2 * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
4 * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
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.
10 * This driver is based on the ds1621 and ina209 drivers.
13 * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/err.h>
20 #include <linux/slab.h>
21 #include <linux/i2c.h>
22 #include <linux/hwmon.h>
23 #include <linux/hwmon-sysfs.h>
24 #include <linux/jiffies.h>
25 #include <linux/i2c/ltc4245.h>
27 /* Here are names of the chip's registers (a.k.a. commands) */
29 LTC4245_STATUS
= 0x00, /* readonly */
31 LTC4245_CONTROL
= 0x02,
33 LTC4245_FAULT1
= 0x04,
34 LTC4245_FAULT2
= 0x05,
36 LTC4245_ADCADR
= 0x07,
39 LTC4245_12VSENSE
= 0x11,
40 LTC4245_12VOUT
= 0x12,
42 LTC4245_5VSENSE
= 0x14,
45 LTC4245_3VSENSE
= 0x17,
48 LTC4245_VEESENSE
= 0x1a,
49 LTC4245_VEEOUT
= 0x1b,
50 LTC4245_GPIOADC
= 0x1c,
54 struct i2c_client
*client
;
56 const struct attribute_group
*groups
[3];
58 struct mutex update_lock
;
60 unsigned long last_updated
; /* in jiffies */
62 /* Control registers */
65 /* Voltage registers */
68 /* GPIO ADC registers */
74 * Update the readings from the GPIO pins. If the driver has been configured to
75 * sample all GPIO's as analog voltages, a round-robin sampling method is used.
76 * Otherwise, only the configured GPIO pin is sampled.
78 * LOCKING: must hold data->update_lock
80 static void ltc4245_update_gpios(struct device
*dev
)
82 struct ltc4245_data
*data
= dev_get_drvdata(dev
);
83 struct i2c_client
*client
= data
->client
;
84 u8 gpio_curr
, gpio_next
, gpio_reg
;
87 /* no extra gpio support, we're basically done */
88 if (!data
->use_extra_gpios
) {
89 data
->gpios
[0] = data
->vregs
[LTC4245_GPIOADC
- 0x10];
94 * If the last reading was too long ago, then we mark all old GPIO
95 * readings as stale by setting them to -EAGAIN
97 if (time_after(jiffies
, data
->last_updated
+ 5 * HZ
)) {
98 dev_dbg(&client
->dev
, "Marking GPIOs invalid\n");
99 for (i
= 0; i
< ARRAY_SIZE(data
->gpios
); i
++)
100 data
->gpios
[i
] = -EAGAIN
;
104 * Get the current GPIO pin
106 * The datasheet calls these GPIO[1-3], but we'll calculate the zero
107 * based array index instead, and call them GPIO[0-2]. This is much
108 * easier to think about.
110 gpio_curr
= (data
->cregs
[LTC4245_GPIO
] & 0xc0) >> 6;
114 /* Read the GPIO voltage from the GPIOADC register */
115 data
->gpios
[gpio_curr
] = data
->vregs
[LTC4245_GPIOADC
- 0x10];
117 /* Find the next GPIO pin to read */
118 gpio_next
= (gpio_curr
+ 1) % ARRAY_SIZE(data
->gpios
);
121 * Calculate the correct setting for the GPIO register so it will
122 * sample the next GPIO pin
124 gpio_reg
= (data
->cregs
[LTC4245_GPIO
] & 0x3f) | ((gpio_next
+ 1) << 6);
126 /* Update the GPIO register */
127 i2c_smbus_write_byte_data(client
, LTC4245_GPIO
, gpio_reg
);
129 /* Update saved data */
130 data
->cregs
[LTC4245_GPIO
] = gpio_reg
;
133 static struct ltc4245_data
*ltc4245_update_device(struct device
*dev
)
135 struct ltc4245_data
*data
= dev_get_drvdata(dev
);
136 struct i2c_client
*client
= data
->client
;
140 mutex_lock(&data
->update_lock
);
142 if (time_after(jiffies
, data
->last_updated
+ HZ
) || !data
->valid
) {
144 dev_dbg(&client
->dev
, "Starting ltc4245 update\n");
146 /* Read control registers -- 0x00 to 0x07 */
147 for (i
= 0; i
< ARRAY_SIZE(data
->cregs
); i
++) {
148 val
= i2c_smbus_read_byte_data(client
, i
);
149 if (unlikely(val
< 0))
152 data
->cregs
[i
] = val
;
155 /* Read voltage registers -- 0x10 to 0x1c */
156 for (i
= 0; i
< ARRAY_SIZE(data
->vregs
); i
++) {
157 val
= i2c_smbus_read_byte_data(client
, i
+0x10);
158 if (unlikely(val
< 0))
161 data
->vregs
[i
] = val
;
164 /* Update GPIO readings */
165 ltc4245_update_gpios(dev
);
167 data
->last_updated
= jiffies
;
171 mutex_unlock(&data
->update_lock
);
176 /* Return the voltage from the given register in millivolts */
177 static int ltc4245_get_voltage(struct device
*dev
, u8 reg
)
179 struct ltc4245_data
*data
= ltc4245_update_device(dev
);
180 const u8 regval
= data
->vregs
[reg
- 0x10];
186 voltage
= regval
* 55;
190 voltage
= regval
* 22;
194 voltage
= regval
* 15;
198 voltage
= regval
* -55;
200 case LTC4245_GPIOADC
:
201 voltage
= regval
* 10;
204 /* If we get here, the developer messed up */
212 /* Return the current in the given sense register in milliAmperes */
213 static unsigned int ltc4245_get_current(struct device
*dev
, u8 reg
)
215 struct ltc4245_data
*data
= ltc4245_update_device(dev
);
216 const u8 regval
= data
->vregs
[reg
- 0x10];
217 unsigned int voltage
;
221 * The strange looking conversions that follow are fixed-point
222 * math, since we cannot do floating point in the kernel.
224 * Step 1: convert sense register to microVolts
225 * Step 2: convert voltage to milliAmperes
227 * If you play around with the V=IR equation, you come up with
228 * the following: X uV / Y mOhm == Z mA
230 * With the resistors that are fractions of a milliOhm, we multiply
231 * the voltage and resistance by 10, to shift the decimal point.
232 * Now we can use the normal division operator again.
236 case LTC4245_12VSENSE
:
237 voltage
= regval
* 250; /* voltage in uV */
238 curr
= voltage
/ 50; /* sense resistor 50 mOhm */
240 case LTC4245_5VSENSE
:
241 voltage
= regval
* 125; /* voltage in uV */
242 curr
= (voltage
* 10) / 35; /* sense resistor 3.5 mOhm */
244 case LTC4245_3VSENSE
:
245 voltage
= regval
* 125; /* voltage in uV */
246 curr
= (voltage
* 10) / 25; /* sense resistor 2.5 mOhm */
248 case LTC4245_VEESENSE
:
249 voltage
= regval
* 250; /* voltage in uV */
250 curr
= voltage
/ 100; /* sense resistor 100 mOhm */
253 /* If we get here, the developer messed up */
262 static ssize_t
ltc4245_show_voltage(struct device
*dev
,
263 struct device_attribute
*da
,
266 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(da
);
267 const int voltage
= ltc4245_get_voltage(dev
, attr
->index
);
269 return snprintf(buf
, PAGE_SIZE
, "%d\n", voltage
);
272 static ssize_t
ltc4245_show_current(struct device
*dev
,
273 struct device_attribute
*da
,
276 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(da
);
277 const unsigned int curr
= ltc4245_get_current(dev
, attr
->index
);
279 return snprintf(buf
, PAGE_SIZE
, "%u\n", curr
);
282 static ssize_t
ltc4245_show_power(struct device
*dev
,
283 struct device_attribute
*da
,
286 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(da
);
287 const unsigned int curr
= ltc4245_get_current(dev
, attr
->index
);
288 const int output_voltage
= ltc4245_get_voltage(dev
, attr
->index
+1);
290 /* current in mA * voltage in mV == power in uW */
291 const unsigned int power
= abs(output_voltage
* curr
);
293 return snprintf(buf
, PAGE_SIZE
, "%u\n", power
);
296 static ssize_t
ltc4245_show_alarm(struct device
*dev
,
297 struct device_attribute
*da
,
300 struct sensor_device_attribute_2
*attr
= to_sensor_dev_attr_2(da
);
301 struct ltc4245_data
*data
= ltc4245_update_device(dev
);
302 const u8 reg
= data
->cregs
[attr
->index
];
303 const u32 mask
= attr
->nr
;
305 return snprintf(buf
, PAGE_SIZE
, "%u\n", (reg
& mask
) ? 1 : 0);
308 static ssize_t
ltc4245_show_gpio(struct device
*dev
,
309 struct device_attribute
*da
,
312 struct sensor_device_attribute
*attr
= to_sensor_dev_attr(da
);
313 struct ltc4245_data
*data
= ltc4245_update_device(dev
);
314 int val
= data
->gpios
[attr
->index
];
316 /* handle stale GPIO's */
320 /* Convert to millivolts and print */
321 return snprintf(buf
, PAGE_SIZE
, "%u\n", val
* 10);
324 /* Construct a sensor_device_attribute structure for each register */
327 static SENSOR_DEVICE_ATTR(in1_input
, S_IRUGO
, ltc4245_show_voltage
, NULL
,
329 static SENSOR_DEVICE_ATTR(in2_input
, S_IRUGO
, ltc4245_show_voltage
, NULL
,
331 static SENSOR_DEVICE_ATTR(in3_input
, S_IRUGO
, ltc4245_show_voltage
, NULL
,
333 static SENSOR_DEVICE_ATTR(in4_input
, S_IRUGO
, ltc4245_show_voltage
, NULL
,
336 /* Input undervoltage alarms */
337 static SENSOR_DEVICE_ATTR_2(in1_min_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
338 1 << 0, LTC4245_FAULT1
);
339 static SENSOR_DEVICE_ATTR_2(in2_min_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
340 1 << 1, LTC4245_FAULT1
);
341 static SENSOR_DEVICE_ATTR_2(in3_min_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
342 1 << 2, LTC4245_FAULT1
);
343 static SENSOR_DEVICE_ATTR_2(in4_min_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
344 1 << 3, LTC4245_FAULT1
);
346 /* Currents (via sense resistor) */
347 static SENSOR_DEVICE_ATTR(curr1_input
, S_IRUGO
, ltc4245_show_current
, NULL
,
349 static SENSOR_DEVICE_ATTR(curr2_input
, S_IRUGO
, ltc4245_show_current
, NULL
,
351 static SENSOR_DEVICE_ATTR(curr3_input
, S_IRUGO
, ltc4245_show_current
, NULL
,
353 static SENSOR_DEVICE_ATTR(curr4_input
, S_IRUGO
, ltc4245_show_current
, NULL
,
356 /* Overcurrent alarms */
357 static SENSOR_DEVICE_ATTR_2(curr1_max_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
358 1 << 4, LTC4245_FAULT1
);
359 static SENSOR_DEVICE_ATTR_2(curr2_max_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
360 1 << 5, LTC4245_FAULT1
);
361 static SENSOR_DEVICE_ATTR_2(curr3_max_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
362 1 << 6, LTC4245_FAULT1
);
363 static SENSOR_DEVICE_ATTR_2(curr4_max_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
364 1 << 7, LTC4245_FAULT1
);
366 /* Output voltages */
367 static SENSOR_DEVICE_ATTR(in5_input
, S_IRUGO
, ltc4245_show_voltage
, NULL
,
369 static SENSOR_DEVICE_ATTR(in6_input
, S_IRUGO
, ltc4245_show_voltage
, NULL
,
371 static SENSOR_DEVICE_ATTR(in7_input
, S_IRUGO
, ltc4245_show_voltage
, NULL
,
373 static SENSOR_DEVICE_ATTR(in8_input
, S_IRUGO
, ltc4245_show_voltage
, NULL
,
376 /* Power Bad alarms */
377 static SENSOR_DEVICE_ATTR_2(in5_min_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
378 1 << 0, LTC4245_FAULT2
);
379 static SENSOR_DEVICE_ATTR_2(in6_min_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
380 1 << 1, LTC4245_FAULT2
);
381 static SENSOR_DEVICE_ATTR_2(in7_min_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
382 1 << 2, LTC4245_FAULT2
);
383 static SENSOR_DEVICE_ATTR_2(in8_min_alarm
, S_IRUGO
, ltc4245_show_alarm
, NULL
,
384 1 << 3, LTC4245_FAULT2
);
387 static SENSOR_DEVICE_ATTR(in9_input
, S_IRUGO
, ltc4245_show_gpio
, NULL
, 0);
388 static SENSOR_DEVICE_ATTR(in10_input
, S_IRUGO
, ltc4245_show_gpio
, NULL
, 1);
389 static SENSOR_DEVICE_ATTR(in11_input
, S_IRUGO
, ltc4245_show_gpio
, NULL
, 2);
391 /* Power Consumption (virtual) */
392 static SENSOR_DEVICE_ATTR(power1_input
, S_IRUGO
, ltc4245_show_power
, NULL
,
394 static SENSOR_DEVICE_ATTR(power2_input
, S_IRUGO
, ltc4245_show_power
, NULL
,
396 static SENSOR_DEVICE_ATTR(power3_input
, S_IRUGO
, ltc4245_show_power
, NULL
,
398 static SENSOR_DEVICE_ATTR(power4_input
, S_IRUGO
, ltc4245_show_power
, NULL
,
402 * Finally, construct an array of pointers to members of the above objects,
403 * as required for sysfs_create_group()
405 static struct attribute
*ltc4245_std_attributes
[] = {
406 &sensor_dev_attr_in1_input
.dev_attr
.attr
,
407 &sensor_dev_attr_in2_input
.dev_attr
.attr
,
408 &sensor_dev_attr_in3_input
.dev_attr
.attr
,
409 &sensor_dev_attr_in4_input
.dev_attr
.attr
,
411 &sensor_dev_attr_in1_min_alarm
.dev_attr
.attr
,
412 &sensor_dev_attr_in2_min_alarm
.dev_attr
.attr
,
413 &sensor_dev_attr_in3_min_alarm
.dev_attr
.attr
,
414 &sensor_dev_attr_in4_min_alarm
.dev_attr
.attr
,
416 &sensor_dev_attr_curr1_input
.dev_attr
.attr
,
417 &sensor_dev_attr_curr2_input
.dev_attr
.attr
,
418 &sensor_dev_attr_curr3_input
.dev_attr
.attr
,
419 &sensor_dev_attr_curr4_input
.dev_attr
.attr
,
421 &sensor_dev_attr_curr1_max_alarm
.dev_attr
.attr
,
422 &sensor_dev_attr_curr2_max_alarm
.dev_attr
.attr
,
423 &sensor_dev_attr_curr3_max_alarm
.dev_attr
.attr
,
424 &sensor_dev_attr_curr4_max_alarm
.dev_attr
.attr
,
426 &sensor_dev_attr_in5_input
.dev_attr
.attr
,
427 &sensor_dev_attr_in6_input
.dev_attr
.attr
,
428 &sensor_dev_attr_in7_input
.dev_attr
.attr
,
429 &sensor_dev_attr_in8_input
.dev_attr
.attr
,
431 &sensor_dev_attr_in5_min_alarm
.dev_attr
.attr
,
432 &sensor_dev_attr_in6_min_alarm
.dev_attr
.attr
,
433 &sensor_dev_attr_in7_min_alarm
.dev_attr
.attr
,
434 &sensor_dev_attr_in8_min_alarm
.dev_attr
.attr
,
436 &sensor_dev_attr_in9_input
.dev_attr
.attr
,
438 &sensor_dev_attr_power1_input
.dev_attr
.attr
,
439 &sensor_dev_attr_power2_input
.dev_attr
.attr
,
440 &sensor_dev_attr_power3_input
.dev_attr
.attr
,
441 &sensor_dev_attr_power4_input
.dev_attr
.attr
,
446 static struct attribute
*ltc4245_gpio_attributes
[] = {
447 &sensor_dev_attr_in10_input
.dev_attr
.attr
,
448 &sensor_dev_attr_in11_input
.dev_attr
.attr
,
452 static const struct attribute_group ltc4245_std_group
= {
453 .attrs
= ltc4245_std_attributes
,
456 static const struct attribute_group ltc4245_gpio_group
= {
457 .attrs
= ltc4245_gpio_attributes
,
460 static void ltc4245_sysfs_add_groups(struct ltc4245_data
*data
)
462 /* standard sysfs attributes */
463 data
->groups
[0] = <c4245_std_group
;
465 /* if we're using the extra gpio support, register it's attributes */
466 if (data
->use_extra_gpios
)
467 data
->groups
[1] = <c4245_gpio_group
;
470 static bool ltc4245_use_extra_gpios(struct i2c_client
*client
)
472 struct ltc4245_platform_data
*pdata
= dev_get_platdata(&client
->dev
);
474 struct device_node
*np
= client
->dev
.of_node
;
477 /* prefer platform data */
479 return pdata
->use_extra_gpios
;
483 if (of_find_property(np
, "ltc4245,use-extra-gpios", NULL
))
490 static int ltc4245_probe(struct i2c_client
*client
,
491 const struct i2c_device_id
*id
)
493 struct i2c_adapter
*adapter
= client
->adapter
;
494 struct ltc4245_data
*data
;
495 struct device
*hwmon_dev
;
497 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_BYTE_DATA
))
500 data
= devm_kzalloc(&client
->dev
, sizeof(*data
), GFP_KERNEL
);
504 data
->client
= client
;
505 mutex_init(&data
->update_lock
);
506 data
->use_extra_gpios
= ltc4245_use_extra_gpios(client
);
508 /* Initialize the LTC4245 chip */
509 i2c_smbus_write_byte_data(client
, LTC4245_FAULT1
, 0x00);
510 i2c_smbus_write_byte_data(client
, LTC4245_FAULT2
, 0x00);
512 /* Add sysfs hooks */
513 ltc4245_sysfs_add_groups(data
);
515 hwmon_dev
= hwmon_device_register_with_groups(&client
->dev
,
518 if (IS_ERR(hwmon_dev
))
519 return PTR_ERR(hwmon_dev
);
521 i2c_set_clientdata(client
, hwmon_dev
);
526 static int ltc4245_remove(struct i2c_client
*client
)
528 struct device
*hwmon_dev
= i2c_get_clientdata(client
);
530 hwmon_device_unregister(hwmon_dev
);
535 static const struct i2c_device_id ltc4245_id
[] = {
539 MODULE_DEVICE_TABLE(i2c
, ltc4245_id
);
541 /* This is the driver that will be inserted */
542 static struct i2c_driver ltc4245_driver
= {
546 .probe
= ltc4245_probe
,
547 .remove
= ltc4245_remove
,
548 .id_table
= ltc4245_id
,
551 module_i2c_driver(ltc4245_driver
);
553 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
554 MODULE_DESCRIPTION("LTC4245 driver");
555 MODULE_LICENSE("GPL");