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authorKevin Hilman <khilman@deeprootsystems.com>2009-02-04 10:51:40 -0800
committerKevin Hilman <khilman@deeprootsystems.com>2009-05-28 10:59:06 -0700
commit4af4016c53f52b26461b8030211f8427a58fa5ed (patch)
tree984ffcb57bcc8158332c10ef799203bd905d7147 /arch/arm/plat-omap
parent5a1a5abdb2e9a301f1ac62feb37228f3f4d3117c (diff)
OMAP3: PM: UART: disable clocks when idle and off-mode support
This patch allows the UART clocks to be disabled when the OMAP UARTs are inactive, thus permitting the chip to hit retention in idle. After the expiration of an activity timer, each UART is allowed to disable its clocks so the system can enter retention. The activity timer is (re)activated on any UART interrupt, UART wake event or any IO pad wakeup. The actual disable of the UART clocks is done in the 'prepare_idle' hook called from the OMAP idle loop. While the activity timer is active, the smart-idle mode of the UART is also disabled. This is due to a "feature" of the UART module that after a UART wakeup, the smart-idle mode may be entered before the UART has communicated the interrupt, or upon TX, an idle mode may be entered before the TX FIFOs are emptied. Upon suspend, the 'prepare_suspend' hook cancels any pending activity timers and allows the clocks to be disabled immediately. In addition, upon disabling clocks the UART state is saved in case of an off-mode transition while clocks are off. Special thanks to Tero Kristo for the initial ideas and first versions of UART idle support, and to Jouni Hogander for extra testing and bugfixes. Tested on OMAP3 (Beagle, RX51, SDP, EVM) and OMAP2 (n810) Cc: Tero Kristo <tero.kristo@nokia.com> Cc: Jouni Hogander <jouni.hogander@nokia.com> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Diffstat (limited to 'arch/arm/plat-omap')
-rw-r--r--arch/arm/plat-omap/include/mach/common.h2
-rw-r--r--arch/arm/plat-omap/include/mach/serial.h9
2 files changed, 9 insertions, 2 deletions
diff --git a/arch/arm/plat-omap/include/mach/common.h b/arch/arm/plat-omap/include/mach/common.h
index 0ecf36deb17..834f0b3aad1 100644
--- a/arch/arm/plat-omap/include/mach/common.h
+++ b/arch/arm/plat-omap/include/mach/common.h
@@ -33,8 +33,6 @@ struct sys_timer;
extern void omap_map_common_io(void);
extern struct sys_timer omap_timer;
-extern void omap_serial_init(void);
-extern void omap_serial_enable_clocks(int enable);
#if defined(CONFIG_I2C_OMAP) || defined(CONFIG_I2C_OMAP_MODULE)
extern int omap_register_i2c_bus(int bus_id, u32 clkrate,
struct i2c_board_info const *info,
diff --git a/arch/arm/plat-omap/include/mach/serial.h b/arch/arm/plat-omap/include/mach/serial.h
index 8a676a04be4..8e895858b3e 100644
--- a/arch/arm/plat-omap/include/mach/serial.h
+++ b/arch/arm/plat-omap/include/mach/serial.h
@@ -40,4 +40,13 @@
__ret; \
})
+#ifndef __ASSEMBLER__
+extern void omap_serial_init(void);
+extern int omap_uart_can_sleep(void);
+extern void omap_uart_check_wakeup(void);
+extern void omap_uart_prepare_suspend(void);
+extern void omap_uart_prepare_idle(int num);
+extern void omap_uart_resume_idle(int num);
+#endif
+
#endif