max1668.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (c) 2011 David George <david.george@ska.ac.za>
  4 *
  5 * based on adm1021.c
  6 * some credit to Christoph Scheurer, but largely a rewrite
  7 */
  8
  9#include <linux/bitops.h>
 10#include <linux/bits.h>
 11#include <linux/err.h>
 12#include <linux/hwmon.h>
 13#include <linux/i2c.h>
 14#include <linux/init.h>
 15#include <linux/module.h>
 16#include <linux/regmap.h>
 17#include <linux/slab.h>
 18
 19/* Addresses to scan */
 20static const unsigned short max1668_addr_list[] = {
 21	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };
 22
 23/* max1668 registers */
 24
 25#define MAX1668_REG_TEMP(nr)	(nr)
 26#define MAX1668_REG_STAT1	0x05
 27#define MAX1668_REG_STAT2	0x06
 28#define MAX1668_REG_MAN_ID	0xfe
 29#define MAX1668_REG_DEV_ID	0xff
 30
 31/* limits */
 32
 33/* high limits */
 34#define MAX1668_REG_LIMH(nr)	(0x08 + 2 * (nr))
 35/* read low limits */
 36#define MAX1668_REG_LIML(nr)	(0x09 + 2 * (nr))
 37
 38/* manufacturer and device ID Constants */
 39#define MAN_ID_MAXIM		0x4d
 40#define DEV_ID_MAX1668		0x3
 41#define DEV_ID_MAX1805		0x5
 42#define DEV_ID_MAX1989		0xb
 43
 44/* read only mode module parameter */
 45static bool read_only;
 46module_param(read_only, bool, 0);
 47MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");
 48
 49struct max1668_data {
 50	struct regmap *regmap;
 51	int channels;
 52};
 53
 54static int max1668_read(struct device *dev, enum hwmon_sensor_types type,
 55			u32 attr, int channel, long *val)
 56{
 57	struct max1668_data *data = dev_get_drvdata(dev);
 58	struct regmap *regmap = data->regmap;
 59	u32 regs[2] = { MAX1668_REG_STAT1, MAX1668_REG_TEMP(channel) };
 60	u8 regvals[2];
 61	u32 regval;
 62	int ret;
 63
 64	switch (attr) {
 65	case hwmon_temp_input:
 66		ret = regmap_read(regmap, MAX1668_REG_TEMP(channel), &regval);
 67		if (ret)
 68			return ret;
 69		*val = sign_extend32(regval, 7) * 1000;
 70		break;
 71	case hwmon_temp_min:
 72		ret = regmap_read(regmap, MAX1668_REG_LIML(channel), &regval);
 73		if (ret)
 74			return ret;
 75		*val = sign_extend32(regval, 7) * 1000;
 76		break;
 77	case hwmon_temp_max:
 78		ret = regmap_read(regmap, MAX1668_REG_LIMH(channel), &regval);
 79		if (ret)
 80			return ret;
 81		*val = sign_extend32(regval, 7) * 1000;
 82		break;
 83	case hwmon_temp_min_alarm:
 84		ret = regmap_read(regmap,
 85				  channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
 86				  &regval);
 87		if (ret)
 88			return ret;
 89		if (channel)
 90			*val = !!(regval & BIT(9 - channel * 2));
 91		else
 92			*val = !!(regval & BIT(5));
 93		break;
 94	case hwmon_temp_max_alarm:
 95		ret = regmap_read(regmap,
 96				  channel ? MAX1668_REG_STAT2 : MAX1668_REG_STAT1,
 97				  &regval);
 98		if (ret)
 99			return ret;
100		if (channel)
101			*val = !!(regval & BIT(8 - channel * 2));
102		else
103			*val = !!(regval & BIT(6));
104		break;
105	case hwmon_temp_fault:
106		ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
107		if (ret)
108			return ret;
109		*val = !!((regvals[0] & BIT(4)) && regvals[1] == 127);
110		break;
111	default:
112		return -EOPNOTSUPP;
113	}
114	return 0;
115}
116
117static int max1668_write(struct device *dev, enum hwmon_sensor_types type,
118			 u32 attr, int channel, long val)
119{
120	struct max1668_data *data = dev_get_drvdata(dev);
121	struct regmap *regmap = data->regmap;
122
123	val = clamp_val(val / 1000, -128, 127);
124
125	switch (attr) {
126	case hwmon_temp_min:
127		return regmap_write(regmap, MAX1668_REG_LIML(channel), val);
128	case hwmon_temp_max:
129		return regmap_write(regmap, MAX1668_REG_LIMH(channel), val);
130	default:
131		return -EOPNOTSUPP;
132	}
133}
134
135static umode_t max1668_is_visible(const void *_data, enum hwmon_sensor_types type,
136				  u32 attr, int channel)
137{
138	const struct max1668_data *data = _data;
139
140	if (channel >= data->channels)
141		return 0;
142
143	switch (attr) {
144	case hwmon_temp_min:
145	case hwmon_temp_max:
146		return read_only ? 0444 : 0644;
147	case hwmon_temp_input:
148	case hwmon_temp_min_alarm:
149	case hwmon_temp_max_alarm:
150		return 0444;
151	case hwmon_temp_fault:
152		if (channel)
153			return 0444;
154		break;
155	default:
156		break;
157	}
158	return 0;
159}
160
161static const struct hwmon_channel_info * const max1668_info[] = {
162	HWMON_CHANNEL_INFO(temp,
163			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
164			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
165			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
166			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
167			   HWMON_T_FAULT,
168			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
169			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
170			   HWMON_T_FAULT,
171			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
172			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
173			   HWMON_T_FAULT,
174			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
175			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
176			   HWMON_T_FAULT),
177	NULL
178};
179
180static const struct hwmon_ops max1668_hwmon_ops = {
181	.is_visible = max1668_is_visible,
182	.read = max1668_read,
183	.write = max1668_write,
184};
185
186static const struct hwmon_chip_info max1668_chip_info = {
187	.ops = &max1668_hwmon_ops,
188	.info = max1668_info,
189};
190
191/* Return 0 if detection is successful, -ENODEV otherwise */
192static int max1668_detect(struct i2c_client *client,
193			  struct i2c_board_info *info)
194{
195	struct i2c_adapter *adapter = client->adapter;
196	const char *type_name;
197	int man_id, dev_id;
198
199	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
200		return -ENODEV;
201
202	/* Check for unsupported part */
203	man_id = i2c_smbus_read_byte_data(client, MAX1668_REG_MAN_ID);
204	if (man_id != MAN_ID_MAXIM)
205		return -ENODEV;
206
207	dev_id = i2c_smbus_read_byte_data(client, MAX1668_REG_DEV_ID);
208	if (dev_id < 0)
209		return -ENODEV;
210
211	type_name = NULL;
212	if (dev_id == DEV_ID_MAX1668)
213		type_name = "max1668";
214	else if (dev_id == DEV_ID_MAX1805)
215		type_name = "max1805";
216	else if (dev_id == DEV_ID_MAX1989)
217		type_name = "max1989";
218
219	if (!type_name)
220		return -ENODEV;
221
222	strscpy(info->type, type_name, I2C_NAME_SIZE);
223
224	return 0;
225}
226
227/* regmap */
228
229static int max1668_reg_read(void *context, unsigned int reg, unsigned int *val)
230{
231	int ret;
232
233	ret = i2c_smbus_read_byte_data(context, reg);
234	if (ret < 0)
235		return ret;
236
237	*val = ret;
238	return 0;
239}
240
241static int max1668_reg_write(void *context, unsigned int reg, unsigned int val)
242{
243	return i2c_smbus_write_byte_data(context, reg + 11, val);
244}
245
246static bool max1668_regmap_is_volatile(struct device *dev, unsigned int reg)
247{
248	return reg <= MAX1668_REG_STAT2;
249}
250
251static bool max1668_regmap_is_writeable(struct device *dev, unsigned int reg)
252{
253	return reg > MAX1668_REG_STAT2 && reg <= MAX1668_REG_LIML(4);
254}
255
256static const struct regmap_config max1668_regmap_config = {
257	.reg_bits = 8,
258	.val_bits = 8,
259	.cache_type = REGCACHE_MAPLE,
260	.volatile_reg = max1668_regmap_is_volatile,
261	.writeable_reg = max1668_regmap_is_writeable,
262};
263
264static const struct regmap_bus max1668_regmap_bus = {
265	.reg_write = max1668_reg_write,
266	.reg_read = max1668_reg_read,
267};
268
269static int max1668_probe(struct i2c_client *client)
270{
271	struct i2c_adapter *adapter = client->adapter;
272	struct device *dev = &client->dev;
273	struct device *hwmon_dev;
274	struct max1668_data *data;
275
276	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
277		return -ENODEV;
278
279	data = devm_kzalloc(dev, sizeof(struct max1668_data), GFP_KERNEL);
280	if (!data)
281		return -ENOMEM;
282
283	data->regmap = devm_regmap_init(dev, &max1668_regmap_bus, client,
284					&max1668_regmap_config);
285	if (IS_ERR(data->regmap))
286		return PTR_ERR(data->regmap);
287
288	data->channels = (uintptr_t)i2c_get_match_data(client);
289
290	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
291							 &max1668_chip_info, NULL);
292	return PTR_ERR_OR_ZERO(hwmon_dev);
293}
294
295static const struct i2c_device_id max1668_id[] = {
296	{ "max1668", 5 },
297	{ "max1805", 3 },
298	{ "max1989", 5 },
299	{ }
300};
301MODULE_DEVICE_TABLE(i2c, max1668_id);
302
303/* This is the driver that will be inserted */
304static struct i2c_driver max1668_driver = {
305	.class = I2C_CLASS_HWMON,
306	.driver = {
307		  .name	= "max1668",
308		  },
309	.probe = max1668_probe,
310	.id_table = max1668_id,
311	.detect	= max1668_detect,
312	.address_list = max1668_addr_list,
313};
314
315module_i2c_driver(max1668_driver);
316
317MODULE_AUTHOR("David George <david.george@ska.ac.za>");
318MODULE_DESCRIPTION("MAX1668 remote temperature sensor driver");
319MODULE_LICENSE("GPL");