xref: /openbmc/linux/drivers/hwmon/ds620.c (revision 1975d167)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  ds620.c - Support for temperature sensor and thermostat DS620
4  *
5  *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
6  *
7  *  based on ds1621.c by Christian W. Zuckschwerdt  <zany@triq.net>
8  */
9 
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/jiffies.h>
14 #include <linux/i2c.h>
15 #include <linux/hwmon.h>
16 #include <linux/hwmon-sysfs.h>
17 #include <linux/err.h>
18 #include <linux/mutex.h>
19 #include <linux/sysfs.h>
20 #include <linux/platform_data/ds620.h>
21 
22 /*
23  * Many DS620 constants specified below
24  *  15   14   13   12   11   10   09    08
25  * |Done|NVB |THF |TLF |R1  |R0  |AUTOC|1SHOT|
26  *
27  *  07   06   05   04   03   02   01    00
28  * |PO2 |PO1 |A2  |A1  |A0  |    |     |     |
29  */
30 #define DS620_REG_CONFIG_DONE		0x8000
31 #define DS620_REG_CONFIG_NVB		0x4000
32 #define DS620_REG_CONFIG_THF		0x2000
33 #define DS620_REG_CONFIG_TLF		0x1000
34 #define DS620_REG_CONFIG_R1		0x0800
35 #define DS620_REG_CONFIG_R0		0x0400
36 #define DS620_REG_CONFIG_AUTOC		0x0200
37 #define DS620_REG_CONFIG_1SHOT		0x0100
38 #define DS620_REG_CONFIG_PO2		0x0080
39 #define DS620_REG_CONFIG_PO1		0x0040
40 #define DS620_REG_CONFIG_A2		0x0020
41 #define DS620_REG_CONFIG_A1		0x0010
42 #define DS620_REG_CONFIG_A0		0x0008
43 
44 /* The DS620 registers */
45 static const u8 DS620_REG_TEMP[3] = {
46 	0xAA,			/* input, word, RO */
47 	0xA2,			/* min, word, RW */
48 	0xA0,			/* max, word, RW */
49 };
50 
51 #define DS620_REG_CONF		0xAC	/* word, RW */
52 #define DS620_COM_START		0x51	/* no data */
53 #define DS620_COM_STOP		0x22	/* no data */
54 
55 /* Each client has this additional data */
56 struct ds620_data {
57 	struct i2c_client *client;
58 	struct mutex update_lock;
59 	bool valid;		/* true if following fields are valid */
60 	unsigned long last_updated;	/* In jiffies */
61 
62 	s16 temp[3];		/* Register values, word */
63 };
64 
ds620_init_client(struct i2c_client * client)65 static void ds620_init_client(struct i2c_client *client)
66 {
67 	struct ds620_platform_data *ds620_info = dev_get_platdata(&client->dev);
68 	u16 conf, new_conf;
69 
70 	new_conf = conf =
71 	    i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
72 
73 	/* switch to continuous conversion mode */
74 	new_conf &= ~DS620_REG_CONFIG_1SHOT;
75 	/* already high at power-on, but don't trust the BIOS! */
76 	new_conf |= DS620_REG_CONFIG_PO2;
77 	/* thermostat mode according to platform data */
78 	if (ds620_info && ds620_info->pomode == 1)
79 		new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
80 	else if (ds620_info && ds620_info->pomode == 2)
81 		new_conf |= DS620_REG_CONFIG_PO1; /* PO_HIGH */
82 	else
83 		new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
84 	/* with highest precision */
85 	new_conf |= DS620_REG_CONFIG_R1 | DS620_REG_CONFIG_R0;
86 
87 	if (conf != new_conf)
88 		i2c_smbus_write_word_swapped(client, DS620_REG_CONF, new_conf);
89 
90 	/* start conversion */
91 	i2c_smbus_write_byte(client, DS620_COM_START);
92 }
93 
ds620_update_client(struct device * dev)94 static struct ds620_data *ds620_update_client(struct device *dev)
95 {
96 	struct ds620_data *data = dev_get_drvdata(dev);
97 	struct i2c_client *client = data->client;
98 	struct ds620_data *ret = data;
99 
100 	mutex_lock(&data->update_lock);
101 
102 	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
103 	    || !data->valid) {
104 		int i;
105 		int res;
106 
107 		dev_dbg(&client->dev, "Starting ds620 update\n");
108 
109 		for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
110 			res = i2c_smbus_read_word_swapped(client,
111 							  DS620_REG_TEMP[i]);
112 			if (res < 0) {
113 				ret = ERR_PTR(res);
114 				goto abort;
115 			}
116 
117 			data->temp[i] = res;
118 		}
119 
120 		data->last_updated = jiffies;
121 		data->valid = true;
122 	}
123 abort:
124 	mutex_unlock(&data->update_lock);
125 
126 	return ret;
127 }
128 
temp_show(struct device * dev,struct device_attribute * da,char * buf)129 static ssize_t temp_show(struct device *dev, struct device_attribute *da,
130 			 char *buf)
131 {
132 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
133 	struct ds620_data *data = ds620_update_client(dev);
134 
135 	if (IS_ERR(data))
136 		return PTR_ERR(data);
137 
138 	return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
139 }
140 
temp_store(struct device * dev,struct device_attribute * da,const char * buf,size_t count)141 static ssize_t temp_store(struct device *dev, struct device_attribute *da,
142 			  const char *buf, size_t count)
143 {
144 	int res;
145 	long val;
146 
147 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
148 	struct ds620_data *data = dev_get_drvdata(dev);
149 	struct i2c_client *client = data->client;
150 
151 	res = kstrtol(buf, 10, &val);
152 
153 	if (res)
154 		return res;
155 
156 	val = (clamp_val(val, -128000, 128000) * 10 / 625) * 8;
157 
158 	mutex_lock(&data->update_lock);
159 	data->temp[attr->index] = val;
160 	i2c_smbus_write_word_swapped(client, DS620_REG_TEMP[attr->index],
161 				     data->temp[attr->index]);
162 	mutex_unlock(&data->update_lock);
163 	return count;
164 }
165 
alarm_show(struct device * dev,struct device_attribute * da,char * buf)166 static ssize_t alarm_show(struct device *dev, struct device_attribute *da,
167 			  char *buf)
168 {
169 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
170 	struct ds620_data *data = ds620_update_client(dev);
171 	struct i2c_client *client;
172 	u16 conf, new_conf;
173 	int res;
174 
175 	if (IS_ERR(data))
176 		return PTR_ERR(data);
177 
178 	client = data->client;
179 
180 	/* reset alarms if necessary */
181 	res = i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
182 	if (res < 0)
183 		return res;
184 
185 	new_conf = conf = res;
186 	new_conf &= ~attr->index;
187 	if (conf != new_conf) {
188 		res = i2c_smbus_write_word_swapped(client, DS620_REG_CONF,
189 						   new_conf);
190 		if (res < 0)
191 			return res;
192 	}
193 
194 	return sprintf(buf, "%d\n", !!(conf & attr->index));
195 }
196 
197 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
198 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
199 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
200 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS620_REG_CONFIG_TLF);
201 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS620_REG_CONFIG_THF);
202 
203 static struct attribute *ds620_attrs[] = {
204 	&sensor_dev_attr_temp1_input.dev_attr.attr,
205 	&sensor_dev_attr_temp1_min.dev_attr.attr,
206 	&sensor_dev_attr_temp1_max.dev_attr.attr,
207 	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
208 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
209 	NULL
210 };
211 
212 ATTRIBUTE_GROUPS(ds620);
213 
ds620_probe(struct i2c_client * client)214 static int ds620_probe(struct i2c_client *client)
215 {
216 	struct device *dev = &client->dev;
217 	struct device *hwmon_dev;
218 	struct ds620_data *data;
219 
220 	data = devm_kzalloc(dev, sizeof(struct ds620_data), GFP_KERNEL);
221 	if (!data)
222 		return -ENOMEM;
223 
224 	data->client = client;
225 	mutex_init(&data->update_lock);
226 
227 	/* Initialize the DS620 chip */
228 	ds620_init_client(client);
229 
230 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
231 							   data, ds620_groups);
232 	return PTR_ERR_OR_ZERO(hwmon_dev);
233 }
234 
235 static const struct i2c_device_id ds620_id[] = {
236 	{"ds620", 0},
237 	{}
238 };
239 
240 MODULE_DEVICE_TABLE(i2c, ds620_id);
241 
242 /* This is the driver that will be inserted */
243 static struct i2c_driver ds620_driver = {
244 	.class = I2C_CLASS_HWMON,
245 	.driver = {
246 		   .name = "ds620",
247 	},
248 	.probe = ds620_probe,
249 	.id_table = ds620_id,
250 };
251 
252 module_i2c_driver(ds620_driver);
253 
254 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
255 MODULE_DESCRIPTION("DS620 driver");
256 MODULE_LICENSE("GPL");
257