[deliverable/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 <hvr@gnu.org>
 *
 * 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>

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)));
}

/* 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(clamp_val(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 = devm_kzalloc(&client->dev, 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)
		return err;

	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);
	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);
	return 0;
}

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

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

module_i2c_driver(g760a_driver);

MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
MODULE_DESCRIPTION("GMT G760A driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
3bcfa9e4	1	/*
1b9c491d GR	2	* g760a - Driver for the Global Mixed-mode Technology Inc. G760A
	3	* fan speed PWM controller chip
	4	*
	5	* Copyright (C) 2007 Herbert Valerio Riedel <hvr@gnu.org>
	6	*
	7	* Complete datasheet is available at GMT's website:
	8	* http://www.gmt.com.tw/product/datasheet/EDS-760A.pdf
	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	*/
3bcfa9e4 HVR	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
3bcfa9e4 HVR	27	enum g760a_regs {
	28	G760A_REG_SET_CNT = 0x00,
	29	G760A_REG_ACT_CNT = 0x01,
	30	G760A_REG_FAN_STA = 0x02
	31	};
	32
	33	#define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */
	34	#define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */
	35
	36	/* register data is read (and cached) at most once per second */
	37	#define G760A_UPDATE_INTERVAL (HZ)
	38
	39	struct g760a_data {
	40	struct i2c_client *client;
	41	struct device *hwmon_dev;
	42	struct mutex update_lock;
	43
	44	/* board specific parameters */
	45	u32 clk; /* default 32kHz */
	46	u16 fan_div; /* default P=2 */
	47
	48	/* g760a register cache */
	49	unsigned int valid:1;
	50	unsigned long last_updated; /* In jiffies */
	51
	52	u8 set_cnt; /* PWM (period) count number; 0xff stops fan */
	53	u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */
	54	u8 fan_sta; /* bit 0: set when actual fan speed more than 20%
	55	* outside requested fan speed
1b9c491d GR	56	* bit 1: set when fan speed below 1920 rpm
1b9c491d GR	57	*/
3bcfa9e4 HVR	58	};
	59
	60	#define G760A_DEFAULT_CLK 32768
	61	#define G760A_DEFAULT_FAN_DIV 2
	62
	63	#define PWM_FROM_CNT(cnt) (0xff-(cnt))
	64	#define PWM_TO_CNT(pwm) (0xff-(pwm))
	65
ebec05bd	66	static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div)
3bcfa9e4 HVR	67	{
	68	return ((val == 0x00) ? 0 : ((clk30)/(valdiv)));
	69	}
	70
3bcfa9e4 HVR	71	/* read/write wrappers */
	72	static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg)
	73	{
	74	return i2c_smbus_read_byte_data(client, reg);
	75	}
	76
	77	static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg,
	78	u16 value)
	79	{
	80	return i2c_smbus_write_byte_data(client, reg, value);
	81	}
	82
1b9c491d	83	/*
3bcfa9e4 HVR	84	* sysfs attributes
	85	*/
	86
	87	static struct g760a_data g760a_update_client(struct device dev)
	88	{
	89	struct i2c_client *client = to_i2c_client(dev);
	90	struct g760a_data *data = i2c_get_clientdata(client);
	91
	92	mutex_lock(&data->update_lock);
	93
	94	if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL)
	95	\|\| !data->valid) {
	96	dev_dbg(&client->dev, "Starting g760a update\n");
	97
	98	data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT);
	99	data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT);
	100	data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA);
	101
	102	data->last_updated = jiffies;
	103	data->valid = 1;
	104	}
	105
	106	mutex_unlock(&data->update_lock);
	107
	108	return data;
	109	}
	110
	111	static ssize_t show_fan(struct device dev, struct device_attribute da,
	112	char *buf)
	113	{
	114	struct g760a_data *data = g760a_update_client(dev);
	115	unsigned int rpm = 0;
	116
	117	mutex_lock(&data->update_lock);
	118	if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW))
	119	rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div);
	120	mutex_unlock(&data->update_lock);
	121
	122	return sprintf(buf, "%d\n", rpm);
	123	}
	124
	125	static ssize_t show_fan_alarm(struct device dev, struct device_attribute da,
	126	char *buf)
	127	{
	128	struct g760a_data *data = g760a_update_client(dev);
	129
	130	int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0;
	131
	132	return sprintf(buf, "%d\n", fan_alarm);
	133	}
	134
	135	static ssize_t get_pwm(struct device dev, struct device_attribute da,
	136	char *buf)
	137	{
	138	struct g760a_data *data = g760a_update_client(dev);
	139
	140	return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt));
	141	}
	142
	143	static ssize_t set_pwm(struct device dev, struct device_attribute da,
	144	const char *buf, size_t count)
	145	{
	146	struct i2c_client *client = to_i2c_client(dev);
	147	struct g760a_data *data = g760a_update_client(dev);
148	unsigned long val;
149
179c4fdb	150	if (kstrtoul(buf, 10, &val))
3bcfa9e4 HVR	151	return -EINVAL;
	152
	153	mutex_lock(&data->update_lock);
2a844c14	154	data->set_cnt = PWM_TO_CNT(clamp_val(val, 0, 255));
3bcfa9e4 HVR	155	g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt);
	156	mutex_unlock(&data->update_lock);
	157
	158	return count;
	159	}
	160
	161	static DEVICE_ATTR(pwm1, S_IWUSR \| S_IRUGO, get_pwm, set_pwm);
	162	static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL);
	163	static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
	164
	165	static struct attribute *g760a_attributes[] = {
	166	&dev_attr_pwm1.attr,
	167	&dev_attr_fan1_input.attr,
	168	&dev_attr_fan1_alarm.attr,
	169	NULL
	170	};
	171
	172	static const struct attribute_group g760a_group = {
	173	.attrs = g760a_attributes,
	174	};
	175
1b9c491d	176	/*
3bcfa9e4 HVR	177	* new-style driver model code
	178	*/
	179
	180	static int g760a_probe(struct i2c_client *client,
	181	const struct i2c_device_id *id)
	182	{
	183	struct g760a_data *data;
	184	int err;
	185
	186	if (!i2c_check_functionality(client->adapter,
	187	I2C_FUNC_SMBUS_BYTE_DATA))
	188	return -EIO;
	189
a81b0f73 GR	190	data = devm_kzalloc(&client->dev, sizeof(struct g760a_data),
a81b0f73 GR	191	GFP_KERNEL);
3bcfa9e4 HVR	192	if (!data)
	193	return -ENOMEM;
	194
	195	i2c_set_clientdata(client, data);
	196
	197	data->client = client;
	198	mutex_init(&data->update_lock);
	199
	200	/* setup default configuration for now */
	201	data->fan_div = G760A_DEFAULT_FAN_DIV;
	202	data->clk = G760A_DEFAULT_CLK;
	203
	204	/* Register sysfs hooks */
	205	err = sysfs_create_group(&client->dev.kobj, &g760a_group);
	206	if (err)
a81b0f73	207	return err;
3bcfa9e4 HVR	208
	209	data->hwmon_dev = hwmon_device_register(&client->dev);
	210	if (IS_ERR(data->hwmon_dev)) {
	211	err = PTR_ERR(data->hwmon_dev);
	212	goto error_hwmon_device_register;
	213	}
	214
	215	return 0;
	216
	217	error_hwmon_device_register:
	218	sysfs_remove_group(&client->dev.kobj, &g760a_group);
3bcfa9e4 HVR	219	return err;
	220	}
	221
	222	static int g760a_remove(struct i2c_client *client)
	223	{
	224	struct g760a_data *data = i2c_get_clientdata(client);
	225	hwmon_device_unregister(data->hwmon_dev);
	226	sysfs_remove_group(&client->dev.kobj, &g760a_group);
3bcfa9e4 HVR	227	return 0;
	228	}
	229
15ac4ddb AL	230	static const struct i2c_device_id g760a_id[] = {
	231	{ "g760a", 0 },
	232	{ }
	233	};
	234	MODULE_DEVICE_TABLE(i2c, g760a_id);
	235
	236	static struct i2c_driver g760a_driver = {
	237	.driver = {
	238	.name = "g760a",
	239	},
	240	.probe = g760a_probe,
	241	.remove = g760a_remove,
	242	.id_table = g760a_id,
	243	};
	244
f0967eea	245	module_i2c_driver(g760a_driver);
3bcfa9e4 HVR	246
	247	MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
	248	MODULE_DESCRIPTION("GMT G760A driver");
	249	MODULE_LICENSE("GPL");