On 09/03/15 16:43, Wolfram Sang wrote: > On Mon, Mar 09, 2015 at 03:39:35PM +0000, Jonathan Cameron wrote: >> On 25/02/15 15:55, Vianney le Clément de Saint-Marcq wrote: >>> Add support for system sleep and runtime power management. >>> >>> To wake up the device, the SDA line should be held low for at least 33ms >>> while SCL is high. As this is not possible using the i2c API (and not >>> supported by all i2c adapters), a GPIO connected to the SDA line is >>> needed. The GPIO is named "wakeup" and can be specified in a device >>> tree with the "wakeup-gpios" binding. >> Needs some i2c specialist input on this! As you mentioned it is liable >> to be controversial. Wolfram, is this a one off special or do >> any other devices do this sort of magic? > > s/magic/insanity/ :) > > I have never heard of something like this. Unsuprisingly, I can > not recommend doing it this way. But we all know hardware... > > And while we could think about reusing the bus_recovery_infrastructure, > I don't think it is worth the hazzle. So, doing this GPIO fallback may > well be the best we can do now. > Fair enough. Lets go with this approach then and hope this is the only bit of hardware ever to do this (yeah right ;) -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
