[PATCH v5 02/16] pwm: Allow chips to support multiple PWMs

[Shawn Guo]

On Wed, Mar 28, 2012 at 04:33:44PM +0200, Thierry Reding wrote:
> Many PWM controllers provide access to more than a single PWM output and
> may even share some resource among them. Allowing a PWM chip to provide
> multiple PWM devices enables better sharing of those resources. As a
> side-effect this change allows easy integration with the device tree
> where a given PWM can be looked up based on the PWM chip's phandle and a
> corresponding index.
> 
> This commit modifies the PWM core to support multiple PWMs per struct
> pwm_chip. It achieves this in a similar way to how gpiolib works, by
> allowing PWM ranges to be requested dynamically (pwm_chip.base == -1) or
> starting at a given offset (pwm_chip.base >= 0). A chip specifies how
> many PWMs it controls using the npwm member. Each of the functions in
> the pwm_ops structure gets an additional argument that specified the PWM
> number (it can be converted to a per-chip index by subtracting the
> chip's base).
> 
> The total maximum number of PWM devices is currently fixed to 1024 while
> the data is actually stored in a radix tree, thus saving resources if
> not all of them are used.
> 
> Signed-off-by: Thierry Reding <thierry.reding at avionic-design.de>

Reviewed-by: Shawn Guo <shawn.guo at linaro.org>

-- 
Regards,
Shawn