Hi,
I have a query on device tree pertaining to modelling a gpio pin as an interrupt source.
I have searched mailing list archives and kernel documentation before posting this and couldn't get any direct solution.
(My understanding is limited and hence posting the query below:)
My SOC has a gpio controller and uart both sharing same interrupt line as specified below.
interrupt-parent = <&gic>;
mygpio: gpio@0x19008000 {
compatible = "mysoc,mygpio-controller,gc";
#address-cells = <1>;
#size-cells = <1>;
#gpio-cells = <2>;
reg = gpio: <0x19008000 0x50>;
ngpios = <12>;
pin-offset = <4>;
pin-base = <4>;
irq-base = <256>; /* sw irq base for irq handlers */
gpio-controller;
interrupt-controller;
interrupts = <GIC_SPI 91 IRQ_TYPE_LEVEL_HIGH>;
};
uart0: serial@0x19000300 {
compatible = "snps,dw-apb-uart";
reg = <0x19000300 0x100>;
interrupts = <GIC_SPI 91 IRQ_TYPE_LEVEL_HIGH>;
clock-frequency = <62500000>;
};
gpio pin 0 of mygpio is used as an interrupt source for detecting the presence of external pluggable device (that is not driven by kernel).
And I intend to detect the presence of the pluggable device from user space by means of generic uio platform driver using below device
tree configuration. (following https://yurovsky.github.io/2014/10/10/linux-uio-gpio-interrupt/)
user_io@0 {
compatible = "mydevice,generic-uio,ui_pdrv";
status = "okay";
interrupt-parent = <&mygpio>;
interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;
};
Running modprobe uio_pdrv_genirq of_id="mydevice,generic-uio,ui_pdrv" and creating /dev/uio0 using mknod (major number from cat /proc/devices | grep uio),
I couldn't see an irq entry bind to uio driver under /proc/interrupts.
Am I doing anything wrong here?
Other method I have tried to get notified of the gpio pin0 interrupt in user space is to poll on /sys/class/gpio/gpio0/value. But merely exporting gpio0
wasn't sufficient as kernel should make a call to request_irq on the gpio0 interrupt line. Is there a generic driver framework (like pinctrl) that can export
a device node to register the gpio pin0 as an interrupt source that allows me to poll on its sysfs entry?
Thanks,
Rajasekhar
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
