Date: Wed, 20 Mar 2019 08:56:17 -0600 From: Ian Lepore <ian@freebsd.org> To: "Jedi Tek'Unum" <jedi@jeditekunum.com> Cc: freebsd-arm@freebsd.org Subject: Re: Options for FBSD support with LCD device - new project Message-ID: <17133d06965e61e7e835c5ea7d69ca9762efad7d.camel@freebsd.org> In-Reply-To: <CE40E2B5-2244-4EF9-B67F-34A54D71E2E8@jeditekunum.com> References: <ad61a598-53af-02a5-41db-0128da7d1a34@optiplex-networks.com> <CAF19XBLAjP4yKtGSBzA4QdT346Bnbnr8MutQNZgmERLbJkWAyA@mail.gmail.com> <8df902f6-20a3-31c4-71ac-91f5d5fdf50d@optiplex-networks.com> <0ecf23e129ca7ac6a92a01bbb34c03f1ac8c6dc8.camel@freebsd.org> <e5d42c67-e1f2-ede1-965f-c89226de46da@optiplex-networks.com> <89f5b8d1ab0614ac8d88b5d5f1afc63e640c3c17.camel@freebsd.org> <4EB5C6C1-7DB9-4DEE-BB23-CD1259581271@jeditekunum.com> <004ddba628b94b80845d8e509ddcb648d21fd6c9.camel@freebsd.org> <C68D7E6E-03C1-448F-8638-8BD1717DBF44@jeditekunum.com> <ac7d434f16f3a89f5ef247678d6becdbeded5c3f.camel@freebsd.org> <CE40E2B5-2244-4EF9-B67F-34A54D71E2E8@jeditekunum.com>
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On Tue, 2019-03-19 at 09:26 -0500, Jedi Tek'Unum wrote: > On Mar 18, 2019, at 2:57 PM, Ian Lepore <ian@freebsd.org> wrote: > > > > On Mon, 2019-03-18 at 14:51 -0500, Jedi Tek'Unum wrote: > > > My impression wasn’t that support wasn’t there - but “out of the > > > box” > > > configuration wasn’t there. In comparison, I didn’t have to do > > > anything to get I2C enabled in the binary distribution of Linux > > > that > > > comes through the manufacturer. > > > > > > Its the enabling part that isn’t obvious to most people IMO. > > > > > > Documentation/wiki is great. But even better would be all the > > > enabling overlays already in place and the entries in loader.conf > > > already there and commented out. It would be so much easier to go > > > to > > > a “common place” (loader.conf), skim through the notes, find the > > > thing that one wants, and then just uncomment the referenced > > > line! > > > (Or any other similarly easy method.) > > > > > > > > > For FBSD to get a better foothold in this space it needs to be > > > better > > > documented. For example, the wiki for NEO2 < > > > http://wiki.friendlyarm.com/wiki/index.php/NanoPi_NEO2>; is a > > > step-by- > > > step guide for how to acquire and configure Linux for it. > > > > > > > > > > On one of my imx6 boards I have 5 SPI devices. Each device can use > > 3 > > or 4 different sets of pins for clock, data-in, and data- > > out. Plus, > > each can use literally any number of whatever gpio pins they want > > as > > chip selects. Even limiting the chipsels to a handfull, there > > would > > literally be thousands of possible combinations of devices and pin > > configurations, each one needing to be a separate overlay. > > > > Maybe you have experience primarily with rpi or some similarly > > crippled > > devices that only offer one or two choices? > > If memory serves correctly, there are only 2 I2C devices on the H3/H5 > and the NanoPi NEO/2 implementations only externalize 1. There is > only 1 SPI AFAIK. > > I wouldn’t call that crippled. I chose this platform exactly because > of its characteristics - small, fast, cheap. It fits the project I’m > using it for perfectly. In fact, I can see uses for even smaller (see > Giant Board <https://groboards.com/giant-board/>). I understand other > projects may have different requirements and would drive one towards > different solutions - and require more of the various interfaces. But > they aren’t going to be typical of hobbyist projects. > > Maybe I should pose the question in another way. What is the > philosophy for choosing GPIO as default for all the pins? These > boards have a very limited number of pins and my preference would be > that the broadest range of interface types would be the default. > There are 2 UARTs exposed so I would have picked 1 to be enabled by > default. After that, with I2C and SPI enabled, there are still 6 GPIO > available. For a tiny board like this that seems to be reasonable. If > people have a need for slightly more GPIO then I would expect they > would be the ones configuring overlays. > > Apparently the developers of the Linux packages for these boards have > chosen the diverse approach (“FriendlyCore” based on UbuntuCore > Xenial). > > IMHO, most “hobbyists” would prefer the diversity approach. I’m > completely capable of becoming an expert in FBSD and this sort of > configuration stuff yet it isn’t a priority for me - I just want to > use it like any other hobbyist. The way things are now pushes this > type of user away from FBSD. > > If there is some philosophical perspective against the diversity > approach then the next best thing is to have documentation that > clearly and simply tells people how to enable the other > functionality. > > Finally, I think there is an opportunity to grow FBSD in the hobbyist > world of these small products. We are past the point where people can > have a real operating system running on systems at Arduino size and > cost. Linux has been aggressively deployed there but I can say from > experience that it ain’t pretty - I won’t say more as everyone > reading this has a clear understanding of why that is. > The default pin assignments in the dts are completely controlled by linux, and I think effectively by the actual board vendors who create the dts and submit it to linux. We (freebsd) are just a consumer of the dts info, we have to work with whatever they shove down our throats, and continually re-adapt ourselves whenever they change their minds and make arbitrary incompatible changes from one release to the next (which they definitely do). -- Ian
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