The following patch:
Author: Kalle Jokiniemi <ext-kalle.jokiniemi@xxxxxxxxx> 2008-08-26 02:56:02
Committer: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> 2009-03-25 10:11:41
OMAP: PM: sysfs interface for enabling voltage off in idle
This patch creates a sysfs interface (/sys/power/voltage_off_while_idle) to
set or clear a variable which can be used in determining wether voltage
regulators should be shut down in idle.
Signed-off-by: Kalle Jokiniemi <ext-kalle.jokiniemi@xxxxxxxxx>
Modifies the PM_VOLTCTRL register of the omap3. It sets AUTO_SLEEP by
default, sets AUTO_OFF when powering off the CORE domain, and sets
SEL_OFF based on the voltage_off_while_idle sysfs file. Several bits
are incomplete.
1.12.5.1.4 PRM_VOLTCTRL (Voltage Source Control Register)
This register allows control of the power IC. The following are
the register bit fields:
• AUTO_SLEEP: Automatically sends the sleep command when the
voltage domain is in the appropriate
standby mode
• AUTO_RET: Automatically sends the retention command when the
voltage domain is in the
appropriate standby mode
• AUTO_OFF: Automatically sends the off command when the
voltage domain is in the appropriate
standby mode
• SEL_OFF: Controls whether the off command is sent through the
voltage controller I2C interface or the
signal sys_off_mode is asserted when entering off mode
• SEL_VMODE: Allows control of the power IC through either the
voltage controller I2C interface or the
VMODE interface
The voltage_off_while idle flag thus does not do what it says it does.
It merely selects the action by which the AUTO_OFF functionality
works.
The patch does set AUTO_OFF to true when sleeping if the core domain
is to be shut off, so in that sense it works. However, on my platform
(Beagleboard), the regulators for VDD1 and/or VDD2 do not shut off
with SEL_OFF=1 or SEL_OFF=0 (further investigation required).
The AUTO_SLEEP flag has been removed by e1c76c42 in order to reduce C
state latency:
Author: Peter 'p2' De Schrijver <peter.de-schrijver@xxxxxxxxx>
2009-01-14 09:32:35
Committer: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> 2009-03-25 10:13:25
OMAP3: PM: Don't scale voltage in C1 state
This patch prevents VDD1 and VDD2 to go to the lowest OPP when entering C1.
It improves wakeup latency from 600us to about 50us.
Signed-off-by: Peter 'p2' De Schrijver <peter.de-schrijver@xxxxxxxxx>
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