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 */
45static 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 */
56struct 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
65static 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
94static 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	}
123abort:
124	mutex_unlock(&data->update_lock);
125
126	return ret;
127}
128
129static 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
141static 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
166static 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
197static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
198static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
199static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
200static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS620_REG_CONFIG_TLF);
201static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS620_REG_CONFIG_THF);
202
203static 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
212ATTRIBUTE_GROUPS(ds620);
213
214static 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
235static const struct i2c_device_id ds620_id[] = {
236	{"ds620"},
237	{}
238};
239
240MODULE_DEVICE_TABLE(i2c, ds620_id);
241
242/* This is the driver that will be inserted */
243static struct i2c_driver ds620_driver = {
244	.driver = {
245		   .name = "ds620",
246	},
247	.probe = ds620_probe,
248	.id_table = ds620_id,
249};
250
251module_i2c_driver(ds620_driver);
252
253MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
254MODULE_DESCRIPTION("DS620 driver");
255MODULE_LICENSE("GPL");
256