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commit 1d375b58c12f08d8570b30b865def4734517f04f upstream.
On some devices the contents of the ctrl register get lost over a
suspend/resume and the PWM comes back up disabled after the resume.
This is seen on some Bay Trail devices with the PWM in ACPI enumerated
mode, so it shows up as a platform device instead of a PCI device.
If we still think it is enabled and then try to change the duty-cycle
after this, we end up with a "PWM_SW_UPDATE was not cleared" error and
the PWM is stuck in that state from then on.
This commit adds suspend and resume pm callbacks to the pwm-lpss-platform
code, which save/restore the ctrl register over a suspend/resume, fixing
this.
Note that:
1) There is no need to do this over a runtime suspend, since we
only runtime suspend when disabled and then we properly set the enable
bit and reprogram the timings when we re-enable the PWM.
2) This may be happening on more systems then we realize, but has been
covered up sofar by a bug in the acpi-lpss.c code which was save/restoring
the regular device registers instead of the lpss private registers due to
lpss_device_desc.prv_offset not being set. This is fixed by a later patch
in this series.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
[bwh: Backported to 3.16:
- pwm-lpss is a single module, so make the new functions static
- Only one PWM per chip is supported; remove the npwm assertion and loops
- Adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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Fixes the following warnings reported by the 0-DAY kernel build testing
backend:
drivers/pwm/pwm-lpss.c: In function 'pwm_lpss_probe_pci':
>> drivers/pwm/pwm-lpss.c:192:2: warning: passing argument 3 of 'pwm_lpss_probe' discards 'const' qualifier from pointer target type [enabled by default]
lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info);
^
drivers/pwm/pwm-lpss.c:130:30: note: expected 'struct pwm_lpss_boardinfo *' but argument is of type 'const struct pwm_lpss_boardinfo *'
static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
^
>> drivers/pwm/pwm-lpss.c:143:28: sparse: incorrect type in return expression (different address spaces)
drivers/pwm/pwm-lpss.c:143:28: expected struct pwm_lpss_chip *
drivers/pwm/pwm-lpss.c:143:28: got void [noderef] <asn:2>*regs
>> drivers/pwm/pwm-lpss.c:192:63: sparse: incorrect type in argument 3 (different modifiers)
drivers/pwm/pwm-lpss.c:192:63: expected struct pwm_lpss_boardinfo *info
drivers/pwm/pwm-lpss.c:192:63: got struct pwm_lpss_boardinfo const *[assigned] info
drivers/pwm/pwm-lpss.c: In function 'pwm_lpss_probe_pci':
drivers/pwm/pwm-lpss.c:192:2: warning: passing argument 3 of 'pwm_lpss_probe' discards 'const' qualifier from pointer target type [enabled by default]
lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info);
^
drivers/pwm/pwm-lpss.c:130:30: note: expected 'struct pwm_lpss_boardinfo *' but argument is of type 'const struct pwm_lpss_boardinfo *'
static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
^
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Not all systems enumerate the PWM devices via ACPI. They can also be
exposed via the PCI interface.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Add support for Intel Low Power I/O subsystem PWM controllers found on
Intel BayTrail SoC.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Chew, Kean Ho <kean.ho.chew@intel.com>
Signed-off-by: Chang, Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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