Messages in this thread | | | Date | Fri, 21 Apr 2017 11:19:52 +0200 | From | Thomas Petazzoni <> | Subject | Re: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support |
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Hello,
On Wed, 12 Apr 2017 17:19:32 +0200, Andrew Lunn wrote:
> Yep. It was a compromise. By adding a new binding for the GPIO driver, > this might be possible. But it did not seem worth such a major change. > > The prime use of this feature is for controlling a fan. So far, i've > not seen any hardware with more than one fan, i.e. needs more than one > PWM. Nor have i seen any hardware with the GPIO for the fan being on > the third bank. A hardware manufacture could add multiple fans, but i > doubt it, they make noise and fail. And if a manufacture does place a > fan on the third bank, it can still be controlled as a plain GPIO fan, > as we have been doing for the last few years.
Right.
> So i personally think it is an O.K. compromise.
I clearly don't want to block this, but I believe this is a very good illustration of why stable DT bindings simply don't work. We are realizing here that having each GPIO bank represented as a separate DT node doesn't work, because this blinking functionality is not per GPIO bank, but global to all GPIO banks.
I am totally fine with compromise, and having things simple first, and extend them later if needed. But this stable DT binding rule makes this quite impossible: what is a compromise today might put you in big troubles tomorrow.
Anyway, it's fine for me, I don't think it's worth the effort making a much more complicated solution/change.
Best regards,
Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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