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i2c: designware-baytrail: Acquire P-Unit access on bus acquire

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Acquire P-Unit access to stop others from accessing the P-Unit while the
PMIC i2c bus is in use. This is necessary because accessing the P-Unit
from the kernel may result in the P-Unit trying to access the PMIC i2c
bus, which results in a hang when it happens while we own the PMIC i2c
bus semaphore.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170210102802.20898-10-hdegoede@redhat.com
This commit is contained in:
Hans de Goede 2017-02-10 11:27:59 +01:00 committed by Daniel Vetter
parent fd476fa22a
commit 5b2cacceb7
1 changed files with 4 additions and 0 deletions
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4
drivers/i2c/busses/i2c-designware-baytrail.c
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@ -62,6 +62,8 @@ static void reset_semaphore(struct dw_i2c_dev *dev)
dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE);
iosf_mbi_punit_release();
}
static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
@ -79,6 +81,8 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
if (!dev->release_lock)
return 0;
iosf_mbi_punit_acquire();
/*
* Disallow the CPU to enter C6 or C7 state, entering these states
* requires the punit to talk to the pmic and if this happens while