Increase matrix scanning speed on xd84 (#7517)

* Increase matrix scanning speed

* Fix func name in failure output

drivers/gpio/pca9555.c

@@ -76,3 +76,20 @@ uint8_t pca9555_readPins(uint8_t slave_addr, uint8_t port) {
     }
     return data;
 }
+
+uint16_t pca9555_readAllPins(uint8_t slave_addr) {
+    uint8_t addr = SLAVE_TO_ADDR(slave_addr);
+
+    typedef union {
+        uint8_t  u8[2];
+        uint16_t u16;
+    } data16;
+
+    data16 data;
+
+    i2c_status_t ret = i2c_readReg(addr, CMD_INPUT_0, &data.u8[0], sizeof(data), TIMEOUT);
+    if (ret != I2C_STATUS_SUCCESS) {
+        print("pca9555_readAllPins::FAILED\n");
+    }
+    return data.u16;
+}

drivers/gpio/pca9555.h

@@ -53,3 +53,5 @@ void pca9555_set_config(uint8_t slave_addr, uint8_t port, uint8_t conf);
 void pca9555_set_output(uint8_t slave_addr, uint8_t port, uint8_t conf);
 
 uint8_t pca9555_readPins(uint8_t slave_addr, uint8_t port);
+
+uint16_t pca9555_readAllPins(uint8_t slave_addr);

keyboards/xd84/matrix.c

@@ -36,6 +36,7 @@ static void init_pins(void) {
 
     // init all rows - IC1 port0 input
     pca9555_set_config(IC1, PCA9555_PORT0, ALL_INPUT);  // same as initial state
+    pca9555_set_output(IC1, PCA9555_PORT0, ALL_LOW);
 }
 
 static void select_row(uint8_t row) {
@@ -44,18 +45,21 @@ static void select_row(uint8_t row) {
     uint8_t pin  = row;
     uint8_t mask = 1 << pin;
 
-  pca9555_set_output(IC1, PCA9555_PORT0, ALL_HIGH & (~mask));
+    // we configure output once in init, as pca9555 remembers state when flipping between input/output 
+    // pca9555_set_output(IC1, PCA9555_PORT0, ALL_HIGH & (~mask));
     pca9555_set_config(IC1, PCA9555_PORT0, ALL_INPUT & (~mask));
 }
 
 static uint16_t read_cols(void) {
-  uint16_t state_1 = pca9555_readPins(IC2, PCA9555_PORT0);
-  uint16_t state_2 = pca9555_readPins(IC2, PCA9555_PORT1);
+    // uint16_t state_1 = pca9555_readPins(IC2, PCA9555_PORT0);
+    // uint16_t state_2 = pca9555_readPins(IC2, PCA9555_PORT1);
+    uint16_t state = pca9555_readAllPins(IC2);
 
     // For the XD84 all cols are on the same IC and mapped sequentially
     // while this technically gives 16 column reads,
     // the 16th column can never be set so is safely ignored
-  return ~((state_2 << 8) | state_1);
+    // return ~((state_2 << 8) | state_1);
+    return ~state;
 }
 
 static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
@@ -67,7 +71,7 @@ static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row)
 
     // Select row and wait for row selection to stabilize
     select_row(current_row);
-  wait_us(30);
+    // Skip the wait_us(30); as i2c is slow enough to debounce the io changes
 
     current_matrix[current_row] = read_cols();