Add a pointer from device tree node to the device created from it. This allows us to find the device corresponding to a device tree node without having to loop through all the platform devices.
However, fallback to looping through the platform devices to handle any devices that might set their own of_node. Signed-off-by: Saravana Kannan <[email protected]> --- drivers/of/platform.c | 20 +++++++++++++++++++- include/linux/of.h | 3 +++ 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 04ad312fd85b..1115a8d80a33 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -42,6 +42,8 @@ static int of_dev_node_match(struct device *dev, void *data) return dev->of_node == data; } +static DEFINE_SPINLOCK(of_dev_lock); + /** * of_find_device_by_node - Find the platform_device associated with a node * @np: Pointer to device tree node @@ -55,7 +57,18 @@ struct platform_device *of_find_device_by_node(struct device_node *np) { struct device *dev; - dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match); + /* + * Spinlock needed to make sure np->dev doesn't get freed between NULL + * check inside and kref count increment inside get_device(). This is + * achieved by grabbing the spinlock before setting np->dev = NULL in + * of_platform_device_destroy(). + */ + spin_lock(&of_dev_lock); + dev = get_device(np->dev); + spin_unlock(&of_dev_lock); + if (!dev) + dev = bus_find_device(&platform_bus_type, NULL, np, + of_dev_node_match); return dev ? to_platform_device(dev) : NULL; } EXPORT_SYMBOL(of_find_device_by_node); @@ -196,6 +209,7 @@ static struct platform_device *of_platform_device_create_pdata( platform_device_put(dev); goto err_clear_flag; } + np->dev = &dev->dev; return dev; @@ -556,6 +570,10 @@ int of_platform_device_destroy(struct device *dev, void *data) if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS)) device_for_each_child(dev, NULL, of_platform_device_destroy); + /* Spinlock is needed for of_find_device_by_node() to work */ + spin_lock(&of_dev_lock); + dev->of_node->dev = NULL; + spin_unlock(&of_dev_lock); of_node_clear_flag(dev->of_node, OF_POPULATED); of_node_clear_flag(dev->of_node, OF_POPULATED_BUS); diff --git a/include/linux/of.h b/include/linux/of.h index 0cf857012f11..f2b4912cbca1 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -48,6 +48,8 @@ struct property { struct of_irq_controller; #endif +struct device; + struct device_node { const char *name; phandle phandle; @@ -68,6 +70,7 @@ struct device_node { unsigned int unique_id; struct of_irq_controller *irq_trans; #endif + struct device *dev; /* Device created from this node */ }; #define MAX_PHANDLE_ARGS 16 -- 2.22.0.rc1.257.g3120a18244-goog
