patch-2.1.94 linux/drivers/char/i2c.c

• Lines: 431
• Date: Wed Apr 8 17:24:48 1998
• Orig file: v2.1.93/linux/drivers/char/i2c.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.93/linux/drivers/char/i2c.c linux/drivers/char/i2c.c
@@ -0,0 +1,430 @@
+/*
+ *	Generic i2c interface for linux
+ *
+ *	(c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/locks.h>
+#include <linux/sched.h>
+#include <linux/malloc.h>
+
+#include "i2c.h"
+
+#define REGPRINT(x)   if (verbose)   (x)
+#define I2C_DEBUG(x)  if (i2c_debug) (x)
+
+static int scan      = 0;
+static int verbose   = 1;
+static int i2c_debug = 0;
+
+MODULE_PARM(scan,"i");
+MODULE_PARM(verbose,"i");
+MODULE_PARM(i2c_debug,"i");
+
+/* ----------------------------------------------------------------------- */
+
+static struct i2c_bus    *busses[I2C_BUS_MAX];
+static struct i2c_driver *drivers[I2C_DRIVER_MAX];
+static int bus_count = 0, driver_count = 0;
+
+int i2c_init(void)
+{
+	printk(KERN_INFO "i2c: initialized%s\n",
+		scan ? " (i2c bus scan enabled)" : "");
+	/* anything to do here ? */
+	return 0;
+}
+
+/* ----------------------------------------------------------------------- */
+
+static void i2c_attach_device(struct i2c_bus *bus, struct i2c_driver *driver)
+{
+	unsigned long flags;
+	struct i2c_device *device;
+	int i,j,ack=1;
+	unsigned char addr;
+    
+	/* probe for device */
+	LOCK_I2C_BUS(bus);
+	for (addr = driver->addr_l; addr <= driver->addr_h; addr += 2) 
+	{
+		i2c_start(bus);
+		ack = i2c_sendbyte(bus,addr,0);
+		i2c_stop(bus);
+		if (!ack)
+			break;
+	}
+	UNLOCK_I2C_BUS(bus);
+	if (ack)
+		return;
+
+	/* got answer */
+	for (i = 0; i < I2C_DEVICE_MAX; i++)
+		if (NULL == driver->devices[i])
+			break;
+	if (I2C_DEVICE_MAX == i)
+		return;
+
+	for (j = 0; j < I2C_DEVICE_MAX; j++)
+		if (NULL == bus->devices[j])
+			break;
+	if (I2C_DEVICE_MAX == j)
+		return;
+
+	if (NULL == (device = kmalloc(sizeof(struct i2c_device),GFP_KERNEL)))
+		return;
+	device->bus = bus;
+	device->driver = driver;
+	device->addr = addr;
+
+	/* Attach */
+	
+	if (driver->attach(device)!=0) 
+	{
+		kfree(device);
+		return;
+	}
+	driver->devices[i] = device;
+	driver->devcount++;
+	bus->devices[j] = device;
+	bus->devcount++;
+
+	if (bus->attach_inform)
+		bus->attach_inform(bus,driver->id);
+	REGPRINT(printk("i2c: device attached: %s (addr=0x%02x, bus=%s, driver=%s)\n",device->name,addr,bus->name,driver->name));
+}
+
+static void i2c_detach_device(struct i2c_device *device)
+{
+	int i;
+
+	if (device->bus->detach_inform)
+		device->bus->detach_inform(device->bus,device->driver->id);
+	device->driver->detach(device);
+
+	for (i = 0; i < I2C_DEVICE_MAX; i++)
+		if (device == device->driver->devices[i])
+			break;
+	if (I2C_DEVICE_MAX == i) 
+	{
+		printk(KERN_WARNING "i2c: detach_device #1: device not found: %s\n",
+			device->name);
+		return;
+	}
+	device->driver->devices[i] = NULL;
+	device->driver->devcount--;
+
+	for (i = 0; i < I2C_DEVICE_MAX; i++)
+		if (device == device->bus->devices[i])
+			break;
+	if (I2C_DEVICE_MAX == i) 
+	{
+		printk(KERN_WARNING "i2c: detach_device #2: device not found: %s\n",
+		       device->name);
+		return;
+	}
+	device->bus->devices[i] = NULL;
+	device->bus->devcount--;
+
+	REGPRINT(printk("i2c: device detached: %s (addr=0x%02x, bus=%s, driver=%s)\n",device->name,device->addr,device->bus->name,device->driver->name));
+	kfree(device);
+}
+
+/* ----------------------------------------------------------------------- */
+
+int i2c_register_bus(struct i2c_bus *bus)
+{
+	unsigned long flags;
+	int i,ack;
+
+	memset(bus->devices,0,sizeof(bus->devices));
+	bus->devcount = 0;
+
+	for (i = 0; i < I2C_BUS_MAX; i++)
+		if (NULL == busses[i])
+			break;
+	if (I2C_BUS_MAX == i)
+		return -ENOMEM;
+
+	busses[i] = bus;
+	bus_count++;
+	REGPRINT(printk("i2c: bus registered: %s\n",bus->name));
+	
+	MOD_INC_USE_COUNT;
+
+	if (scan) 
+	{
+		/* scan whole i2c bus */
+		LOCK_I2C_BUS(bus);
+		for (i = 0; i < 256; i+=2) 
+		{
+			i2c_start(bus);
+			ack = i2c_sendbyte(bus,i,0);
+			i2c_stop(bus);
+			if (!ack) 
+			{
+				printk(KERN_INFO "i2c: scanning bus %s: found device at addr=0x%02x\n",
+					bus->name,i);
+			}
+		}
+		UNLOCK_I2C_BUS(bus);
+	}
+
+	/* probe available drivers */
+	for (i = 0; i < I2C_DRIVER_MAX; i++)
+		if (drivers[i])
+			i2c_attach_device(bus,drivers[i]);
+	return 0;
+}
+
+int i2c_unregister_bus(struct i2c_bus *bus)
+{
+	int i;
+
+	/* detach devices */
+	for (i = 0; i < I2C_DEVICE_MAX; i++)
+		if (bus->devices[i])
+			i2c_detach_device(bus->devices[i]);
+
+	for (i = 0; i < I2C_BUS_MAX; i++)
+		if (bus == busses[i])
+			break;
+	if (I2C_BUS_MAX == i) 
+	{
+		printk(KERN_WARNING "i2c: unregister_bus #1: bus not found: %s\n",
+			bus->name);
+		return -ENODEV;
+	}
+	
+	MOD_DEC_USE_COUNT;
+	
+	busses[i] = NULL;
+	bus_count--;
+	REGPRINT(printk("i2c: bus unregistered: %s\n",bus->name));
+
+	return 0;    
+}
+
+/* ----------------------------------------------------------------------- */
+
+int i2c_register_driver(struct i2c_driver *driver)
+{
+	int i;
+
+	memset(driver->devices,0,sizeof(driver->devices));
+	driver->devcount = 0;
+
+	for (i = 0; i < I2C_DRIVER_MAX; i++)
+		if (NULL == drivers[i])
+			break;
+	if (I2C_DRIVER_MAX == i)
+		return -ENOMEM;
+
+	drivers[i] = driver;
+	driver_count++;
+	
+	MOD_INC_USE_COUNT;
+	
+	REGPRINT(printk("i2c: driver registered: %s\n",driver->name));
+
+	/* Probe available busses */
+	for (i = 0; i < I2C_BUS_MAX; i++)
+		if (busses[i])
+			i2c_attach_device(busses[i],driver);
+
+	return 0;
+}
+
+int i2c_unregister_driver(struct i2c_driver *driver)
+{
+	int i;
+
+	/* detach devices */
+	for (i = 0; i < I2C_DEVICE_MAX; i++)
+		if (driver->devices[i])
+			i2c_detach_device(driver->devices[i]);
+
+	for (i = 0; i < I2C_DRIVER_MAX; i++)
+		if (driver == drivers[i])
+			break;
+	if (I2C_DRIVER_MAX == i) 
+	{
+		printk(KERN_WARNING "i2c: unregister_driver: driver not found: %s\n",
+			driver->name);
+		return -ENODEV;
+	}
+
+	MOD_DEC_USE_COUNT;
+	
+	drivers[i] = NULL;
+	driver_count--;
+	REGPRINT(printk("i2c: driver unregistered: %s\n",driver->name));
+
+	return 0;
+}
+
+/* ----------------------------------------------------------------------- */
+
+int i2c_control_device(struct i2c_bus *bus, int id,
+		       unsigned int cmd, void *arg)
+{
+	int i;
+
+	for (i = 0; i < I2C_DEVICE_MAX; i++)
+		if (bus->devices[i] && bus->devices[i]->driver->id == id)
+			break;
+	if (i == I2C_DEVICE_MAX)
+		return -ENODEV;
+	if (NULL == bus->devices[i]->driver->command)
+		return -ENODEV;
+	return bus->devices[i]->driver->command(bus->devices[i],cmd,arg);
+}
+
+/* ----------------------------------------------------------------------- */
+
+#define I2C_SET(bus,ctrl,data)  (bus->i2c_setlines(bus,ctrl,data))
+#define I2C_GET(bus)            (bus->i2c_getdataline(bus))
+
+void i2c_start(struct i2c_bus *bus)
+{
+	I2C_SET(bus,0,1);
+	I2C_SET(bus,1,1);
+	I2C_SET(bus,1,0);
+	I2C_SET(bus,0,0);
+	I2C_DEBUG(printk("%s: < ",bus->name));
+}
+
+void i2c_stop(struct i2c_bus *bus)
+{
+	I2C_SET(bus,0,0);
+	I2C_SET(bus,1,0);
+	I2C_SET(bus,1,1);
+	I2C_DEBUG(printk(">\n"));
+}
+
+void i2c_one(struct i2c_bus *bus)
+{
+	I2C_SET(bus,0,1);
+	I2C_SET(bus,1,1);
+	I2C_SET(bus,0,1);
+}
+
+void i2c_zero(struct i2c_bus *bus)
+{
+	I2C_SET(bus,0,0);
+	I2C_SET(bus,1,0);
+	I2C_SET(bus,0,0);
+}
+
+int i2c_ack(struct i2c_bus *bus)
+{
+	int ack;
+    
+	I2C_SET(bus,0,1);
+	I2C_SET(bus,1,1);
+	ack = I2C_GET(bus);
+	I2C_SET(bus,0,1);
+	return ack;
+}
+
+int i2c_sendbyte(struct i2c_bus *bus,unsigned char data,int wait_for_ack)
+{
+	int i, ack;
+    
+	I2C_SET(bus,0,0);
+	for (i=7; i>=0; i--)
+		(data&(1<<i)) ? i2c_one(bus) : i2c_zero(bus);
+	if (wait_for_ack)
+		udelay(wait_for_ack);
+	ack=i2c_ack(bus);
+	I2C_DEBUG(printk("%02x%c ",(int)data,ack?'-':'+'));
+	return ack;
+}
+
+unsigned char i2c_readbyte(struct i2c_bus *bus,int last)
+{
+	int i;
+	unsigned char data=0;
+    
+	I2C_SET(bus,0,1);
+	for (i=7; i>=0; i--) 
+	{
+		I2C_SET(bus,1,1);
+		if (I2C_GET(bus))
+			data |= (1<<i);
+		I2C_SET(bus,0,1);
+	}
+	last ? i2c_one(bus) : i2c_zero(bus);
+	I2C_DEBUG(printk("=%02x%c ",(int)data,last?'-':'+'));
+	return data;
+}
+
+/* ----------------------------------------------------------------------- */
+
+int i2c_read(struct i2c_bus *bus, unsigned char addr)
+{
+	int ret;
+    
+	if (bus->i2c_read)
+		return bus->i2c_read(bus, addr);
+
+	i2c_start(bus);
+	i2c_sendbyte(bus,addr,0);
+	ret = i2c_readbyte(bus,1);
+	i2c_stop(bus);
+	return ret;
+}
+
+int i2c_write(struct i2c_bus *bus, unsigned char addr,
+	      unsigned char data1, unsigned char data2, int both)
+{
+	int ack;
+
+	if (bus->i2c_write)
+		return bus->i2c_write(bus, addr, data1, data2, both);
+
+	i2c_start(bus);
+	i2c_sendbyte(bus,addr,0);
+	ack = i2c_sendbyte(bus,data1,0);
+	if (both)
+		ack = i2c_sendbyte(bus,data2,0);
+	i2c_stop(bus);
+	return ack ? -1 : 0 ;
+}
+
+/* ----------------------------------------------------------------------- */
+
+#ifdef MODULE
+
+EXPORT_SYMBOL(i2c_register_bus);
+EXPORT_SYMBOL(i2c_unregister_bus);
+EXPORT_SYMBOL(i2c_register_driver);
+EXPORT_SYMBOL(i2c_unregister_driver);
+EXPORT_SYMBOL(i2c_control_device);
+EXPORT_SYMBOL(i2c_start);
+EXPORT_SYMBOL(i2c_stop);
+EXPORT_SYMBOL(i2c_one);
+EXPORT_SYMBOL(i2c_zero);
+EXPORT_SYMBOL(i2c_ack);
+EXPORT_SYMBOL(i2c_sendbyte);
+EXPORT_SYMBOL(i2c_readbyte);
+EXPORT_SYMBOL(i2c_read);
+EXPORT_SYMBOL(i2c_write);
+
+
+int init_module(void)
+{
+	return i2c_init();
+}
+
+void cleanup_module(void)
+{
+}
+#endif