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v6.8
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller
  4 *
  5 * Copyright (C) 2010 Ericsson AB.
  6 *
  7 * Derived from:
  8 *
  9 *  Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
 10 *  Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
 11 *
 12 * Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.pdf
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 13 */
 14
 15#include <linux/kernel.h>
 16#include <linux/module.h>
 17#include <linux/init.h>
 18#include <linux/err.h>
 19#include <linux/slab.h>
 20#include <linux/i2c.h>
 21#include <linux/hwmon.h>
 22#include <linux/hwmon-sysfs.h>
 23#include <linux/jiffies.h>
 24
 25/* chip registers */
 26#define LTC4261_STATUS	0x00	/* readonly */
 27#define LTC4261_FAULT	0x01
 28#define LTC4261_ALERT	0x02
 29#define LTC4261_CONTROL	0x03
 30#define LTC4261_SENSE_H	0x04
 31#define LTC4261_SENSE_L	0x05
 32#define LTC4261_ADIN2_H	0x06
 33#define LTC4261_ADIN2_L	0x07
 34#define LTC4261_ADIN_H	0x08
 35#define LTC4261_ADIN_L	0x09
 36
 37/*
 38 * Fault register bits
 39 */
 40#define FAULT_OV	(1<<0)
 41#define FAULT_UV	(1<<1)
 42#define FAULT_OC	(1<<2)
 43
 44struct ltc4261_data {
 45	struct i2c_client *client;
 46
 47	struct mutex update_lock;
 48	bool valid;
 49	unsigned long last_updated;	/* in jiffies */
 50
 51	/* Registers */
 52	u8 regs[10];
 53};
 54
 55static struct ltc4261_data *ltc4261_update_device(struct device *dev)
 56{
 57	struct ltc4261_data *data = dev_get_drvdata(dev);
 58	struct i2c_client *client = data->client;
 59	struct ltc4261_data *ret = data;
 60
 61	mutex_lock(&data->update_lock);
 62
 63	if (time_after(jiffies, data->last_updated + HZ / 4) || !data->valid) {
 64		int i;
 65
 66		/* Read registers -- 0x00 to 0x09 */
 67		for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
 68			int val;
 69
 70			val = i2c_smbus_read_byte_data(client, i);
 71			if (unlikely(val < 0)) {
 72				dev_dbg(dev,
 73					"Failed to read ADC value: error %d\n",
 74					val);
 75				ret = ERR_PTR(val);
 76				data->valid = false;
 77				goto abort;
 78			}
 79			data->regs[i] = val;
 80		}
 81		data->last_updated = jiffies;
 82		data->valid = true;
 83	}
 84abort:
 85	mutex_unlock(&data->update_lock);
 86	return ret;
 87}
 88
 89/* Return the voltage from the given register in mV or mA */
 90static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
 91{
 92	u32 val;
 93
 94	val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);
 95
 96	switch (reg) {
 97	case LTC4261_ADIN_H:
 98	case LTC4261_ADIN2_H:
 99		/* 2.5mV resolution. Convert to mV. */
100		val = val * 25 / 10;
101		break;
102	case LTC4261_SENSE_H:
103		/*
104		 * 62.5uV resolution. Convert to current as measured with
105		 * an 1 mOhm sense resistor, in mA. If a different sense
106		 * resistor is installed, calculate the actual current by
107		 * dividing the reported current by the sense resistor value
108		 * in mOhm.
109		 */
110		val = val * 625 / 10;
111		break;
112	default:
113		/* If we get here, the developer messed up */
114		WARN_ON_ONCE(1);
115		val = 0;
116		break;
117	}
118
119	return val;
120}
121
122static ssize_t ltc4261_value_show(struct device *dev,
123				  struct device_attribute *da, char *buf)
124{
125	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
126	struct ltc4261_data *data = ltc4261_update_device(dev);
127	int value;
128
129	if (IS_ERR(data))
130		return PTR_ERR(data);
131
132	value = ltc4261_get_value(data, attr->index);
133	return sysfs_emit(buf, "%d\n", value);
134}
135
136static ssize_t ltc4261_bool_show(struct device *dev,
137				 struct device_attribute *da, char *buf)
138{
139	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 
140	struct ltc4261_data *data = ltc4261_update_device(dev);
141	u8 fault;
142
143	if (IS_ERR(data))
144		return PTR_ERR(data);
145
146	fault = data->regs[LTC4261_FAULT] & attr->index;
147	if (fault)		/* Clear reported faults in chip register */
148		i2c_smbus_write_byte_data(data->client, LTC4261_FAULT, ~fault);
149
150	return sysfs_emit(buf, "%d\n", fault ? 1 : 0);
151}
152
153/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
154 * Input voltages.
155 */
156static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4261_value, LTC4261_ADIN_H);
157static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4261_value, LTC4261_ADIN2_H);
158
159/*
160 * Voltage alarms. The chip has only one set of voltage alarm status bits,
161 * triggered by input voltage alarms. In many designs, those alarms are
162 * associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
163 * to the OV pin. ADIN2 is, however, not available on all chip variants.
164 * To ensure that the alarm condition is reported to the user, report it
165 * with both voltage sensors.
166 */
167static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4261_bool, FAULT_UV);
168static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4261_bool, FAULT_OV);
169static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc4261_bool, FAULT_UV);
170static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc4261_bool, FAULT_OV);
171
172/* Currents (via sense resistor) */
173static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4261_value, LTC4261_SENSE_H);
174
175/* Overcurrent alarm */
176static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4261_bool, FAULT_OC);
177
178static struct attribute *ltc4261_attrs[] = {
179	&sensor_dev_attr_in1_input.dev_attr.attr,
180	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
181	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
182	&sensor_dev_attr_in2_input.dev_attr.attr,
183	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
184	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,
185
186	&sensor_dev_attr_curr1_input.dev_attr.attr,
187	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
188
189	NULL,
190};
191ATTRIBUTE_GROUPS(ltc4261);
192
193static int ltc4261_probe(struct i2c_client *client)
 
 
 
 
 
194{
195	struct i2c_adapter *adapter = client->adapter;
196	struct device *dev = &client->dev;
197	struct ltc4261_data *data;
198	struct device *hwmon_dev;
199
200	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
201		return -ENODEV;
202
203	if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
204		dev_err(dev, "Failed to read status register\n");
205		return -ENODEV;
206	}
207
208	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
209	if (!data)
210		return -ENOMEM;
211
212	data->client = client;
213	mutex_init(&data->update_lock);
214
215	/* Clear faults */
216	i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);
217
218	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
219							   data,
220							   ltc4261_groups);
221	return PTR_ERR_OR_ZERO(hwmon_dev);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
222}
223
224static const struct i2c_device_id ltc4261_id[] = {
225	{"ltc4261", 0},
226	{}
227};
228
229MODULE_DEVICE_TABLE(i2c, ltc4261_id);
230
231/* This is the driver that will be inserted */
232static struct i2c_driver ltc4261_driver = {
233	.driver = {
234		   .name = "ltc4261",
235		   },
236	.probe = ltc4261_probe,
 
237	.id_table = ltc4261_id,
238};
239
240module_i2c_driver(ltc4261_driver);
241
242MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
243MODULE_DESCRIPTION("LTC4261 driver");
244MODULE_LICENSE("GPL");
v3.5.6
 
  1/*
  2 * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller
  3 *
  4 * Copyright (C) 2010 Ericsson AB.
  5 *
  6 * Derived from:
  7 *
  8 *  Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
  9 *  Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
 10 *
 11 * Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.pdf
 12 *
 13 * This program is free software; you can redistribute it and/or modify
 14 * it under the terms of the GNU General Public License as published by
 15 * the Free Software Foundation; either version 2 of the License, or
 16 * (at your option) any later version.
 17 *
 18 * This program is distributed in the hope that it will be useful,
 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 21 * GNU General Public License for more details.
 22 *
 23 * You should have received a copy of the GNU General Public License
 24 * along with this program; if not, write to the Free Software
 25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 26 */
 27
 28#include <linux/kernel.h>
 29#include <linux/module.h>
 30#include <linux/init.h>
 31#include <linux/err.h>
 32#include <linux/slab.h>
 33#include <linux/i2c.h>
 34#include <linux/hwmon.h>
 35#include <linux/hwmon-sysfs.h>
 
 36
 37/* chip registers */
 38#define LTC4261_STATUS	0x00	/* readonly */
 39#define LTC4261_FAULT	0x01
 40#define LTC4261_ALERT	0x02
 41#define LTC4261_CONTROL	0x03
 42#define LTC4261_SENSE_H	0x04
 43#define LTC4261_SENSE_L	0x05
 44#define LTC4261_ADIN2_H	0x06
 45#define LTC4261_ADIN2_L	0x07
 46#define LTC4261_ADIN_H	0x08
 47#define LTC4261_ADIN_L	0x09
 48
 49/*
 50 * Fault register bits
 51 */
 52#define FAULT_OV	(1<<0)
 53#define FAULT_UV	(1<<1)
 54#define FAULT_OC	(1<<2)
 55
 56struct ltc4261_data {
 57	struct device *hwmon_dev;
 58
 59	struct mutex update_lock;
 60	bool valid;
 61	unsigned long last_updated;	/* in jiffies */
 62
 63	/* Registers */
 64	u8 regs[10];
 65};
 66
 67static struct ltc4261_data *ltc4261_update_device(struct device *dev)
 68{
 69	struct i2c_client *client = to_i2c_client(dev);
 70	struct ltc4261_data *data = i2c_get_clientdata(client);
 71	struct ltc4261_data *ret = data;
 72
 73	mutex_lock(&data->update_lock);
 74
 75	if (time_after(jiffies, data->last_updated + HZ / 4) || !data->valid) {
 76		int i;
 77
 78		/* Read registers -- 0x00 to 0x09 */
 79		for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
 80			int val;
 81
 82			val = i2c_smbus_read_byte_data(client, i);
 83			if (unlikely(val < 0)) {
 84				dev_dbg(dev,
 85					"Failed to read ADC value: error %d\n",
 86					val);
 87				ret = ERR_PTR(val);
 88				data->valid = 0;
 89				goto abort;
 90			}
 91			data->regs[i] = val;
 92		}
 93		data->last_updated = jiffies;
 94		data->valid = 1;
 95	}
 96abort:
 97	mutex_unlock(&data->update_lock);
 98	return ret;
 99}
100
101/* Return the voltage from the given register in mV or mA */
102static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
103{
104	u32 val;
105
106	val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);
107
108	switch (reg) {
109	case LTC4261_ADIN_H:
110	case LTC4261_ADIN2_H:
111		/* 2.5mV resolution. Convert to mV. */
112		val = val * 25 / 10;
113		break;
114	case LTC4261_SENSE_H:
115		/*
116		 * 62.5uV resolution. Convert to current as measured with
117		 * an 1 mOhm sense resistor, in mA. If a different sense
118		 * resistor is installed, calculate the actual current by
119		 * dividing the reported current by the sense resistor value
120		 * in mOhm.
121		 */
122		val = val * 625 / 10;
123		break;
124	default:
125		/* If we get here, the developer messed up */
126		WARN_ON_ONCE(1);
127		val = 0;
128		break;
129	}
130
131	return val;
132}
133
134static ssize_t ltc4261_show_value(struct device *dev,
135				  struct device_attribute *da, char *buf)
136{
137	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
138	struct ltc4261_data *data = ltc4261_update_device(dev);
139	int value;
140
141	if (IS_ERR(data))
142		return PTR_ERR(data);
143
144	value = ltc4261_get_value(data, attr->index);
145	return snprintf(buf, PAGE_SIZE, "%d\n", value);
146}
147
148static ssize_t ltc4261_show_bool(struct device *dev,
149				 struct device_attribute *da, char *buf)
150{
151	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
152	struct i2c_client *client = to_i2c_client(dev);
153	struct ltc4261_data *data = ltc4261_update_device(dev);
154	u8 fault;
155
156	if (IS_ERR(data))
157		return PTR_ERR(data);
158
159	fault = data->regs[LTC4261_FAULT] & attr->index;
160	if (fault)		/* Clear reported faults in chip register */
161		i2c_smbus_write_byte_data(client, LTC4261_FAULT, ~fault);
162
163	return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0);
164}
165
166/*
167 * These macros are used below in constructing device attribute objects
168 * for use with sysfs_create_group() to make a sysfs device file
169 * for each register.
170 */
171
172#define LTC4261_VALUE(name, ltc4261_cmd_idx) \
173	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
174	ltc4261_show_value, NULL, ltc4261_cmd_idx)
175
176#define LTC4261_BOOL(name, mask) \
177	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
178	ltc4261_show_bool, NULL, (mask))
179
180/*
181 * Input voltages.
182 */
183LTC4261_VALUE(in1_input, LTC4261_ADIN_H);
184LTC4261_VALUE(in2_input, LTC4261_ADIN2_H);
185
186/*
187 * Voltage alarms. The chip has only one set of voltage alarm status bits,
188 * triggered by input voltage alarms. In many designs, those alarms are
189 * associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
190 * to the OV pin. ADIN2 is, however, not available on all chip variants.
191 * To ensure that the alarm condition is reported to the user, report it
192 * with both voltage sensors.
193 */
194LTC4261_BOOL(in1_min_alarm, FAULT_UV);
195LTC4261_BOOL(in1_max_alarm, FAULT_OV);
196LTC4261_BOOL(in2_min_alarm, FAULT_UV);
197LTC4261_BOOL(in2_max_alarm, FAULT_OV);
198
199/* Currents (via sense resistor) */
200LTC4261_VALUE(curr1_input, LTC4261_SENSE_H);
201
202/* Overcurrent alarm */
203LTC4261_BOOL(curr1_max_alarm, FAULT_OC);
204
205static struct attribute *ltc4261_attributes[] = {
206	&sensor_dev_attr_in1_input.dev_attr.attr,
207	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
208	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
209	&sensor_dev_attr_in2_input.dev_attr.attr,
210	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
211	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,
212
213	&sensor_dev_attr_curr1_input.dev_attr.attr,
214	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
215
216	NULL,
217};
 
218
219static const struct attribute_group ltc4261_group = {
220	.attrs = ltc4261_attributes,
221};
222
223static int ltc4261_probe(struct i2c_client *client,
224			 const struct i2c_device_id *id)
225{
226	struct i2c_adapter *adapter = client->adapter;
 
227	struct ltc4261_data *data;
228	int ret;
229
230	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
231		return -ENODEV;
232
233	if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
234		dev_err(&client->dev, "Failed to read status register\n");
235		return -ENODEV;
236	}
237
238	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
239	if (!data)
240		return -ENOMEM;
241
242	i2c_set_clientdata(client, data);
243	mutex_init(&data->update_lock);
244
245	/* Clear faults */
246	i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);
247
248	/* Register sysfs hooks */
249	ret = sysfs_create_group(&client->dev.kobj, &ltc4261_group);
250	if (ret)
251		return ret;
252
253	data->hwmon_dev = hwmon_device_register(&client->dev);
254	if (IS_ERR(data->hwmon_dev)) {
255		ret = PTR_ERR(data->hwmon_dev);
256		goto out_hwmon_device_register;
257	}
258
259	return 0;
260
261out_hwmon_device_register:
262	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);
263	return ret;
264}
265
266static int ltc4261_remove(struct i2c_client *client)
267{
268	struct ltc4261_data *data = i2c_get_clientdata(client);
269
270	hwmon_device_unregister(data->hwmon_dev);
271	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);
272
273	return 0;
274}
275
276static const struct i2c_device_id ltc4261_id[] = {
277	{"ltc4261", 0},
278	{}
279};
280
281MODULE_DEVICE_TABLE(i2c, ltc4261_id);
282
283/* This is the driver that will be inserted */
284static struct i2c_driver ltc4261_driver = {
285	.driver = {
286		   .name = "ltc4261",
287		   },
288	.probe = ltc4261_probe,
289	.remove = ltc4261_remove,
290	.id_table = ltc4261_id,
291};
292
293module_i2c_driver(ltc4261_driver);
294
295MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
296MODULE_DESCRIPTION("LTC4261 driver");
297MODULE_LICENSE("GPL");