input: twl4030: Keypad scan and input

This allows scanning the twl4030 keypad, storing the result in a 64-byte long
matrix with the twl4030_keypad_scan function.

Detecting a key at a given column and row is made easier with the
twl4030_keypad_key function.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-by: Tom Rini <trini@konsulko.com>

drivers/input/twl4030.c

@@ -47,3 +47,42 @@ int twl4030_input_usb(void)
 
 	return 0;
 }
+
+int twl4030_keypad_scan(unsigned char *matrix)
+{
+	u8 data;
+	u8 c, r;
+
+	twl4030_i2c_read_u8(TWL4030_CHIP_KEYPAD,
+			    TWL4030_KEYPAD_KEYP_CTRL_REG, &data);
+
+	data |= TWL4030_KEYPAD_CTRL_SOFT_NRST | TWL4030_KEYPAD_CTRL_KBD_ON;
+	data &= ~TWL4030_KEYPAD_CTRL_SOFTMODEN;
+
+	twl4030_i2c_write_u8(TWL4030_CHIP_KEYPAD,
+			     TWL4030_KEYPAD_KEYP_CTRL_REG, data);
+
+	for (c = 0; c < 8; c++) {
+		data = 0xff & ~(1 << c);
+		twl4030_i2c_write_u8(TWL4030_CHIP_KEYPAD,
+				     TWL4030_KEYPAD_KBC_REG, data);
+
+		data = 0xff;
+		twl4030_i2c_read_u8(TWL4030_CHIP_KEYPAD,
+				    TWL4030_KEYPAD_KBR_REG, &data);
+
+		for (r = 0; r < 8; r++)
+			matrix[c * 8 + r] = !(data & (1 << r));
+	}
+
+	data = 0xff & ~(TWL4030_KEYPAD_CTRL_SOFT_NRST);
+	twl4030_i2c_write_u8(TWL4030_CHIP_KEYPAD,
+			     TWL4030_KEYPAD_KEYP_CTRL_REG, data);
+
+	return 0;
+}
+
+int twl4030_keypad_key(unsigned char *matrix, u8 c, u8 r)
+{
+	return matrix[c * 8 + r];
+}

include/twl4030.h

@@ -683,6 +683,9 @@ int twl4030_input_power_button(void);
 int twl4030_input_charger(void);
 int twl4030_input_usb(void);
 
+int twl4030_keypad_scan(unsigned char *matrix);
+int twl4030_keypad_key(unsigned char *matrix, u8 c, u8 r);
+
 /*
  * LED
  */