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Groups > linux.kernel > #1628079
| From | Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support |
| Date | 2017-04-21 11:30 +0200 |
| Message-ID | <tyD33-45V-3@gated-at.bofh.it> (permalink) |
| References | <tuprH-6qM-7@gated-at.bofh.it> <tupBn-6uA-9@gated-at.bofh.it> <tvrB9-5Bn-31@gated-at.bofh.it> <tvsdQ-64C-23@gated-at.bofh.it> |
| Organization | Free Electrons |
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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Re: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support Thomas Petazzoni <thomas.petazzoni@free-electrons.com> - 2017-04-12 16:40 +0200
Re: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support Andrew Lunn <andrew@lunn.ch> - 2017-04-12 17:20 +0200
Re: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support Thomas Petazzoni <thomas.petazzoni@free-electrons.com> - 2017-04-21 11:30 +0200
Re: [PATCH v5 1/4] gpio: mvebu: Add limited PWM support Linus Walleij <linus.walleij@linaro.org> - 2017-04-24 11:20 +0200
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