Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Driver for Linear Technology LTC4215 I2C Hot Swap Controller |
| 3 | * |
| 4 | * Copyright (C) 2009 Ira W. Snyder <iws@ovro.caltech.edu> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; version 2 of the License. |
| 9 | * |
| 10 | * Datasheet: |
| 11 | * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1163,P17572,D12697 |
| 12 | */ |
| 13 | |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/err.h> |
| 18 | #include <linux/slab.h> |
| 19 | #include <linux/i2c.h> |
| 20 | #include <linux/hwmon.h> |
| 21 | #include <linux/hwmon-sysfs.h> |
Jean Delvare | dcd8f39 | 2012-10-10 15:25:56 +0200 | [diff] [blame] | 22 | #include <linux/jiffies.h> |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 23 | |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 24 | /* Here are names of the chip's registers (a.k.a. commands) */ |
| 25 | enum ltc4215_cmd { |
| 26 | LTC4215_CONTROL = 0x00, /* rw */ |
| 27 | LTC4215_ALERT = 0x01, /* rw */ |
| 28 | LTC4215_STATUS = 0x02, /* ro */ |
| 29 | LTC4215_FAULT = 0x03, /* rw */ |
| 30 | LTC4215_SENSE = 0x04, /* rw */ |
| 31 | LTC4215_SOURCE = 0x05, /* rw */ |
| 32 | LTC4215_ADIN = 0x06, /* rw */ |
| 33 | }; |
| 34 | |
| 35 | struct ltc4215_data { |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 36 | struct i2c_client *client; |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 37 | |
| 38 | struct mutex update_lock; |
| 39 | bool valid; |
| 40 | unsigned long last_updated; /* in jiffies */ |
| 41 | |
| 42 | /* Registers */ |
| 43 | u8 regs[7]; |
| 44 | }; |
| 45 | |
| 46 | static struct ltc4215_data *ltc4215_update_device(struct device *dev) |
| 47 | { |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 48 | struct ltc4215_data *data = dev_get_drvdata(dev); |
| 49 | struct i2c_client *client = data->client; |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 50 | s32 val; |
| 51 | int i; |
| 52 | |
| 53 | mutex_lock(&data->update_lock); |
| 54 | |
| 55 | /* The chip's A/D updates 10 times per second */ |
| 56 | if (time_after(jiffies, data->last_updated + HZ / 10) || !data->valid) { |
| 57 | |
| 58 | dev_dbg(&client->dev, "Starting ltc4215 update\n"); |
| 59 | |
| 60 | /* Read all registers */ |
| 61 | for (i = 0; i < ARRAY_SIZE(data->regs); i++) { |
| 62 | val = i2c_smbus_read_byte_data(client, i); |
| 63 | if (unlikely(val < 0)) |
| 64 | data->regs[i] = 0; |
| 65 | else |
| 66 | data->regs[i] = val; |
| 67 | } |
| 68 | |
| 69 | data->last_updated = jiffies; |
| 70 | data->valid = 1; |
| 71 | } |
| 72 | |
| 73 | mutex_unlock(&data->update_lock); |
| 74 | |
| 75 | return data; |
| 76 | } |
| 77 | |
| 78 | /* Return the voltage from the given register in millivolts */ |
| 79 | static int ltc4215_get_voltage(struct device *dev, u8 reg) |
| 80 | { |
| 81 | struct ltc4215_data *data = ltc4215_update_device(dev); |
| 82 | const u8 regval = data->regs[reg]; |
| 83 | u32 voltage = 0; |
| 84 | |
| 85 | switch (reg) { |
| 86 | case LTC4215_SENSE: |
| 87 | /* 151 uV per increment */ |
| 88 | voltage = regval * 151 / 1000; |
| 89 | break; |
| 90 | case LTC4215_SOURCE: |
| 91 | /* 60.5 mV per increment */ |
| 92 | voltage = regval * 605 / 10; |
| 93 | break; |
| 94 | case LTC4215_ADIN: |
Guenter Roeck | 790fa38 | 2012-01-19 11:02:21 -0800 | [diff] [blame] | 95 | /* |
| 96 | * The ADIN input is divided by 12.5, and has 4.82 mV |
| 97 | * per increment, so we have the additional multiply |
| 98 | */ |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 99 | voltage = regval * 482 * 125 / 1000; |
| 100 | break; |
| 101 | default: |
| 102 | /* If we get here, the developer messed up */ |
| 103 | WARN_ON_ONCE(1); |
| 104 | break; |
| 105 | } |
| 106 | |
| 107 | return voltage; |
| 108 | } |
| 109 | |
| 110 | /* Return the current from the sense resistor in mA */ |
| 111 | static unsigned int ltc4215_get_current(struct device *dev) |
| 112 | { |
| 113 | struct ltc4215_data *data = ltc4215_update_device(dev); |
| 114 | |
Guenter Roeck | 790fa38 | 2012-01-19 11:02:21 -0800 | [diff] [blame] | 115 | /* |
| 116 | * The strange looking conversions that follow are fixed-point |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 117 | * math, since we cannot do floating point in the kernel. |
| 118 | * |
| 119 | * Step 1: convert sense register to microVolts |
| 120 | * Step 2: convert voltage to milliAmperes |
| 121 | * |
| 122 | * If you play around with the V=IR equation, you come up with |
| 123 | * the following: X uV / Y mOhm == Z mA |
| 124 | * |
| 125 | * With the resistors that are fractions of a milliOhm, we multiply |
| 126 | * the voltage and resistance by 10, to shift the decimal point. |
| 127 | * Now we can use the normal division operator again. |
| 128 | */ |
| 129 | |
| 130 | /* Calculate voltage in microVolts (151 uV per increment) */ |
| 131 | const unsigned int voltage = data->regs[LTC4215_SENSE] * 151; |
| 132 | |
| 133 | /* Calculate current in milliAmperes (4 milliOhm sense resistor) */ |
| 134 | const unsigned int curr = voltage / 4; |
| 135 | |
| 136 | return curr; |
| 137 | } |
| 138 | |
| 139 | static ssize_t ltc4215_show_voltage(struct device *dev, |
| 140 | struct device_attribute *da, |
| 141 | char *buf) |
| 142 | { |
| 143 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
| 144 | const int voltage = ltc4215_get_voltage(dev, attr->index); |
| 145 | |
| 146 | return snprintf(buf, PAGE_SIZE, "%d\n", voltage); |
| 147 | } |
| 148 | |
| 149 | static ssize_t ltc4215_show_current(struct device *dev, |
| 150 | struct device_attribute *da, |
| 151 | char *buf) |
| 152 | { |
| 153 | const unsigned int curr = ltc4215_get_current(dev); |
| 154 | |
| 155 | return snprintf(buf, PAGE_SIZE, "%u\n", curr); |
| 156 | } |
| 157 | |
| 158 | static ssize_t ltc4215_show_power(struct device *dev, |
| 159 | struct device_attribute *da, |
| 160 | char *buf) |
| 161 | { |
| 162 | const unsigned int curr = ltc4215_get_current(dev); |
| 163 | const int output_voltage = ltc4215_get_voltage(dev, LTC4215_ADIN); |
| 164 | |
| 165 | /* current in mA * voltage in mV == power in uW */ |
| 166 | const unsigned int power = abs(output_voltage * curr); |
| 167 | |
| 168 | return snprintf(buf, PAGE_SIZE, "%u\n", power); |
| 169 | } |
| 170 | |
| 171 | static ssize_t ltc4215_show_alarm(struct device *dev, |
| 172 | struct device_attribute *da, |
| 173 | char *buf) |
| 174 | { |
Guenter Roeck | b5f0f1e | 2013-01-10 10:30:31 -0800 | [diff] [blame] | 175 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 176 | struct ltc4215_data *data = ltc4215_update_device(dev); |
Guenter Roeck | b5f0f1e | 2013-01-10 10:30:31 -0800 | [diff] [blame] | 177 | const u8 reg = data->regs[LTC4215_STATUS]; |
| 178 | const u32 mask = attr->index; |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 179 | |
Guenter Roeck | b5f0f1e | 2013-01-10 10:30:31 -0800 | [diff] [blame] | 180 | return snprintf(buf, PAGE_SIZE, "%u\n", !!(reg & mask)); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 181 | } |
| 182 | |
Guenter Roeck | 790fa38 | 2012-01-19 11:02:21 -0800 | [diff] [blame] | 183 | /* |
| 184 | * These macros are used below in constructing device attribute objects |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 185 | * for use with sysfs_create_group() to make a sysfs device file |
| 186 | * for each register. |
| 187 | */ |
| 188 | |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 189 | /* Construct a sensor_device_attribute structure for each register */ |
| 190 | |
| 191 | /* Current */ |
Guenter Roeck | b5f0f1e | 2013-01-10 10:30:31 -0800 | [diff] [blame] | 192 | static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4215_show_current, NULL, 0); |
| 193 | static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4215_show_alarm, NULL, |
| 194 | 1 << 2); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 195 | |
| 196 | /* Power (virtual) */ |
Guenter Roeck | b5f0f1e | 2013-01-10 10:30:31 -0800 | [diff] [blame] | 197 | static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ltc4215_show_power, NULL, 0); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 198 | |
| 199 | /* Input Voltage */ |
Guenter Roeck | b5f0f1e | 2013-01-10 10:30:31 -0800 | [diff] [blame] | 200 | static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4215_show_voltage, NULL, |
| 201 | LTC4215_ADIN); |
| 202 | static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4215_show_alarm, NULL, |
| 203 | 1 << 0); |
| 204 | static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4215_show_alarm, NULL, |
| 205 | 1 << 1); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 206 | |
| 207 | /* Output Voltage */ |
Guenter Roeck | b5f0f1e | 2013-01-10 10:30:31 -0800 | [diff] [blame] | 208 | static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4215_show_voltage, NULL, |
| 209 | LTC4215_SOURCE); |
| 210 | static SENSOR_DEVICE_ATTR(in2_min_alarm, S_IRUGO, ltc4215_show_alarm, NULL, |
| 211 | 1 << 3); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 212 | |
Guenter Roeck | 790fa38 | 2012-01-19 11:02:21 -0800 | [diff] [blame] | 213 | /* |
| 214 | * Finally, construct an array of pointers to members of the above objects, |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 215 | * as required for sysfs_create_group() |
| 216 | */ |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 217 | static struct attribute *ltc4215_attrs[] = { |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 218 | &sensor_dev_attr_curr1_input.dev_attr.attr, |
| 219 | &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, |
| 220 | |
| 221 | &sensor_dev_attr_power1_input.dev_attr.attr, |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 222 | |
| 223 | &sensor_dev_attr_in1_input.dev_attr.attr, |
| 224 | &sensor_dev_attr_in1_max_alarm.dev_attr.attr, |
| 225 | &sensor_dev_attr_in1_min_alarm.dev_attr.attr, |
| 226 | |
| 227 | &sensor_dev_attr_in2_input.dev_attr.attr, |
Ira W. Snyder | 0a6bf65 | 2010-12-13 11:42:30 -0500 | [diff] [blame] | 228 | &sensor_dev_attr_in2_min_alarm.dev_attr.attr, |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 229 | |
| 230 | NULL, |
| 231 | }; |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 232 | ATTRIBUTE_GROUPS(ltc4215); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 233 | |
| 234 | static int ltc4215_probe(struct i2c_client *client, |
| 235 | const struct i2c_device_id *id) |
| 236 | { |
Jean Delvare | 2d2a7cf | 2009-10-04 22:53:42 +0200 | [diff] [blame] | 237 | struct i2c_adapter *adapter = client->adapter; |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 238 | struct device *dev = &client->dev; |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 239 | struct ltc4215_data *data; |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 240 | struct device *hwmon_dev; |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 241 | |
Jean Delvare | 2d2a7cf | 2009-10-04 22:53:42 +0200 | [diff] [blame] | 242 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
| 243 | return -ENODEV; |
| 244 | |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 245 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
Guenter Roeck | d2b95e5 | 2012-06-02 10:35:52 -0700 | [diff] [blame] | 246 | if (!data) |
| 247 | return -ENOMEM; |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 248 | |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 249 | data->client = client; |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 250 | mutex_init(&data->update_lock); |
| 251 | |
| 252 | /* Initialize the LTC4215 chip */ |
Ira W. Snyder | b6b9d69 | 2009-09-23 22:59:43 +0200 | [diff] [blame] | 253 | i2c_smbus_write_byte_data(client, LTC4215_FAULT, 0x00); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 254 | |
Guenter Roeck | 6c588b4 | 2014-02-15 22:05:17 -0800 | [diff] [blame^] | 255 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
| 256 | data, |
| 257 | ltc4215_groups); |
| 258 | return PTR_ERR_OR_ZERO(hwmon_dev); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 259 | } |
| 260 | |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 261 | static const struct i2c_device_id ltc4215_id[] = { |
Jean Delvare | 2d2a7cf | 2009-10-04 22:53:42 +0200 | [diff] [blame] | 262 | { "ltc4215", 0 }, |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 263 | { } |
| 264 | }; |
| 265 | MODULE_DEVICE_TABLE(i2c, ltc4215_id); |
| 266 | |
| 267 | /* This is the driver that will be inserted */ |
| 268 | static struct i2c_driver ltc4215_driver = { |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 269 | .driver = { |
| 270 | .name = "ltc4215", |
| 271 | }, |
| 272 | .probe = ltc4215_probe, |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 273 | .id_table = ltc4215_id, |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 274 | }; |
| 275 | |
Axel Lin | f0967ee | 2012-01-20 15:38:18 +0800 | [diff] [blame] | 276 | module_i2c_driver(ltc4215_driver); |
Ira Snyder | 72f5de9 | 2009-03-31 15:24:29 -0700 | [diff] [blame] | 277 | |
| 278 | MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>"); |
| 279 | MODULE_DESCRIPTION("LTC4215 driver"); |
| 280 | MODULE_LICENSE("GPL"); |