diff --git a/st7567/st7567-common.h b/st7567/st7567-common.h
index c6afca5..e9d3af5 100644
--- a/st7567/st7567-common.h
+++ b/st7567/st7567-common.h
@@ -27,6 +27,18 @@
 #define ST7567_CMD_STATIC_INDICATOR_OFF 0xAC
 #define ST7567_CMD_NOP               0xE3
 
+// Display dimensions
+#define ST7567_WIDTH  128
+#define ST7567_HEIGHT 64
+#define ST7567_PAGES  (ST7567_HEIGHT / 8)
+
+
+typedef struct {
+    void* bus;
+    gpio_num_t dc_gpio;
+    uint8_t framebuffer[ST7567_WIDTH * ST7567_PAGES];
+} st7567_device_t;
+
 /**
  * @brief Send a single command byte to the ST7567
  *
diff --git a/st7567/st7567-i2c.h b/st7567/st7567-i2c.h
index 85e95ea..5989dfe 100644
--- a/st7567/st7567-i2c.h
+++ b/st7567/st7567-i2c.h
@@ -17,12 +17,6 @@ typedef struct {
     uint8_t contrast;                 // 0-63, 0 = use a sane default (0x20)
 } st7567_i2c_config_t;
 
-// Handle for ST7567 device
-typedef struct {
-    i2c_master_dev_handle_t i2c_dev;
-    uint8_t framebuffer[ST7567_WIDTH * ST7567_PAGES];
-} st7567_device_t;
-
 /**
  * @brief Initialize ST7567 display
  *
diff --git a/st7567/st7567-spi.h b/st7567/st7567-spi.h
index 6a3c8a0..1952e44 100644
--- a/st7567/st7567-spi.h
+++ b/st7567/st7567-spi.h
@@ -5,11 +5,6 @@
 #include "driver/spi_master.h"
 #include "driver/gpio.h"
 
-// Display dimensions
-#define ST7567_WIDTH  128
-#define ST7567_HEIGHT 64
-#define ST7567_PAGES  (ST7567_HEIGHT / 8)
-
 // Configuration structure
 typedef struct {
     spi_host_device_t spi_host;       // already-initialized SPI bus (spi_bus_initialize called by caller)
@@ -20,12 +15,6 @@ typedef struct {
     uint8_t contrast;                  // 0-63, 0 = use a sane default (0x20)
 } st7567_spi_config_t;
 
-// Handle for ST7567 device
-typedef struct {
-    spi_device_handle_t spi_dev;
-    gpio_num_t dc_gpio;
-    uint8_t framebuffer[ST7567_WIDTH * ST7567_PAGES];
-} st7567_device_t;
 
 /**
  * @brief Initialize ST7567 display
diff --git a/st7567/st7567.c b/st7567/st7567.c
index 4dc6984..48ea96f 100644
--- a/st7567/st7567.c
+++ b/st7567/st7567.c
@@ -22,15 +22,15 @@ static esp_err_t st7567_write(const st7567_device_t *dev, uint8_t ctrl, const ui
 
     buf[0] = ctrl;
     memcpy(&buf[1], data, len);
-    return i2c_master_transmit(dev->i2c_dev, buf, len + 1, ST7567_I2C_TIMEOUT_MS);
+    return i2c_master_transmit(dev->bus, buf, len + 1, ST7567_I2C_TIMEOUT_MS);
 }
 
 esp_err_t st7567_send_cmd(const st7567_device_t *dev, const uint8_t cmd) {
-    return st7567_i2c_write(dev, ST7567_I2C_CTRL_CMD, &cmd, 1);
+    return st7567_write(dev, ST7567_I2C_CTRL_CMD, &cmd, 1);
 }
 
 esp_err_t st7567_send_data(const st7567_device_t *dev, const uint8_t *data, size_t len) {
-    return st7567_i2c_write(dev, ST7567_I2C_CTRL_DATA, data, len);
+    return st7567_write(dev, ST7567_I2C_CTRL_DATA, data, len);
 }
 
 
@@ -95,16 +95,16 @@ static esp_err_t st7567_write(const st7567_device_t *dev, int dc_level, const ui
 
     // blocking polling transmit: this driver is only ever called from one task
     // (ui_task), so there's no need for the queued/async SPI API here
-    return spi_device_polling_transmit(dev->spi_dev, &t);
+    return spi_device_polling_transmit(dev->bus, &t);
 }
 
 
 esp_err_t st7567_send_cmd(const st7567_device_t *dev, const uint8_t cmd) {
-    return st7567_spi_write(dev, ST7567_DC_CMD, &cmd, 1);
+    return st7567_write(dev, ST7567_DC_CMD, &cmd, 1);
 }
 
 esp_err_t st7567_send_data(const st7567_device_t *dev, const uint8_t *data, size_t len) {
-    return st7567_spi_write(dev, ST7567_DC_DATA, data, len);
+    return st7567_write(dev, ST7567_DC_DATA, data, len);
 }