On 10/07/2016 05:33 PM, Ralf Ramsauer wrote:
Hi Stephen,
On 10/07/2016 08:33 PM, Stephen Warren wrote:
On 10/07/2016 07:25 AM, Ralf Ramsauer wrote:
Hi,
I'm running a Jetson TK1 on mainline Linux. To enable userspace SPI, I
modified the device-tree by:
/* Expansion TS_SPI_* */
spi@7000d400 {
status = "okay";
+ spidev@0 {
+ compatible = "spidev";
+ reg = <0>;
+ spi-max-frequency = <25000000>;
+ };
};
This works fine. Is it possible to use arbitrary GPIOs as additional
chip-selects?
What would I have to do If I'd like to add PU0 or PU1 (sysfs
gpio160/161) as chip-selects?
According to Documentation/devicetree/bindings/spi/spi-bus.txt, there
are standard properties you can use for GPIO chip-select signals, and it
looks like the SPI core code handles this itself. However, judging by a
Yes, I already followed those instructions and it didn't work. Other CSs
seem to be ignored, without any warnings while the native CS line still
keeps working. That's why I came up with this post. Adding a line to the
DT like
cs-gpios = <0>, <&gpio TEGRA_GPIO(X, Y) GPIO_ACTIVE_LOW>;
should actually (at least syntactically and semantically) be fine for an
additional CS, right?
I don't think you can mix non-GPIO and GPIO-based CS lines; I'd expect
either no cs-gpios property (to use purely HW CS lines), or a cs-gpios
property that contained an entry for every valid CS line, all as GPIOs.
--
To unsubscribe from this list: send the line "unsubscribe linux-tegra" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
