Add HEER S1 macropad (#26373)

* Add HEER S1 macropad

* Address review feedback for HEER S1

- readme: add product image, correct maintainer link and availability URL
- config.h: drop OLED_DISPLAY_ADDRESS, already the driver default
- keyboard.json: drop the i2c block, which only feeds split transport
- move the OLED to heer_s1.c as oled_task_kb
- default keymap reduced to keymaps[] and encoder_map[]

The default keymap also configured GP16/GP17 as GPIO inputs at boot. Those are
the OLED's I2C SDA/SCL lines, so it tore down the display bus on every start.
The encoder switches are on GP2/GP14. Removed along with the rest of the code.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* Update keyboards/heer_s1/keymaps/default/keymap.c

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/keymaps/default/keymap.c

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/keymaps/default/keymap.c

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/keymaps/default/keymap.c

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/keyboard.json

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/readme.md

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/keymaps/default/keymap.c

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/keyboard.json

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/keyboard.json

Co-authored-by: Joel Challis <git@zvecr.com>

* Fix duplicated enumerators in default keymap

The suggested enum replacement was applied alongside the original entries
rather than in place of them, leaving L_BASE, L_MEDIA and L_EDIT declared
twice.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* Update keyboards/heer_s1/readme.md

Co-authored-by: Joel Challis <git@zvecr.com>

* Update keyboards/heer_s1/keyboard.json

Co-authored-by: Joel Challis <git@zvecr.com>

---------

Co-authored-by: HEER <heerelectronix@gmail.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: Joel Challis <git@zvecr.com>

keyboards/heer_s1/config.h

@@ -0,0 +1,32 @@
+// Copyright 2026 Heer (@heer)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+// ── OLED (SH1106 1.3", 128×64, I2C address 0x3C) ────────────────────────────
+#define OLED_DISPLAY_128X64
+#define OLED_IC              OLED_IC_SH1106
+#define OLED_COLUMN_OFFSET   2
+#define OLED_BRIGHTNESS      180
+#define OLED_TIMEOUT              0
+#define OLED_UPDATE_INTERVAL      10
+// NOTE: do NOT raise OLED_UPDATE_PROCESS_LIMIT. The default of 1 keeps each I2C
+// transaction to a single 32-byte block.
+//
+// TESTED, TWICE, ON HARDWARE: a limit of 4 — only 128 bytes, one page, the write
+// size stock SSD1306/SH1106 drivers use — blanks this panel completely. The board
+// keeps running (keys and encoders work) but the display never comes up. The
+// reasoning that "a page is safe because everyone writes pages" is wrong for this
+// module. Do not try it again.
+//
+// OLED_UPDATE_INTERVAL is a different knob and is safe to shorten: it changes how
+// OFTEN a block is flushed, not how BIG the transaction is, which stays one
+// 32-byte block. At the old 33ms, swapping the right-hand panel between the key
+// grid and the encoder bars took ~21 blocks * 33ms = ~700ms to reach the glass —
+// you would turn the knob and see the bar most of a second later. 10ms puts that
+// at ~210ms. If the panel ever misbehaves, this is the first value to put back.
+
+// ── I2C (OLED on GP16=SDA, GP17=SCL via RP2040 I2C0) ────────────────────────
+#define I2C_DRIVER   I2CD0
+#define I2C1_SDA_PIN GP16
+#define I2C1_SCL_PIN GP17

keyboards/heer_s1/halconf.h

@@ -0,0 +1,8 @@
+// Copyright 2026 Heer (@heer)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#define HAL_USE_I2C TRUE
+
+#include_next <halconf.h>

keyboards/heer_s1/heer_s1.c

@@ -0,0 +1,51 @@
+// Copyright 2026 Heer (@heer)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "quantum.h"
+
+#ifdef OLED_ENABLE
+
+// The panel is mounted upside-down on the PCB, so the rotation belongs to the
+// board rather than to any one keymap.
+//
+// This returns the rotation and nothing else. oled_driver.c does:
+//
+//     oled_rotation = oled_init_user(oled_init_kb(rotation));
+//
+// so the driver already chains the keymap's hook onto this one's result —
+// calling oled_init_user() from in here would run it twice.
+oled_rotation_t oled_init_kb(oled_rotation_t rotation) {
+    return OLED_ROTATION_180;
+}
+
+// A keymap that draws its own screen returns false from oled_task_user, which
+// stops the board's default display painting over it. This mirrors the weak
+// default in oled_driver.c, which is simply `return oled_task_user();`.
+bool oled_task_kb(void) {
+    if (!oled_task_user()) {
+        return false;
+    }
+
+    oled_set_cursor(0, 0);
+    oled_write_P(PSTR("   HEER  S1"), false);
+
+    oled_set_cursor(0, 1);
+    oled_write_P(PSTR("---------------"), false);
+
+    // Shown as a number, not a name: a board-level default cannot know what any
+    // given keymap calls its layers.
+    oled_set_cursor(0, 2);
+    oled_write_P(PSTR("LAYER "), false);
+    oled_write_char('0' + get_highest_layer(layer_state), false);
+
+    oled_set_cursor(0, 3);
+    oled_write_P(PSTR("["), false);
+    for (uint8_t i = 0; i < 4; i++) {
+        oled_write_P(get_highest_layer(layer_state) == i ? PSTR("*") : PSTR("-"), false);
+    }
+    oled_write_P(PSTR("]"), false);
+
+    return true;
+}
+
+#endif // OLED_ENABLE

keyboards/heer_s1/keyboard.json

@@ -0,0 +1,56 @@
+{
+    "manufacturer": "Heer Works",
+    "keyboard_name": "HEER S1",
+    "maintainer": "heer",
+    "bootloader": "rp2040",
+    "processor": "RP2040",
+    "usb": {
+        "vid": "0x4857",
+        "pid": "0x5331",
+        "device_version": "1.0.0"
+    },
+    "matrix_pins": {
+        "masked": true,
+        "cols": ["GP8", "GP9", "GP10", "GP11"],
+        "rows": ["GP4", "GP5", "GP6", "GP7", "GP2", "GP14"]
+    },
+    "diode_direction": "ROW2COL",
+    "encoder": {
+        "rotary": [
+            {"pin_a": "GP0", "pin_b": "GP1"},
+            {"pin_a": "GP12", "pin_b": "GP13"}
+        ]
+    },
+    "features": {
+        "bootmagic": true,
+        "encoder": true,
+        "extrakey": true,
+        "mousekey": true,
+        "nkro": true,
+        "oled": true
+    },
+    "layouts": {
+        "LAYOUT": {
+            "layout": [
+                {"matrix": [4, 0], "x": 0, "y": 0, "encoder": 0},
+                {"matrix": [5, 0], "x": 1, "y": 0, "encoder": 1},
+                {"matrix": [0, 0], "x": 0, "y": 1},
+                {"matrix": [0, 1], "x": 1, "y": 1},
+                {"matrix": [0, 2], "x": 2, "y": 1},
+                {"matrix": [0, 3], "x": 3, "y": 1},
+                {"matrix": [1, 0], "x": 0, "y": 2},
+                {"matrix": [1, 1], "x": 1, "y": 2},
+                {"matrix": [1, 2], "x": 2, "y": 2},
+                {"matrix": [1, 3], "x": 3, "y": 2},
+                {"matrix": [2, 0], "x": 0, "y": 3},
+                {"matrix": [2, 1], "x": 1, "y": 3},
+                {"matrix": [2, 2], "x": 2, "y": 3},
+                {"matrix": [2, 3], "x": 3, "y": 3},
+                {"matrix": [3, 0], "x": 0, "y": 4},
+                {"matrix": [3, 1], "x": 1, "y": 4},
+                {"matrix": [3, 2], "x": 2, "y": 4},
+                {"matrix": [3, 3], "x": 3, "y": 4}
+            ]
+        }
+    }
+}

keyboards/heer_s1/keymaps/default/keymap.c

@@ -0,0 +1,56 @@
+// Copyright 2026 Heer (@heer)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include QMK_KEYBOARD_H
+
+enum layers {
+    L_BASE,
+    L_MEDIA,
+    L_EDIT,
+    L_SYS,
+};
+
+// The bottom-right key advances to the next layer and wraps, so all four are
+// reachable using nothing but standard keycodes.
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+    [L_BASE] = LAYOUT(
+        TO(L_MEDIA), TO(L_BASE),
+        KC_1,    KC_2,    KC_3,    KC_4,
+        KC_5,    KC_6,    KC_7,    KC_8,
+        KC_9,    KC_0,    KC_MINS, KC_EQL,
+        KC_BSPC, KC_ENT,  KC_ESC,  TO(L_MEDIA)
+    ),
+
+    [L_MEDIA] = LAYOUT(
+        TO(L_EDIT), TO(L_BASE),
+        KC_MPLY, KC_MSTP, KC_MPRV, KC_MNXT,
+        KC_VOLD, KC_VOLU, KC_MUTE, _______,
+        KC_BRID, KC_BRIU, _______, _______,
+        _______, _______, _______, TO(L_EDIT)
+    ),
+
+    [L_EDIT] = LAYOUT(
+        TO(L_SYS), TO(L_BASE),
+        LCTL(KC_Z), LCTL(KC_X), LCTL(KC_C), LCTL(KC_V),
+        LCTL(KC_A), LCTL(KC_S), LCTL(KC_F), LCTL(KC_H),
+        LCTL(KC_N), LCTL(KC_W), LCTL(KC_T), LCTL(KC_P),
+        KC_DEL,     KC_HOME,    KC_END,     TO(L_SYS)
+    ),
+
+    [L_SYS] = LAYOUT(
+        TO(L_BASE), TO(L_BASE),
+        KC_F1,   KC_F2,   KC_F3,   KC_F4,
+        KC_F5,   KC_F6,   KC_F7,   KC_F8,
+        KC_F9,   KC_F10,  KC_F11,  KC_F12,
+        KC_PSCR, KC_SCRL, KC_PAUS, TO(L_BASE)
+    ),
+};
+
+#if defined(ENCODER_MAP_ENABLE)
+const uint16_t PROGMEM encoder_map[][NUM_ENCODERS][NUM_DIRECTIONS] = {
+    [L_BASE]  = { ENCODER_CCW_CW(KC_VOLD, KC_VOLU),       ENCODER_CCW_CW(KC_LEFT, KC_RGHT) },
+    [L_MEDIA] = { ENCODER_CCW_CW(KC_MPRV, KC_MNXT),       ENCODER_CCW_CW(KC_BRID, KC_BRIU) },
+    [L_EDIT]  = { ENCODER_CCW_CW(LCTL(KC_Z), LCTL(KC_Y)), ENCODER_CCW_CW(KC_UP,   KC_DOWN) },
+    [L_SYS]   = { ENCODER_CCW_CW(KC_F11,  KC_F12),        ENCODER_CCW_CW(KC_PGDN, KC_PGUP) },
+};
+#endif

keyboards/heer_s1/keymaps/default/rules.mk

@@ -0,0 +1 @@
+ENCODER_MAP_ENABLE = yes

keyboards/heer_s1/mcuconf.h

@@ -0,0 +1,9 @@
+// Copyright 2026 Heer (@heer)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include_next <mcuconf.h>
+
+#undef RP_I2C_USE_I2C0
+#define RP_I2C_USE_I2C0 TRUE

keyboards/heer_s1/readme.md

@@ -0,0 +1,27 @@
+# HEER S1
+
+![HEER S1](https://i.imgur.com/rSxQHUi.png)
+
+A 4x4 RP2040 macropad with two EC11 rotary encoders and a 128x64 SH1106 OLED.
+
+* Keyboard Maintainer: [Heer Electronics](https://github.com/heerelectronics)
+* Hardware Supported: HEER S1 PCB (RP2040 QFN-56)
+* Hardware Availability: https://www.heerelectronics.com
+
+Make example for this keyboard (after setting up your build environment):
+
+    make heer_s1:default
+
+Flashing example for this keyboard:
+
+    make heer_s1:default:flash
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
+
+## Bootloader
+
+Enter the bootloader in 3 ways:
+
+* **Bootmagic reset**: Hold down the key at (0,0) in the matrix (the top left key) and plug in the keyboard
+* **Physical reset button**: Briefly press the button on the back of the PCB
+* **Keycode in layout**: Press the key mapped to `QK_BOOT` (bottom row of the SYSTEM layer)