On čtvrtek 7. března 2019 22:35:15 CET, Thomas Petazzoni wrote:
Hello Jan,
On Thu, 7 Mar 2019 14:31:02 +0100
Jan Kundrát <jan.kundrat@xxxxxxxxx> wrote:
+Line naming
+===========
+
+Because several gpio_chip instances are hidden below a single device tree
Mentioning a Linux specific data structure (gpio_chip here) in a Device
Tree binding documentation does not seem like a good idea. Bindings are
supposed to be OS-agnostic.
Hi Thomas, that's a fair comment. On the other hand, this driver's DT
bindings are already quite Linux specific with their
"microchip,spi-present-mask" workaround. The way I understand this, Linux
does not support multiple child devices "within" one SPI slave. If there
was proper support for this, this patch would be superfluous.
I, too, would love to see this driver changed so that the bindings look,
e.g., like this:
gpio_spi_chips: gpio@1 {
compatible = "microchip,mcp23s17-multiple";
gpio-bank@1 {
compatible = "microchip,mcp23s17";
reg = <1>;
interrupt-parent = <&gpio1>;
interrupts = <22 IRQ_TYPE_LEVEL_LOW>;
interrupt-controller;
#interrupt-cells = <2>;
gpio-controller;
#gpio-cells = <2>;
microchip,irq-mirror;
drive-open-drain;
spi-max-frequency = <10000000>;
gpio-line-names =
"foo",
//...
;
random_pin {
gpio-hog;
gpios = <6 GPIO_ACTIVE_HIGH>;
input;
line-name = "this hogs just one pin";
};
};
gpio-bank@2 {
compatible = "microchip,mcp23s17";
reg = <2>;
interrupt-parent = <&gpio1>;
interrupts = <22 IRQ_TYPE_LEVEL_LOW>;
interrupt-controller;
#interrupt-cells = <2>;
gpio-controller;
#gpio-cells = <2>;
microchip,irq-mirror;
drive-open-drain;
spi-max-frequency = <10000000>;
gpio-line-names =
"bar",
//...
;
};
However, I am not volunteering to do this work -- that's quite out of my
league and available time.
With kind regards,
Jan
