From 1718dfa658dbe8ad144100b561794c5596ac5f08 Mon Sep 17 00:00:00 2001
From: Joel Challis <git@zvecr.com>
Date: Tue, 3 Dec 2019 19:39:21 +0000
Subject: Increase matrix scanning speed on xd84 (#7517)

* Increase matrix scanning speed

* Fix func name in failure output
---
 keyboards/xd84/matrix.c | 80 ++++++++++++++++++++++++++-----------------------
 1 file changed, 42 insertions(+), 38 deletions(-)

(limited to 'keyboards/xd84/matrix.c')

diff --git a/keyboards/xd84/matrix.c b/keyboards/xd84/matrix.c
index 4cb5544ca4..a4ddbee9a0 100644
--- a/keyboards/xd84/matrix.c
+++ b/keyboards/xd84/matrix.c
@@ -30,65 +30,69 @@
 //_____Utility funcs___________________________________________________________
 
 static void init_pins(void) {
-  // init all cols high - IC2 all input
-  pca9555_set_config(IC2, PCA9555_PORT0, ALL_INPUT);//same as initial state
-  pca9555_set_config(IC2, PCA9555_PORT1, ALL_INPUT);//same as initial state
+    // init all cols high - IC2 all input
+    pca9555_set_config(IC2, PCA9555_PORT0, ALL_INPUT);  // same as initial state
+    pca9555_set_config(IC2, PCA9555_PORT1, ALL_INPUT);  // same as initial state
 
-  // init all rows - IC1 port0 input
-  pca9555_set_config(IC1, PCA9555_PORT0, ALL_INPUT);//same as initial state
+    // 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) {
-  // For the XD84 all rows are on the same IC and port
-  // so its safe enough to assume here row == pin
-  uint8_t pin = row;
-  uint8_t mask = 1 << pin;
-
-  pca9555_set_output(IC1, PCA9555_PORT0, ALL_HIGH & (~mask));
-  pca9555_set_config(IC1, PCA9555_PORT0, ALL_INPUT & (~mask));
+    // For the XD84 all rows are on the same IC and port
+    // so its safe enough to assume here row == pin
+    uint8_t pin  = row;
+    uint8_t mask = 1 << pin;
+
+    // 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);
-
-  // 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);
+    // 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;
 }
 
 static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
-  // Store last value of row prior to reading
-  matrix_row_t last_row_value = current_matrix[current_row];
+    // Store last value of row prior to reading
+    matrix_row_t last_row_value = current_matrix[current_row];
 
-  // Clear data in matrix row
-  current_matrix[current_row] = 0;
+    // Clear data in matrix row
+    current_matrix[current_row] = 0;
 
-  // Select row and wait for row selection to stabilize
-  select_row(current_row);
-  wait_us(30);
+    // Select row and wait for row selection to stabilize
+    select_row(current_row);
+    // Skip the wait_us(30); as i2c is slow enough to debounce the io changes
 
-  current_matrix[current_row] = read_cols();
+    current_matrix[current_row] = read_cols();
 
-  // No need to Unselect row as the next `select_row` will blank everything
+    // No need to Unselect row as the next `select_row` will blank everything
 
-  return (last_row_value != current_matrix[current_row]);
+    return (last_row_value != current_matrix[current_row]);
 }
 
 //_____CUSTOM MATRIX IMPLEMENTATION____________________________________________________
 
 void custom_matrix_init(void) {
-  pca9555_init(IC1);
-  pca9555_init(IC2);
+    pca9555_init(IC1);
+    pca9555_init(IC2);
 
-  init_pins();
+    init_pins();
 }
 
 bool custom_matrix_scan(matrix_row_t current_matrix[]) {
-  bool changed = false;
-  for (uint8_t current_row = 0; current_row < MATRIX_ROWS; current_row++) {
-    changed |= read_cols_on_row(current_matrix, current_row);
-  }
-  return changed;
-}
\ No newline at end of file
+    bool changed = false;
+    for (uint8_t current_row = 0; current_row < MATRIX_ROWS; current_row++) {
+        changed |= read_cols_on_row(current_matrix, current_row);
+    }
+    return changed;
+}
-- 
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