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Author SHA1 Message Date
Uwe Kleine-König d64dc6118a pwm: jz4740: Fix build failure
When commit 9017dc4fbd ("pwm: jz4740: Enhance precision in calculation
of duty cycle") from v5.8-rc1 was backported to v5.4.x its dependency on
commit ce1f9cece0 ("pwm: jz4740: Use clocks from TCU driver") was not
noticed which made the pwm-jz4740 driver fail to build.

As ce1f9cece0 depends on still more rework, just backport a small part
of this commit to make the driver build again. (There is no dependency
on the functionality introduced in ce1f9cece0, just the rate variable
is needed.)

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-16 08:16:48 +02:00
Paul Cercueil a6030d71e6 pwm: jz4740: Enhance precision in calculation of duty cycle
commit 9017dc4fbd upstream.

Calculating the hardware value for the duty from the hardware value of
the period resulted in a precision loss versus calculating it from the
clock rate directly.

(Also remove a cast that doesn't really need to be here)

Fixes: f6b8a57000 ("pwm: Add Ingenic JZ4740 support")
Cc: <stable@vger.kernel.org>
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
[ukl: backport to v5.4.y and adapt commit log accordingly]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-24 17:50:52 +02:00
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 3b442c60cf pwm: jz4740: Document known limitations
The JZ4740 PWM implementation doesn't fulfill the (up to now
insufficiently documented) requirements of the PWM API. At least
document them in the driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21 00:55:33 +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
Paul Cercueil 6580fd1730 pwm: jz4740: Force TCU2 channels to return to their init level
When the PWM mode of TCU2 channels is disabled, their corresponding pin
does not always return to its initial level. Force this by using a small
trick: we set duty > period, which is an invalid configuration for the
hardware, which then correctly resets the pin to the initial level.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-06-26 11:39:05 +02:00
Paul Cercueil 1ac99c58bd pwm: jz4740: Apply configuration atomically
This is cleaner, more future-proof, and incidentally it also fixes the
PWM resetting its config when stopped/started several times.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-06-25 15:02:51 +02:00
Paul Cercueil 93808aca34 pwm: jz4740: Remove unused devicetree compatible strings
Right now none of the Ingenic-based boards probe this driver from
devicetree. This driver defined three compatible strings for the exact
same behaviour. Before these strings are used, we can remove two of
them.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-06-25 15:02:39 +02:00
Thomas Gleixner a912e80bd0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 151
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 you should have received a copy of the
  gnu general public license along with this program if not write to
  the free software foundation inc 675 mass ave cambridge ma 02139 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 35 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.655028468@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:28 -07:00
Paul Cercueil cc20173304 pwm: jz4740: Add support for devicetree
Add support for probing the pwm-jz4740 directly from devicetree.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-03-28 00:23:56 +02:00
Paul Cercueil 174dcc8eae pwm: jz4740: Implement ->set_polarity()
This permits clients of this driver to specify the polarity to use for
their PWM channel.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-03-28 00:23:45 +02:00
Maarten ter Huurne df56b1712d pwm: jz4740: Make disable operation compatible with TCU2 mode
On the JZ4750 and later SoCs, channel 1 and 2 operate in a different
way (TCU2 mode) as the other channels. If a TCU2 mode counter is
stopped before its PWM functionality is disabled, the output is not
guaranteed to return to the initial level.

Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2018-03-28 00:22:03 +02:00
Paul Cercueil 47096d702c pwm: jz4740: Let the pinctrl driver configure the pins
Now that the JZ4740 and similar SoCs have a pinctrl driver, we rely on
the pins being properly configured before the driver probes.

One inherent problem of this new approach is that the pinctrl framework
does not allow us to configure each pin on demand, when the various PWM
channels are requested or released. For instance, the PWM channels can
be configured from sysfs, which would require all PWM pins to be configured
properly beforehand for the PWM function, eventually causing conflicts
with other platform or board drivers.

The proper solution here would be to modify the pwm-jz4740 driver to
handle only one PWM channel, and create an instance of this driver
for each one of the 8 PWM channels. Then, it could use the pinctrl
framework to dynamically configure the PWM pin it controls.

Until this can be done, the only jz4740 board supported upstream
(Qi lb60) can configure all of its connected PWM pins in PWM function
mode, since those are not used by other drivers nor by GPIOs on the
board.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-05-22 17:21:06 +02:00
Wolfram Sang f05fae14a1 pwm: drop owner assignment from platform_drivers
A platform_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-10-20 16:21:28 +02:00
Lars-Peter Clausen 0dc1135fdf pwm: jz4740: Use devm_clk_get()
Using the managed version of clk_get() makes the code a bit shorter and the
error paths less complicated.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-12-12 13:23:23 +01:00
Lars-Peter Clausen 078c6ac1bd pwm: jz4740: Pass device to clk_get()
In preparation to switching the jz4740 clk driver to the common clk framework
make sure to pass the device to clk_get().

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-12-12 13:23:23 +01:00
Bill Pemberton 77f37917a6 pwm: remove use of __devexit
CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-28 12:23:41 -08:00
Bill Pemberton 3e9fe83d27 pwm: remove use of __devinit
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-28 12:23:41 -08:00
Bill Pemberton fd1091125a pwm: remove use of __devexit_p
CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-28 12:23:41 -08:00
Thierry Reding f6b8a57000 pwm: Add Ingenic JZ4740 support
This commit moves the driver to drivers/pwm and converts it to the new
PWM framework.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
2012-10-05 20:56:42 +02:00