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@xxxxxxxxxxxxxxxxx> Reviewed-by: Shawn Guo <shawn.guo@xxxxxxxxxx> -- Regards, Shawn -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
