Hi,
I worked with it on SPI recently.
On Tuesday 20 October 2015 11:49:05 Maarten Brock wrote:
> Off-topic rant: I had to install and configure a different email client
> just because the mailing list bounces any mail with an HTML attachment,
> even though my message was sent in plain text as well. (I cannot not
> disable HTML output in my normal email client.)
That's actually a good thing! Now you have a proper email client ;)
> Oct 16 14:52:02 vmipi kernel: [ 9.201766] spi_master
> spi0: Failed to create SPI device
> for /soc/spi@7e204000/sc16is740@0
Looks to me like a configuration problem. The sc16 driver is not actually
loaded by the spi_master. And if you load it manually, it can't find its
hardware. I guess the problem is in the device tree.
> Here's my dts overlay:
>
> // Definitions for SC16IS740 UART
> /dts-v1/;
> /plugin/;
>
> / {
> compatible = "brcm,bcm2708";
>
> fragment@0 {
> target = <&spi0>;
> __overlay__ {
> status = "okay";
>
> spidev@0 {
> status = "disabled";
> };
>
> sc16is740: sc16is740@0 {
> compatible = "nxp,sc16is740";
> reg = <0>;
> clocks = <&clk1M8>;
> interrupt-parent = <&gpio>;
> interrupts = <25 2>; /*
> IRQ_TYPE_EDGE_FALLING */
> #gpio-controller;
> #gpio-cells = <2>;
> #spi-max-frequency = <4000000>;
I think spi-max-frequency is mandatory.
>
> clk1M8: clk1M8 {
> compatible = "fixed-clock";
> #clock-cells = <0>;
> clock-frequency = <1843200>;
> };
> };
> };
> };
> };
Anyways, I am not familiar with this overlay concept.
Florian
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