From mboxrd@z Thu Jan 1 00:00:00 1970 From: ranshalit@gmail.com (Ran Shalit) Date: Sat, 13 Sep 2014 10:50:31 +0300 Subject: Any char device example for runtime PM ? Message-ID: To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org On Sat, Sep 13, 2014 at 4:14 AM, Peter Teoh wrote: > please elaborate your requirements. char dev is for I/O to hardware. but > runtime PM is for hibernating machine. what is the connection u trying to > achieve? > > On Mon, Sep 8, 2014 at 1:22 PM, Ran Shalit wrote: >> >> Hello, >> >> Is there any character device example using runtime PM available ? >> It is most helpful, >> Hi, Some of the drivers I'm using are char devices, while I only saw platform device registration for runtime PM, so my question stem from this. As to the system requirement I have, it is as following: 1. make everything as automatic as possible , so that there won't be any need to add any userspace application for the matter. 2. wakeup from all relevant wakeup sources 3. should not use sysfs (it should be disabled from kernel) 4. platform is OMAP3530. Now, As I understand this far, I have the following options ( requirement 3 above I will ignore, don't know how to handle it yet, and assume for meanwhile that I have sysfs) : 1. use suspend scheme (no runtime PM) 1.a. create some kernel periodic thread who check cpu load and will decide to disable system only if its below some minimum threshold (which should indicate no activity) 1.b. initialize all HW interrupts (gpio, uart, etc) as wakeup sources with this scheme only this thread is responsible for the suspend, and there is no use of the runtime PM, right ? 2. use runtime PM scheme : With this scheme I don't understand how some device will wake the system , or doesn't it need to ? If a driver wakes up maybe it need to deliver some info to system ? Thanks for any ideas, Ran