owner@vger.kernel.org To: Thierry Reding , Lorenzo Pieralisi , Bjorn Helgaas Cc: linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Manikanta Maddireddy , Jon Hunter List-Id: linux-tegra@vger.kernel.org Commit 5e5e9c23f82a ("PCI: tegra: Add support for GPIO based PERST#") calls the function devm_gpiod_get_from_of_node() to request a GPIO. Unfortunately, around the same time this was merged, commit 025bf37725f1 ("gpio: Fix return value mismatch of function gpiod_get_from_of_node()") was also merged to fix the return value of the function devm_gpiod_get_from_of_node() that was incorrectly returning NULL instead of an error pointer encoded with -ENOENT if no GPIO was found. When this fix for the GPIO subsystem was merged, PCI support for Tegra devices that did not provide a GPIO for the PERST# (which is optional) broke because the Tegra PCI driver was expecting NULL to be returned if no GPIO was present and not -ENOENT. Fix this by checking to see if -ENOENT is returned from the function devm_gpiod_get_from_of_node(), to indicate there is no GPIO for PERST# present, and if this is the case set the variable 'reset_gpio' to NULL. If the variable 'reset_gpio' is NULL then the Tegra PCI driver will fallback to using the AFI register to toggle the PERST#. Finally, correct the comment now that NULL is no longer returned from devm_gpiod_get_from_of_node(). Fixes: 5e5e9c23f82a ("PCI: tegra: Add support for GPIO based PERST#") Signed-off-by: Jon Hunter --- drivers/pci/controller/pci-tegra.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c index 9cc03a2549c0..ff8a346f3e04 100644 --- a/drivers/pci/controller/pci-tegra.c +++ b/drivers/pci/controller/pci-tegra.c @@ -2295,18 +2295,22 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie) } /* - * Returns null if reset-gpios property is not populated and - * fall back to using AFI per port register to toggle PERST# - * SFIO line. + * Returns -ENOENT if reset-gpios property is not populated + * and in this case fall back to using AFI per port register + * to toggle PERST# SFIO line. */ rp->reset_gpio = devm_gpiod_get_from_of_node(dev, port, "reset-gpios", 0, GPIOD_OUT_LOW, label); if (IS_ERR(rp->reset_gpio)) { - err = PTR_ERR(rp->reset_gpio); - dev_err(dev, "failed to get reset GPIO: %d\n", err); - return err; + if (PTR_ERR(rp->reset_gpio) == -ENOENT) { + rp->reset_gpio = NULL; + } else { + dev_err(dev, "failed to get reset GPIO: %d\n", + err); + return PTR_ERR(rp->reset_gpio); + } } list_add_tail(&rp->list, &pcie->ports); -- 2.17.1