Use dynamic buffer everywhere

sys/arm-linux/examples/c-examples/u8g2_sw_i2c_thread/u8g2_sw_i2c_thread.c

@@ -26,16 +26,12 @@ void* do_display(void *arg) {
 	display_t disp = *((display_t*) arg);
 	pthread_t id = pthread_self();
 	uint8_t h, w, y1, y2;
-	uint8_t *buf;
 
 	printf("Thread %lu start\n", id);
 	u8g2_t u8g2;
 	// Initialization
 	u8g2_Setup_ssd1306_i2c_128x32_univision_f(&u8g2, U8G2_R0, u8x8_byte_sw_i2c,
 			u8x8_arm_linux_gpio_and_delay);
-	// We need unique buffer for each display in order to be thread friendly
-	buf = (uint8_t*)malloc(u8g2_GetBufferSize(&u8g2));
-	u8g2_SetBufferPtr(&u8g2, buf);
 	init_i2c_sw(&u8g2, disp.gpio_chip, disp.scl, disp.sda, disp.res,
 			disp.delay);
 	u8g2_InitDisplay(&u8g2);
@@ -54,7 +50,6 @@ void* do_display(void *arg) {
 	u8g2_SetPowerSave(&u8g2, 1);
 	// Close and deallocate GPIO resources
 	done_user_data(&u8g2);
-	free(buf);
 	printf("Thread %lu end\n", id);
 	return NULL;
 }

sys/arm-linux/port/U8g2lib.h

@@ -142,7 +142,8 @@ public:
 	}
 	void initSpiHw(uint8_t gpio_chip, uint8_t bus, uint8_t dc, uint8_t res,
 			uint8_t cs, unsigned int spi_mode, uint32_t max_speed) {
-		init_spi_hw_advanced(&u8g2, gpio_chip, bus, dc, res, cs, spi_mode, max_speed);
+		init_spi_hw_advanced(&u8g2, gpio_chip, bus, dc, res, cs, spi_mode,
+				max_speed);
 	}
 	void initSpiHw(uint8_t gpio_chip, uint8_t bus, uint8_t dc, uint8_t res,
 			uint8_t cs) {
@@ -209,15 +210,10 @@ public:
 	}
 
 	bool begin(void) {
-		/* note: call to u8x8_utf8_init is not required here, this is done in the setup procedures before */
-#ifndef U8G2_USE_DYNAMIC_ALLOC
 		initDisplay();
 		clearDisplay();
 		setPowerSave(0);
 		return 1;
-#else
-      return 0;
-      #endif
 	}
 
 	void beginSimple(void) {

sys/arm-linux/port/u8g2port.c

@@ -48,8 +48,12 @@ void sleep_ns(unsigned long nanoseconds) {
  * Allocate user_data_struct, set common values and set user_ptr.
  */
 user_data_t* init_user_data(u8g2_t *u8g2) {
-	// Dynamically allocate u8x8_buffer_struct
+	// Dynamically allocate user data_struct
 	user_data_t *user_data = (user_data_t*) malloc(sizeof(user_data_t));
+	// Dynamically allocate internal buffer
+	user_data->int_buf = (uint8_t*)malloc(u8g2_GetBufferSize(u8g2));
+	// We need a unique buffer for each display in order to be thread friendly
+	u8g2_SetBufferPtr(u8g2, user_data->int_buf);
 	for (int i = 0; i < U8X8_PIN_CNT; ++i) {
 		user_data->pins[i] = NULL;
 	}
@@ -124,12 +128,16 @@ void init_spi_sw(u8g2_t *u8g2, uint8_t gpio_chip, uint8_t dc, uint8_t res,
 void done_user_data(u8g2_t *u8g2) {
 	user_data_t *user_data = u8g2_GetUserPtr(u8g2);
 	if (user_data != NULL) {
+		// Close all GPIO pins
 		for (int i = 0; i < U8X8_PIN_CNT; ++i) {
 			if (user_data->pins[i] != NULL) {
 				gpio_close(user_data->pins[i]);
 				gpio_free(user_data->pins[i]);
 			}
 		}
+		// Free internal buffer
+		free(user_data->int_buf);
+		// Free user data struct
 		free(user_data);
 		u8g2_SetUserPtr(u8g2, NULL);
 	}

sys/arm-linux/port/u8g2port.h

@@ -28,7 +28,7 @@ struct user_data_struct {
 	uint8_t bus;
 	// Index into buffer
 	uint8_t index;
-	// Display buffer, I2C should send 32 bytes max and SPI 128 bytes max
+	// Callback buffer, I2C should send 32 bytes max and SPI 128 bytes max
 	uint8_t buffer[128];
 	// Nanosecond delay for U8X8_MSG_DELAY_I2C
 	unsigned long delay;
@@ -36,6 +36,8 @@ struct user_data_struct {
 	unsigned int spi_mode;
 	// SPI max speed
 	uint32_t max_speed;
+	// Internal buffer
+	uint8_t *int_buf;
 };
 
 typedef struct user_data_struct user_data_t;