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How to add touch screen support to the imx6 dual light board

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Hello,
I am working with a imx6 dual light digi board. I want to add Ad7879 touch support. I 've been followed the next steps:

-First I changed the kernel config file adding support fo touchscreen and ad7879. In kernel config file I 've made the following changes:

CONFIG_INPUT_TOUCHSCREEN=y
CONFIG_TOUCHSCREEN_AD7879=y
CONFIG_TOUCHSCREEN_AD7879_I2C=y

At the first I configured ad7879 as module doing:

CONFIG_INPUT_TOUCHSCREEN=y
CONFIG_TOUCHSCREEN_AD7879=m
CONFIG_TOUCHSCREEN_AD7879_I2C=m

After that I made the device initialization in the device tree.

In imx6qdl-ccimx6sbc.dtsi file I put the next:

&i2c3 {
...


ad7879@2c {
compatible = "adi,ad7879-1";
reg = <0x2c>;
interrupt-parent = <&gpio6>;
interrupts = <15 IRQ_TYPE_EDGE_FALLING>;
touchscreen-max-pressure = <4096>;
adi,resistance-plate-x = <120>;
adi,first-conversion-delay = /bits/ 8 <3>;
adi,acquisition-time = /bits/ 8 <1>;
adi,median-filter-size = /bits/ 8 <2>;
adi,averaging = /bits/ 8 <1>;
adi,conversion-interval = /bits/ 8 <255>;

...

};

The ad7879 interrupt controller is conected to the imx6 in EXP_I2C_IRQ_N pin that is the GPIO_6_15, for that reason I put interrupt-parent = <&gpio6> and interrupts = <15 IRQ_TYPE_EDGE_FALLING>;.

In imx6qdl-ccimx6sbc.dts file I put:

&i2c3 {
...

ad7879@2c {
status ="okay";
};
...
};

Then I followed with compile the linux image and device tree.
In the imx6 with the linux image that I configures the ad7879 as module I loaded the ad7879 modules doing this:
root:~> modprobe ad7879
root:~> modprobe ad7879-i2c
but there is not log messages abaout the ad7879 and there is no ad7879 node asociated.

If I check the device node to chek the device node:
root@ccimx6sbc: ls -la /dev/input/
drwxr-xr-x 4 root root 180 Jan 1 2000 .
drwxr-xr-x 14 root root 3480 May 16 14:49 ..
drwxr-xr-x 2 root root 80 Jan 1 2000 by-id
drwxr-xr-x 2 root root 120 Jan 1 2000 by-path
crw-rw---- 1 root input 13, 64 Jan 1 2000 event0
crw-rw---- 1 root input 13, 65 Jan 1 2000 event1
crw-rw---- 1 root input 13, 66 Jan 1 2000 event2
crw-rw---- 1 root input 13, 63 Jan 1 2000 mice
crw-rw---- 1 root input 13, 32 Jan 1 2000 mouse0

root@ccimx6sbc:# cat /sys/class/input/input0/name
da9063-onkey
root@ccimx6sbc:# cat /sys/class/input/input1/name
Genius 4D Scroll Mouse
root@ccimx6sbc:# cat /sys/class/input/input2/name
sgtl5000-audio Headphone Jack

You can see that there is no node asociated.

root@ccimx6sbc:# cat /proc/interrupts
CPU0 CPU1
29: 140884 13795 GIC 29 twd
34: 406 0 GIC 34 sdma
35: 0 0 GIC 35 VPU_JPG_IRQ
37: 1 0 GIC 37 2400000.ipu
38: 12 0 GIC 38 2400000.ipu
42: 28 0 GIC 42
44: 0 0 GIC 44 VPU_CODEC_IRQ
50: 0 0 GIC 50 vdoa
51: 0 0 GIC 51 rtc alarm
54: 52 0 GIC 54 mmc3
55: 52 0 GIC 55 mmc1
57: 3580 0 GIC 57 mmc0
61: 353 0 GIC 61 21f0000.serial
63: 0 0 GIC 63 2008000.ecspi
69: 472 0 GIC 69 21a4000.i2c
70: 1367 0 GIC 70 21a8000.i2c
72: 109 0 GIC 72 2184200.usb
75: 0 0 GIC 75 2184000.usb
79: 0 0 GIC 79 202c000.ssi
81: 0 0 GIC 81 imx_thermal
87: 167 0 GIC 87 i.MX Timer Tick
112: 0 0 GIC 112 20bc000.wdog
134: 0 0 GIC 134 mipi_dsi
137: 466 0 GIC 137 2101000.jr0
138: 0 0 GIC 138 2102000.jr1
139: 0 0 GIC 139 mmdc_1
144: 0 0 GIC 144 mmdc_1
147: 0 0 GIC 147 20e0000.hdmi_video
150: 62234 0 GIC 150 2188000.ethernet
151: 0 0 GIC 151 2188000.ethernet
192: 0 0 gpio-mxc 0 headphone detect
364: 1 0 gpio-mxc 12 da9063-irq
413: 0 1 da9063-irq 3 HWMON
414: 0 0 da9063-irq 0 ONKEY
415: 0 0 da9063-irq 1 ALARM
IPI0: 0 0 CPU wakeup interrupts
IPI1: 0 58 Timer broadcast interrupts
IPI2: 1405 2387 Rescheduling interrupts
IPI3: 0 0 Function call interrupts
IPI4: 19 33 Single function call interrupts
IPI5: 0 0 CPU stop interrupts
IPI6: 426 476 IRQ work interrupts
IPI7: 0 0 completion interrupts
Err: 0

You can se that there is not interrupts asociated to ad7879.

There is no difference when I build the linux kernel with this configuration:
CONFIG_INPUT_TOUCHSCREEN=y
CONFIG_TOUCHSCREEN_AD7879=y
CONFIG_TOUCHSCREEN_AD7879_I2C=y

I did run dmesg and there is no log entries associated with ad7879.

In the imx6 linux I did the following commands:

>root@ccimx6sbc:i2cdetect 2
with this response:

WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-2.
I will probe address range 0x03-0x77.
Continue? [Y/n] y
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- UU -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- 2c -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

If you can see the identifier of the device is detected (0x2c).

Then I made:

>root@ccimx6sbc: i2cdump -r 0-0x40 2 0x2c

With this response:

No size specified (using byte-data access)
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-2, address 0x2c, mode byte
Probe range limited to 0x00-0x40.
Continue? [Y/n] y
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 00 00 40 00 00 00 00 00 00 00 00 00 00 00 03 00 ..@...........?.
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
40: 00

You can se in 0x02 and 0x0e are two of the default values for the registers of ad7879 and they are correct. So I concluded that the controller is well connected.
asked May 17, 2018 in Linux by emmanuel_perea New to the Community (38 points)

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