lm90.c

《linux驱动程序设计从入门到精通》一书中所有的程序代码含驱动和相应的应用程序

/*
 * Real code
 */

static int lm90_attach_adapter(struct i2c_adapter *adapter)
{
	if (!(adapter->class & I2C_CLASS_HWMON))
		return 0;
	return i2c_detect(adapter, &addr_data, lm90_detect);
}

/*
 * The following function does more than just detection. If detection
 * succeeds, it also registers the new chip.
 */
static int lm90_detect(struct i2c_adapter *adapter, int address, int kind)
{
	struct i2c_client *new_client;
	struct lm90_data *data;
	int err = 0;
	const char *name = "";

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		goto exit;

	if (!(data = kmalloc(sizeof(struct lm90_data), GFP_KERNEL))) {
		err = -ENOMEM;
		goto exit;
	}
	memset(data, 0, sizeof(struct lm90_data));

	/* The common I2C client data is placed right before the
	   LM90-specific data. */
	new_client = &data->client;
	i2c_set_clientdata(new_client, data);
	new_client->addr = address;
	new_client->adapter = adapter;
	new_client->driver = &lm90_driver;
	new_client->flags = 0;

	/*
	 * Now we do the remaining detection. A negative kind means that
	 * the driver was loaded with no force parameter (default), so we
	 * must both detect and identify the chip. A zero kind means that
	 * the driver was loaded with the force parameter, the detection
	 * step shall be skipped. A positive kind means that the driver
	 * was loaded with the force parameter and a given kind of chip is
	 * requested, so both the detection and the identification steps
	 * are skipped.
	 */

	/* Default to an LM90 if forced */
	if (kind == 0)
		kind = lm90;

	if (kind < 0) { /* detection and identification */
		u8 man_id, chip_id, reg_config1, reg_convrate;

		man_id = i2c_smbus_read_byte_data(new_client,
			 LM90_REG_R_MAN_ID);
		chip_id = i2c_smbus_read_byte_data(new_client,
			  LM90_REG_R_CHIP_ID);
		reg_config1 = i2c_smbus_read_byte_data(new_client,
			      LM90_REG_R_CONFIG1);
		reg_convrate = i2c_smbus_read_byte_data(new_client,
			       LM90_REG_R_CONVRATE);
		
		if (man_id == 0x01) { /* National Semiconductor */
			u8 reg_config2;

			reg_config2 = i2c_smbus_read_byte_data(new_client,
				      LM90_REG_R_CONFIG2);

			if ((reg_config1 & 0x2A) == 0x00
			 && (reg_config2 & 0xF8) == 0x00
			 && reg_convrate <= 0x09) {
				if (address == 0x4C
				 && (chip_id & 0xF0) == 0x20) { /* LM90 */
					kind = lm90;
				} else
				if ((chip_id & 0xF0) == 0x30) { /* LM89/LM99 */
					kind = lm99;
				} else
				if (address == 0x4C
				 && (chip_id & 0xF0) == 0x10) { /* LM86 */
					kind = lm86;
				}
			}
		} else
		if (man_id == 0x41) { /* Analog Devices */
			if (address == 0x4C
			 && (chip_id & 0xF0) == 0x40 /* ADM1032 */
			 && (reg_config1 & 0x3F) == 0x00
			 && reg_convrate <= 0x0A) {
				kind = adm1032;
			}
		} else
		if (man_id == 0x4D) { /* Maxim */
			if (address == 0x4C
			 && (reg_config1 & 0x1F) == 0
			 && reg_convrate <= 0x09) {
			 	kind = max6657;
			}
		}

		if (kind <= 0) { /* identification failed */
			dev_info(&adapter->dev,
			    "Unsupported chip (man_id=0x%02X, "
			    "chip_id=0x%02X).\n", man_id, chip_id);
			goto exit_free;
		}
	}

	if (kind == lm90) {
		name = "lm90";
	} else if (kind == adm1032) {
		name = "adm1032";
	} else if (kind == lm99) {
		name = "lm99";
	} else if (kind == lm86) {
		name = "lm86";
	} else if (kind == max6657) {
		name = "max6657";
	}

	/* We can fill in the remaining client fields */
	strlcpy(new_client->name, name, I2C_NAME_SIZE);
	new_client->id = lm90_id++;
	data->valid = 0;
	init_MUTEX(&data->update_lock);

	/* Tell the I2C layer a new client has arrived */
	if ((err = i2c_attach_client(new_client)))
		goto exit_free;

	/* Initialize the LM90 chip */
	lm90_init_client(new_client);

	/* Register sysfs hooks */
	device_create_file(&new_client->dev, &dev_attr_temp1_input);
	device_create_file(&new_client->dev, &dev_attr_temp2_input);
	device_create_file(&new_client->dev, &dev_attr_temp1_min);
	device_create_file(&new_client->dev, &dev_attr_temp2_min);
	device_create_file(&new_client->dev, &dev_attr_temp1_max);
	device_create_file(&new_client->dev, &dev_attr_temp2_max);
	device_create_file(&new_client->dev, &dev_attr_temp1_crit);
	device_create_file(&new_client->dev, &dev_attr_temp2_crit);
	device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
	device_create_file(&new_client->dev, &dev_attr_temp2_crit_hyst);
	device_create_file(&new_client->dev, &dev_attr_alarms);

	return 0;

exit_free:
	kfree(data);
exit:
	return err;
}

static void lm90_init_client(struct i2c_client *client)
{
	u8 config;

	/*
	 * Start the conversions.
	 */
	i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE,
				  5); /* 2 Hz */
	config = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG1);
	if (config & 0x40)
		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
					  config & 0xBF); /* run */
}

static int lm90_detach_client(struct i2c_client *client)
{
	int err;

	if ((err = i2c_detach_client(client))) {
		dev_err(&client->dev, "Client deregistration failed, "
			"client not detached.\n");
		return err;
	}

	kfree(i2c_get_clientdata(client));
	return 0;
}

static struct lm90_data *lm90_update_device(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lm90_data *data = i2c_get_clientdata(client);

	down(&data->update_lock);

	if ((jiffies - data->last_updated > HZ * 2) ||
	    (jiffies < data->last_updated) ||
	    !data->valid) {
		u8 oldh, newh;

		dev_dbg(&client->dev, "Updating lm90 data.\n");
		data->temp_input1 = i2c_smbus_read_byte_data(client,
				    LM90_REG_R_LOCAL_TEMP);
		data->temp_high1 = i2c_smbus_read_byte_data(client,
				   LM90_REG_R_LOCAL_HIGH);
		data->temp_low1 = i2c_smbus_read_byte_data(client,
				  LM90_REG_R_LOCAL_LOW);
		data->temp_crit1 = i2c_smbus_read_byte_data(client,
				   LM90_REG_R_LOCAL_CRIT);
		data->temp_crit2 = i2c_smbus_read_byte_data(client,
				   LM90_REG_R_REMOTE_CRIT);
		data->temp_hyst = i2c_smbus_read_byte_data(client,
				  LM90_REG_R_TCRIT_HYST);

		/*
		 * There is a trick here. We have to read two registers to
		 * have the remote sensor temperature, but we have to beware
		 * a conversion could occur inbetween the readings. The
		 * datasheet says we should either use the one-shot
		 * conversion register, which we don't want to do (disables
		 * hardware monitoring) or monitor the busy bit, which is
		 * impossible (we can't read the values and monitor that bit
		 * at the exact same time). So the solution used here is to
		 * read the high byte once, then the low byte, then the high
		 * byte again. If the new high byte matches the old one,
		 * then we have a valid reading. Else we have to read the low
		 * byte again, and now we believe we have a correct reading.
		 */
		oldh = i2c_smbus_read_byte_data(client,
		       LM90_REG_R_REMOTE_TEMPH);
		data->temp_input2 = i2c_smbus_read_byte_data(client,
				    LM90_REG_R_REMOTE_TEMPL);
		newh = i2c_smbus_read_byte_data(client,
		       LM90_REG_R_REMOTE_TEMPH);
		if (newh != oldh) {
			data->temp_input2 = i2c_smbus_read_byte_data(client,
					    LM90_REG_R_REMOTE_TEMPL);
#ifdef DEBUG
			oldh = i2c_smbus_read_byte_data(client,
			       LM90_REG_R_REMOTE_TEMPH);
			/* oldh is actually newer */
			if (newh != oldh)
				dev_warn(&client->dev, "Remote temperature may be "
					 "wrong.\n");
#endif
		}
		data->temp_input2 |= (newh << 8);

		data->temp_high2 = (i2c_smbus_read_byte_data(client,
				   LM90_REG_R_REMOTE_HIGHH) << 8) +
				   i2c_smbus_read_byte_data(client,
				   LM90_REG_R_REMOTE_HIGHL);
		data->temp_low2 = (i2c_smbus_read_byte_data(client,
				  LM90_REG_R_REMOTE_LOWH) << 8) +
				  i2c_smbus_read_byte_data(client,
				  LM90_REG_R_REMOTE_LOWL);
		data->alarms = i2c_smbus_read_byte_data(client,
			       LM90_REG_R_STATUS);

		data->last_updated = jiffies;
		data->valid = 1;
	}

	up(&data->update_lock);

	return data;
}

static int __init sensors_lm90_init(void)
{
	return i2c_add_driver(&lm90_driver);
}

static void __exit sensors_lm90_exit(void)
{
	i2c_del_driver(&lm90_driver);
}

MODULE_AUTHOR("Jean Delvare <[e-mail]>");
MODULE_DESCRIPTION("LM90/ADM1032 driver");
MODULE_LICENSE("GPL");

module_init(sensors_lm90_init);
module_exit(sensors_lm90_exit);