Updated drivers

Author: himalayanelixir

README.md

@@ -3,3 +3,9 @@
 The CH341 and CH340 USB controllers are commonly found on 3rd party Arduinos and to use them with the Arduino IDE or CLI you need to install extra drivers.
 
 This repo contains the drivers for Windows, macOS, and Linux. Just download the repo and follow the instructions in the corresponding folder. If you have a previously installed a version of these USB drivers, you will likely need to uninstall them before installing the new ones.
+
+| OS      | Source URL                                          |
+|---------|-----------------------------------------------------|
+| Linux   | http://www.wch.cn/downloads/CH341SER_LINUX_ZIP.html |
+| macOS   | http://www.wch.cn/downloads/CH341SER_MAC_ZIP.html   |
+| Windows | http://www.wch.cn/download/CH341SER_EXE.html        |

linux/Makefile

@@ -329,29 +329,44 @@ static int set_control_lines( struct usb_serial *serial,
 }
 
 static int ch34x_get_baud_rate( unsigned int baud_rate,
-		unsigned char *a, unsigned char *b )
+		unsigned char *factor, unsigned char *divisor)
 {
-	unsigned long factor = 0;
-	short divisor = 0;
-
-	if( !baud_rate )
-		return -EINVAL;
-
-	factor = (CH34x_BAUDRATE_FACTOR / baud_rate);
-	divisor = CH34x_BAUDRATE_DIVMAX;
-
-	while( (factor > 0xfff0) && divisor ) {
-		factor >>= 3;
-		divisor --;
+	unsigned char a;
+	unsigned char b;
+	unsigned long c;
+
+	switch ( baud_rate ) {
+	case 921600: 
+		a = 0xf3; 
+		b = 7; 
+		break; 
+	case 307200:
+		a = 0xd9; 
+		b = 7; 
+		break; 
+	default: 
+		if ( baud_rate > 6000000/255 ) { 
+			b = 3;
+			c = 6000000;
+		} else if ( baud_rate > 750000/255 ) {  
+			b = 2;
+			c = 750000;
+		} else if (baud_rate > 93750/255) { 
+			b = 1;
+			c = 93750;
+		} else {
+			b = 0;
+			c = 11719;
+		}
+		a = (unsigned char)(c / baud_rate);
+		if (a == 0 || a == 0xFF) return -EINVAL;
+		if ((c / a - baud_rate) > (baud_rate - c / (a + 1))) 
+			a ++;
+		a = 256 - a;
+		break;
 	}
-
-	if( factor > 0xfff0 )
-		return -EINVAL;
-
-	factor = 0x10000 - factor;
-	*a = (factor & 0xff00) >> 8;
-	*b = divisor;
-
+	*factor = a;
+	*divisor = b;
 	return 0;
 }
 
@@ -443,15 +458,25 @@ static void ch34x_set_termios( struct usb_serial_port *port,
 		dbg_ch34x("%s - stop bits = 1", __func__);
 
 	// Determine the parity
-	if( cflag & PARENB )
-		if( cflag & PARODD ) {
-			reg_value |= (0x08 | 0x00);
-			dbg_ch34x("%s - parity = odd", __func__);
-		}
-		else {
-			reg_value |= (0x08 | 0x10);
-			dbg_ch34x("%s - parity = even", __func__);
+	if (cflag & PARENB) {
+		if (cflag & CMSPAR) {
+			if (cflag & PARODD) {
+    			reg_value |= (0x28 | 0x00);
+    			dbg_ch34x("%s - parity = mark", __func__);
+			} else {
+    			reg_value |= (0x38 | 0x10);
+    			dbg_ch34x("%s - parity = space", __func__);
+			}
+		} else {
+			if (cflag & PARODD) {
+    			reg_value |= (0x08 | 0x00);
+    			dbg_ch34x("%s - parity = odd", __func__);
+			} else {
+    			reg_value |= (0x18 | 0x10);
+    			dbg_ch34x("%s - parity = even", __func__);
+			}
 		}
+	}
 	else
 		dbg_ch34x("%s - parity = none", __func__);