Commit a0245f7a authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman
Browse files

[PATCH] platform_bus learns about modalias 



This patch adds modalias support to platform devices, for simpler
hotplug/coldplug driven driver setup.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 05967118

drivers/base/platform.c

+33 −0
Original line number Diff line number Diff line
@@ -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,

};