Runtime PM is used to turn clocks on and off when the controller is
not in use. There are 2 use-cases for the controller:
When the controller is used for messaging, pm_runtime_get is called
before sending the message. pm_runtime_put is called when message is
sent and/or response is received.
When the controller is used for data channels, pm_runtime_get is
called when data channel slot usage goes from 0 to non-zero.
pm_runtime_put can't be just called when data channel is scheduled
since data channel activity is going on until the data channel is
explicitly taken down. In that case, pm_runtime_put is called when
data channels are no longer using any slots on the bus.
pm_runtime_autosuspend is used to ensure that runtime_suspend doesn't
happen right after runtime enters idle state. This serves 2 purposes:
1. Resources aren't turned on/off too frequently.
2. There is a use case from audio where it does read/write to some
registers and the following data-channel setup happens from the LPASS
(satellite side). The timer ensures that there is no runtime_suspend
between these 2 activities.
Change-Id: I282e779380ae76058198e63c088aabfa3f1686fd
CRs-Fixed: 318901
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Clock pause message informs all devices on the bus that the active
manager having framer device pause the bus. This allows stopping the
clock to conserve power.
Clock is paused only if there are no active data channels on the bus
and no response is pending for any READ message.
Slimbus framework wakes up the controller using a wakeup function
pointer. Controller should then program the active framer to be out of
clock pause.
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Slimbus can run in clock gears 1 through 10 per spec. Scheduling
algorithm tries to find the optimum clock gear depending on bandwidth
usage for messaging and active data channels.
However, not all controllers may have the ability to support all the
10 clock gears. This patch provides ability so that scheduling
algorithm will only run the bus in supported slimbus clock gear.
Controllers can specify supported minimum and maximum clock gear
during registration with the framework.
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
