linux-toradex.git/drivers/pwm, branch v4.4.78

pwm: pca9685: Fix period change with same duty cycle

2017-03-15T01:57:14+00:00

commit 8d254a340efb12b40c4c1ff25a48a4f48f7bbd6b upstream.

When first implementing support for changing the output frequency, an
optimization was added to continue the PWM after changing the prescaler
without having to reprogram the ON and OFF registers for the duty cycle,
in case the duty cycle stayed the same. This was flawed, because we
compared the absolute value of the duty cycle in nanoseconds instead of
the ratio to the period.

Fix the problem by removing the shortcut.

Fixes: 01ec8472009c9 ("pwm-pca9685: Support changing the output frequency")
Signed-off-by: Clemens Gruber 
Reviewed-by: Mika Westerberg 
Signed-off-by: Thierry Reding 
Signed-off-by: Greg Kroah-Hartman

pwm: Fix device reference leak

2016-12-08T06:15:24+00:00

commit 0e1614ac84f1719d87bed577963bb8140d0c9ce8 upstream.

Make sure to drop the reference to the parent device taken by
class_find_device() after "unexporting" any children when deregistering
a PWM chip.

Fixes: 0733424c9ba9 ("pwm: Unexport children before chip removal")
Signed-off-by: Johan Hovold 
Signed-off-by: Thierry Reding 
Signed-off-by: Greg Kroah-Hartman

pwm: Unexport children before chip removal

2016-11-10T15:36:37+00:00

commit 0733424c9ba9f42242409d1ece780777272f7ea1 upstream.

Exported pwm channels aren't removed before the pwmchip and are
leaked. This results in invalid sysfs files. This fix removes
all exported pwm channels before chip removal.

Signed-off-by: David Hsu 
Fixes: 76abbdde2d95 ("pwm: Add sysfs interface")
Signed-off-by: Thierry Reding 
Signed-off-by: Greg Kroah-Hartman

pwm: Mark all devices as "might sleep"

2016-09-30T08:18:37+00:00

commit ff01c944cfa939f3474c28d88223213494aedf0b upstream.

Commit d1cd21427747 ("pwm: Set enable state properly on failed call to
enable") introduced a mutex that is needed to protect internal state of
PWM devices. Since that mutex is acquired in pwm_set_polarity() and in
pwm_enable() and might potentially block, all PWM devices effectively
become "might sleep".

It's rather pointless to keep the .can_sleep field around, but given
that there are external users let's postpone the removal for the next
release cycle.

Signed-off-by: Thierry Reding 
Signed-off-by: Greg Kroah-Hartman 
Fixes: d1cd21427747 ("pwm: Set enable state properly on failed call to enable")
Signed-off-by: Krzysztof Kozlowski

pwm: lpc32xx: fix and simplify duty cycle and period calculations

2016-09-15T06:27:43+00:00

[ Upstream commit 5a9fc9c666d5d759699cf5495bda85f1da0d747e ]

The change fixes a problem, if duty_ns is too small in comparison
to period_ns (as a valid corner case duty_ns is 0 ns), then due to
PWM_DUTY() macro applied on a value the result is overflowed over 8
bits, and instead of the highest bitfield duty cycle value 0xff the
invalid duty cycle bitfield value 0x00 is written.

For reference the LPC32xx spec defines PWMx_DUTY bitfield description
is this way and it seems to be correct:

 [Low]/[High] = [PWM_DUTY]/[256-PWM_DUTY], where 0 < PWM_DUTY <= 255.

In addition according to my oscilloscope measurements LPC32xx PWM is
"tristate" in sense that it produces a wave with floating min/max
voltage levels for different duty cycle values, for corner cases:

  PWM_DUTY == 0x01 => signal is in range from -1.05v to 0v
  ....
  PWM_DUTY == 0x80 => signal is in range from -0.75v to +0.75v
  ....
  PWM_DUTY == 0xff => signal is in range from 0v to +1.05v

  PWM_DUTY == 0x00 => signal is around 0v, PWM is off

Due to this peculiarity on very long period ranges (less than 1KHz)
and odd pre-divider values PWM generated wave does not remind a
clock shape signal, but rather a heartbit shape signal with positive
and negative peaks, so I would recommend to use high-speed HCLK clock
as a PWM parent clock and avoid using RTC clock as a parent.

The change corrects PWM output in corner cases and prevents any
possible overflows in calculation of values for PWM_DUTY and
PWM_RELOADV bitfields, thus helper macro definitions may be removed.

Signed-off-by: Vladimir Zapolskiy 
Signed-off-by: Thierry Reding 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

pwm: lpc32xx: correct number of PWM channels from 2 to 1

2016-09-15T06:27:43+00:00

[ Upstream commit ebe1fca35038df28b5c183e8486863e765364ec1 ]

LPC32xx SoC has two independent PWM controllers, they have different
clock parents, clock gates and even slightly different controls, and
each of these two PWM controllers has one output channel. Due to
almost similar controls arranged in a row it is incorrectly set that
there is one PWM controller with two channels, fix this problem, which
at the moment prevents separate configuration of different clock
parents and gates for both PWM controllers.

The change makes previous PWM device node description incompatible
with this update.

Signed-off-by: Vladimir Zapolskiy 
Signed-off-by: Thierry Reding 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

pwm: fsl-ftm: Fix clock enable/disable when using PM

2016-09-15T06:27:43+00:00

[ Upstream commit 816aec2325e620b6454474372a21f90a8740cb28 ]

A FTM PWM instance enables/disables three clocks: The bus clock, the
counter clock and the PWM clock. The bus clock gets enabled on
pwm_request, whereas the counter and PWM clocks will be enabled upon
pwm_enable.

The driver has three closesly related issues when enabling/disabling
clocks during suspend/resume:
- The three clocks are not treated differently in regards to the
  individual PWM state enabled/requested. This can lead to clocks
  getting disabled which have not been enabled in the first place
  (a PWM channel which only has been requested going through
  suspend/resume).

- When entering suspend, the current behavior relies on the
  FTM_OUTMASK register: If a PWM output is unmasked, the driver
  assumes the clocks are enabled. However, some PWM instances
  have only 2 channels connected (e.g. Vybrid's FTM1). In that case,
  the FTM_OUTMASK reads 0x3 if all channels are disabled, even if
  the code wrote 0xff to it before. For those PWM instances, the
  current approach to detect enabled PWM signals does not work.

- A third issue applies to the bus clock only, which can get enabled
  multiple times (once for each PWM channel of a PWM chip). This is
  fine, however when entering suspend mode, the clock only gets
  disabled once.

This change introduces a different approach by relying on the enable
and prepared counters of the clock framework and using the frameworks
PWM signal states to address all three issues.

Clocks get disabled during suspend and back enabled on resume
regarding to the PWM channels individual state (requested/enabled).

Since we do not count the clock enables in the driver, this change no
longer clears the Status and Control registers Clock Source Selection
(FTM_SC[CLKS]). However, since we disable the selected clock anyway,
and we explicitly select the clock source on reenabling a PWM channel
this approach should not make a difference in practice.

Signed-off-by: Stefan Agner 
Signed-off-by: Thierry Reding 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

pwm: brcmstb: Fix check of devm_ioremap_resource() return code

2016-05-04T21:48:47+00:00

commit c5857e3f94ab2719dfac649a146cb5dd6f21fcf3 upstream.

The change fixes potential oops while accessing iomem on invalid address
if devm_ioremap_resource() fails due to some reason.

The devm_ioremap_resource() function returns ERR_PTR() and never returns
NULL, which makes useless a following check for NULL.

Signed-off-by: Vladimir Zapolskiy 
Fixes: 3a9f5957020f ("pwm: Add Broadcom BCM7038 PWM controller support")
Acked-by: Florian Fainelli 
Signed-off-by: Thierry Reding 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'pwm/for-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

2015-11-11T17:16:10+00:00

Pull pwm updates from Thierry Reding:
 "This round contains a couple of new drivers for the Marvell Berlin
  family of SoCs, various SoCs from Renesas and Broadcom as well as the
  backlight PWM present on MediaTek SoCs.

  Further existing drivers are extended to support a wider range of
  hardware.

  The remaining patches are minor fixes and cleanups across the board.

  Note that one of the patches included in this pull request is against
  arch/unicore32.  I've included it here because I couldn't get a
  response from Guan Xuetao and I consider the change low-risk.
  Equivalent patches have been merged and tested in Samsung and PXA
  trees.  The goal is to finally get rid of legacy code paths that have
  repeatedly been causing headaches"

* tag 'pwm/for-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (24 commits)
  pwm: sunxi: Fix whitespace issue
  pwm: sysfs: Make use of the DEVICE_ATTR_[RW][WO] macro's
  pwm: sysfs: Remove unnecessary temporary variable
  unicore32: nb0916: Use PWM lookup table
  pwm: pwm-rcar: Revise the device tree binding document about compatible
  pwm: Return -ENODEV if no PWM lookup match is found
  pwm: sun4i: Add support for PWM controller on sun5i SoCs
  pwm: Set enable state properly on failed call to enable
  pwm: lpss: Add support for runtime PM
  pwm: lpss: Add more Intel Broxton IDs
  pwm: lpss: Support all four PWMs on Intel Broxton
  pwm: lpss: Add support for multiple PWMs
  pwm-pca9685: enable ACPI device found on Galileo Gen2
  pwm: Add MediaTek display PWM driver support
  dt-bindings: pwm: Add MediaTek display PWM bindings
  pwm: tipwmss: Enable on TI DRA7x and AM437x
  pwm: atmel-hlcdc: add sama5d2 SoC support.
  pwm: Add Broadcom BCM7038 PWM controller support
  Documentation: dt: add Broadcom BCM7038 PWM controller binding
  pwm: Add support for R-Car PWM Timer
  ...

pwm: sunxi: Fix whitespace issue

2015-11-10T12:06:47+00:00

This patch changes no code, it just fixes the whitespacing. Operators
should be separated from operands by a single space.

Signed-off-by: Olliver Schinagl 
Signed-off-by: Thierry Reding