how to set pins for "gpio-matrix-keypad" in am335x-boneblack-emmc-overlay.dts

GoogleGroups
#1

I want to use matrix-keypad with beaglebone black.I completed these steps:
1.Modprobe matrix_keypad
output of zcat /proc/config.gz | grep MATRIX

CONFIG_INPUT_MATRIXKMAP=m
CONFIG_KEYBOARD_MATRIX=m

I am looking into am335x-evm.dts
It has pin settings as:

matrix_keypad@0 {
compatible = “gpio-matrix-keypad”;
debounce-delay-ms = <0x5>;
col-scan-delay-us = <0x2>;
row-gpios = <0x5a 0x19 0x0 0x5a 0x1a 0x0 0x5a 0x1b 0x0>;
col-gpios = <0x5a 0x15 0x0 0x5a 0x16 0x0>;
linux,keymap = <0x8b 0x100009e 0x2000069 0x1006a 0x101001c 0x201006c>;
linux,phandle = <0xdd>;
phandle = <0xdd>;
};

How can I use this information in am335x-boneblack-emmc-overlay.dts
Please guide me:

#2

The easiest way is to search Google for "how to use a matrix keyboard in linux”. Here is one example that was listed.

https://wiki.analog.com/resources/tools-software/linux-drivers/input-keyboard/adp5589

Regards,
John

#3

thanks John,
But I need only GPIO based keypad not i2c based. Please help what should be my next step after modprobing the driver. How can I define rows and columns pins.
Someone had posted this link https://groups.google.com/forum/#!searchin/beagleboard/matrix_keypad|sort:relevance/beagleboard/OED_rjD5dVI/lGQ2kynER0kJ
But when I compile this dts file into .dtbo , dtc compiler shows syntax error.

root@beaglebone:/lib/firmware# dtc -O dtb -o keypad-00A0.dtbo -b 0 -@ keypad-00A0.dts
Error: keypad-00A0.dts:18.31-32 syntax error
FATAL ERROR: Unable to parse input tree

#4

I have successfully compiled .dts file into .dtb file including these additions:
1.matrix_keypad@0 {
compatible = “gpio-matrix-keypad”;
debounce-delay-ms = <0x5>;
col-scan-delay-us = <0x2>;
row-gpios = <0x5a 0x19 0x0 0x5a 0x1a 0x0 0x5a 0x1b 0x0>;
col-gpios = <0x5a 0x15 0x0 0x5a 0x16 0x0>;
linux,keymap = <0x8b 0x100009e 0x2000069 0x1006a 0x101001c 0x201006c>;
linux,phandle = <0xdd>;
phandle = <0xdd>;
};

matrix_keypad_s0 {
pinctrl-single,pins = <0x54 0x7 0x58 0x7 0x64 0x27 0x68 0x27 0x6c 0x27>;
linux,phandle = <0x26aa>;
phandle = <0x26aa>;
};

matrix_keypad@0 {
row-gpios = <0x0 0xc 0x18>;
col-gpios = <0x0 0xc>;
};

matrix_keypad_s0 = “/ocp/l4_wkup@44c00000/scm@210000/pinmux@800/matrix_keypad_s0”;
matrix_keypad = “/matrix_keypad@0”;

But I am unable to understand these lines:

row-gpios = <0x5a 0x19 0x0 0x5a 0x1a 0x0 0x5a 0x1b 0x0>;
col-gpios = <0x5a 0x15 0x0 0x5a 0x16 0x0>;
linux,keymap = <0x8b 0x100009e 0x2000069 0x1006a 0x101001c 0x201006c>;

I want to use pins P8_39 - P8_46 as matrix keypad, How can I map these pins to above hex values.

#5

It doesn’t matter if the keyboard is connected via GPIO or I2C, the driver abstracts the interface so that all keyboards act the same way.

Regards,
John

#6

I facing problem while doing keymap for matrix_keypad for beaglebone. I am refering Linux/Documentation/devicetree/bindings/input/matrix-keymap.txt
how to decode linux,keymap = < 0x00030012 >;

I want to write keymap for 16 keys in 4 x 4 matrix.

#7

On Fri, 10 Feb 2017 22:31:42 -0800 (PST), Gurpartap Singh
<gurpartapsingh007@gmail.com> declaimed the
following:

I facing problem while doing keymap for matrix_keypad for beaglebone. I am
refering Linux/Documentation/devicetree/bindings/input/matrix-keymap.txt
*how to decode linux,keymap = < 0x00030012 >;*
I want to write keymap for 16 keys in 4 x 4 matrix.

  And what part of
http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/input/matrix-keymap.txt
are you having trouble understanding? (other than possibly having to fight
big vs little endian -- I'm not going to search for which the BBB uses)

  As defined in line 9: 8-bit row, 8-bit column, 16-bit keycode to be
returned

  Maybe look at
http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/input/matrix-keymap.txt
which gives a GPIO variant showing full keymap for a 3-row 2-column matrix.
You can see the row and column specification easily, where the first link
only shows two keys out of an unknown sized matrix (it is at least 2x4)

#8

I just responded to the latest in the thread, and then decided to look
backwards... This will be a bit of a rambling post as I jump around in
Google looking for stuff.

On Fri, 10 Feb 2017 00:57:59 -0800 (PST), Gurpartap Singh
<gurpartapsingh007@gmail.com> declaimed the
following:

compatible = "gpio-matrix-keypad";
debounce-delay-ms = <0x5>;
col-scan-delay-us = <0x2>;
row-gpios = <0x5a 0x19 0x0 0x5a 0x1a 0x0 0x5a 0x1b 0x0>;
col-gpios = <0x5a 0x15 0x0 0x5a 0x16 0x0>;

  Where did the 0x5A come from? Based on
http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/input/gpio-matrix-keypad.txt
where your x5A field is shown with &gpio2; though the documentation does
state the precise form per gpio depends on the system) -- see
http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/gpio/gpio.txt

  Regretably, I've not found a reference for what the BBB uses...
http://www.jumpnowtek.com/beaglebone/BeagleBone-Black-pinmuxing-and-other-device-tree-notes.html
appears to show a definition for gpio banks, but doesn't show anything
later to referencing them... I'm guessing it would be something like
<&gpio0 xx yy> (the yy based on the LED control in another file using a
third field for some mode control){I've found one PDF from two years ago
using 0x5, not 0x5A for the LED definition... I suspect using a hard-coded
integer is not safe as the node may change as the device tree changes --
integers may be the result of running a decompile on the device tree}

  All the references I've found seem to focus on the pinmux in the device
tree, and not on defining a pseudo-device using GPIO pin assignments.

linux,keymap = <0x8b 0x100009e 0x2000069 0x1006a 0x101001c 0x201006c>;

  Well, that much is the same as the first link -- a 3x2 matrix

  0 1
0 8b 6a
1 9e 1c
2 69 6c

#9

I resolved the issue and use correct values according to gpio banks:

matrix_keypad@0 {
compatible = “gpio-matrix-keypad”;
debounce-delay-ms = <0x50>;
col-scan-delay-us = <0x2>;
keypad,num-rows = <4>;
keypad,num-columns= <4>;
row-gpios = <&gpio2 7 0x17
&gpio2 9 0x17
&gpio2 11 0x17
&gpio2 13 0x17>;
col-gpios = <&gpio2 6 0x17
&gpio2 8 0x17
&gpio2 10 0x17
&gpio2 12 0x17>;
linux,keymap = <

/row0/
0x000000002 /* row 0 col 0 KEY_1 */
0x000100003 /*row 0 col 1 KEY_2 */
0x000200004 /*row 0 col 2 KEY_3 */
0x000300005 /*row 0 col 3 KEY_4 */

/row1/
0x01000005 /* row 1 col 0 KEY_4 /
0x01010006 / row 1 col 1 KEY_5 /
0x01020007 / row 1 col 2 KEY_6 /
0x01030008 / row 1 col 3 KEY_7 */

;

}
Now It is working … There are some issues with certain keys… Row0 keys are working But ROW1 keys are not working… IS there anything wrong with my dts settings.

#10

Thank you a lot for solving this in public.

#11

hi gurpartap_Singh I am facing the same problem interfacing keypad with beaglebone black I tried a lot of procedures but not able to get it .can you please help me with this issue?

Thanks in Advance