Kevin,
On Thu, Jun 19, 2014 at 11:43 AM, Kevin Hilman khil...@linaro.org wrote:
Doug Anderson diand...@chromium.org writes:
The original code for the exynos i2c controller registered for the
noirq variants. However during review feedback it was moved to
SIMPLE_DEV_PM_OPS without anyone noticing that it meant we were no
longer actually noirq (despite functions named
exynos5_i2c_suspend_noirq and exynos5_i2c_resume_noirq).
i2c controllers that might have wakeup sources on them seem to need to
resume at noirq time so that the individual drivers can actually read
the i2c bus to handle their wakeup.
I suspect usage of the noirq variants pre-dates the existence of the
late/early callbacks in the PM core, but based on the description above,
I suspect what you actually want is the late/early callbacks.
I think it actually really needs noirq. ;)
Specifically as soon as IRQs are enabled one of our children might get
an interrupt. To respond to that interrupt it might want to do an i2c
transfer.
Here's a snippet from me moving it to resume early. You can see
that max77686 failed pretty much right away (the dummy is just the
max77686 RTC for various reasons). Note that the max77686 isn't doing
anything tricky. It uses regmap_irq (as per Javier's patches) and
calls enable_irq_wake() at suspend time. It uses a simple threaded
IRQ:
[ 117.968055] PM: noirq resume of devices complete after 1.391 msecs
[ 117.968200] max77686 0-0009: Failed to read IRQ status: -5
[ 117.968697] dummy 0-0006: Failed to read IRQ status: -5
[ 117.968793] calling 12c6.i2c+ @ 5891, parent: none
[ 117.968805] s3c-i2c 12c6.i2c: slave address 0x00
[ 117.968814] s3c-i2c 12c6.i2c: bus frequency set to 378 KHz
[ 117.968824] call 12c6.i2c+ returned 0 after 23 usecs
[ 117.968831] calling 12c7.i2c+ @ 5891, parent: none
[ 117.968841] s3c-i2c 12c7.i2c: slave address 0x00
[ 117.968849] s3c-i2c 12c7.i2c: bus frequency set to 378 KHz
[ 117.968858] call 12c7.i2c+ returned 0 after 20 usecs
[ 117.968864] calling 12c8.i2c+ @ 5891, parent: none
[ 117.968874] s3c-i2c 12c8.i2c: slave address 0x00
[ 117.968882] s3c-i2c 12c8.i2c: bus frequency set to 65 KHz
[ 117.968891] call 12c8.i2c+ returned 0 after 20 usecs
[ 117.968897] calling 12c9.i2c+ @ 5891, parent: none
[ 117.968907] s3c-i2c 12c9.i2c: slave address 0x00
[ 117.968915] s3c-i2c 12c9.i2c: bus frequency set to 65 KHz
[ 117.968923] call 12c9.i2c+ returned 0 after 19 usecs
[ 117.968930] calling 12ca.i2c+ @ 5891, parent: none
[ 117.968940] s3c-i2c 12ca.i2c: slave address 0x00
[ 117.968948] s3c-i2c 12ca.i2c: bus frequency set to 65 KHz
[ 117.968957] call 12ca.i2c+ returned 0 after 20 usecs
[ 117.968964] calling 12cb.i2c+ @ 5891, parent: none
[ 117.968974] s3c-i2c 12cb.i2c: slave address 0x00
[ 117.968982] s3c-i2c 12cb.i2c: bus frequency set to 65 KHz
[ 117.968990] call 12cb.i2c+ returned 0 after 20 usecs
[ 117.968997] calling 12cd.i2c+ @ 5891, parent: none
[ 117.969006] s3c-i2c 12cd.i2c: slave address 0x00
[ 117.969014] s3c-i2c 12cd.i2c: bus frequency set to 65 KHz
[ 117.969022] call 12cd.i2c+ returned 0 after 19 usecs
[ 117.969029] calling 12ce.i2c+ @ 5891, parent: none
[ 117.969039] s3c-i2c 12ce.i2c: slave address 0x00
[ 117.969048] s3c-i2c 12ce.i2c: bus frequency set to 378 KHz
[ 117.969056] call 12ce.i2c+ returned 0 after 20 usecs
[ 117.969625] PM: early resume of devices complete after 1.469 msecs
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