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>