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i2c: designware-baytrail: Acquire P-Unit access on bus acquire
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
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@ -62,6 +62,8 @@ static void reset_semaphore(struct dw_i2c_dev *dev)
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dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
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pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE);
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iosf_mbi_punit_release();
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}
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static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
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@ -79,6 +81,8 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
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if (!dev->release_lock)
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return 0;
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iosf_mbi_punit_acquire();
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/*
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* Disallow the CPU to enter C6 or C7 state, entering these states
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* requires the punit to talk to the pmic and if this happens while
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