How to add custom dts entries
Bernd Walter
ticso at cicely7.cicely.de
Sun Nov 4 22:06:32 UTC 2018
On Sun, Nov 04, 2018 at 08:57:00PM +0100, Bernd Walter wrote:
> On Sun, Nov 04, 2018 at 07:53:38PM +0100, Bernd Walter wrote:
> > On Sun, Nov 04, 2018 at 07:49:39PM +0100, Bernd Walter wrote:
> > > On Sun, Nov 04, 2018 at 07:32:47PM +0100, Bernd Walter wrote:
> > > > On Sat, Nov 03, 2018 at 03:25:38PM -0600, Ian Lepore wrote:
> > > > > Add a status = "okay" to the spi node in your patch/overlay.
> > > >
> > > > Makes sense.
> > > >
> > > > So the spigen overlay works fine, once I set fdt_overlays in loader.conf
> > > > to use the overlay file.
> > > >
> > > > spi0: <BCM2708/2835 SPI controller> mem 0x7e204000-0x7e204fff irq 25 on simplebus0
> > > > spibus0: <OFW SPI bus> on spi0
> > > > spibus0: <unknown card> at cs 1 mode 0
> > > > spibus0: <unknown card> at cs 0 mode 0
> > > > spibus0: <unknown card> at cs 0 mode 0
> > > > spibus0: <unknown card> at cs 1 mode 0
> > > >
> > > > With my own overlay I do this to install it:
> > > > dtc -I dts -O dtb -o rpi-apa102-matrix.dtbo rpi-apa102-matrix.dts
> > > > cp rpi-apa102-matrix.dtbo /boot/dtb/overlays
> > > >
> > > > [77]cicely1> cat rpi-apa102-matrix.dts
> > > > /dts-v1/;
> > > > /plugin/;
> > > >
> > > > / {
> > > > compatible = "brcm,bcm2835";
> > > > };
> > > >
> > > > /* &spi0 { */
> > > > &{/soc/spi at 7e204000} {
> > > > status = "okay";
> > > >
> > > > apa102led0 {
> > > > compatible = "led,apa102";
> > > > reg = <0>;
> > > > spi-max-frequency = <20000000>;
> > > > status = "okay";
> > > > };
> > > > };
> > > >
> > > > &onewire {
> > > > compatible = "w1-gpio";
> > > > gpios = <&gpio 4 1>;
> > > > };
> > > >
> > > > Still puzzled with the format.
> > > > With &spi0 it didn't work, neither with the current format, which is
> > > > copied from the spigen.dts.
> > > > Neither spi0 attaches, nor the onewire bus.
> > > >
> > > > Some other, mostly beaglebone related examples use a more complex
> > > > setup with overlay_ entries and everything inside the compatible block.
> > > >
> > > > Can I have a device.hints please ;-)
> > > >
> > > > ofwdump shows:
> > > > ...
> > > > Node 0x20fc: spi at 7e204000
> > > > compatible:
> > > > 62 72 63 6d 2c 62 63 6d 32 38 33 35 2d 73 70 69 00
> > > > 'brcm,bcm2835-spi'
> > > > ...
> > > > status:
> > > > 64 69 73 61 62 6c 65 64 00
> > > > 'disabled'
> > > > ...
> > > >
> > > > Havn't checked ofwdump with the spigen overlay.
> > >
> > > Interesting.
> > > When I use &spi0 and leave out the &onewire block, it attaches something.
> > > spi0: <BCM2708/2835 SPI controller> mem 0x7e204000-0x7e204fff irq 25 on simplebus0
> > > spibus0: <OFW SPI bus> on spi0
> > > spibus0: <unknown card> at cs 0 mode 0
> > > spibus0: <unknown card> at cs 0 mode 0
> > > spibus0: <unknown card> at cs 1 mode 0
> > >
> > > And also my driver attaches just fine:
> > > apa102led0: <APA102> at cs 0 mode 0 on spibus0
> > >
> > > And ofwdump shows the spi0 es enabled:
> > > Node 0x20fc: spi at 7e204000
> > > compatible:
> > > 62 72 63 6d 2c 62 63 6d 32 38 33 35 2d 73 70 69 00
> > > 'brcm,bcm2835-spi'
> > > ...
> > > status:
> > > 6f 6b 61 79 00
> > > 'okay'
> > > ...
> > >
> > > I'm not on the real hardware, so no LED connected to test the driver.
> > > It would probably also attach with the &{/soc/spi at 7e204000}.
> > > But why does the &onewire entry make such a difference?
> > > Is the whole file revoked because of an error?
> > > I have no console connected, so I don't see loader messages.
> > >
> > > Also it is a bit puzzling about the "unknown card" entries.
> >
> > Ah ok.
> > Those 4 with the spigen driver are 2 devices defined by the generic DTS,
> > plus 2 devices from the spigen overlay - the spigen module wasn't laoded.
> > Same for my overlay, 2 generic, plus my LED definition.
> > spi0 pnpinfo name=spi at 7e204000 compat=brcm,bcm2835-spi
> > spibus0
> > apa102led0 pnpinfo name=apa102led0 compat=led,apa102 at bus=0 cs=0
> > unknown pnpinfo name=spidev at 0 compat=spidev at bus=0 cs=0
> > unknown pnpinfo name=spidev at 1 compat=spidev at bus=0 cs=1
> >
> > Makes sense.
>
> Ok, no surprise that &onewire can't work if it isn't defined yet.
>
> owc0: <FDT GPIO attached one-wire bus> at pin 4 on gpiobus0
> ow0: <1 Wire Bus> on owc0
> ow0: Reset discovered bus wired wrong.
> gpioc0: <GPIO controller> on gpio0
> uart0: <PrimeCell UART (PL011)> mem 0x7e201000-0x7e201fff irq 23 on simplebus0
> uart0: console (115200,n,8,1)
> spi0: <BCM2708/2835 SPI controller> mem 0x7e204000-0x7e204fff irq 25 on simplebus0
> spibus0: <OFW SPI bus> on spi0
> apa102led0: <APA102> at cs 0 mode 0 on spibus0
> spibus0: <unknown card> at cs 0 mode 0
> spibus0: <unknown card> at cs 1 mode 0
>
> With the following dts:
> [96]cicely1> cat rpi-apa102-matrix.dts
> /dts-v1/;
> /plugin/;
>
> &spi0 {
> status = "okay";
>
> apa102led0 {
> compatible = "led,apa102";
> reg = <0>;
> spi-max-frequency = <20000000>;
> status = "okay";
> };
> };
>
> / {
> fragment at 0 {
> target-path = "/";
> __overlay__ {
> onewire {
> compatible = "w1-gpio";
> gpios = <&gpio 4 1>;
> };
> };
> };
> };
>
> I tried the same without the fragment and overlay blocks, but it didn't
> work.
> Why does it work for the spi0?
>
> Have to put the SD card into the real system to see if the spi and the onewire
> works.
> So far everything looks fine, although I don't exactly know why.
> I understand that I would have to setup the CS pin for normal spi use.
The DS18B20 look good:
owc0: <FDT GPIO attached one-wire bus> at pin 4 on gpiobus0
ow0: <1 Wire Bus> on owc0
ow_temp0: <Advanced One Wire Temperature> romid 28:b0:6b:29:05:00:00:ae on ow0
ow_temp1: <Advanced One Wire Temperature> romid 28:04:87:29:05:00:00:8e on ow0
ow_temp2: <Advanced One Wire Temperature> romid 28:e6:2c:29:05:00:00:8a on ow0
ow_temp3: <Advanced One Wire Temperature> romid 28:71:34:29:05:00:00:fc on ow0
ow_temp4: <Advanced One Wire Temperature> romid 28:99:3b:29:05:00:00:1b on ow0
ow_temp5: <Advanced One Wire Temperature> romid 28:05:d6:29:05:00:00:e1 on ow0
ow_temp6: <Advanced One Wire Temperature> romid 28:75:e6:1a:05:00:00:3d on ow0
ow_temp7: <Advanced One Wire Temperature> romid 28:37:d3:29:05:00:00:b0 on ow0
[55]rpi-b# sysctl dev.ow_temp | grep temper
dev.ow_temp.7.temperature: 24.437C
dev.ow_temp.6.temperature: 24.125C
dev.ow_temp.5.temperature: 24.312C
dev.ow_temp.4.temperature: 24.312C
dev.ow_temp.3.temperature: 23.937C
dev.ow_temp.2.temperature: 24.250C
dev.ow_temp.1.temperature: 24.250C
dev.ow_temp.0.temperature: 24.312C
And the LEDs also work fine.
--
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
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