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| /linux/drivers/extcon/ |
| H A D | extcon-axp288.c | diff 968bd3f0388b8eaf6746336856348dc3ddf2ed39 Thu Sep 16 09:12:55 CEST 2021 Fabio Aiuto <fabioaiuto83@gmail.com> extcon: extcon-axp288: Use P-Unit semaphore lock for register accesses
use low level P-Unit semaphore lock for axp288 register
accesses directly and for more than one access a time,
to reduce the number of times this semaphore is locked
and released which is an expensive operation.
i2c-bus to the XPower is shared between the kernel and the
SoCs P-Unit. The P-Unit has a semaphore wich the kernel must
lock for axp288 register accesses. When the P-Unit semaphore
is locked CPU and GPU power states cannot change or the system
will freeze.
The P-Unit semaphore lock is already managed inside the regmap
access logic, but for each access the semaphore is locked and
released. So use directly iosf_mbi_(un)block_punit_i2c_access(),
we are safe in doing so because nested calls to the same
semaphore are turned to nops.
Suggested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
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| H A D | Kconfig | diff 968bd3f0388b8eaf6746336856348dc3ddf2ed39 Thu Sep 16 09:12:55 CEST 2021 Fabio Aiuto <fabioaiuto83@gmail.com> extcon: extcon-axp288: Use P-Unit semaphore lock for register accesses
use low level P-Unit semaphore lock for axp288 register
accesses directly and for more than one access a time,
to reduce the number of times this semaphore is locked
and released which is an expensive operation.
i2c-bus to the XPower is shared between the kernel and the
SoCs P-Unit. The P-Unit has a semaphore wich the kernel must
lock for axp288 register accesses. When the P-Unit semaphore
is locked CPU and GPU power states cannot change or the system
will freeze.
The P-Unit semaphore lock is already managed inside the regmap
access logic, but for each access the semaphore is locked and
released. So use directly iosf_mbi_(un)block_punit_i2c_access(),
we are safe in doing so because nested calls to the same
semaphore are turned to nops.
Suggested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
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