mai2io/led15070: add LED control APIs and PWM/fade handling (#89)

## Summary

- feat(io4): implement PWM/GPIO support for Billboard and Code Reader lights
- feat(mai2io): expose LED control APIs to support new io4 features
- fix(led15070): correct multi-LED color logic and add fade support

## Description

**io4 & mai2io Updates**
Introduced PWM control and GPIO write support in `io4`. These additions allow `mai2io` to properly drive the **Billboard LEDs** and **Code Reader / Player Camera lights**. The APIs have been exposed through `mai2hook` to facilitate scriptable control of these peripherals.

**led15070 Improvements**
Fixed an issue with the multi-LED color changing logic in the `led15070` driver. This ensures correct color output sequence and includes improvements for fade calculation.

Reviewed-on: https://gitea.tendokyu.moe/TeamTofuShop/segatools/pulls/89
Co-authored-by: グローランプ <130208311+Gl0w1amp@users.noreply.github.com>
Co-committed-by: グローランプ <130208311+Gl0w1amp@users.noreply.github.com>

games/mai2hook/io4.c

@@ -11,11 +11,17 @@
 #include "util/dprintf.h"
 
 static HRESULT mai2_io4_poll(void* ctx, struct io4_state* state);
+static HRESULT mai2_io4_write_gpio(uint8_t* payload, size_t len);
+static HRESULT mai2_io4_write_pwm(uint8_t* payload, size_t len);
+static HRESULT mai2_io4_write_unique(uint8_t* payload, size_t len);
 
 static uint16_t coins;
 
 static const struct io4_ops mai2_io4_ops = {
     .poll = mai2_io4_poll,
+    .write_gpio = mai2_io4_write_gpio,
+    .write_pwm = mai2_io4_write_pwm,
+    .write_unique = mai2_io4_write_unique,
 };
 
 HRESULT mai2_io4_hook_init(const struct io4_config* cfg) {
@@ -148,5 +154,62 @@ static HRESULT mai2_io4_poll(void* ctx, struct io4_state* state) {
         state->buttons[1] |= 1 << 4;
     }
 
+    return S_OK;
+}
+
+static HRESULT mai2_io4_write_gpio(uint8_t* payload, size_t len) {
+    if (len >= 4) {
+        char bin0[9];
+        char bin1[9];
+        for (int i = 0; i < 8; i++) {
+            bin0[7 - i] = (payload[0] & (1 << i)) ? '1' : '0';
+            bin1[7 - i] = (payload[1] & (1 << i)) ? '1' : '0';
+        }
+        bin0[8] = '\0';
+        bin1[8] = '\0';
+
+#if defined(LOG_IO4)
+        dprintf("IO4 LED: [%02X %02X %02X %02X] (Byte0: %s, Byte1: %s)\n", 
+            payload[0], payload[1], payload[2], payload[3], bin0, bin1);
+
+        dprintf("  1P Code Reader: %s\n", (payload[0] & 0x20) ? "ON" : "OFF");
+        dprintf("  2P Code Reader: %s\n", (payload[0] & 0x04) ? "ON" : "OFF");
+        dprintf("  Camera Ring:    %s\n", (payload[1] & 0x80) ? "ON" : "OFF");
+        dprintf("  Camera Rec:     %s\n", (payload[1] & 0x40) ? "ON" : "OFF");
+#endif
+    }
+    return S_OK;
+}
+
+static HRESULT mai2_io4_write_pwm(uint8_t* payload, size_t len) {
+    if (len >= 16) {
+#if defined(LOG_IO4)
+        dprintf("IO4 PWM: %02X %02X %02X %02X %02X %02X %02X %02X ...\n", 
+            payload[0], payload[1], payload[2], payload[3],
+            payload[4], payload[5], payload[6], payload[7]);
+#endif
+    }
+    return S_OK;
+}
+
+static HRESULT mai2_io4_write_unique(uint8_t* payload, size_t len) {
+    if (len < 8) {
+        return S_OK;
+    }
+
+#if defined(LOG_IO4)
+    dprintf("IO4 Unique: %02X %02X %02X %02X %02X %02X %02X %02X ...\n", 
+        payload[0], payload[1], payload[2], payload[3],
+        payload[4], payload[5], payload[6], payload[7]);
+#endif
+
+    if (mai2_dll.led_set_leds) {
+        uint8_t rgb_1p[3] = { payload[2], payload[4], payload[6] };
+        uint8_t rgb_2p[3] = { payload[3], payload[5], payload[7] };
+
+        mai2_dll.led_set_leds(0, rgb_1p);
+        mai2_dll.led_set_leds(1, rgb_2p);
+    }
+
     return S_OK;
 }

games/mai2hook/mai2-dll.c

@@ -8,6 +8,11 @@
 #include "util/dll-bind.h"
 #include "util/dprintf.h"
 
+enum {
+    MAI2_DLL_SYM_COUNT_V101 = 11,
+    MAI2_DLL_SYM_COUNT_V102 = 12,
+};
+
 const struct dll_bind_sym mai2_dll_syms[] = {
     {
         .sym = "mai2_io_init",
@@ -42,6 +47,9 @@ const struct dll_bind_sym mai2_dll_syms[] = {
     }, {
         .sym = "mai2_io_led_gs_update",
         .off = offsetof(struct mai2_dll, led_gs_update),
+    }, {
+        .sym = "mai2_io_led_billboard_set",
+        .off = offsetof(struct mai2_dll, led_set_leds),
     },
 };
 
@@ -60,6 +68,7 @@ HRESULT mai2_dll_init(const struct mai2_dll_config *cfg, HINSTANCE self)
     HINSTANCE owned;
     HINSTANCE src;
     HRESULT hr;
+    size_t sym_count;
 
     assert(cfg != NULL);
     assert(self != NULL);
@@ -104,7 +113,11 @@ HRESULT mai2_dll_init(const struct mai2_dll_config *cfg, HINSTANCE self)
     }
 
     sym = mai2_dll_syms;
-    hr = dll_bind(&mai2_dll, src, &sym, _countof(mai2_dll_syms));
+    sym_count = (mai2_dll.api_version < 0x0102)
+            ? MAI2_DLL_SYM_COUNT_V101
+            : MAI2_DLL_SYM_COUNT_V102;
+
+    hr = dll_bind(&mai2_dll, src, &sym, sym_count);
 
     if (FAILED(hr)) {
         if (src != self) {

games/mai2hook/mai2-dll.h

@@ -17,6 +17,7 @@ struct mai2_dll {
     void (*led_set_fet_output)(uint8_t board, const uint8_t *rgb);
     void (*led_dc_update)(uint8_t board, const uint8_t *rgb);
     void (*led_gs_update)(uint8_t board, const uint8_t *rgb);
+    void (*led_set_leds)(uint8_t board, const uint8_t *rgb);
 };
 
 struct mai2_dll_config {

games/mai2hook/mai2hook.def

@@ -23,3 +23,4 @@ EXPORTS
     mai2_io_led_set_fet_output
     mai2_io_led_dc_update
     mai2_io_led_gs_update
+    mai2_io_led_billboard_set

games/mai2io/mai2io.c

@@ -19,7 +19,7 @@ static bool mai2_io_touch_1p_stop_flag;
 static HANDLE mai2_io_touch_2p_thread;
 static bool mai2_io_touch_2p_stop_flag;
 
-uint16_t mai2_io_get_api_version(void) { return 0x0101; }
+uint16_t mai2_io_get_api_version(void) { return 0x0102; }
 
 HRESULT mai2_io_init(void) {
     mai2_io_config_load(&mai2_io_cfg, get_config_path());
@@ -265,3 +265,11 @@ void mai2_io_led_gs_update(uint8_t board, const uint8_t *rgb) {
 #endif
     return;
 }
+
+void mai2_io_led_billboard_set(uint8_t board, const uint8_t *rgb) {
+#if 0
+    uint8_t player = board + 1;
+    dprintf("Mai2 LED %dP: Billboard set R:%02X G:%02X B:%02X\n", player, rgb[0], rgb[1], rgb[2]);
+#endif
+    return;
+}

games/mai2io/mai2io.h

@@ -28,7 +28,7 @@ enum {
    the major version and the low byte is the minor version (as defined by the
    Semantic Versioning standard).
 
-   The latest API version as of this writing is 0x0100. */
+   The latest API version as of this writing is 0x0102. */
 
 uint16_t mai2_io_get_api_version(void);
 
@@ -190,3 +190,12 @@ void mai2_io_led_dc_update(uint8_t board, const uint8_t *rgb);
    Minimum API version: 0x0101 */
 
 void mai2_io_led_gs_update(uint8_t board, const uint8_t *rgb);
+
+/* Update the Billboard LEDs. rgb is a pointer to an array.
+
+   maimai DX uses two boards. Board 0 is for the player 1 side (left) and board 1
+   is for the player 2 side (right).
+
+   Minimum API version: 0x0102 */
+
+void mai2_io_led_billboard_set(uint8_t board, const uint8_t *rgb);