1 files changed, 107 insertions, 0 deletions
diff --git a/keyboards/nek_type_a/mcp23017.c b/keyboards/nek_type_a/mcp23017.c
new file mode 100644
index 0000000000..e242316804
--- /dev/null
+++ b/keyboards/nek_type_a/mcp23017.c
@@ -0,0 +1,107 @@
+/* Copyright 2018 Mike Roberts
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdbool.h>
+#include "action.h"
+#include "lib/lufa/LUFA/Drivers/Peripheral/TWI.h"
+#include "lib/lufa/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c"
+#include "mcp23017.h"
+#include "debug.h"
+#include "wait.h"
+
+uint8_t bit_for_pin(uint8_t pin);
+
+uint8_t expander_write(uint8_t reg, uint8_t data);
+
+uint8_t expander_read(uint8_t reg, uint8_t *data);
+
+void expander_config(void);
+
+static const char *twi_err_str(uint8_t res) {
+    switch (res) {
+        case TWI_ERROR_NoError:
+            return "OK";
+        case TWI_ERROR_BusFault:
+            return "BUSFAULT";
+        case TWI_ERROR_BusCaptureTimeout:
+            return "BUSTIMEOUT";
+        case TWI_ERROR_SlaveResponseTimeout:
+            return "SLAVETIMEOUT";
+        case TWI_ERROR_SlaveNotReady:
+            return "SLAVENOTREADY";
+        case TWI_ERROR_SlaveNAK:
+            return "SLAVENAK";
+        default:
+            return "UNKNOWN";
+    }
+}
+
+void expander_init(void) {
+    TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 400000));
+}
+
+// set IN and HI
+void expander_unselect_all() {
+    expander_write(EXPANDER_REG_IODIRA, 0xff);
+    expander_write(EXPANDER_REG_IODIRB, 0xff);
+    expander_write(EXPANDER_REG_OLATA, 0xff);
+    expander_write(EXPANDER_REG_OLATB, 0xff);
+    wait_us(EXPANDER_PAUSE);
+}
+
+// set OUT and LOW
+void expander_select(uint8_t pin) {
+    const uint8_t mask = 0xff & ~(1 << bit_for_pin(pin));
+    if (pin < 8) {
+        expander_write(EXPANDER_REG_IODIRA, mask);
+        expander_write(EXPANDER_REG_OLATA, mask);
+    } else {
+        expander_write(EXPANDER_REG_IODIRB, mask);
+        expander_write(EXPANDER_REG_OLATB, mask);
+    }
+    wait_us(EXPANDER_PAUSE);
+}
+
+void expander_config() {
+    // set everything to input
+    expander_write(EXPANDER_REG_IODIRA, 0xff);
+    expander_write(EXPANDER_REG_IODIRB, 0xff);
+
+    // turn on pull-ups
+    expander_write(EXPANDER_REG_GPPUA, 0xff);
+    expander_write(EXPANDER_REG_GPPUB, 0xff);
+
+    // disable interrupts
+    expander_write(EXPANDER_REG_GPINTENA, 0x0);
+    expander_write(EXPANDER_REG_GPINTENB, 0x0);
+
+    // polarity
+    expander_write(EXPANDER_REG_IPOLA, 0x0);
+    expander_write(EXPANDER_REG_IPOLB, 0x0);
+}
+
+uint8_t bit_for_pin(uint8_t pin) {
+    return pin % 8;
+}
+
+uint8_t expander_write(uint8_t reg, unsigned char val) {
+    uint8_t addr = reg;
+    uint8_t result = TWI_WritePacket(EXPANDER_ADDR << 1, I2C_TIMEOUT, &addr, sizeof(addr), &val, sizeof(val));
+    if (result) {
+        xprintf("mcp: set_register %d = %d failed: %s\n", reg, val, twi_err_str(result));
+    }
+    return result == 0;
+}
+