From d776fdb776681cd013be513ba70ffa51d934f19d Mon Sep 17 00:00:00 2001 From: Shawn Lin Date: Tue, 18 Oct 2016 09:45:09 +0800 Subject: [PATCH] UPSTREAM: of/pci: Add helper function to parse max-link-speed from dt This new helper function could be used by host drivers to get the limitaion of max link speed provided by dt. If the property isn't assigned or is invalid, it will return -EINVAL to the caller. Change-Id: I430b05fa5fd25fe17cf1bd8b1226e460eb7dd14b Signed-off-by: Shawn Lin Acked-by: Rob Herring Signed-off-by: Bjorn Helgaas Signed-off-by: Shawn Lin (am from git.kernel.org/cgit/linux/kernel/git/next/linux-next.git commit 9a1dc3891255afd836f355b117fd6b975d0b1eb2) --- drivers/of/of_pci.c | 21 +++++++++++++++++++++ include/linux/of_pci.h | 7 +++++++ 2 files changed, 28 insertions(+) diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c index b1449f71601c..038c0ec1b0c5 100644 --- a/drivers/of/of_pci.c +++ b/drivers/of/of_pci.c @@ -118,6 +118,27 @@ int of_get_pci_domain_nr(struct device_node *node) } EXPORT_SYMBOL_GPL(of_get_pci_domain_nr); +/** + * This function will try to find the limitation of link speed by finding + * a property called "max-link-speed" of the given device node. + * + * @node: device tree node with the max link speed information + * + * Returns the associated max link speed from DT, or a negative value if the + * required property is not found or is invalid. + */ +int of_pci_get_max_link_speed(struct device_node *node) +{ + u32 max_link_speed; + + if (of_property_read_u32(node, "max-link-speed", &max_link_speed) || + max_link_speed > 4) + return -EINVAL; + + return max_link_speed; +} +EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed); + /** * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only * is present and valid diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h index 2c51ee78b1c0..7a6fd1c2e074 100644 --- a/include/linux/of_pci.h +++ b/include/linux/of_pci.h @@ -16,6 +16,7 @@ int of_pci_get_devfn(struct device_node *np); int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin); int of_pci_parse_bus_range(struct device_node *node, struct resource *res); int of_get_pci_domain_nr(struct device_node *node); +int of_pci_get_max_link_speed(struct device_node *node); void of_pci_check_probe_only(void); #else static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq) @@ -52,6 +53,12 @@ of_get_pci_domain_nr(struct device_node *node) return -1; } +static inline int +of_pci_get_max_link_speed(struct device_node *node) +{ + return -EINVAL; +} + static inline void of_pci_check_probe_only(void) { } #endif -- 2.34.1