GPIO output high impedance mode

Previously GPIO output pins were set to low when the output value was
0 and high when the output value was 1.

This commit adds a second mode in which the GPIO pin is set to high
impedance when the output value is 0 and to low when the output value
is 1.

This should make it easier to use the GPIO outputs as inputs on other
controller devices.

config-tool-web/code.js

@@ -22,6 +22,7 @@ const NMACROS = 32;
 const NEXPRESSIONS = 8;
 const MACRO_ITEMS_IN_PACKET = 6;
 const IGNORE_AUTH_DEV_INPUTS_FLAG = 1 << 4;
+const GPIO_OUTPUT_MODE_FLAG = 1 << 5;
 
 const LAYERS_USAGE_PAGE = 0xFFF10000;
 const EXPR_USAGE_PAGE = 0xFFF30000;
@@ -107,6 +108,7 @@ let config = {
     'our_descriptor_number': 0,
     'ignore_auth_dev_inputs': false,
     'macro_entry_duration': DEFAULT_MACRO_ENTRY_DURATION,
+    'gpio_output_mode': 0,
     mappings: [{
         'source_usage': '0x00000000',
         'target_usage': '0x00000000',
@@ -155,6 +157,7 @@ document.addEventListener("DOMContentLoaded", function () {
     }
     document.getElementById("interval_override_dropdown").addEventListener("change", interval_override_onchange);
     document.getElementById("our_descriptor_number_dropdown").addEventListener("change", our_descriptor_number_onchange);
+    document.getElementById("gpio_output_mode_dropdown").addEventListener("change", gpio_output_mode_onchange);
     document.getElementById("ignore_auth_dev_inputs_checkbox").addEventListener("change", ignore_auth_dev_inputs_onchange);
 
     document.getElementById("nav-monitor-tab").addEventListener("shown.bs.tab", monitor_tab_shown);
@@ -224,6 +227,7 @@ async function load_from_device() {
         config['interval_override'] = interval_override;
         config['our_descriptor_number'] = our_descriptor_number;
         config['ignore_auth_dev_inputs'] = !!(flags & IGNORE_AUTH_DEV_INPUTS_FLAG);
+        config['gpio_output_mode'] = (flags & GPIO_OUTPUT_MODE_FLAG) ? 1 : 0;
         config['macro_entry_duration'] = macro_entry_duration + 1;
         config['mappings'] = [];
 
@@ -321,7 +325,8 @@ async function save_to_device() {
     try {
         await send_feature_command(SUSPEND);
         const flags = layer_list_to_mask(config['unmapped_passthrough_layers']) |
-            (config['ignore_auth_dev_inputs'] ? IGNORE_AUTH_DEV_INPUTS_FLAG : 0);
+            (config['ignore_auth_dev_inputs'] ? IGNORE_AUTH_DEV_INPUTS_FLAG : 0) |
+            (config['gpio_output_mode'] ? GPIO_OUTPUT_MODE_FLAG : 0);
         await send_feature_command(SET_CONFIG, [
             [UINT8, flags],
             [UINT32, config['partial_scroll_timeout']],
@@ -469,6 +474,7 @@ function set_config_ui_state() {
     document.getElementById('our_descriptor_number_dropdown').value = config['our_descriptor_number'];
     document.getElementById('ignore_auth_dev_inputs_checkbox').checked = config['ignore_auth_dev_inputs'];
     document.getElementById('macro_entry_duration_input').value = config['macro_entry_duration'];
+    document.getElementById('gpio_output_mode_dropdown').value = config['gpio_output_mode'];
 }
 
 function set_mappings_ui_state() {
@@ -574,6 +580,7 @@ function set_ui_state() {
     }
     if (config['version'] < 10) {
         config['macro_entry_duration'] = DEFAULT_MACRO_ENTRY_DURATION;
+        config['gpio_output_mode'] = 0;
     }
     if (config['version'] < CONFIG_VERSION) {
         config['version'] = CONFIG_VERSION;
@@ -1112,6 +1119,10 @@ function our_descriptor_number_onchange() {
     set_ui_state();
 }
 
+function gpio_output_mode_onchange() {
+    config['gpio_output_mode'] = parseInt(document.getElementById("gpio_output_mode_dropdown").value, 10);
+}
+
 function ignore_auth_dev_inputs_onchange() {
     config['ignore_auth_dev_inputs'] = document.getElementById("ignore_auth_dev_inputs_checkbox").checked;
 }

config-tool-web/index.html

@@ -164,6 +164,17 @@ <h1 class="mt-sm-5 mt-3">HID Remapper Configuration</h1>
                         </select>
                     </div>
                 </div>
+                <div class="row mt-3">
+                    <div class="col-4 text-end">
+                        <label for="gpio_output_mode_dropdown" class="col-form-label">GPIO output mode</label>
+                    </div>
+                    <div class="col-auto">
+                        <select class="form-select" id="gpio_output_mode_dropdown">
+                            <option value="0">0=low, 1=high</option>
+                            <option value="1">0=high-Z, 1=low</option>
+                        </select>
+                    </div>
+                </div>
                 <div class="row mt-3">
                     <div class="col-4 text-end">
                         <label for="ignore_auth_dev_inputs_checkbox" class="col-form-label">Ignore auth device inputs</label>

config-tool/common.py

@@ -51,6 +51,7 @@
 HOLD_FLAG = 1 << 2
 
 IGNORE_AUTH_DEV_INPUTS_FLAG = 1 << 4
+GPIO_OUTPUT_MODE_FLAG = 1 << 5
 
 NMACROS = 32
 NEXPRESSIONS = 8

config-tool/get_config.py

@@ -40,6 +40,7 @@
     "our_descriptor_number": our_descriptor_number,
     "ignore_auth_dev_inputs": bool(flags & IGNORE_AUTH_DEV_INPUTS_FLAG),
     "macro_entry_duration": macro_entry_duration + 1,
+    "gpio_output_mode": 1 if (flags & GPIO_OUTPUT_MODE_FLAG) else 0,
     "mappings": [],
     "macros": [],
     "expressions": [],

config-tool/set_config.py

@@ -33,8 +33,13 @@
 our_descriptor_number = config.get("our_descriptor_number", 0)
 ignore_auth_dev_inputs = config.get("ignore_auth_dev_inputs", False)
 macro_entry_duration = config.get("macro_entry_duration", 1) - 1
+gpio_output_mode = config.get("gpio_output_mode", 0)
 
-flags = unmapped_passthrough_layer_mask | (IGNORE_AUTH_DEV_INPUTS_FLAG if ignore_auth_dev_inputs else 0)
+flags = (
+    unmapped_passthrough_layer_mask
+    | (IGNORE_AUTH_DEV_INPUTS_FLAG if ignore_auth_dev_inputs else 0)
+    | (GPIO_OUTPUT_MODE_FLAG if gpio_output_mode == 1 else 0)
+)
 
 data = struct.pack(
     "<BBBBLBLBBB13B",

firmware/src/config.cc

@@ -15,6 +15,7 @@ const uint8_t CONFIG_FLAG_UNMAPPED_PASSTHROUGH = 0x01;
 const uint8_t CONFIG_FLAG_UNMAPPED_PASSTHROUGH_MASK = 0b00001111;
 const uint8_t CONFIG_FLAG_UNMAPPED_PASSTHROUGH_BIT = 0;
 const uint8_t CONFIG_FLAG_IGNORE_AUTH_DEV_INPUTS_BIT = 4;
+const uint8_t CONFIG_FLAG_GPIO_OUTPUT_MODE_BIT = 5;
 
 ConfigCommand last_config_command = ConfigCommand::NO_COMMAND;
 uint32_t requested_index = 0;
@@ -313,6 +314,7 @@ void load_config(const uint8_t* persisted_config) {
     unmapped_passthrough_layer_mask =
         (config->flags & CONFIG_FLAG_UNMAPPED_PASSTHROUGH_MASK) >> CONFIG_FLAG_UNMAPPED_PASSTHROUGH_BIT;
     ignore_auth_dev_inputs = config->flags & (1 << CONFIG_FLAG_IGNORE_AUTH_DEV_INPUTS_BIT);
+    gpio_output_mode = !!(config->flags & (1 << CONFIG_FLAG_GPIO_OUTPUT_MODE_BIT));
     partial_scroll_timeout = config->partial_scroll_timeout;
     tap_hold_threshold = config->tap_hold_threshold;
     gpio_debounce_time = config->gpio_debounce_time_ms * 1000;
@@ -374,6 +376,7 @@ void fill_get_config(get_config_t* config) {
     config->flags |=
         (unmapped_passthrough_layer_mask << CONFIG_FLAG_UNMAPPED_PASSTHROUGH_BIT) & CONFIG_FLAG_UNMAPPED_PASSTHROUGH_MASK;
     config->flags |= ignore_auth_dev_inputs << CONFIG_FLAG_IGNORE_AUTH_DEV_INPUTS_BIT;
+    config->flags |= gpio_output_mode << CONFIG_FLAG_GPIO_OUTPUT_MODE_BIT;
     config->partial_scroll_timeout = partial_scroll_timeout;
     config->tap_hold_threshold = tap_hold_threshold;
     config->gpio_debounce_time_ms = gpio_debounce_time / 1000;
@@ -391,6 +394,7 @@ void fill_persist_config(persist_config_t* config) {
     config->flags |=
         (unmapped_passthrough_layer_mask << CONFIG_FLAG_UNMAPPED_PASSTHROUGH_BIT) & CONFIG_FLAG_UNMAPPED_PASSTHROUGH_MASK;
     config->flags |= ignore_auth_dev_inputs << CONFIG_FLAG_IGNORE_AUTH_DEV_INPUTS_BIT;
+    config->flags |= gpio_output_mode << CONFIG_FLAG_GPIO_OUTPUT_MODE_BIT;
     config->partial_scroll_timeout = partial_scroll_timeout;
     config->tap_hold_threshold = tap_hold_threshold;
     config->gpio_debounce_time_ms = gpio_debounce_time / 1000;
@@ -581,6 +585,7 @@ void handle_set_report1(uint8_t report_id, uint8_t const* buffer, uint16_t bufsi
                     unmapped_passthrough_layer_mask =
                         (config->flags & CONFIG_FLAG_UNMAPPED_PASSTHROUGH_MASK) >> CONFIG_FLAG_UNMAPPED_PASSTHROUGH_BIT;
                     ignore_auth_dev_inputs = config->flags & (1 << CONFIG_FLAG_IGNORE_AUTH_DEV_INPUTS_BIT);
+                    gpio_output_mode = !!(config->flags & (1 << CONFIG_FLAG_GPIO_OUTPUT_MODE_BIT));
                     partial_scroll_timeout = config->partial_scroll_timeout;
                     tap_hold_threshold = config->tap_hold_threshold;
                     gpio_debounce_time = config->gpio_debounce_time_ms * 1000;

firmware/src/globals.cc

@@ -29,6 +29,7 @@ uint64_t gpio_debounce_time = 5000;
 uint8_t our_descriptor_number = 0;
 bool ignore_auth_dev_inputs = false;
 uint8_t macro_entry_duration = 0; // 0 means 1ms
+uint8_t gpio_output_mode = 0;
 
 std::vector<mapping_config_t> config_mappings;
 

firmware/src/globals.h

@@ -36,6 +36,7 @@ extern uint64_t gpio_debounce_time;
 extern uint8_t our_descriptor_number;
 extern bool ignore_auth_dev_inputs;
 extern uint8_t macro_entry_duration;
+extern uint8_t gpio_output_mode;
 
 extern std::vector<mapping_config_t> config_mappings;
 

firmware/src/main.cc

@@ -35,6 +35,7 @@ uint32_t gpio_in_mask = 0;
 uint32_t gpio_out_mask = 0;
 uint32_t prev_gpio_state = 0;
 uint64_t last_gpio_change[32] = { 0 };
+bool set_gpio_dir_pending = false;
 
 void print_stats_maybe() {
     uint64_t now = time_us_64();
@@ -65,7 +66,12 @@ void set_gpio_inout_masks(uint32_t in_mask, uint32_t out_mask) {
     gpio_out_mask = (out_mask & ~in_mask) & gpio_valid_pins_mask;
     // we treat all pins except the output ones as input so that the monitor works
     gpio_in_mask = gpio_valid_pins_mask & ~gpio_out_mask;
-    gpio_set_dir_masked(gpio_valid_pins_mask, gpio_out_mask);
+    set_gpio_dir_pending = true;
+}
+
+void set_gpio_dir() {
+    gpio_set_dir_masked(gpio_in_mask, 0);
+    // output pin direction will be set in write_gpio()
     for (uint8_t i = 0; i <= 29; i++) {
         uint32_t bit = 1 << i;
         if (gpio_valid_pins_mask & bit) {
@@ -102,8 +108,21 @@ bool read_gpio(uint64_t now) {
 }
 
 void write_gpio() {
+    if (suspended) {
+        return;
+    }
+
     uint32_t value = gpio_out_state[0] | (gpio_out_state[1] << 8) | (gpio_out_state[2] << 16) | (gpio_out_state[3] << 24);
-    gpio_put_masked(gpio_out_mask, value);
+    switch (gpio_output_mode) {
+        case 0:
+            gpio_put_masked(gpio_out_mask, value);
+            gpio_set_dir_masked(gpio_out_mask, gpio_out_mask);
+            break;
+        case 1:
+            gpio_put_masked(gpio_out_mask, 0);
+            gpio_set_dir_masked(gpio_out_mask, value);
+            break;
+    }
     memset(gpio_out_state, 0, sizeof(gpio_out_state));
 }
 
@@ -197,6 +216,10 @@ int main() {
             set_mapping_from_config();
             config_updated = false;
         }
+        if (set_gpio_dir_pending && !suspended) {
+            set_gpio_dir();
+            set_gpio_dir_pending = false;
+        }
         if (tud_hid_n_ready(0)) {
             send_report(do_send_report);
         }