Patch to LCDproc-0.5.5 for use with common/Sainsmart/eBay HD44780+PCF8574 (I2C) 16x02 LCD modules.

hd44780-i2c.c.patch

--- hd44780-i2c.c.orig  2010-12-27 13:32:57.000000000 +0000
+++ lcdproc-0.5.5/server/drivers/hd44780-i2c.c  2014-04-17 14:10:24.455061114 +0000
@@ -76,10 +76,10 @@
 void i2c_HD44780_backlight(PrivateData *p, unsigned char state);
 void i2c_HD44780_close(PrivateData *p);

-#define RS     0x10
-#define RW     0x20
-#define EN     0x40
-#define BL     0x80
+#define RS     0x01
+#define RW     0x02
+#define EN     0x04
+#define BL     0x08
 // note that the above bits are all meant for the data port of PCF8574

 #define I2C_ADDR_MASK 0x7f
@@ -168,43 +168,43 @@
        // powerup the lcd now
        /* We'll now send 0x03 a couple of times,
         * which is in fact (FUNCSET | IF_8BIT) >> 4 */
-       i2c_out(p, 0x03);
+       i2c_out(p, 0x30);
        if (p->delayBus)
                hd44780_functions->uPause(p, 1);

-       i2c_out(p, enableLines | 0x03);
+       i2c_out(p, enableLines | 0x30);
        if (p->delayBus)
                hd44780_functions->uPause(p, 1);
-       i2c_out(p, 0x03);
+       i2c_out(p, 0x30);
        hd44780_functions->uPause(p, 15000);

-       i2c_out(p, enableLines | 0x03);
+       i2c_out(p, enableLines | 0x30);
        if (p->delayBus)
                hd44780_functions->uPause(p, 1);
-       i2c_out(p, 0x03);
+       i2c_out(p, 0x30);
        hd44780_functions->uPause(p, 5000);

-       i2c_out(p, enableLines | 0x03);
+       i2c_out(p, enableLines | 0x30);
        if (p->delayBus)
                hd44780_functions->uPause(p, 1);
-       i2c_out(p, 0x03);
+       i2c_out(p, 0x30);
        hd44780_functions->uPause(p, 100);

-       i2c_out(p, enableLines | 0x03);
+       i2c_out(p, enableLines | 0x30);
        if (p->delayBus)
                hd44780_functions->uPause(p, 1);
-       i2c_out(p, 0x03);
+       i2c_out(p, 0x30);
        hd44780_functions->uPause(p, 100);

        // now in 8-bit mode...  set 4-bit mode
-       i2c_out(p, 0x02);
+       i2c_out(p, 0x20);
        if (p->delayBus)
                hd44780_functions->uPause(p, 1);

-       i2c_out(p, enableLines | 0x02);
+       i2c_out(p, enableLines | 0x20);
        if (p->delayBus)
                hd44780_functions->uPause(p, 1);
-       i2c_out(p, 0x02);
+       i2c_out(p, 0x20);
        hd44780_functions->uPause(p, 100);

        // Set up two-line, small character (5x8) mode
@@ -240,8 +240,8 @@
 i2c_HD44780_senddata(PrivateData *p, unsigned char displayID, unsigned char flags, unsigned char ch)
 {
        unsigned char enableLines = 0, portControl = 0;
-       unsigned char h = (ch >> 4) & 0x0f;     // high and low nibbles
-       unsigned char l = ch & 0x0f;
+       unsigned char h = ch & 0xf0;     // high and low nibbles
+       unsigned char l = (ch << 4) & 0xf0;

        if (flags == RS_INSTR)
                portControl = 0;
@@ -277,7 +277,7 @@
  */
 void i2c_HD44780_backlight(PrivateData *p, unsigned char state)
 {
-       p->backlight_bit = ((!p->have_backlight||state) ? 0 : BL);
+       p->backlight_bit = ((p->have_backlight && state) ? BL : 0);

        i2c_out(p, p->backlight_bit);
 }