GPIO keys in device tree for external GPIO controller (PCA9554)

adrocohen — Sun, 03 May 2020 12:53:30 GMT

Hello everyone!

I use iMX6qp board with PCA9554 as a button controller. I made it work with proper driver in my device tree:

i2c3 {
...
pca9554_expander1: pca9554@22 {
compatible = "nxp,pca9554";
reg = <0x22>;
gpio-controller;
};
...
};

And now I see my GPIO expander in sysfs like

gpiochip7: GPIOs 504-511, parent: i2c/2-0022, pca9554

I want to configure buttons connected to PCA9554 as gpio-keys like:

enter_btn: enter_btn {
compatible = "gpio-keys";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_gpiobuttons1>;
enter-button {
label = "enter-button";
linux,code = <28>; /* ENTER */
gpios = <&gpio7 2 0>;
};
};

But I cannot do it in a device tree because gpio-expander gpiochip7 is created just when pca9554 driver is loaded.

How can I set this device as a correct gpio controller and configure it for gpio-buttons?

Thanks for any useful information!

Re: GPIO keys in device tree for external GPIO controller (PCA9554)

igorpadykov — Mon, 04 May 2020 23:27:28 GMT

Hi Maksim

one can look at PCA95x dts examples, for example:

linux-fslc/imx28-tx28.dts at 4.14.x+fslc · Freescale/linux-fslc · GitHub

linux-fslc/imx6q-gw5400-a.dts at 4.14.x+fslc · Freescale/linux-fslc · GitHub

Best regards
igor
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i.MX ProcessorsのトピックRe: GPIO keys in device tree for external GPIO controller (PCA9554)

GPIO keys in device tree for external GPIO controller (PCA9554)

Re: GPIO keys in device tree for external GPIO controller (PCA9554)