Commit Graph

25 Commits

Author SHA1 Message Date
Uwe Kleine-König
5ba3eb4bb3 pwm: fsl-ftm: Simplify using devm_pwmchip_add()
This allows to drop the platform_driver's remove function.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-09-02 21:38:41 +02:00
Uwe Kleine-König
e9fdf122cf pwm: Simplify all drivers with explicit of_pwm_n_cells = 3
With the previous commit there is no need for the lowlevel driver any
more to specify it it uses two or three cells. So simplify accordingly.

The only non-trival change affects the pwm-rockchip driver: It used to only
support three cells if the hardware supports polarity. Now the default
number depends on the device tree which has to match hardware anyhow
(and if it doesn't the error is just a bit delayed as a PWM handle with
an inverted setting is catched when pwm_apply_state() is called).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-05-25 18:19:15 +02:00
Uwe Kleine-König
f9a8ee8c8b pwm: Always allocate PWM chip base ID dynamically
Since commit 5e5da1e9fb ("pwm: ab8500: Explicitly allocate pwm chip
base dynamically") all drivers use dynamic ID allocation explicitly. New
drivers are supposed to do the same, so remove support for driver
specified base IDs and drop all assignments in the low-level drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-03-22 11:53:00 +01:00
Yangtao Li
e9534031f0 pwm: fsl-ftm: Convert to devm_platform_ioremap_resource()
Use devm_platform_ioremap_resource() to simplify code.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-12-17 14:18:38 +01:00
Uwe Kleine-König
71523d1812 pwm: Ensure pwm_apply_state() doesn't modify the state argument
It is surprising for a PWM consumer when the variable holding the
requested state is modified by pwm_apply_state(). Consider for example a
driver doing:

        #define PERIOD 5000000
        #define DUTY_LITTLE 10
        ...
        struct pwm_state state = {
                .period = PERIOD,
                .duty_cycle = DUTY_LITTLE,
                .polarity = PWM_POLARITY_NORMAL,
                .enabled = true,
        };

        pwm_apply_state(mypwm, &state);
        ...
        state.duty_cycle = PERIOD / 2;
        pwm_apply_state(mypwm, &state);

For sure the second call to pwm_apply_state() should still have
state.period = PERIOD and not something the hardware driver chose for a
reason that doesn't necessarily apply to the second call.

So declare the state argument as a pointer to a const type and adapt all
drivers' .apply callbacks.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21 03:25:10 +02:00
Uwe Kleine-König
c9675829ba pwm: fsl-ftm: Don't update the state for the caller of pwm_apply_state()
The pwm-fsl-ftm driver is one of only three PWM drivers which updates
the state for the caller of pwm_apply_state(). This might have
surprising results if the caller reuses the values expecting them to
still represent the same state.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21 01:48:55 +02:00
Linus Torvalds
6e2bbb688a pwm: Changes for v5.3-rc1
This set of changes contains a new driver for SiFive SoCs as well as
 enhancements to the core (device links are used to track dependencies
 between PWM providers and consumers, support for PWM controllers via
 ACPI, sysfs will now suspend/resume PWMs that it has claimed) and
 various existing drivers.
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Merge tag 'pwm/for-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This set of changes contains a new driver for SiFive SoCs as well as
  enhancements to the core (device links are used to track dependencies
  between PWM providers and consumers, support for PWM controllers via
  ACPI, sysfs will now suspend/resume PWMs that it has claimed) and
  various existing drivers"

* tag 'pwm/for-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (37 commits)
  pwm: fsl-ftm: Make sure to unlock mutex on failure
  pwm: fsl-ftm: Use write protection for prescaler & polarity
  pwm: fsl-ftm: More relaxed permissions for updating period
  pwm: atmel-hlcdc: Add compatible for SAM9X60 HLCDC's PWM
  pwm: bcm2835: Improve precision of PWM
  leds: pwm: Support ACPI via firmware-node framework
  pwm: Add support referencing PWMs from ACPI
  pwm: rcar: Remove suspend/resume support
  pwm: sysfs: Add suspend/resume support
  pwm: Add power management descriptions
  pwm: meson: Add documentation to the driver
  pwm: meson: Add support PWM_POLARITY_INVERSED when disabling
  pwm: meson: Don't cache struct pwm_state internally
  pwm: meson: Read the full hardware state in meson_pwm_get_state()
  pwm: meson: Simplify the calculation of the pre-divider and count
  pwm: meson: Move pwm_set_chip_data() to meson_pwm_request()
  pwm: meson: Add the per-channel register offsets and bits in a struct
  pwm: meson: Add the meson_pwm_channel data to struct meson_pwm
  pwm: meson: Pass struct pwm_device to meson_pwm_calc()
  pwm: meson: Don't duplicate the polarity internally
  ...
2019-07-09 08:57:45 -07:00
Thierry Reding
3d25025ce9 pwm: fsl-ftm: Make sure to unlock mutex on failure
Upon failure to enable clocks while trying to enable the PWM, make sure
to unlock the mutex that was taken to avoid a deadlock during subsequent
operations.

Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-06-26 11:39:25 +02:00
Patrick Havelange
a2a28229cd pwm: fsl-ftm: Use write protection for prescaler & polarity
Modifying the prescaler or polarity value must be done with the
write protection disabled. Currently this is working by chance as
the write protection is in a disabled state by default.
This patch makes sure that we enable/disable the write protection
when needed.

Signed-off-by: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-06-26 11:39:18 +02:00
Patrick Havelange
3479bbd1e1 pwm: fsl-ftm: More relaxed permissions for updating period
The Flextimer has only one period for several channels. The PWM
subsystem doesn't allow to model something like that. The current
implementation simply disallows changing the period once it has
been set, having as a side effect that you need to enable and
disable the PWM if you want to change the period.

The driver should allow as much freedom as possible for configuring
the period and duty cycle. Therefore, this patch reworks the code
to allow the following:

- period and duty_cycle can be set at will when the PWM is disabled;
- when enabling a PWM, verify that the period is either not set yet,
  or the same as the other already enabled PWM(s), and fail if not;
- allow to change the period on the fly when the PWM is the only one
  enabled.

It also allows to have different periods configured for different PWMs.
Only one period can be used at a time, thus the first PWM to be enabled
will set that period, only other PWMs with that same period can be
enabled at the same time. To use another PWM with another period, the
enabled PWMs must be disabled first.

Example scenario :
echo 5000000 > pwm0/period	#OK
echo 1000000 > pwm0/duty_cycle	#OK
echo 1000000 > pwm1/period	#OK
echo 1000000 > pwm1/duty_cycle	#OK
echo 1 > pwm0/enable		#OK
echo 1 > pwm1/enable		#FAIL (pwm0/period != pwm1/period)
echo 0 > pwm0/enable		#OK
echo 1 > pwm1/enable		#OK
echo 1000000 > pwm0/period	#OK
echo 2000000 > pwm0/period	#OK
echo 1 > pwm0/enable		#FAIL (pwm0/period != pwm1/period)
echo 2000000 > pwm1/period	#OK (pwm1 still running, changed on the fly)
echo 1 > pwm0/enable		#OK (now pwm0/period == pwm1/period)
echo 3000000 > pwm1/period	#FAIL (other PWMs running)
echo 0 > pwm0/enable		#OK
echo 3000000 > pwm1/period	#OK (only this PWM running)

Adapting the code to satisfy these constraints turned up a number of
additional issues with the current implementation:
- the prescaler value 0 was not used (when it could have been);
- when setting the period was not possible, the internal state was
  inconsistent;
- the maximal value for configuring the period was never used;

Since all of these interact with each other, rather than trying to fix
each individual issue, this patch reworks how the period and duty cycle
are set entirely, with the following additional improvements:
- implement the new apply() method instead of the individual methods;
- return the exact used period/duty_cycle values;
- more coherent argument types for period, duty_cycle;

Signed-off-by: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-06-26 11:39:16 +02:00
Thomas Gleixner
2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00
Patrick Havelange
e590eb408c drivers/pwm: pwm-fsl-ftm: use common header for FlexTimer #defines
This also fixes the wrong value for the previously defined
FTM_MODE_INIT macro (it was not used).

Reviewed-by: Esben Haabendal <esben@haabendal.dk>
Signed-off-by: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 21:33:41 +02:00
shenwei.wang@nxp.com
2c4f2e326b pwm: fsl-ftm: Enable support for the new SoC i.MX8QM
Enabled the support for the new SoC i.MX8QM by adding the compatible
string of "fsl,imx8qm-ftm-pwm" and its per-compatible data with setting
"has_enable_bits" to "true".

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-07-09 19:08:26 +02:00
shenwei.wang@nxp.com
db6c51ab15 pwm: fsl-ftm: Added the support of per-compatible data
On the i.MX8x SoC family, an additional PWM enable bit is added for each
PWM channel in the register FTM_SC[23:16]. It supports 8 channels. Bit
16 is for channel 0, and bit 23 is for channel 7. As the IP version
information can not be obtained via any of the FTM registers, a property
of "has_enable_bits" is added via per-compatible data structure.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-07-09 19:06:21 +02:00
shenwei.wang@nxp.com
82a9c55a2b pwm: fsl-ftm: Added a dedicated IP interface clock
The current driver assumes that the ftm_sys clock works as one of the
clock sources for the IP block as well as the IP interface clock. This
assumption does not apply any more on the latest i.MX8x SoC family. On
i.MX8x SoCs, a dedicated IP interface clock is introduced and it must be
enabled before accessing any FTM registers. Moreover, the clock can not
be used as the source clock for the FTM IP block. This patch introduces
the ipg_clk as the dedicated IP interface clock and by default it is the
same as the ftm_sys clock if not specified.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-07-09 19:04:19 +02:00
Thierry Reding
8c0216f377 pwm: Remove .can_sleep from struct pwm_chip
All PWM devices have been marked as "might sleep" since v4.5, there is
no longer a need to differentiate on a per-chip basis.

Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-01-04 09:40:54 +01:00
Stefan Agner
ad06fdeeef pwm: fsl-ftm: Use flat regmap cache
Use flat regmap cache to avoid lockdep warning at probe:

[    0.697285] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2755 lockdep_trace_alloc+0x15c/0x160()
[    0.697449] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))

The RB-tree regmap cache needs to allocate new space on first writes.
However, allocations in an atomic context (e.g. when a spinlock is held)
are not allowed. The function regmap_write calls map->lock, which
acquires a spinlock in the fast_io case. Since the pwm-fsl-ftm driver
uses MMIO, the regmap bus of type regmap_mmio is being used which has
fast_io set to true.

The MMIO space of the pwm-fsl-ftm driver is reasonable condense, hence
using the much faster flat regmap cache is anyway the better choice.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-04-14 16:54:00 +02:00
Stefan Agner
816aec2325 pwm: fsl-ftm: Fix clock enable/disable when using PM
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 <stefan@agner.ch>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-12-16 16:54:32 +01:00
Xiubo Li
97d0b42e39 pwm: ftm: Add Power Management support for FTM PWM
Add PM support for FTM PWM driver using callback function suspend
and resume in .driver.pm of platform_driver.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-12-01 10:48:54 +01:00
Xiubo Li
49599cf6bb pwm: ftm: Add regmap rbtree type cache support
This patch is to prepare for adding PM support for FTM PWM driver using
callback function suspend and resume in .driver.pm of platform_driver.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-12-01 10:44:48 +01:00
Xiubo Li
8e6e765102 pwm: ftm: Correctly track usage count
No matter how many times the FTM PWM is enabled, the use_count will
always be one.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-12-01 10:43:45 +01:00
Xiubo Li
42fa98a9c3 pwm: fsl-ftm: Convert to direct regmap API usage
The regmap core supports different endian modes for devices. This patch
convert to direct regmap API usage, preparing to support big endianness
for LS1 SoC.

Using the regmap framework it will be easy to support devices that only
differ in endianness with the same device driver.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-08-20 10:10:12 +02:00
Xiubo Li
cd6d92d2aa pwm: fsl-ftm: Clean up the code
This patch intends to prepare for converting to direct regmap API usage.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-08-20 10:09:54 +02:00
Axel Lin
39fd3f99ab pwm: fsl-ftm: set pwm_chip can_sleep flag
The implementation of .config(), .enable() and .disable() operations in this
driver may sleep, thus set pwm_chip can_sleep flag.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-05-23 09:11:21 +02:00
Xiubo Li
b505183b51 pwm: Add Freescale FTM PWM driver support
The FTM PWM device can be found on Vybrid VF610 Tower and
Layerscape LS-1 SoCs.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Alison Wang <b18965@freescale.com>
Signed-off-by: Jingchang Lu <b35083@freescale.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Yuan Yao <yao.yuan@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-03-18 18:01:56 +01:00