treewide: make use of PTR_ERR_OR_ZERO ...

PTR_ERR_OR_ZERO is designed to replace boiler plate like:

	if (IS_ERR(x))
		return PTR_ERR(x);
	return 0;

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

pwm: Replace license and copyright boilerplate by SPDX identfiers ...

This adapts all files that were identifed by licensecheck
(https://salsa.debian.org/build-common-team/licensecheck.git) as
licensed under the GPL and that have a (IMHO) clear copyright statement.

The advantage is that these specifiers are machine-parseable which helps
license conformance, e.g. for packaging barebox in Debian.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: core: add apply API support for polarity ...

Some PWM chips support outputting an inverted PWM signal.
Add API support for this.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: core: apply initial state in of_pwm_request ...

This functions prepares a state that can later be tweaked and applied
to the PWM device with pwm_apply_state(). This is a convenient function
that first retrieves the current PWM state and the replaces the period
with the reference values defined in pwm->args.
Once the function returns, you can adjust the ->enabled and ->duty_cycle
fields according to your needs before calling pwm_apply_state().

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: core: retire pwm_set_period ...

Client code can use pwm_apply_state or pwm_config to set period as well
as duty cycle. Having a pwm_set_period thus doesn't add any value.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: core: remove old PWM API in favor of Linux ->apply ...

Linux has the new atomic PWM API in addition to the old one for backward
compatibility. We only have three PWM drivers in here, so port them over
to the new ->apply API.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: core: group PWM state into new struct pwm_state ...

As a prerequisite for moving to the new apply API, we need to group all
state into one struct that we can apply at once. Prepare for this.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: core: remove ineffectual pwm_{set,get}_duty_cycle ...

The setter sets a value unused anywhere, but in the getter.
As the functions are unused, just drop them.
There's pwm_config that can be used for this instead.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: core: remove FLAG_ENABLED ...

In preparation for moving to a struct pwm_state like Linux does, turn
the flag into a variable.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers: Introduce dev_set_name() ...

Introduce dev_set_name() in order to hide implementation details of
setting device's name so it'd be easier to change it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

param: make parameter functions more consistent ...

This patch creates a consitent set of device parameter functions.

With this we have: dev_add_param_<type><access>

"type" is one of: int32, uint32, int64, uint64, string, mac, ipv4, enum, bitmask
The improvement here is that we now can exactly specify the width of the
int type parameters and also correctly distinguish between signed and
unsigned variables which means that a variable no longer ends up with
INT_MAX when it's assigned -1.

"access" can be empty for regular read/write parameter, "_ro" for readonly
parameters which get their value from a variable pointer in the
background or "_fixed" for parameters which are set to a fixed value
(without a pointer in the background).

Some more exotic types are not (yet) implemented, like
dev_add_param_ip_ro.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: update enable status when using the internal API ...

Without these, 'devinfo pwmX' will show enabled=0 even though the PWM
was enabled (for example by a pwm-backlight).

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: Allow multiple PWMs per device node ...

Matching a device node is enough since a device node may have
multiple PWMs. Check for a id aswell.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: Implement devicetree support ...

This implements of_pwm_request() for PWM client drivers.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: Add functions for getting/setting period/duty cycle ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

PWM: Use a separate device for PWMs ...

Instead of directly using the hardware devicet for PWMs register
a logical PWM device so that the user operates on pwmx devices rather
than pxa-pwmx.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

pwm: sanity check values before passing them to the drivers ...

Check for valid period size before calling ops->config. This fixes
the pxa driver which otherwise does a division by zero. While at
it, also check for duty_ns being smaller or equal to period_ns.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>

pwm: Use dev_add_param_int for pwm parameters ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>

Treewide: remove address of the Free Software Foundation ...

The FSF address has changed in the past. Instead of updating it
each time the address changes, just drop it completely treewide.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers/pwm: add duty_ns and period_ns to core pwm chip ...

Add variables to control the duty_ns and period_ns of PWM
chips. When these variables are set, a call to either
pwm_enable() or pwm_config() is performed to enforce the
setup values.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add pwm core support ...

This patch adds framework support for PWM (pulse width modulation)
devices.
A new pwm can be registered from a hardware driver using
pwmchip_add(). It can then be requested from a client driver using
pwm_request(). A string is used as a unique identifier for the
pwms. It should usually be initialized by the hardware drivers
using dev_name(dev). The client API is the same as currently
in the Linux Kernel.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>