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>

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>