linux/drivers/i2c
Rafael J. Wysocki 02e45646d5 PM: i2c-designware-platdrv: Optimize power management
Optimize the power management in i2c-designware-platdrv by making it
set the DPM_FLAG_SMART_SUSPEND and DPM_FLAG_LEAVE_SUSPENDED which
allows some code to be dropped from its PM callbacks.

First, setting DPM_FLAG_SMART_SUSPEND causes the intel-lpss driver
to avoid resuming i2c-designware-platdrv devices in its ->prepare
callback, so they can stay in runtime suspend after that point even
if the direct-complete feature is not used for them.

It also causes the ACPI PM domain and the PM core to avoid invoking
"late" and "noirq" suspend callbacks for these devices if they are
in runtime suspend at the beginning of the "late" phase of device
suspend during system suspend.  That guarantees dw_i2c_plat_suspend()
to be called for a device only if it is not in runtime suspend.

Moreover, it causes the device's runtime PM status to be set to
"active" after calling dw_i2c_plat_resume() for it, so the
driver doesn't need internal flags to avoid invoking either
dw_i2c_plat_suspend() or dw_i2c_plat_resume() twice in a row.

Second, setting DPM_FLAG_LEAVE_SUSPENDED enables the optimization
allowing the device to stay suspended after system resume under
suitable conditions, so again the driver doesn't need to take
care of that by itself.

Accordingly, the internal "suspended" and "skip_resume" flags
used by the driver are not necessary any more, so drop them and
simplify the driver's PM callbacks.

Additionally, notice that dw_i2c_plat_complete() only needs to
schedule runtime PM resume for the device if platform firmware
has been involved in resuming the system, so make it call
pm_resume_via_firmware() to check that.  Also make it check the
runtime PM status of the device instead of its direct_complete
flag which also works if the device remained suspended due to
the DPM_FLAG_LEAVE_SUSPENDED driver flag.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
2018-01-10 00:48:25 +01:00
..
algos i2c: algo-bit: add support for I2C_M_STOP 2017-06-23 20:45:43 +02:00
busses PM: i2c-designware-platdrv: Optimize power management 2018-01-10 00:48:25 +01:00
muxes Merge branch 'i2c/for-4.15' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2017-11-14 17:52:21 -08:00
i2c-boardinfo.c i2c: i2c-boardinfo: fix memory leaks on devinfo 2017-11-27 19:14:29 +01:00
i2c-core-acpi.c i2c: core: Allow empty id_table in ACPI case as well 2017-07-31 15:50:33 +02:00
i2c-core-base.c i2c: Make i2c_unregister_device() NULL-aware 2017-11-02 00:00:28 +01:00
i2c-core-of.c i2c: Convert to using %pOF instead of full_name 2017-07-31 17:19:35 +02:00
i2c-core-slave.c i2c: break out slave support into separate file 2017-05-31 21:01:03 +02:00
i2c-core-smbus.c i2c: i2c-smbus: add of_i2c_setup_smbus_alert 2017-10-28 23:42:47 +02:00
i2c-core.h i2c: core: Allow empty id_table in ACPI case as well 2017-07-31 15:50:33 +02:00
i2c-dev.c i2c compat ioctls: move to ->compat_ioctl() 2017-09-20 01:02:27 -04:00
i2c-mux.c i2c: mux: only print failure message on error 2017-05-15 18:49:11 +02:00
i2c-slave-eeprom.c i2c: Drop owner assignment from i2c_driver 2015-08-10 08:37:35 +02:00
i2c-smbus.c i2c: i2c-smbus: add of_i2c_setup_smbus_alert 2017-10-28 23:42:47 +02:00
i2c-stub.c i2c: stub: fix build warning regression 2017-06-15 23:22:11 +02:00
Kconfig Merge branch 'i2c/for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2016-12-15 12:56:35 -08:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00