Low-level Power Management (PM) Driver
i.MX51 EVK Linux Reference Manual
7-2
Freescale Semiconductor
d) Program TZIC wakeup register to set wakeup interrupts
4. Call
cpu_do_idle
to execute WFI pending instructions for wait mode
5. If STOP mode, execute
cpu_do_suspend_workaround
in RAM. Change the drive strength of DDR
SDCLK as “low” to minum the power leakage in SDCLK. Execute WFI pending instructions for
stop mode
6. Generate a wakeup interrupt and exit low power mode. If STOP mode, restore DDR drive strength.
7. Disable gpc_dvfs_clk
In STOP mode, the i.MX51 can assert the VSTBY signal to the PMIC and request a voltage change. The
Machine Specific Layer (MSL) usually sets the standby voltage in STOP mode according to i.MX51 data
sheet. See
<ltib_dir>/rpm/BUILD/linux/arch/arm/mach-mx5/mx51_babbage_pmic_mc13892.c
for the
details.
7.3
Source Code Structure
shows the PM driver source files. These files are available in
<ltib_dir>/rpm/BUILD/linux/arch/arm/mach-mx5/
7.4
Menu Configuration Options
The following Linux kernel configuration options are provided for this module. To get to these options,
use the
./ltib -c
command when located in the
<ltib dir>
. On the screen displayed, select
Configure
the Kernel
and exit. When the next screen appears, select the following options to enable this module:
•
CONFIG_PM—Build support for power management. In menuconfig, this option is available
under
Power management options
>
Power Management support
By default, this option is Y.
•
CONFIG_SUSPEND—Build support for suspend. In menuconfig, this option is available under
Power management options
>
Suspend to RAM and standby
7.5
Programming Interface
The
mxc_cpu_ip_set
API in the
system.c
function is provided for low-power modes. This implements all
the steps required to put the system into WAIT and STOP modes.
Table 7-2. PM Driver Files
File
Description
pm.c
Supports suspend operation
system.c
Supports low-power modes
wfi.S
Assemble file for
cpu_cortexa8_do_idle
suspend.S
Assemble file for
cpu_do_suspend_workaround
Summary of Contents for i.MX51 EVK
Page 1: ...Part Number 924 76374 Rev 10 11 01 11 2010 i MX51 EVK Linux Reference Manual...
Page 14: ...i MX51 EVK Linux Reference Manual xiv Freescale Semiconductor...
Page 18: ...i MX51 EVK Linux Reference Manual xviii Freescale Semiconductor...
Page 24: ...i MX51 EVK Linux Reference Manual xxiv Freescale Semiconductor...
Page 38: ...Machine Specific Layer MSL i MX51 EVK Linux Reference Manual 2 8 Freescale Semiconductor...
Page 52: ...MC13892 Digitizer Driver i MX51 EVK Linux Reference Manual 5 4 Freescale Semiconductor...
Page 64: ...TV Encoder TVE Driver i MX51 EVK Linux Reference Manual 10 4 Freescale Semiconductor...
Page 82: ...Video for Linux Two V4L2 Driver i MX51 EVK Linux Reference Manual 12 8 Freescale Semiconductor...
Page 86: ...i MX5 Dual Display i MX51 EVK Linux Reference Manual 13 4 Freescale Semiconductor...
Page 100: ...X Windows Acceleration i MX51 EVK Linux Reference Manual 16 6 Freescale Semiconductor...
Page 118: ...Low Level Keypad Driver i MX51 EVK Linux Reference Manual 20 6 Freescale Semiconductor...
Page 134: ...Security Drivers i MX51 EVK Linux Reference Manual 22 10 Freescale Semiconductor...
Page 148: ...Inter IC I2C Driver i MX51 EVK Linux Reference Manual 24 4 Freescale Semiconductor...
Page 178: ...ARC USB Driver i MX51 EVK Linux Reference Manual 29 10 Freescale Semiconductor...
Page 194: ...OProfile i MX51 EVK Linux Reference Manual 33 6 Freescale Semiconductor...