to quote the fedoraproject wiki on the raspberry pi:
Are Device Tree Overlays supported? There's basic support for overlays in u-boot and the linux kernel but an overlay manager isn't yet upstream. There's (sic)
Is GPIO supported? GPIO isn't supported well as they need to be mapped with Device Tree overlays. This will be improved in the F-27 cycle, and in Fedora 28.
Is SPI supported? Yes, basic SPI is supported.
Is I2C supported? Yes, basic I2C is supported.
by default, i know that i2c is functional since i added an rtc and added a simple udev rule to make it work, however, spi isn't that simple
i have an enc28j60 wired to the gpio in hopes of having a secondary ethernet interface, i know it's wired correctly since i downloaded raspbian and added the appropriate overlay magic to config.txt and it automatically registers as eth1
on fedora, a simple modprobe spidev or modprobe spi-bcm2835{,aux} doesn't seem to populate /dev/ with any spidev*
i even grafted all of the fedora kernel patches (https://src.fedoraproject.org/rpms/kernel.git) onto the raspberry pi kernel (https://github.com/raspberrypi/linux.git, rpi-4.15.y), built it (make olddefconfig), installed it, did all that funny mkimage crap, booted off it (raspberries instead of penguins (everything else still worked)), and still no functional spi
i think this implies that between raspbian and fedora there's a specific CONFIG_ option in the kernel i need to add, but i don't know what one (ones?) it would be
any help would be appreciated
---- Sent using Sharklasers.com Block or report abuse: https://www.sharklasers.com//abuse/?a=QFN5JQEJUKAGxgix9HENcwTVQsCV0cMeyLZF
You might try Fedberry. I uncommented "dtparam=spi=on" in /boot/config.txt and now see the /dev/spidev0.0 and /dev/spidev0.1 devices. The GPIO devices (gpiochip0, gpiochip1, and gpiochip2) are present by default, without any special configuration.
With F27, uncertain about what device tree overlay capabilities actually exist, I experimented by manually adding the SPI text to the initial binary device tree file (dtc from binary or tree to source, edit, dtc back to binary) but this did not work. I wonder whether the F27 SPI DT overlay data may be incomplete (Raspbian has more detail), or if your suspicion about kernel configuration is the fundamental problem.
I2C is what I need currently, and F27 has been very good for that.
for the sake of completeness:
diff --git a/arch/arm/boot/dts/bcm283x.dtsi b/arch/arm/boot/dts/bcm283x.dtsi index 9d293decf8d3..d32d4861c98d 100644 --- a/arch/arm/boot/dts/bcm283x.dtsi +++ b/arch/arm/boot/dts/bcm283x.dtsi @@ -26,2 +26,3 @@ serial1 = &uart1; + ethernet1 = ð1; }; @@ -375,2 +377,15 @@ }; + spi0_pins: spi0_pins { + brcm,pins = <9 10 11>; + brcm,function = <BCM2835_FSEL_ALT0>; + }; + spi0_cs_pins: spi0_cs_pins { + brcm,pins = <8 7>; + brcm,function = <BCM2835_FSEL_GPIO_OUT>; + }; + eth1_pins: eth1_pins { + brcm,pins = <25>; + brcm,function = <BCM2835_FSEL_GPIO_IN>; + brcm,pull = <BCM2835_PUD_OFF>; + }; }; @@ -415,3 +430,17 @@ #size-cells = <0>; - status = "disabled"; + status = "okay"; + dmas = <&dma 6>, <&dma 7>; + dma-names = "tx", "rx"; + pinctrl-names = "default"; + pinctrl-0 = <&spi0_pins &spi0_cs_pins>; + cs-gpios = <&gpio 8 GPIO_ACTIVE_LOW>, <&gpio 7 GPIO_ACTIVE_LOW>; + eth1: enc28j60@0 { + compatible = "microchip,enc28j60"; + reg = <0>; + pinctrl-names = "default"; + pinctrl-0 = <ð1_pins>; + interrupt-parent = <&gpio>; + interrupts = <25 IRQ_TYPE_EDGE_FALLING>; + spi-max-frequency = <24000000>; + }; };
$CPP -I../../../../include -E -P -x assembler-with-cpp bcm2837-rpi-3-b.dts | dtc -I dts -O dtb -o bcm2837-rpi-3-b.dtb -
-
adpdyj+4aw13di0ccx1w＠sharklasers.com -
Richard Ryniker