drv_HD44780: add 8bit i2c mode for HD44780 by Michael Grzeschik <m.grzeschik@pengutronix.de>

git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@1202 3ae390bd-cb1e-0410-b409-cd5a39f66f1f

drv_HD44780.c

@@ -706,10 +706,10 @@ static void drv_HD_PP_stop(void)
 
      */
 
-static void drv_HD_I2C_nibble(unsigned char controller, unsigned char nibble)
+static void drv_HD_I2C(unsigned char controller, unsigned char byte, int rs, int rw)
 {
     unsigned char enable;
-    unsigned char command;	/* this is actually the first data byte on the PCF8574 */
+    unsigned char command = 0;	/* this is actually the first data byte on the PCF8574 */
     unsigned char data_block[2];
     /* enable signal: 'controller' is a bitmask */
     /* bit n .. send to controller #n */
@@ -738,28 +738,51 @@ static void drv_HD_I2C_nibble(unsigned char controller, unsigned char nibble)
        The main advantage we see is that we do 2 less IOCTL's from our driver.
      */
 
-    command = nibble;
-    data_block[0] = nibble | enable;
-    data_block[1] = nibble;
+    if (Bits == 4) {
+	if (rw)
+	    byte |= SIGNAL_RW;
+	if (rs)
+	    byte |= SIGNAL_RS;
+	command = byte;
+	data_block[0] = byte | enable;
+	data_block[1] = byte;
 
-    drv_generic_i2c_command(command, data_block, 2);
+    } else if (Bits == 8) {
+	if (rw)
+	    command |= SIGNAL_RW;
+	if (rs)
+	    command |= SIGNAL_RS;
+
+	data_block[0] = byte;
+	data_block[1] = enable;
+    }
+
+    drv_generic_i2c_command(command, data_block, 2, Bits);
 }
 
 
 static void drv_HD_I2C_byte(const unsigned char controller, const unsigned char data)
 {
     /* send data with RS enabled */
-    drv_HD_I2C_nibble(controller, ((data >> 4) & 0x0f) | SIGNAL_RS);
-    drv_HD_I2C_nibble(controller, (data & 0x0f) | SIGNAL_RS);
+    if (Bits == 4) {
+	drv_HD_I2C(controller, ((data >> 4) & 0x0f), 1, 0);
+	drv_HD_I2C(controller, (data & 0x0f), 1, 0);
+    } else if (Bits == 8) {
+	drv_HD_I2C(controller, data, 1, 0);
+    }
 }
 
 
 static void drv_HD_I2C_command(const unsigned char controller, const unsigned char cmd, __attribute__ ((unused))
 			       const unsigned long delay)
 {
-    /* send data with RS disabled */
-    drv_HD_I2C_nibble(controller, ((cmd >> 4) & 0x0f));
-    drv_HD_I2C_nibble(controller, ((cmd) & 0x0f));
+    /* send command data with RS disabled */
+    if (Bits == 4) {
+	drv_HD_I2C(controller, ((cmd >> 4) & 0x0f), 0, 0);
+	drv_HD_I2C(controller, ((cmd) & 0x0f), 0, 0);
+    } else if (Bits == 8) {
+	drv_HD_I2C(controller, cmd, 0, 0);
+    }
 }
 
 static void drv_HD_I2C_data(const unsigned char controller, const char *string, const int len, __attribute__ ((unused))
@@ -781,13 +804,14 @@ static int drv_HD_I2C_load(const char *section)
 {
     if (cfg_number(section, "Bits", 8, 4, 8, &Bits) < 0)
 	return -1;
-    if (Bits != 4) {
-	error("%s: bad %s.Bits '%d' from %s, should be '4'", Name, section, Bits, cfg_source());
-	return -1;
-    }
 
     info("%s: using %d bit mode", Name, Bits);
 
+    if (Bits != 4 && Bits != 8) {
+	error("%s: bad %s.Bits '%d' from %s, should be '4' or '8'", Name, section, Bits, cfg_source());
+	return -1;
+    }
+
     if (drv_generic_i2c_open(section, Name) != 0) {
 	error("%s: could not initialize i2c attached device!", Name);
 	return -1;
@@ -804,16 +828,24 @@ static int drv_HD_I2C_load(const char *section)
     if ((SIGNAL_GPO = drv_generic_i2c_wire("GPO", "GND")) == 0xff)
 	return -1;
 
-    /* initialize display */
-    drv_HD_I2C_nibble(allControllers, 0x03);
-    udelay(T_INIT1);		/* 4 Bit mode, wait 4.1 ms */
-    drv_HD_I2C_nibble(allControllers, 0x03);
-    udelay(T_INIT2);		/* 4 Bit mode, wait 100 us */
-    drv_HD_I2C_nibble(allControllers, 0x03);
-    udelay(T_INIT1);		/* 4 Bit mode, wait 4.1 ms */
-    drv_HD_I2C_nibble(allControllers, 0x02);
-    udelay(T_INIT2);		/* 4 Bit mode, wait 100 us */
-    drv_HD_I2C_command(allControllers, 0x28, T_EXEC);	/* 4 Bit mode, 1/16 duty cycle, 5x8 font */
+    if (Bits == 4) {
+	/* initialize display */
+	drv_HD_I2C(allControllers, 0x02, 0, 0);
+	udelay(T_INIT1);	/* 4 Bit mode, wait 4.1 ms */
+	drv_HD_I2C(allControllers, 0x03, 0, 0);
+	udelay(T_INIT2);	/* 4 Bit mode, wait 100 us */
+	drv_HD_I2C(allControllers, 0x03, 0, 0);
+	udelay(T_INIT1);	/* 4 Bit mode, wait 4.1 ms */
+	drv_HD_I2C(allControllers, 0x02, 0, 0);
+	udelay(T_INIT2);	/* 4 Bit mode, wait 100 us */
+	drv_HD_I2C_command(allControllers, 0x28, T_EXEC);	/* 4 Bit mode, 1/16 duty cycle, 5x8 font */
+    } else if (Bits == 8) {
+	drv_HD_I2C(allControllers, 0x30, 0, 0);	/* 8 Bit mode, wait 4.1 ms */
+	udelay(T_INIT1);	/* 8 Bit mode, wait 4.1 ms */
+	drv_HD_I2C(allControllers, 0x30, 0, 0);	/* 8 Bit mode, wait 100 us */
+	udelay(T_INIT2);	/* 8 Bit mode, wait 4.1 ms */
+	drv_HD_I2C_command(allControllers, 0x38, T_EXEC);	/* 8 Bit mode, 1/16 duty cycle, 5x8 font */
+    }
 
     info("%s: I2C initialization done", Name);
 

drv_generic_i2c.c

@@ -62,7 +62,8 @@
 static char *Driver = "";
 static char *Section = "";
 static int i2c_device;
-
+static int ctrldev;
+static int datadev;
 
 static void my_i2c_smbus_write_byte_data(const int device, const unsigned char val)
 {
@@ -91,33 +92,49 @@ static void my_i2c_smbus_read_byte_data(const int device, const unsigned char da
 }
 #endif
 
+int drv_generic_i2c_pre_write(int dev)
+{
+
+    info("%s: selecting slave device 0x%x", Driver, dev);
+    if (ioctl(i2c_device, I2C_SLAVE, dev) < 0) {
+	error("%s: error selecting slave device 0x%x\n", Driver, dev);
+	return -EPIPE;
+    }
+
+    info("%s: initializing I2C slave device 0x%x for output", Driver, dev);
+    if (i2c_smbus_write_byte_data(i2c_device, 3, 0) < 0) {
+	error("%s: error initializing device 0x%x\n", Driver, dev);
+	close(i2c_device);
+    }
+
+    return 0;
+}
 
 int drv_generic_i2c_open(const char *section, const char *driver)
 {
-    int dev;
     char *bus, *device;
     udelay_init();
     Section = (char *) section;
     Driver = (char *) driver;
     bus = cfg_get(Section, "Port", NULL);
     device = cfg_get(Section, "Device", NULL);
-    dev = atoi(device);
+    ctrldev = atoi(device);
+    device = cfg_get(Section, "DDevice", NULL);
+    datadev = atoi(device);
+
     info("%s: initializing I2C bus %s", Driver, bus);
     if ((i2c_device = open(bus, O_WRONLY)) < 0) {
 	error("%s: I2C bus %s open failed !\n", Driver, bus);
 	goto exit_error;
     }
-    info("%s: selecting slave device 0x%x", Driver, dev);
-    if (ioctl(i2c_device, I2C_SLAVE, dev) < 0) {
-	error("%s: error selecting slave device 0x%x\n", Driver, dev);
-	goto exit_error;
+
+    if (datadev) {
+	if (drv_generic_i2c_pre_write(datadev) < 0)
+	    goto exit_error;
     }
 
-    info("%s: initializing I2C slave device 0x%x", Driver, dev);
-    if (i2c_smbus_write_quick(i2c_device, I2C_SMBUS_WRITE) < 0) {
-	error("%s: error initializing device 0x%x\n", Driver, dev);
-	close(i2c_device);
-    }
+    if (drv_generic_i2c_pre_write(ctrldev) < 0)
+	goto exit_error;
 
     return 0;
 
@@ -172,8 +189,30 @@ void drv_generic_i2c_data(const unsigned char data)
     my_i2c_smbus_write_byte_data(i2c_device, data);
 }
 
-
-void drv_generic_i2c_command(const unsigned char command, /*const */ unsigned char *data, const unsigned char length)
+static void i2c_out(int dev, unsigned char val)
 {
-    i2c_smbus_write_block_data(i2c_device, command, length, data);
+    info("%s: initializing I2C slave device 0x%x", Driver, dev);
+    if (ioctl(i2c_device, I2C_SLAVE, dev) < 0) {
+	error("%s: error selecting slave device 0x%x\n", Driver, dev);
+	return;
+    }
+
+    i2c_smbus_write_byte_data(i2c_device, 1, val);
+}
+
+void drv_generic_i2c_command(const unsigned char command, /*const */ unsigned char *data, const unsigned char length,
+			     int bits)
+{
+    if (bits == 4) {
+	i2c_smbus_write_block_data(i2c_device, command, length, data);
+    } else if (bits == 8 && datadev) {
+	/* set data on pins */
+	info("cmd: %08x, data0: %08x, data1: %08x\n", command, data[0], data[1]);
+	i2c_out(datadev, data[0]);
+	/* set enable pin including optional rs and rw */
+	i2c_out(ctrldev, command | data[1]);
+	/* unset enable pin including optional rs and rw */
+	i2c_out(ctrldev, command);
+    }
+
 }

drv_generic_i2c.h

@@ -57,6 +57,7 @@ int drv_generic_i2c_close(void);
 unsigned char drv_generic_i2c_wire(const char *name, const char *deflt);
 void drv_generic_i2c_byte(const unsigned char data);
 void drv_generic_i2c_data(const unsigned char data);
-void drv_generic_i2c_command(const unsigned char command, /*const */ unsigned char *data, const unsigned char length);
+void drv_generic_i2c_command(const unsigned char command, /*const */ unsigned char *data, const unsigned char length,
+			     int bits);
 
 #endif