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>
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>
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
...
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
