[linux.git] / drivers / hwmon / g760a.c

/*
    g760a - Driver for the Global Mixed-mode Technology Inc. G760A
	    fan speed PWM controller chip

    Copyright (C) 2007  Herbert Valerio Riedel <[email protected]>

    Complete datasheet is available at GMT's website:
      http://www.gmt.com.tw/product/datasheet/EDS-760A.pdf

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>

static const struct i2c_device_id g760a_id[] = {
	{ "g760a", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, g760a_id);

enum g760a_regs {
	G760A_REG_SET_CNT = 0x00,
	G760A_REG_ACT_CNT = 0x01,
	G760A_REG_FAN_STA = 0x02
};

#define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */
#define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */

/* register data is read (and cached) at most once per second */
#define G760A_UPDATE_INTERVAL (HZ)

struct g760a_data {
	struct i2c_client *client;
	struct device *hwmon_dev;
	struct mutex update_lock;

	/* board specific parameters */
	u32 clk; /* default 32kHz */
	u16 fan_div; /* default P=2 */

	/* g760a register cache */
	unsigned int valid:1;
	unsigned long last_updated; /* In jiffies */

	u8 set_cnt; /* PWM (period) count number; 0xff stops fan */
	u8 act_cnt; /*   formula: cnt = (CLK * 30)/(rpm * P) */
	u8 fan_sta; /* bit 0: set when actual fan speed more than 20%
		     *   outside requested fan speed
		     * bit 1: set when fan speed below 1920 rpm */
};

#define G760A_DEFAULT_CLK 32768
#define G760A_DEFAULT_FAN_DIV 2

#define PWM_FROM_CNT(cnt)	(0xff-(cnt))
#define PWM_TO_CNT(pwm)		(0xff-(pwm))

static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div)
{
	return ((val == 0x00) ? 0 : ((clk*30)/(val*div)));
}

/* new-style driver model */
static int g760a_probe(struct i2c_client *client,
			const struct i2c_device_id *id);
static int g760a_remove(struct i2c_client *client);

static struct i2c_driver g760a_driver = {
	.driver = {
		.name	= "g760a",
	},
	.probe	  = g760a_probe,
	.remove	  = g760a_remove,
	.id_table = g760a_id,
};

/* read/write wrappers */
static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg)
{
	return i2c_smbus_read_byte_data(client, reg);
}

static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg,
			     u16 value)
{
	return i2c_smbus_write_byte_data(client, reg, value);
}

/****************************************************************************
 * sysfs attributes
 */

static struct g760a_data *g760a_update_client(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct g760a_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL)
	    || !data->valid) {
		dev_dbg(&client->dev, "Starting g760a update\n");

		data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT);
		data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT);
		data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA);

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

	mutex_unlock(&data->update_lock);

	return data;
}

static ssize_t show_fan(struct device *dev, struct device_attribute *da,
			char *buf)
{
	struct g760a_data *data = g760a_update_client(dev);
	unsigned int rpm = 0;

	mutex_lock(&data->update_lock);
	if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW))
		rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div);
	mutex_unlock(&data->update_lock);

	return sprintf(buf, "%d\n", rpm);
}

static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da,
			      char *buf)
{
	struct g760a_data *data = g760a_update_client(dev);

	int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0;

	return sprintf(buf, "%d\n", fan_alarm);
}

static ssize_t get_pwm(struct device *dev, struct device_attribute *da,
		       char *buf)
{
	struct g760a_data *data = g760a_update_client(dev);

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

static ssize_t set_pwm(struct device *dev, struct device_attribute *da,
		       const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct g760a_data *data = g760a_update_client(dev);
	unsigned long val;

	if (kstrtoul(buf, 10, &val))
		return -EINVAL;

	mutex_lock(&data->update_lock);
	data->set_cnt = PWM_TO_CNT(SENSORS_LIMIT(val, 0, 255));
	g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt);
	mutex_unlock(&data->update_lock);

	return count;
}

static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL);
static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);

static struct attribute *g760a_attributes[] = {
	&dev_attr_pwm1.attr,
	&dev_attr_fan1_input.attr,
	&dev_attr_fan1_alarm.attr,
	NULL
};

static const struct attribute_group g760a_group = {
	.attrs = g760a_attributes,
};

/****************************************************************************
 * new-style driver model code
 */

static int g760a_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct g760a_data *data;
	int err;

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_BYTE_DATA))
		return -EIO;

	data = kzalloc(sizeof(struct g760a_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	i2c_set_clientdata(client, data);

	data->client = client;
	mutex_init(&data->update_lock);

	/* setup default configuration for now */
	data->fan_div = G760A_DEFAULT_FAN_DIV;
	data->clk = G760A_DEFAULT_CLK;

	/* Register sysfs hooks */
	err = sysfs_create_group(&client->dev.kobj, &g760a_group);
	if (err)
		goto error_sysfs_create_group;

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto error_hwmon_device_register;
	}

	return 0;

error_hwmon_device_register:
	sysfs_remove_group(&client->dev.kobj, &g760a_group);
error_sysfs_create_group:
	kfree(data);

	return err;
}

static int g760a_remove(struct i2c_client *client)
{
	struct g760a_data *data = i2c_get_clientdata(client);
	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &g760a_group);
	kfree(data);

	return 0;
}

module_i2c_driver(g760a_driver);

MODULE_AUTHOR("Herbert Valerio Riedel <[email protected]>");
MODULE_DESCRIPTION("GMT G760A driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
3bcfa9e4 HVR	1	/*
3bcfa9e4 HVR	2	g760a - Driver for the Global Mixed-mode Technology Inc. G760A
4d7c5d4f	3	fan speed PWM controller chip
3bcfa9e4 HVR	4
	5	Copyright (C) 2007 Herbert Valerio Riedel <[email protected]>
	6
	7	Complete datasheet is available at GMT's website:
4d7c5d4f	8	http://www.gmt.com.tw/product/datasheet/EDS-760A.pdf
3bcfa9e4 HVR	9
	10	This program is free software; you can redistribute it and/or modify
	11	it under the terms of the GNU General Public License as published by
	12	the Free Software Foundation; either version 2 of the License, or
	13	(at your option) any later version.
	14	*/
	15
	16	#include <linux/module.h>
	17	#include <linux/init.h>
	18	#include <linux/slab.h>
	19	#include <linux/jiffies.h>
	20	#include <linux/i2c.h>
	21	#include <linux/hwmon.h>
	22	#include <linux/hwmon-sysfs.h>
	23	#include <linux/err.h>
	24	#include <linux/mutex.h>
	25	#include <linux/sysfs.h>
	26
	27	static const struct i2c_device_id g760a_id[] = {
	28	{ "g760a", 0 },
	29	{ }
	30	};
	31	MODULE_DEVICE_TABLE(i2c, g760a_id);
	32
	33	enum g760a_regs {
	34	G760A_REG_SET_CNT = 0x00,
	35	G760A_REG_ACT_CNT = 0x01,
	36	G760A_REG_FAN_STA = 0x02
	37	};
	38
	39	#define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */
	40	#define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */
	41
	42	/* register data is read (and cached) at most once per second */
	43	#define G760A_UPDATE_INTERVAL (HZ)
	44
	45	struct g760a_data {
	46	struct i2c_client *client;
	47	struct device *hwmon_dev;
	48	struct mutex update_lock;
	49
	50	/* board specific parameters */
	51	u32 clk; /* default 32kHz */
	52	u16 fan_div; /* default P=2 */
	53
	54	/* g760a register cache */
	55	unsigned int valid:1;
	56	unsigned long last_updated; /* In jiffies */
	57
	58	u8 set_cnt; /* PWM (period) count number; 0xff stops fan */
	59	u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */
	60	u8 fan_sta; /* bit 0: set when actual fan speed more than 20%
	61	* outside requested fan speed
	62	* bit 1: set when fan speed below 1920 rpm */
	63	};
	64
	65	#define G760A_DEFAULT_CLK 32768
	66	#define G760A_DEFAULT_FAN_DIV 2
	67
	68	#define PWM_FROM_CNT(cnt) (0xff-(cnt))
	69	#define PWM_TO_CNT(pwm) (0xff-(pwm))
	70
ebec05bd	71	static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div)
3bcfa9e4 HVR	72	{
	73	return ((val == 0x00) ? 0 : ((clk30)/(valdiv)));
	74	}
	75
	76	/* new-style driver model */
	77	static int g760a_probe(struct i2c_client *client,
	78	const struct i2c_device_id *id);
	79	static int g760a_remove(struct i2c_client *client);
	80
	81	static struct i2c_driver g760a_driver = {
	82	.driver = {
	83	.name = "g760a",
	84	},
	85	.probe = g760a_probe,
	86	.remove = g760a_remove,
	87	.id_table = g760a_id,
	88	};
	89
	90	/* read/write wrappers */
	91	static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg)
	92	{
	93	return i2c_smbus_read_byte_data(client, reg);
	94	}
	95
	96	static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg,
	97	u16 value)
	98	{
	99	return i2c_smbus_write_byte_data(client, reg, value);
	100	}
	101
	102	/****************************************************************************
	103	* sysfs attributes
	104	*/
	105
	106	static struct g760a_data g760a_update_client(struct device dev)
	107	{
	108	struct i2c_client *client = to_i2c_client(dev);
	109	struct g760a_data *data = i2c_get_clientdata(client);
	110
	111	mutex_lock(&data->update_lock);
	112
	113	if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL)
	114	\|\| !data->valid) {
	115	dev_dbg(&client->dev, "Starting g760a update\n");
	116
	117	data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT);
	118	data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT);
	119	data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA);
	120
	121	data->last_updated = jiffies;
	122	data->valid = 1;
	123	}
	124
	125	mutex_unlock(&data->update_lock);
	126
	127	return data;
	128	}
	129
	130	static ssize_t show_fan(struct device dev, struct device_attribute da,
	131	char *buf)
	132	{
	133	struct g760a_data *data = g760a_update_client(dev);
	134	unsigned int rpm = 0;
	135
136	mutex_lock(&data->update_lock);
137	if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW))
138	rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div);
139	mutex_unlock(&data->update_lock);
140
141	return sprintf(buf, "%d\n", rpm);
142	}
143
144	static ssize_t show_fan_alarm(struct device dev, struct device_attribute da,
145	char *buf)
146	{
147	struct g760a_data *data = g760a_update_client(dev);
148
149	int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0;
150
151	return sprintf(buf, "%d\n", fan_alarm);
152	}
153
154	static ssize_t get_pwm(struct device dev, struct device_attribute da,
155	char *buf)
156	{
157	struct g760a_data *data = g760a_update_client(dev);
158
159	return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt));
160	}
161
162	static ssize_t set_pwm(struct device dev, struct device_attribute da,
163	const char *buf, size_t count)
164	{
165	struct i2c_client *client = to_i2c_client(dev);
166	struct g760a_data *data = g760a_update_client(dev);
167	unsigned long val;
168
179c4fdb	169	if (kstrtoul(buf, 10, &val))
3bcfa9e4 HVR	170	return -EINVAL;
	171
	172	mutex_lock(&data->update_lock);
	173	data->set_cnt = PWM_TO_CNT(SENSORS_LIMIT(val, 0, 255));
	174	g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt);
	175	mutex_unlock(&data->update_lock);
	176
	177	return count;
	178	}
	179
	180	static DEVICE_ATTR(pwm1, S_IWUSR \| S_IRUGO, get_pwm, set_pwm);
	181	static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL);
	182	static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
	183
	184	static struct attribute *g760a_attributes[] = {
	185	&dev_attr_pwm1.attr,
	186	&dev_attr_fan1_input.attr,
	187	&dev_attr_fan1_alarm.attr,
	188	NULL
	189	};
	190
	191	static const struct attribute_group g760a_group = {
	192	.attrs = g760a_attributes,
	193	};
	194
	195	/****************************************************************************
	196	* new-style driver model code
	197	*/
	198
	199	static int g760a_probe(struct i2c_client *client,
	200	const struct i2c_device_id *id)
	201	{
	202	struct g760a_data *data;
	203	int err;
	204
	205	if (!i2c_check_functionality(client->adapter,
	206	I2C_FUNC_SMBUS_BYTE_DATA))
	207	return -EIO;
	208
	209	data = kzalloc(sizeof(struct g760a_data), GFP_KERNEL);
	210	if (!data)
	211	return -ENOMEM;
	212
	213	i2c_set_clientdata(client, data);
	214
	215	data->client = client;
	216	mutex_init(&data->update_lock);
	217
	218	/* setup default configuration for now */
	219	data->fan_div = G760A_DEFAULT_FAN_DIV;
	220	data->clk = G760A_DEFAULT_CLK;
	221
	222	/* Register sysfs hooks */
	223	err = sysfs_create_group(&client->dev.kobj, &g760a_group);
	224	if (err)
	225	goto error_sysfs_create_group;
	226
	227	data->hwmon_dev = hwmon_device_register(&client->dev);
	228	if (IS_ERR(data->hwmon_dev)) {
	229	err = PTR_ERR(data->hwmon_dev);
	230	goto error_hwmon_device_register;
	231	}
	232
	233	return 0;
234
235	error_hwmon_device_register:
236	sysfs_remove_group(&client->dev.kobj, &g760a_group);
237	error_sysfs_create_group:
238	kfree(data);
3bcfa9e4 HVR	239
	240	return err;
	241	}
	242
	243	static int g760a_remove(struct i2c_client *client)
	244	{
	245	struct g760a_data *data = i2c_get_clientdata(client);
	246	hwmon_device_unregister(data->hwmon_dev);
	247	sysfs_remove_group(&client->dev.kobj, &g760a_group);
	248	kfree(data);
3bcfa9e4 HVR	249
	250	return 0;
	251	}
	252
f0967eea	253	module_i2c_driver(g760a_driver);
3bcfa9e4 HVR	254
	255	MODULE_AUTHOR("Herbert Valerio Riedel <[email protected]>");
	256	MODULE_DESCRIPTION("GMT G760A driver");
	257	MODULE_LICENSE("GPL");