diff options
| -rw-r--r-- | drivers/base/platform.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 83f5c5984d1..f8071976fe0 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -452,6 +452,37 @@ void platform_driver_unregister(struct platform_driver *drv) EXPORT_SYMBOL_GPL(platform_driver_unregister); +/* modalias support enables more hands-off userspace setup: + * (a) environment variable lets new-style hotplug events work once system is + * fully running: "modprobe $MODALIAS" + * (b) sysfs attribute lets new-style coldplug recover from hotplug events + * mishandled before system is fully running: "modprobe $(cat modalias)" + */ +static ssize_t +modalias_show(struct device *dev, struct device_attribute *a, char *buf) +{ + struct platform_device *pdev = to_platform_device(dev); + int len = snprintf(buf, PAGE_SIZE, "%s\n", pdev->name); + + return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len; +} + +static struct device_attribute platform_dev_attrs[] = { + __ATTR_RO(modalias), + __ATTR_NULL, +}; + +static int platform_uevent(struct device *dev, char **envp, int num_envp, + char *buffer, int buffer_size) +{ + struct platform_device *pdev = to_platform_device(dev); + + envp[0] = buffer; + snprintf(buffer, buffer_size, "MODALIAS=%s", pdev->name); + return 0; +} + + /** * platform_match - bind platform device to platform driver. * @dev: device. @@ -496,7 +527,9 @@ static int platform_resume(struct device * dev) struct bus_type platform_bus_type = { .name = "platform", + .dev_attrs = platform_dev_attrs, .match = platform_match, + .uevent = platform_uevent, .suspend = platform_suspend, .resume = platform_resume, }; |