max6650.c

linux 内核源代码

	i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);

	mutex_unlock(&data->update_lock);

	return count;
}

/*
 * Read/write functions for fan1_div sysfs file. The MAX6650 has no such
 * divider. We handle this by converting between divider and counttime:
 *
 * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3
 *
 * Lower values of k allow to connect a faster fan without the risk of
 * counter overflow. The price is lower resolution. You can also set counttime
 * using the module parameter. Note that the module parameter "prescaler" also
 * influences the behaviour. Unfortunately, there's no sysfs attribute
 * defined for that. See the data sheet for details.
 */

static ssize_t get_div(struct device *dev, struct device_attribute *devattr,
		       char *buf)
{
	struct max6650_data *data = max6650_update_device(dev);

	return sprintf(buf, "%d\n", DIV_FROM_REG(data->count));
}

static ssize_t set_div(struct device *dev, struct device_attribute *devattr,
		       const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct max6650_data *data = i2c_get_clientdata(client);
	int div = simple_strtoul(buf, NULL, 10);

	mutex_lock(&data->update_lock);
	switch (div) {
	case 1:
		data->count = 0;
		break;
	case 2:
		data->count = 1;
		break;
	case 4:
		data->count = 2;
		break;
	case 8:
		data->count = 3;
		break;
	default:
		dev_err(&client->dev,
			"illegal value for fan divider (%d)\n", div);
		return -EINVAL;
	}

	i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count);
	mutex_unlock(&data->update_lock);

	return count;
}

static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target);
static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div);
static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable);
static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);


static struct attribute *max6650_attrs[] = {
	&sensor_dev_attr_fan1_input.dev_attr.attr,
	&sensor_dev_attr_fan2_input.dev_attr.attr,
	&sensor_dev_attr_fan3_input.dev_attr.attr,
	&sensor_dev_attr_fan4_input.dev_attr.attr,
	&dev_attr_fan1_target.attr,
	&dev_attr_fan1_div.attr,
	&dev_attr_pwm1_enable.attr,
	&dev_attr_pwm1.attr,
	NULL
};

static struct attribute_group max6650_attr_grp = {
	.attrs = max6650_attrs,
};

/*
 * Real code
 */

static int max6650_attach_adapter(struct i2c_adapter *adapter)
{
	if (!(adapter->class & I2C_CLASS_HWMON)) {
		dev_dbg(&adapter->dev,
			"FATAL: max6650_attach_adapter class HWMON not set\n");
		return 0;
	}

	return i2c_probe(adapter, &addr_data, max6650_detect);
}

/*
 * The following function does more than just detection. If detection
 * succeeds, it also registers the new chip.
 */

static int max6650_detect(struct i2c_adapter *adapter, int address, int kind)
{
	struct i2c_client *client;
	struct max6650_data *data;
	int err = -ENODEV;

	dev_dbg(&adapter->dev, "max6650_detect called, kind = %d\n", kind);

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
		dev_dbg(&adapter->dev, "max6650: I2C bus doesn't support "
					"byte read mode, skipping.\n");
		return 0;
	}

	if (!(data = kzalloc(sizeof(struct max6650_data), GFP_KERNEL))) {
		dev_err(&adapter->dev, "max6650: out of memory.\n");
		return -ENOMEM;
	}

	client = &data->client;
	i2c_set_clientdata(client, data);
	client->addr = address;
	client->adapter = adapter;
	client->driver = &max6650_driver;

	/*
	 * 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 (actually there is only
	 * one possible kind of chip for now, max6650). 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.
	 *
	 * Currently I can find no way to distinguish between a MAX6650 and
	 * a MAX6651. This driver has only been tried on the former.
	 */

	if ((kind < 0) &&
	   (  (i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG) & 0xC0)
	    ||(i2c_smbus_read_byte_data(client, MAX6650_REG_GPIO_STAT) & 0xE0)
	    ||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN) & 0xE0)
	    ||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM) & 0xE0)
	    ||(i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT) & 0xFC))) {
		dev_dbg(&adapter->dev,
			"max6650: detection failed at 0x%02x.\n", address);
		goto err_free;
	}

	dev_info(&adapter->dev, "max6650: chip found at 0x%02x.\n", address);

	strlcpy(client->name, "max6650", I2C_NAME_SIZE);
	mutex_init(&data->update_lock);

	if ((err = i2c_attach_client(client))) {
		dev_err(&adapter->dev, "max6650: failed to attach client.\n");
		goto err_free;
	}

	/*
	 * Initialize the max6650 chip
	 */
	if (max6650_init_client(client))
		goto err_detach;

	err = sysfs_create_group(&client->dev.kobj, &max6650_attr_grp);
	if (err)
		goto err_detach;

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (!IS_ERR(data->hwmon_dev))
		return 0;

	err = PTR_ERR(data->hwmon_dev);
	dev_err(&client->dev, "error registering hwmon device.\n");
	sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
err_detach:
	i2c_detach_client(client);
err_free:
	kfree(data);
	return err;
}

static int max6650_detach_client(struct i2c_client *client)
{
	struct max6650_data *data = i2c_get_clientdata(client);
	int err;

	sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp);
	hwmon_device_unregister(data->hwmon_dev);
	err = i2c_detach_client(client);
	if (!err)
		kfree(data);
	return err;
}

static int max6650_init_client(struct i2c_client *client)
{
	struct max6650_data *data = i2c_get_clientdata(client);
	int config;
	int err = -EIO;

	config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);

	if (config < 0) {
		dev_err(&client->dev, "Error reading config, aborting.\n");
		return err;
	}

	switch (fan_voltage) {
		case 0:
			break;
		case 5:
			config &= ~MAX6650_CFG_V12;
			break;
		case 12:
			config |= MAX6650_CFG_V12;
			break;
		default:
			dev_err(&client->dev,
				"illegal value for fan_voltage (%d)\n",
				fan_voltage);
	}

	dev_info(&client->dev, "Fan voltage is set to %dV.\n",
		 (config & MAX6650_CFG_V12) ? 12 : 5);

	switch (prescaler) {
		case 0:
			break;
		case 1:
			config &= ~MAX6650_CFG_PRESCALER_MASK;
			break;
		case 2:
			config = (config & ~MAX6650_CFG_PRESCALER_MASK)
				 | MAX6650_CFG_PRESCALER_2;
			break;
		case  4:
			config = (config & ~MAX6650_CFG_PRESCALER_MASK)
				 | MAX6650_CFG_PRESCALER_4;
			break;
		case  8:
			config = (config & ~MAX6650_CFG_PRESCALER_MASK)
				 | MAX6650_CFG_PRESCALER_8;
			break;
		case 16:
			config = (config & ~MAX6650_CFG_PRESCALER_MASK)
				 | MAX6650_CFG_PRESCALER_16;
			break;
		default:
			dev_err(&client->dev,
				"illegal value for prescaler (%d)\n",
				prescaler);
	}

	dev_info(&client->dev, "Prescaler is set to %d.\n",
		 1 << (config & MAX6650_CFG_PRESCALER_MASK));

	/* If mode is set to "full off", we change it to "open loop" and
	 * set DAC to 255, which has the same effect. We do this because
	 * there's no "full off" mode defined in hwmon specifcations.
	 */

	if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
		dev_dbg(&client->dev, "Change mode to open loop, full off.\n");
		config = (config & ~MAX6650_CFG_MODE_MASK)
			 | MAX6650_CFG_MODE_OPEN_LOOP;
		if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
			dev_err(&client->dev, "DAC write error, aborting.\n");
			return err;
		}
	}

	if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
		dev_err(&client->dev, "Config write error, aborting.\n");
		return err;
	}

	data->config = config;
	data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);

	return 0;
}

static const u8 tach_reg[] = {
	MAX6650_REG_TACH0,
	MAX6650_REG_TACH1,
	MAX6650_REG_TACH2,
	MAX6650_REG_TACH3,
};

static struct max6650_data *max6650_update_device(struct device *dev)
{
	int i;
	struct i2c_client *client = to_i2c_client(dev);
	struct max6650_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
		data->speed = i2c_smbus_read_byte_data(client,
						       MAX6650_REG_SPEED);
		data->config = i2c_smbus_read_byte_data(client,
							MAX6650_REG_CONFIG);
		for (i = 0; i < 4; i++) {
			data->tach[i] = i2c_smbus_read_byte_data(client,
								 tach_reg[i]);
		}
		data->count = i2c_smbus_read_byte_data(client,
							MAX6650_REG_COUNT);
		data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);

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

	mutex_unlock(&data->update_lock);

	return data;
}

static int __init sensors_max6650_init(void)
{
	return i2c_add_driver(&max6650_driver);
}

static void __exit sensors_max6650_exit(void)
{
	i2c_del_driver(&max6650_driver);
}

MODULE_AUTHOR("Hans J. Koch");
MODULE_DESCRIPTION("MAX6650 sensor driver");
MODULE_LICENSE("GPL");

module_init(sensors_max6650_init);
module_exit(sensors_max6650_exit);