From 557a642a8da0ec888e8250980a683cce901c93c1 Mon Sep 17 00:00:00 2001
From: Jesper <jesper@handskemager.xyz>
Date: Tue, 7 Nov 2023 15:05:51 +0100
Subject: [PATCH] Intitial commit

---
 grove_lcd.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 grove_lcd.c

diff --git a/grove_lcd.c b/grove_lcd.c
new file mode 100644
index 0000000..0545ab0
--- /dev/null
+++ b/grove_lcd.c
@@ -0,0 +1,114 @@
+#include <errno.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdint.h>
+#include <linux/i2c-dev.h>
+#include <i2c/smbus.h>
+#include <getopt.h>
+
+//Device specific information. (Perhaps better as command options or config file)
+#define MPC9808_BUS     "/dev/i2c-2"
+#define DISPLAY_RGB_ADDR 0x62
+#define DISPLAY_TEXT_ADDR 0x3e
+
+void init_display(int file) {
+    // Function set 0010 1000 // 2 line mode and 5x8
+	i2c_smbus_write_byte_data(file, 0x00, 0x28);
+    // Display on/off control 0000 1110 // Diplay on; cursor off; blink off
+	i2c_smbus_write_byte_data(file, 0x00, 0x0C);
+    // Clear display
+	i2c_smbus_write_byte_data(file, 0x00, 0x01);
+	i2c_smbus_write_byte_data(file, 0x00, 0x06);
+    
+	i2c_smbus_write_byte_data(file, 0x00, 0x02);
+	i2c_smbus_write_byte_data(file, 0x00, 0x84);
+}
+
+void clear_display(int file) {
+	i2c_smbus_write_byte_data(file, 0x00, 0x01);
+}
+
+void write_to_display_xy(int file, int x, int y, char* message) {
+	int line;
+	if(x > 16) {
+        fprintf(stderr, "Invalid line position");
+		return;
+    }
+	if(y == 1)
+		line = 0x80; // first line (1000 0000 to 1000 1111 possible on 16 characters line) = 0x80 to 0x8f
+	else if(y == 2)
+		line = 0xC0; // second  line (1100 0000 to 1100 1111 possible on 16 characters line) = 0xC0 to 0xCf
+	else {
+        fprintf(stderr, "Invalid line position");
+		return;
+    }
+	line += x-1;
+
+	i2c_smbus_write_byte_data(file, 0x00, line);
+	while (*message != 0) {
+		i2c_smbus_write_byte_data(file, 0x40, *message);
+		message++;
+	}
+}
+
+int i2c_init(char *bus, unsigned int address) {
+        int file;
+
+        file = open(bus, O_RDWR);
+        if (file < 0) { // If error
+                fprintf(stderr, "ERROR: opening %s - %s\n", bus, strerror(errno));
+                exit(1);
+        }
+
+        if (ioctl(file, I2C_SLAVE, address) == -1 ) { // If error
+             fprintf(stderr, "ERROR: setting  address %d on i2c bus %s with ioctl() - %s", address, bus, strerror(errno) );
+             exit(1);
+        }
+        return(file);
+}
+
+void set_backlight(int r, int g, int b) {
+	int file;
+	file = i2c_init(MPC9808_BUS, DISPLAY_RGB_ADDR);
+	i2c_smbus_write_byte_data(file, 0, 0);
+	i2c_smbus_write_byte_data(file, 1, 0);
+	i2c_smbus_write_byte_data(file, 0x08,0xaa);
+
+	i2c_smbus_write_byte_data(file, 4, r);
+	i2c_smbus_write_byte_data(file, 3, g);
+	i2c_smbus_write_byte_data(file, 2, b);
+}
+
+int main(int argc, char *argv[]) {
+    int l1p = 1;
+    int l2p = 1;
+    int option;
+
+    while ((option = getopt (argc, argv, "l1:l2:")) != -1) {
+       switch (option) {
+        case '1':
+           l1p = atoi(optarg);
+           break;
+        case '2':
+            l2p = atoi(optarg);
+            break;
+        default:
+            fprintf(stderr, "Usage: %s -l1 <value> -l2 <value>\n", argv[0]);
+            exit(EXIT_FAILURE);
+        }
+    }
+
+    printf("l1p = %d, l2p = %d\n", l1p, l2p);
+
+	int file;
+    set_backlight(1, 0, 0);
+	file = i2c_init(MPC9808_BUS, DISPLAY_TEXT_ADDR);
+	init_display(file);
+    write_to_display_xy(file, l1p, 1, "Mercantec");
+    write_to_display_xy(file, l2p, 2, "Mercantec");
+	return 0;
+}