@@ -1,11 +1,46 @@
* GPIO driven matrix keypad device tree bindings
GPIO driven matrix keypad is used to interface a SoC with a matrix keypad.
+
+Generic mode:
The matrix keypad supports multiple row and column lines, a key can be
placed at each intersection of a unique row and a unique column. The matrix
keypad can sense a key-press and key-release by means of GPIO lines and
report the event using GPIO interrupts to the cpu.
+Reduced mode:
+The reduced matric keypad supports multiple gpio lines, all gpio lines
+act as row as well as column lines, a key can be placed at each intersection
+of a row number not equal to a column number and they are diagonally
+symmetric.
+
+Example- For 5 gpio lines, possible matrix is 5x5 and maximum possible
+ keys are 10.
+
+ Sample matrix table for 7 buttons and 5 gpio lines
+
+ ------------------------------------------------------
+ |Row\Col |GPIO 0 | GPIO 1 | GPIO 2 | GPIO 3 | GPIO 4 |
+ ------------------------------------------------------
+ | GPIO 0 | X | KEY_9 | KEY_2 | X | KEY_1 |
+ ------------------------------------------------------
+ | GPIO 1 | KEY_9 | X | KEY_6 | X | X |
+ ------------------------------------------------------
+ | GPIO 2 | KEY_2 | KEY_6 | X | KEY_4 | KEY_7 |
+ ------------------------------------------------------
+ | GPIO 3 | X | X | KEY_4 | X | KEY_8 |
+ ------------------------------------------------------
+ | GPIO 4 | KEY_1 | X | KEY_7 | KEY_8 | X |
+ ------------------------------------------------------
+ X - invalid key
+ KEY_x - preferred key code
+
+The reduced mode sense a key-press and key-release by polling
+GPIO lines and report the event.
+
+
+Generic mode:
+
Required Properties:
- compatible: Should be "gpio-matrix-keypad"
- row-gpios: List of gpios used as row lines. The gpio specifier
@@ -47,3 +82,64 @@ Example:
0x0101001C
0x0201006C>;
};
+
+Reduced mode:
+
+Required Properties:
+- compatible: Should be "gpio-matrix-keypad-reduced"
+- number-of-buttons: Number of buttons connected to the keypad controller.
+- line-gpios: Gpio lines connected to keypad controller.
+ all gpio lines act as row as well as column lines.
+- linux,keymap: An array of packed 1-cell entries containing the
+ equivalent of row, column and linux key-code.
+ The 32-bit big endian cell is packed as:
+ row << 24 | column << 16 | key-code
+
+Optional Properties:
+- poll-interval-ms: Time interval between poll.
+- linux,no-autorepeat: Do no enable autorepeat feature.
+- col-scan-delay-us: Delay before scanning next active line.
+
+Example:
+ keypad {
+ compatible = "gpio-matrix-keypad-reduced";
+ poll-interval-ms = <10>;
+ col-scan-delay-us = <2>;
+ number-of-buttons = <7>;
+ linux,no-autorepeat;
+ line-gpios = <
+ &gpio1 24 1 /*gpio_56*/
+ &gpio1 23 1 /*gpio_55*/
+ &gpio1 22 1 /*gpio_54*/
+ &gpio1 20 1 /*gpio_52*/
+ &gpio1 16 1 /*gpio_48*/
+ >;
+ linux,keymap = <
+ 0x00000000 /* row 0, col 0, KEY_RESERVED */
+ 0x0001000a /* row 0, col 1, KEY_9 */
+ 0x00020003 /* row 0, col 2, KEY_2 */
+ 0x00030000 /* row 0, col 3, KEY_RESERVED */
+ 0x00040002 /* row 0, col 4, KEY_1 */
+ 0x0100000a /* row 1, col 0, KEY_9 */
+ 0x01010000 /* row 1, col 1, KEY_RESERVED */
+ 0x01020007 /* row 1, col 2, KEY_6 */
+ 0x01030000 /* row 1, col 3, KEY_RESERVED */
+ 0x01040000 /* row 1, col 4, KEY_RESERVED */
+ 0x02000003 /* row 2, col 0, KEY_2 */
+ 0x02010007 /* row 2, col 1, KEY_6 */
+ 0x02020000 /* row 2, col 2, KEY_RESERVED */
+ 0x02030005 /* row 2, col 3, KEY_4 */
+ 0x02040008 /* row 2, col 4, KEY_7 */
+ 0x03000000 /* row 3, col 0, KEY_RESERVED */
+ 0x03010000 /* row 3, col 1, KEY_RESERVED */
+ 0x03020005 /* row 3, col 2, KEY_4 */
+ 0x03030000 /* row 3, col 3, KEY_RESERVED */
+ 0x03040009 /* row 3, col 4, KEY_8 */
+ 0x04000002 /* row 4, col 0, KEY_1 */
+ 0x04010000 /* row 4, col 1, KEY_RESERVED */
+ 0x04020008 /* row 4, col 2, KEY_7 */
+ 0x04030009 /* row 4, col 3, KEY_8 */
+ 0x04040000 /* row 4, col 4, KEY_RESERVED */
+ >;
+
+ };