Hi Stephen, > Subject: Re: [PATCH 4/4] Documentation: Add device tree bindings for > Freescale FTM PWM > > On 08/25/2013 11:35 PM, Xiubo Li-B47053 wrote: > >> Subject: Re: [PATCH 4/4] Documentation: Add device tree bindings for > ... > >>> Why do you need to manipulate the pinctrl to en/disable a channel? > >> > >> This is because in Vybrid VF610 TOWER board, there are 4 leds, and > >> each led's one point(diode's positive pole) is connected to 3.3V, and > >> the other point is connected to pwm's one channel. When the 4 > >> pinctrls are configured as enable at the same time, the 4 pinctrls is > >> low valtage, and the 4 leds will be lighted up as default, then when > >> you enable/disable one led will effects others. > >> > >> These pinctrls are belong to pwm, and I don't think led or other > >> customer could control them directly. > >> So, here I authorize the 4 pinctrls to each channel controls. > >> > > " > > For the reason above, I have to control the pinctrls separately. > > > > If all the pinctrls set as default state, the 8 pinctrls must be > controlled together. > > And the 4 leds will all be lighted up as default and will influence > each other. > > Sorry, that still doesn't make much sense. Either way though, having > separate pinctrl setup for a single device isn't going to work. You'll > either need to have all combinations of 4 (8?) PWMs represented as > pinctrl states(!), or register separate PWM devices so that they get > independant pinctrl states. > Well, I have ever thought about registering separate PWM device for each channel. But, if so, how should I control the pinctrl of each PWM(actually one channel of FTM PWM) ? I must select "default" state(the "default" state here, the pinctrl must be setup as "dsN" or "chN-idle" state we discussed before) when probing, and when customers .request-->.config-->.enable the PWM I also must select an "active" state to config the pinctrl... Thus, this is still not static. I think this isn't much different from the current. Also if having all combinations of 8 PWMs represented as pinctrl states, how could I deal with the problem about LEDs ? Thanks very much, -- Best Regards, Xiubo -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
