1 files changed, 87 insertions, 0 deletions
diff --git a/keyboards/fc660c/actuation_point.c b/keyboards/fc660c/actuation_point.c
new file mode 100644
index 0000000000..5f4cb16f40
--- /dev/null
+++ b/keyboards/fc660c/actuation_point.c
@@ -0,0 +1,87 @@
+/*
+Copyright 2017 Balz Guenat
+based on work by Jun Wako <wakojun@gmail.com>
+
+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 "actuation_point.h"
+#include "i2c.h"
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// AD5258 I2C digital potentiometer
+// http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf
+//
+#define AD5258_ADDR 0b0011000
+#define AD5258_INST_RDAC        0x00
+#define AD5258_INST_EEPROM      0x20
+
+uint8_t read_rdac(void) {
+    // read RDAC register
+    i2c_start_write(AD5258_ADDR);
+    i2c_master_write(AD5258_INST_RDAC);
+    i2c_start_read(AD5258_ADDR);
+    uint8_t ret = i2c_master_read(I2C_NACK);
+    i2c_master_stop();
+    return ret;
+};
+
+uint8_t read_eeprom(void) {
+    i2c_start_write(AD5258_ADDR);
+    i2c_master_write(AD5258_INST_EEPROM);
+    i2c_start_read(AD5258_ADDR);
+    uint8_t ret = i2c_master_read(I2C_NACK);
+    i2c_master_stop();
+    return ret;
+};
+
+void write_rdac(uint8_t rdac) {
+    // write RDAC register:
+    i2c_start_write(AD5258_ADDR);
+    i2c_master_write(AD5258_INST_RDAC);
+    i2c_master_write(rdac & 0x3F);
+    i2c_master_stop();
+};
+
+void actuation_point_up(void) {
+    // write RDAC register: lower value makes actuation point shallow
+    uint8_t rdac = read_rdac();
+    if (rdac == 0)
+        write_rdac(0);
+    else
+        write_rdac(rdac-1);
+};
+
+void actuation_point_down(void) {
+    // write RDAC register: higher value makes actuation point deep
+    uint8_t rdac = read_rdac();
+    if (rdac == 63)
+        write_rdac(63);
+    else
+        write_rdac(rdac+1);
+};
+
+void adjust_actuation_point(int offset) {
+    i2c_master_init();
+    uint8_t rdac = read_eeprom() + offset;
+    if (rdac > 63) { // protects from under and overflows
+        if (offset > 0)
+            write_rdac(63);
+        else
+            write_rdac(0);
+    } else {
+        write_rdac(rdac);
+    }
+}