How to configure user button 1 on sabresd imx7 to interrupt

[sudipmidya]

Hi, All,
I am working on sabresd board with imx7. I want to make user button 1 as interruptible gpio. I have followed the following steps:

as in schematics, user button 1 is connected to SD2_WP pad. From trm, we see that alt 5 functionality for the same pad is gpio 5(ALT5_GPIO5_IO10).

In imx7d-sdb.dts file doing the pad control changes:
pinctrl_gpio: gpiogrp {
                       fsl,pins = <
                               MX7D_PAD_SD2_WP__GPIO5_IO10     0x14
                       >;
               };

Now, have written a small module which does the following:
(1)set 10th bit of 0x3024000C(setting 10th bit of GPIO5_EDGE_SEL). I also tried setting 20-21st bit of GPIO5_ICR1 to 10 or 11, but didnot work
(2)set 10th bit of GPIO5_IMR
(3)reset 10th bit of GPIO5_GDIR
(4)set request_irq to 172 as returned value from, gpio_to_irq(138)=172

Q1)I am not seeing any interrupt generated on pressing of user button 1 key. Wonder where I am going wrong.
Q2)I saw somewhere in datasheet the irq for gpio5 is 72, why gpio_to_irq returns 172?

Q3) Is there any better way to do? maybe just by changes in dts file? I am not sure if /proc/interrupts entry can get generated by just change in dts file.

Thanks for the help.

[igorpadykov · Accepted solution]

Hi sudip

please check documentation in Linux/Documentation/arm/Interrupts and

attached Linux Manual sect.3.2 Interrupts (Operation),

http://developer.toradex.com/device-tree-customization
There is i.MX7SDB gpio interrupt example (from SiI9022A INT) in imx7d-sdb.dts

http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/arch/arm/boot/dts/imx7d-sdb.dts?id=...
    tsc2046 {
        interrupts = <13 0>;
        pendown-gpio = <&gpio2 13 0>;
    };
    sii902x: sii902x@39 {
        interrupt-parent = <&gpio2>;
        interrupts = <13 IRQ_TYPE_EDGE_FALLING>;

interrupt drivers examples can be found in linux/arch/arm/plat-mxc/epit.c

linux-2.6-imx.git - Freescale i.MX Linux Tree 

Best regards
igor
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[sudipmidya]

I just changed the value of MX7D_PAD_SD2_WP__GPIO5_IO10  from   0x14 to 12, ie Hystersis enabled and slew rate field = slow slew rate, now  am getting interrupt, but not sure what happens exactly by these settings, i think i am seeing flurry of interrupts now. What settings should i select to configure for interrupt? I am testing this by sysfs, have set the edge to "rising". Can somebody please explain?