Re: [RFC 2/7] tty: add support for "tty slave" devices
From: Pavel Machek <hidden>
Date: 2016-08-14 08:48:30
Also in:
linux-bluetooth, linux-devicetree, linux-serial, lkml
On Sat 2016-08-13 12:03:45, Greg Kroah-Hartman wrote:
On Sat, Aug 13, 2016 at 05:14:33AM +0200, Sebastian Reichel wrote:quoted
From: NeilBrown <redacted> A "tty slave" is a device connected via UART. It may need a driver to, for example, power the device on when the tty is opened, and power it off when the tty is released. Signed-off-by: NeilBrown <redacted> Signed-off-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Pavel Machek <redacted>
quoted
@@ -3317,6 +3318,11 @@ struct device *tty_register_device_attr(struct tty_driver *driver, retval = device_register(dev); if (retval) goto error; + if (device && device->of_node) + /* Children are platform devices and will be + * runtime_pm managed by this tty. + */ + of_platform_populate(device->of_node, NULL, NULL, dev);Why are these platform devices? And why only OF?
OF based systems are the only ones that have this problem, so that's the only place where we can test this solution. Given that these devices are connected over the UART, it seems right to categorize them as platform devices... You can't connect PCI, SATA or USB device over UART port. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html