hwmon: Add support for LTC4151

LTC4151 is High Voltage I2C Current and Voltage Monitor from Linear Technology. Signed-off-by: Per Dalen <per.dalen@appeartv.com> Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

hwmon: Add support for LTC4151
LTC4151 is High Voltage I2C Current and Voltage Monitor from Linear Technology. Signed-off-by: Per Dalen <per.dalen@appeartv.com> Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
per.dalen@appeartv.com · Guenter Roeck
1 parent 9f6ad1ce64
Showing 4 changed files with 315 additions and 0 deletions Side-by-side Diff
Documentation/hwmon/ltc4151
drivers/hwmon/Kconfig
drivers/hwmon/Makefile
drivers/hwmon/ltc4151.c
+Kernel driver ltc4151
+=====================
+
+Supported chips:
+  * Linear Technology LTC4151
+    Prefix: 'ltc4151'
+    Addresses scanned: -
+    Datasheet:
+        http://www.linear.com/docs/Datasheet/4151fc.pdf
+
+Author: Per Dalen <per.dalen@appeartv.com>
+
+
+Description
+-----------
+
+The LTC4151 is a High Voltage I2C Current and Voltage Monitor.
+
+
+Usage Notes
+-----------
+
+This driver does not probe for LTC4151 devices, since there is no register
+which can be safely used to identify the chip. You will have to instantiate
+the devices explicitly.
+
+Example: the following will load the driver for an LTC4151 at address 0x6f
+on I2C bus #0:
+# modprobe ltc4151
+# echo ltc4151 0x6f > /sys/bus/i2c/devices/i2c-0/new_device
+
+
+Sysfs entries
+-------------
+
+Voltage readings provided by this driver are reported as obtained from the ADIN
+and VIN registers.
+
+Current reading provided by this driver is reported as obtained from the Current
+Sense register. The reported value assumes that a 1 mOhm sense resistor is
+installed.
+
+in1_input		VDIN voltage (mV)
+
+in2_input		ADIN voltage (mV)
+
+curr1_input		SENSE current (mA)
@@ -636,6 +636,17 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called lm93.
  
+config SENSORS_LTC4151
+	tristate "Linear Technology LTC4151"
+	depends on I2C
+	default n
+	help
+	  If you say yes here you get support for Linear Technology LTC4151
+	  High Voltage I2C Current and Voltage Monitor interface.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called ltc4151.
+
 config SENSORS_LTC4215
 	tristate "Linear Technology LTC4215"
 	depends on I2C && EXPERIMENTAL
@@ -80,6 +80,7 @@
 obj-$(CONFIG_SENSORS_LM92)	+= lm92.o
 obj-$(CONFIG_SENSORS_LM93)	+= lm93.o
 obj-$(CONFIG_SENSORS_LM95241)	+= lm95241.o
+obj-$(CONFIG_SENSORS_LTC4151)	+= ltc4151.o
 obj-$(CONFIG_SENSORS_LTC4215)	+= ltc4215.o
 obj-$(CONFIG_SENSORS_LTC4245)	+= ltc4245.o
 obj-$(CONFIG_SENSORS_LTC4261)	+= ltc4261.o
+/*
+ * Driver for Linear Technology LTC4151 High Voltage I2C Current
+ * and Voltage Monitor
+ *
+ * Copyright (C) 2011 AppearTV AS
+ *
+ * Derived from:
+ *
+ *  Driver for Linear Technology LTC4261 I2C Negative Voltage Hot
+ *  Swap Controller
+ *  Copyright (C) 2010 Ericsson AB.
+ *
+ * Datasheet: http://www.linear.com/docs/Datasheet/4151fc.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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+/* chip registers */
+#define LTC4151_SENSE_H	0x00
+#define LTC4151_SENSE_L	0x01
+#define LTC4151_VIN_H	0x02
+#define LTC4151_VIN_L	0x03
+#define LTC4151_ADIN_H	0x04
+#define LTC4151_ADIN_L	0x05
+
+struct ltc4151_data {
+	struct device *hwmon_dev;
+
+	struct mutex update_lock;
+	bool valid;
+	unsigned long last_updated; /* in jiffies */
+
+	/* Registers */
+	u8 regs[6];
+};
+
+static struct ltc4151_data *ltc4151_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ltc4151_data *data = i2c_get_clientdata(client);
+	struct ltc4151_data *ret = data;
+
+	mutex_lock(&data->update_lock);
+
+	/*
+	 * The chip's A/D updates 6 times per second
+	 * (Conversion Rate 6 - 9 Hz)
+	 */
+	if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) {
+		int i;
+
+		dev_dbg(&client->dev, "Starting ltc4151 update\n");
+
+		/* Read all registers */
+		for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
+			int val;
+
+			val = i2c_smbus_read_byte_data(client, i);
+			if (unlikely(val < 0)) {
+				dev_dbg(dev,
+					"Failed to read ADC value: error %d\n",
+					val);
+				ret = ERR_PTR(val);
+				goto abort;
+			}
+			data->regs[i] = val;
+		}
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+abort:
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+/* Return the voltage from the given register in mV */
+static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
+{
+	u32 val;
+
+	val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4);
+
+	switch (reg) {
+	case LTC4151_ADIN_H:
+		/* 500uV resolution. Convert to mV. */
+		val = val * 500 / 1000;
+		break;
+	case LTC4151_SENSE_H:
+		/*
+		 * 20uV resolution. Convert to current as measured with
+		 * an 1 mOhm sense resistor, in mA.
+		 */
+		val = val * 20;
+		break;
+	case LTC4151_VIN_H:
+		/* 25 mV per increment */
+		val = val * 25;
+		break;
+	default:
+		/* If we get here, the developer messed up */
+		WARN_ON_ONCE(1);
+		val = 0;
+		break;
+	}
+
+	return val;
+}
+
+static ssize_t ltc4151_show_value(struct device *dev,
+				  struct device_attribute *da, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ltc4151_data *data = ltc4151_update_device(dev);
+	int value;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	value = ltc4151_get_value(data, attr->index);
+	return snprintf(buf, PAGE_SIZE, "%d\n", value);
+}
+
+/*
+ * Input voltages.
+ */
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
+	ltc4151_show_value, NULL, LTC4151_VIN_H);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, \
+	ltc4151_show_value, NULL, LTC4151_ADIN_H);
+
+/* Currents (via sense resistor) */
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
+	ltc4151_show_value, NULL, LTC4151_SENSE_H);
+
+/* Finally, construct an array of pointers to members of the above objects,
+ * as required for sysfs_create_group()
+ */
+static struct attribute *ltc4151_attributes[] = {
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+
+	&sensor_dev_attr_curr1_input.dev_attr.attr,
+
+	NULL,
+};
+
+static const struct attribute_group ltc4151_group = {
+	.attrs = ltc4151_attributes,
+};
+
+static int ltc4151_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct ltc4151_data *data;
+	int ret;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data) {
+		ret = -ENOMEM;
+		goto out_kzalloc;
+	}
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->update_lock);
+
+	/* Register sysfs hooks */
+	ret = sysfs_create_group(&client->dev.kobj, &ltc4151_group);
+	if (ret)
+		goto out_sysfs_create_group;
+
+	data->hwmon_dev = hwmon_device_register(&client->dev);
+	if (IS_ERR(data->hwmon_dev)) {
+		ret = PTR_ERR(data->hwmon_dev);
+		goto out_hwmon_device_register;
+	}
+
+	return 0;
+
+out_hwmon_device_register:
+	sysfs_remove_group(&client->dev.kobj, &ltc4151_group);
+out_sysfs_create_group:
+	kfree(data);
+out_kzalloc:
+	return ret;
+}
+
+static int ltc4151_remove(struct i2c_client *client)
+{
+	struct ltc4151_data *data = i2c_get_clientdata(client);
+
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &ltc4151_group);
+
+	kfree(data);
+
+	return 0;
+}
+
+static const struct i2c_device_id ltc4151_id[] = {
+	{ "ltc4151", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ltc4151_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ltc4151_driver = {
+	.driver = {
+		.name	= "ltc4151",
+	},
+	.probe		= ltc4151_probe,
+	.remove		= ltc4151_remove,
+	.id_table	= ltc4151_id,
+};
+
+static int __init ltc4151_init(void)
+{
+	return i2c_add_driver(&ltc4151_driver);
+}
+
+static void __exit ltc4151_exit(void)
+{
+	i2c_del_driver(&ltc4151_driver);
+}
+
+MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
+MODULE_DESCRIPTION("LTC4151 driver");
+MODULE_LICENSE("GPL");
+
+module_init(ltc4151_init);
+module_exit(ltc4151_exit);
	1	+Kernel driver ltc4151
	2	+=====================
	3	+
	4	+Supported chips:
	5	+ * Linear Technology LTC4151
	6	+ Prefix: 'ltc4151'
	7	+ Addresses scanned: -
	8	+ Datasheet:
	9	+ http://www.linear.com/docs/Datasheet/4151fc.pdf
	10	+
	11	+Author: Per Dalen <per.dalen@appeartv.com>
	12	+
	13	+
	14	+Description
	15	+-----------
	16	+
	17	+The LTC4151 is a High Voltage I2C Current and Voltage Monitor.
	18	+
	19	+
	20	+Usage Notes
	21	+-----------
	22	+
	23	+This driver does not probe for LTC4151 devices, since there is no register
	24	+which can be safely used to identify the chip. You will have to instantiate
	25	+the devices explicitly.
	26	+
	27	+Example: the following will load the driver for an LTC4151 at address 0x6f
	28	+on I2C bus #0:
	29	+# modprobe ltc4151
	30	+# echo ltc4151 0x6f > /sys/bus/i2c/devices/i2c-0/new_device
	31	+
	32	+
	33	+Sysfs entries
	34	+-------------
	35	+
	36	+Voltage readings provided by this driver are reported as obtained from the ADIN
	37	+and VIN registers.
	38	+
	39	+Current reading provided by this driver is reported as obtained from the Current
	40	+Sense register. The reported value assumes that a 1 mOhm sense resistor is
	41	+installed.
	42	+
	43	+in1_input VDIN voltage (mV)
	44	+
	45	+in2_input ADIN voltage (mV)
	46	+
	47	+curr1_input SENSE current (mA)
...	...	@@ -636,6 +636,17 @@
636	636	This driver can also be built as a module. If so, the module
637	637	will be called lm93.
638	638
	639	+config SENSORS_LTC4151
	640	+ tristate "Linear Technology LTC4151"
	641	+ depends on I2C
	642	+ default n
	643	+ help
	644	+ If you say yes here you get support for Linear Technology LTC4151
	645	+ High Voltage I2C Current and Voltage Monitor interface.
	646	+
	647	+ This driver can also be built as a module. If so, the module will
	648	+ be called ltc4151.
	649	+
639	650	config SENSORS_LTC4215
640	651	tristate "Linear Technology LTC4215"
641	652	depends on I2C && EXPERIMENTAL
...	...	@@ -80,6 +80,7 @@
80	80	obj-$(CONFIG_SENSORS_LM92) += lm92.o
81	81	obj-$(CONFIG_SENSORS_LM93) += lm93.o
82	82	obj-$(CONFIG_SENSORS_LM95241) += lm95241.o
	83	+obj-$(CONFIG_SENSORS_LTC4151) += ltc4151.o
83	84	obj-$(CONFIG_SENSORS_LTC4215) += ltc4215.o
84	85	obj-$(CONFIG_SENSORS_LTC4245) += ltc4245.o
85	86	obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o
	1	+/*
	2	+ * Driver for Linear Technology LTC4151 High Voltage I2C Current
	3	+ * and Voltage Monitor
	4	+ *
	5	+ * Copyright (C) 2011 AppearTV AS
	6	+ *
	7	+ * Derived from:
	8	+ *
	9	+ * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot
	10	+ * Swap Controller
	11	+ * Copyright (C) 2010 Ericsson AB.
	12	+ *
	13	+ * Datasheet: http://www.linear.com/docs/Datasheet/4151fc.pdf
	14	+ *
	15	+ * This program is free software; you can redistribute it and/or modify
	16	+ * it under the terms of the GNU General Public License as published by
	17	+ * the Free Software Foundation; either version 2 of the License, or
	18	+ * (at your option) any later version.
	19	+ *
	20	+ * This program is distributed in the hope that it will be useful,
	21	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	22	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	23	+ * GNU General Public License for more details.
	24	+ *
	25	+ * You should have received a copy of the GNU General Public License
	26	+ * along with this program; if not, write to the Free Software
	27	+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	28	+ *
	29	+ */
	30	+
	31	+#include <linux/kernel.h>
	32	+#include <linux/module.h>
	33	+#include <linux/init.h>
	34	+#include <linux/err.h>
	35	+#include <linux/slab.h>
	36	+#include <linux/i2c.h>
	37	+#include <linux/hwmon.h>
	38	+#include <linux/hwmon-sysfs.h>
	39	+
	40	+/* chip registers */
	41	+#define LTC4151_SENSE_H 0x00
	42	+#define LTC4151_SENSE_L 0x01
	43	+#define LTC4151_VIN_H 0x02
	44	+#define LTC4151_VIN_L 0x03
	45	+#define LTC4151_ADIN_H 0x04
	46	+#define LTC4151_ADIN_L 0x05
	47	+
	48	+struct ltc4151_data {
	49	+ struct device *hwmon_dev;
	50	+
	51	+ struct mutex update_lock;
	52	+ bool valid;
	53	+ unsigned long last_updated; /* in jiffies */
	54	+
	55	+ /* Registers */
	56	+ u8 regs[6];
	57	+};
	58	+
	59	+static struct ltc4151_data ltc4151_update_device(struct device dev)
	60	+{
	61	+ struct i2c_client *client = to_i2c_client(dev);
	62	+ struct ltc4151_data *data = i2c_get_clientdata(client);
	63	+ struct ltc4151_data *ret = data;
	64	+
	65	+ mutex_lock(&data->update_lock);
	66	+
	67	+ /*
	68	+ * The chip's A/D updates 6 times per second
	69	+ * (Conversion Rate 6 - 9 Hz)
	70	+ */
	71	+ if (time_after(jiffies, data->last_updated + HZ / 6) \|\| !data->valid) {
	72	+ int i;
	73	+
	74	+ dev_dbg(&client->dev, "Starting ltc4151 update\n");
	75	+
	76	+ /* Read all registers */
	77	+ for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
	78	+ int val;
	79	+
	80	+ val = i2c_smbus_read_byte_data(client, i);
	81	+ if (unlikely(val < 0)) {
	82	+ dev_dbg(dev,
	83	+ "Failed to read ADC value: error %d\n",
	84	+ val);
	85	+ ret = ERR_PTR(val);
	86	+ goto abort;
	87	+ }
	88	+ data->regs[i] = val;
	89	+ }
	90	+ data->last_updated = jiffies;
	91	+ data->valid = 1;
	92	+ }
	93	+abort:
	94	+ mutex_unlock(&data->update_lock);
	95	+ return ret;
	96	+}
	97	+
	98	+/* Return the voltage from the given register in mV */
	99	+static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
	100	+{
	101	+ u32 val;
	102	+
	103	+ val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4);
	104	+
	105	+ switch (reg) {
	106	+ case LTC4151_ADIN_H:
	107	+ /* 500uV resolution. Convert to mV. */
	108	+ val = val * 500 / 1000;
	109	+ break;
	110	+ case LTC4151_SENSE_H:
	111	+ /*
	112	+ * 20uV resolution. Convert to current as measured with
	113	+ * an 1 mOhm sense resistor, in mA.
	114	+ */
	115	+ val = val * 20;
	116	+ break;
	117	+ case LTC4151_VIN_H:
	118	+ /* 25 mV per increment */
	119	+ val = val * 25;
	120	+ break;
	121	+ default:
	122	+ /* If we get here, the developer messed up */
	123	+ WARN_ON_ONCE(1);
	124	+ val = 0;
	125	+ break;
	126	+ }
	127	+
	128	+ return val;
	129	+}
	130	+
	131	+static ssize_t ltc4151_show_value(struct device *dev,
	132	+ struct device_attribute da, char buf)
	133	+{
	134	+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	135	+ struct ltc4151_data *data = ltc4151_update_device(dev);
	136	+ int value;
	137	+
	138	+ if (IS_ERR(data))
	139	+ return PTR_ERR(data);
	140	+
	141	+ value = ltc4151_get_value(data, attr->index);
	142	+ return snprintf(buf, PAGE_SIZE, "%d\n", value);
	143	+}
	144	+
	145	+/*
	146	+ * Input voltages.
	147	+ */
	148	+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
	149	+ ltc4151_show_value, NULL, LTC4151_VIN_H);
	150	+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, \
	151	+ ltc4151_show_value, NULL, LTC4151_ADIN_H);
	152	+
	153	+/* Currents (via sense resistor) */
	154	+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
	155	+ ltc4151_show_value, NULL, LTC4151_SENSE_H);
	156	+
	157	+/* Finally, construct an array of pointers to members of the above objects,
	158	+ * as required for sysfs_create_group()
	159	+ */
	160	+static struct attribute *ltc4151_attributes[] = {
	161	+ &sensor_dev_attr_in1_input.dev_attr.attr,
	162	+ &sensor_dev_attr_in2_input.dev_attr.attr,
	163	+
	164	+ &sensor_dev_attr_curr1_input.dev_attr.attr,
	165	+
	166	+ NULL,
	167	+};
	168	+
	169	+static const struct attribute_group ltc4151_group = {
	170	+ .attrs = ltc4151_attributes,
	171	+};
	172	+
	173	+static int ltc4151_probe(struct i2c_client *client,
	174	+ const struct i2c_device_id *id)
	175	+{
	176	+ struct i2c_adapter *adapter = client->adapter;
	177	+ struct ltc4151_data *data;
	178	+ int ret;
	179	+
	180	+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
	181	+ return -ENODEV;
	182	+
	183	+ data = kzalloc(sizeof(*data), GFP_KERNEL);
	184	+ if (!data) {
	185	+ ret = -ENOMEM;
	186	+ goto out_kzalloc;
	187	+ }
	188	+
	189	+ i2c_set_clientdata(client, data);
	190	+ mutex_init(&data->update_lock);
	191	+
	192	+ /* Register sysfs hooks */
	193	+ ret = sysfs_create_group(&client->dev.kobj, &ltc4151_group);
	194	+ if (ret)
	195	+ goto out_sysfs_create_group;
	196	+
	197	+ data->hwmon_dev = hwmon_device_register(&client->dev);
	198	+ if (IS_ERR(data->hwmon_dev)) {
	199	+ ret = PTR_ERR(data->hwmon_dev);
	200	+ goto out_hwmon_device_register;
	201	+ }
	202	+
	203	+ return 0;
	204	+
	205	+out_hwmon_device_register:
	206	+ sysfs_remove_group(&client->dev.kobj, &ltc4151_group);
	207	+out_sysfs_create_group:
	208	+ kfree(data);
	209	+out_kzalloc:
	210	+ return ret;
	211	+}
	212	+
	213	+static int ltc4151_remove(struct i2c_client *client)
	214	+{
	215	+ struct ltc4151_data *data = i2c_get_clientdata(client);
	216	+
	217	+ hwmon_device_unregister(data->hwmon_dev);
	218	+ sysfs_remove_group(&client->dev.kobj, &ltc4151_group);
	219	+
	220	+ kfree(data);
	221	+
	222	+ return 0;
	223	+}
	224	+
	225	+static const struct i2c_device_id ltc4151_id[] = {
	226	+ { "ltc4151", 0 },
	227	+ { }
	228	+};
	229	+MODULE_DEVICE_TABLE(i2c, ltc4151_id);
	230	+
	231	+/* This is the driver that will be inserted */
	232	+static struct i2c_driver ltc4151_driver = {
	233	+ .driver = {
	234	+ .name = "ltc4151",
	235	+ },
	236	+ .probe = ltc4151_probe,
	237	+ .remove = ltc4151_remove,
	238	+ .id_table = ltc4151_id,
	239	+};
	240	+
	241	+static int __init ltc4151_init(void)
	242	+{
	243	+ return i2c_add_driver(&ltc4151_driver);
	244	+}
	245	+
	246	+static void __exit ltc4151_exit(void)
	247	+{
	248	+ i2c_del_driver(&ltc4151_driver);
	249	+}
	250	+
	251	+MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
	252	+MODULE_DESCRIPTION("LTC4151 driver");
	253	+MODULE_LICENSE("GPL");
	254	+
	255	+module_init(ltc4151_init);
	256	+module_exit(ltc4151_exit);