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b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
6e34b187 IS |
2 | /* |
3 | * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller | |
4 | * | |
5 | * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu> | |
6 | * | |
6e34b187 IS |
7 | * This driver is based on the ds1621 and ina209 drivers. |
8 | * | |
9 | * Datasheet: | |
10 | * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517 | |
11 | */ | |
12 | ||
13 | #include <linux/kernel.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/init.h> | |
a584287c | 16 | #include <linux/bitops.h> |
6e34b187 IS |
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> | |
dcd8f392 | 22 | #include <linux/jiffies.h> |
8116e8dd | 23 | #include <linux/platform_data/ltc4245.h> |
6e34b187 | 24 | |
6e34b187 IS |
25 | /* Here are names of the chip's registers (a.k.a. commands) */ |
26 | enum ltc4245_cmd { | |
27 | LTC4245_STATUS = 0x00, /* readonly */ | |
28 | LTC4245_ALERT = 0x01, | |
29 | LTC4245_CONTROL = 0x02, | |
30 | LTC4245_ON = 0x03, | |
31 | LTC4245_FAULT1 = 0x04, | |
32 | LTC4245_FAULT2 = 0x05, | |
33 | LTC4245_GPIO = 0x06, | |
34 | LTC4245_ADCADR = 0x07, | |
35 | ||
36 | LTC4245_12VIN = 0x10, | |
37 | LTC4245_12VSENSE = 0x11, | |
38 | LTC4245_12VOUT = 0x12, | |
39 | LTC4245_5VIN = 0x13, | |
40 | LTC4245_5VSENSE = 0x14, | |
41 | LTC4245_5VOUT = 0x15, | |
42 | LTC4245_3VIN = 0x16, | |
43 | LTC4245_3VSENSE = 0x17, | |
44 | LTC4245_3VOUT = 0x18, | |
45 | LTC4245_VEEIN = 0x19, | |
46 | LTC4245_VEESENSE = 0x1a, | |
47 | LTC4245_VEEOUT = 0x1b, | |
df16dd53 | 48 | LTC4245_GPIOADC = 0x1c, |
6e34b187 IS |
49 | }; |
50 | ||
51 | struct ltc4245_data { | |
9a85d53c GR |
52 | struct i2c_client *client; |
53 | ||
6e34b187 IS |
54 | struct mutex update_lock; |
55 | bool valid; | |
56 | unsigned long last_updated; /* in jiffies */ | |
57 | ||
58 | /* Control registers */ | |
59 | u8 cregs[0x08]; | |
60 | ||
61 | /* Voltage registers */ | |
df16dd53 | 62 | u8 vregs[0x0d]; |
5950ec8d IS |
63 | |
64 | /* GPIO ADC registers */ | |
65 | bool use_extra_gpios; | |
66 | int gpios[3]; | |
6e34b187 IS |
67 | }; |
68 | ||
5950ec8d IS |
69 | /* |
70 | * Update the readings from the GPIO pins. If the driver has been configured to | |
71 | * sample all GPIO's as analog voltages, a round-robin sampling method is used. | |
72 | * Otherwise, only the configured GPIO pin is sampled. | |
73 | * | |
74 | * LOCKING: must hold data->update_lock | |
75 | */ | |
76 | static void ltc4245_update_gpios(struct device *dev) | |
77 | { | |
9a85d53c GR |
78 | struct ltc4245_data *data = dev_get_drvdata(dev); |
79 | struct i2c_client *client = data->client; | |
5950ec8d IS |
80 | u8 gpio_curr, gpio_next, gpio_reg; |
81 | int i; | |
82 | ||
83 | /* no extra gpio support, we're basically done */ | |
84 | if (!data->use_extra_gpios) { | |
85 | data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10]; | |
86 | return; | |
87 | } | |
88 | ||
89 | /* | |
90 | * If the last reading was too long ago, then we mark all old GPIO | |
91 | * readings as stale by setting them to -EAGAIN | |
92 | */ | |
93 | if (time_after(jiffies, data->last_updated + 5 * HZ)) { | |
5950ec8d IS |
94 | for (i = 0; i < ARRAY_SIZE(data->gpios); i++) |
95 | data->gpios[i] = -EAGAIN; | |
96 | } | |
97 | ||
98 | /* | |
99 | * Get the current GPIO pin | |
100 | * | |
101 | * The datasheet calls these GPIO[1-3], but we'll calculate the zero | |
102 | * based array index instead, and call them GPIO[0-2]. This is much | |
103 | * easier to think about. | |
104 | */ | |
105 | gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6; | |
106 | if (gpio_curr > 0) | |
107 | gpio_curr -= 1; | |
108 | ||
109 | /* Read the GPIO voltage from the GPIOADC register */ | |
110 | data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10]; | |
111 | ||
112 | /* Find the next GPIO pin to read */ | |
113 | gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios); | |
114 | ||
115 | /* | |
116 | * Calculate the correct setting for the GPIO register so it will | |
117 | * sample the next GPIO pin | |
118 | */ | |
119 | gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6); | |
120 | ||
121 | /* Update the GPIO register */ | |
122 | i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg); | |
123 | ||
124 | /* Update saved data */ | |
125 | data->cregs[LTC4245_GPIO] = gpio_reg; | |
126 | } | |
127 | ||
6e34b187 IS |
128 | static struct ltc4245_data *ltc4245_update_device(struct device *dev) |
129 | { | |
9a85d53c GR |
130 | struct ltc4245_data *data = dev_get_drvdata(dev); |
131 | struct i2c_client *client = data->client; | |
6e34b187 IS |
132 | s32 val; |
133 | int i; | |
134 | ||
135 | mutex_lock(&data->update_lock); | |
136 | ||
137 | if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { | |
138 | ||
6e34b187 IS |
139 | /* Read control registers -- 0x00 to 0x07 */ |
140 | for (i = 0; i < ARRAY_SIZE(data->cregs); i++) { | |
141 | val = i2c_smbus_read_byte_data(client, i); | |
142 | if (unlikely(val < 0)) | |
143 | data->cregs[i] = 0; | |
144 | else | |
145 | data->cregs[i] = val; | |
146 | } | |
147 | ||
df16dd53 | 148 | /* Read voltage registers -- 0x10 to 0x1c */ |
6e34b187 IS |
149 | for (i = 0; i < ARRAY_SIZE(data->vregs); i++) { |
150 | val = i2c_smbus_read_byte_data(client, i+0x10); | |
151 | if (unlikely(val < 0)) | |
152 | data->vregs[i] = 0; | |
153 | else | |
154 | data->vregs[i] = val; | |
155 | } | |
156 | ||
5950ec8d IS |
157 | /* Update GPIO readings */ |
158 | ltc4245_update_gpios(dev); | |
159 | ||
6e34b187 | 160 | data->last_updated = jiffies; |
a584287c | 161 | data->valid = true; |
6e34b187 IS |
162 | } |
163 | ||
164 | mutex_unlock(&data->update_lock); | |
165 | ||
166 | return data; | |
167 | } | |
168 | ||
169 | /* Return the voltage from the given register in millivolts */ | |
170 | static int ltc4245_get_voltage(struct device *dev, u8 reg) | |
171 | { | |
172 | struct ltc4245_data *data = ltc4245_update_device(dev); | |
173 | const u8 regval = data->vregs[reg - 0x10]; | |
174 | u32 voltage = 0; | |
175 | ||
176 | switch (reg) { | |
177 | case LTC4245_12VIN: | |
178 | case LTC4245_12VOUT: | |
179 | voltage = regval * 55; | |
180 | break; | |
181 | case LTC4245_5VIN: | |
182 | case LTC4245_5VOUT: | |
183 | voltage = regval * 22; | |
184 | break; | |
185 | case LTC4245_3VIN: | |
186 | case LTC4245_3VOUT: | |
187 | voltage = regval * 15; | |
188 | break; | |
189 | case LTC4245_VEEIN: | |
190 | case LTC4245_VEEOUT: | |
191 | voltage = regval * -55; | |
192 | break; | |
df16dd53 | 193 | case LTC4245_GPIOADC: |
6e34b187 IS |
194 | voltage = regval * 10; |
195 | break; | |
196 | default: | |
197 | /* If we get here, the developer messed up */ | |
198 | WARN_ON_ONCE(1); | |
199 | break; | |
200 | } | |
201 | ||
202 | return voltage; | |
203 | } | |
204 | ||
205 | /* Return the current in the given sense register in milliAmperes */ | |
206 | static unsigned int ltc4245_get_current(struct device *dev, u8 reg) | |
207 | { | |
208 | struct ltc4245_data *data = ltc4245_update_device(dev); | |
209 | const u8 regval = data->vregs[reg - 0x10]; | |
210 | unsigned int voltage; | |
211 | unsigned int curr; | |
212 | ||
430b4fcd GR |
213 | /* |
214 | * The strange looking conversions that follow are fixed-point | |
6e34b187 IS |
215 | * math, since we cannot do floating point in the kernel. |
216 | * | |
217 | * Step 1: convert sense register to microVolts | |
218 | * Step 2: convert voltage to milliAmperes | |
219 | * | |
220 | * If you play around with the V=IR equation, you come up with | |
221 | * the following: X uV / Y mOhm == Z mA | |
222 | * | |
223 | * With the resistors that are fractions of a milliOhm, we multiply | |
224 | * the voltage and resistance by 10, to shift the decimal point. | |
225 | * Now we can use the normal division operator again. | |
226 | */ | |
227 | ||
228 | switch (reg) { | |
229 | case LTC4245_12VSENSE: | |
230 | voltage = regval * 250; /* voltage in uV */ | |
231 | curr = voltage / 50; /* sense resistor 50 mOhm */ | |
232 | break; | |
233 | case LTC4245_5VSENSE: | |
234 | voltage = regval * 125; /* voltage in uV */ | |
235 | curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */ | |
236 | break; | |
237 | case LTC4245_3VSENSE: | |
238 | voltage = regval * 125; /* voltage in uV */ | |
239 | curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */ | |
240 | break; | |
241 | case LTC4245_VEESENSE: | |
242 | voltage = regval * 250; /* voltage in uV */ | |
243 | curr = voltage / 100; /* sense resistor 100 mOhm */ | |
244 | break; | |
245 | default: | |
246 | /* If we get here, the developer messed up */ | |
247 | WARN_ON_ONCE(1); | |
248 | curr = 0; | |
249 | break; | |
250 | } | |
251 | ||
252 | return curr; | |
253 | } | |
254 | ||
a584287c | 255 | /* Map from voltage channel index to voltage register */ |
6e34b187 | 256 | |
a584287c GR |
257 | static const s8 ltc4245_in_regs[] = { |
258 | LTC4245_12VIN, LTC4245_5VIN, LTC4245_3VIN, LTC4245_VEEIN, | |
259 | LTC4245_12VOUT, LTC4245_5VOUT, LTC4245_3VOUT, LTC4245_VEEOUT, | |
260 | }; | |
261 | ||
262 | /* Map from current channel index to current register */ | |
6e34b187 | 263 | |
a584287c GR |
264 | static const s8 ltc4245_curr_regs[] = { |
265 | LTC4245_12VSENSE, LTC4245_5VSENSE, LTC4245_3VSENSE, LTC4245_VEESENSE, | |
266 | }; | |
267 | ||
268 | static int ltc4245_read_curr(struct device *dev, u32 attr, int channel, | |
269 | long *val) | |
6e34b187 | 270 | { |
a584287c | 271 | struct ltc4245_data *data = ltc4245_update_device(dev); |
6e34b187 | 272 | |
a584287c GR |
273 | switch (attr) { |
274 | case hwmon_curr_input: | |
275 | *val = ltc4245_get_current(dev, ltc4245_curr_regs[channel]); | |
276 | return 0; | |
277 | case hwmon_curr_max_alarm: | |
278 | *val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel + 4)); | |
279 | return 0; | |
280 | default: | |
281 | return -EOPNOTSUPP; | |
282 | } | |
6e34b187 IS |
283 | } |
284 | ||
a584287c | 285 | static int ltc4245_read_in(struct device *dev, u32 attr, int channel, long *val) |
6e34b187 | 286 | { |
a584287c | 287 | struct ltc4245_data *data = ltc4245_update_device(dev); |
6e34b187 | 288 | |
a584287c GR |
289 | switch (attr) { |
290 | case hwmon_in_input: | |
291 | if (channel < 8) { | |
292 | *val = ltc4245_get_voltage(dev, | |
293 | ltc4245_in_regs[channel]); | |
294 | } else { | |
295 | int regval = data->gpios[channel - 8]; | |
296 | ||
297 | if (regval < 0) | |
298 | return regval; | |
299 | *val = regval * 10; | |
300 | } | |
301 | return 0; | |
302 | case hwmon_in_min_alarm: | |
303 | if (channel < 4) | |
304 | *val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel)); | |
305 | else | |
306 | *val = !!(data->cregs[LTC4245_FAULT2] & | |
307 | BIT(channel - 4)); | |
308 | return 0; | |
309 | default: | |
310 | return -EOPNOTSUPP; | |
311 | } | |
312 | } | |
6e34b187 | 313 | |
a584287c GR |
314 | static int ltc4245_read_power(struct device *dev, u32 attr, int channel, |
315 | long *val) | |
316 | { | |
317 | unsigned long curr; | |
318 | long voltage; | |
319 | ||
320 | switch (attr) { | |
321 | case hwmon_power_input: | |
322 | (void)ltc4245_update_device(dev); | |
323 | curr = ltc4245_get_current(dev, ltc4245_curr_regs[channel]); | |
324 | voltage = ltc4245_get_voltage(dev, ltc4245_in_regs[channel]); | |
325 | *val = abs(curr * voltage); | |
326 | return 0; | |
327 | default: | |
328 | return -EOPNOTSUPP; | |
329 | } | |
6e34b187 IS |
330 | } |
331 | ||
a584287c GR |
332 | static int ltc4245_read(struct device *dev, enum hwmon_sensor_types type, |
333 | u32 attr, int channel, long *val) | |
6e34b187 | 334 | { |
6e34b187 | 335 | |
a584287c GR |
336 | switch (type) { |
337 | case hwmon_curr: | |
338 | return ltc4245_read_curr(dev, attr, channel, val); | |
339 | case hwmon_power: | |
340 | return ltc4245_read_power(dev, attr, channel, val); | |
341 | case hwmon_in: | |
342 | return ltc4245_read_in(dev, attr, channel - 1, val); | |
343 | default: | |
344 | return -EOPNOTSUPP; | |
345 | } | |
6e34b187 IS |
346 | } |
347 | ||
a584287c GR |
348 | static umode_t ltc4245_is_visible(const void *_data, |
349 | enum hwmon_sensor_types type, | |
350 | u32 attr, int channel) | |
5950ec8d | 351 | { |
a584287c GR |
352 | const struct ltc4245_data *data = _data; |
353 | ||
354 | switch (type) { | |
355 | case hwmon_in: | |
356 | if (channel == 0) | |
357 | return 0; | |
358 | switch (attr) { | |
359 | case hwmon_in_input: | |
360 | if (channel > 9 && !data->use_extra_gpios) | |
361 | return 0; | |
d703e7f1 | 362 | return 0444; |
a584287c GR |
363 | case hwmon_in_min_alarm: |
364 | if (channel > 8) | |
365 | return 0; | |
d703e7f1 | 366 | return 0444; |
a584287c GR |
367 | default: |
368 | return 0; | |
369 | } | |
370 | case hwmon_curr: | |
371 | switch (attr) { | |
372 | case hwmon_curr_input: | |
373 | case hwmon_curr_max_alarm: | |
d703e7f1 | 374 | return 0444; |
a584287c GR |
375 | default: |
376 | return 0; | |
377 | } | |
378 | case hwmon_power: | |
379 | switch (attr) { | |
380 | case hwmon_power_input: | |
d703e7f1 | 381 | return 0444; |
a584287c GR |
382 | default: |
383 | return 0; | |
384 | } | |
385 | default: | |
386 | return 0; | |
387 | } | |
388 | } | |
5950ec8d | 389 | |
a584287c | 390 | static const struct hwmon_channel_info *ltc4245_info[] = { |
0ee508f0 GR |
391 | HWMON_CHANNEL_INFO(in, |
392 | HWMON_I_INPUT, | |
393 | HWMON_I_INPUT | HWMON_I_MIN_ALARM, | |
394 | HWMON_I_INPUT | HWMON_I_MIN_ALARM, | |
395 | HWMON_I_INPUT | HWMON_I_MIN_ALARM, | |
396 | HWMON_I_INPUT | HWMON_I_MIN_ALARM, | |
397 | HWMON_I_INPUT | HWMON_I_MIN_ALARM, | |
398 | HWMON_I_INPUT | HWMON_I_MIN_ALARM, | |
399 | HWMON_I_INPUT | HWMON_I_MIN_ALARM, | |
400 | HWMON_I_INPUT | HWMON_I_MIN_ALARM, | |
401 | HWMON_I_INPUT, | |
402 | HWMON_I_INPUT, | |
403 | HWMON_I_INPUT), | |
404 | HWMON_CHANNEL_INFO(curr, | |
405 | HWMON_C_INPUT | HWMON_C_MAX_ALARM, | |
406 | HWMON_C_INPUT | HWMON_C_MAX_ALARM, | |
407 | HWMON_C_INPUT | HWMON_C_MAX_ALARM, | |
408 | HWMON_C_INPUT | HWMON_C_MAX_ALARM), | |
409 | HWMON_CHANNEL_INFO(power, | |
410 | HWMON_P_INPUT, | |
411 | HWMON_P_INPUT, | |
412 | HWMON_P_INPUT, | |
413 | HWMON_P_INPUT), | |
a584287c | 414 | NULL |
6e34b187 IS |
415 | }; |
416 | ||
a584287c GR |
417 | static const struct hwmon_ops ltc4245_hwmon_ops = { |
418 | .is_visible = ltc4245_is_visible, | |
419 | .read = ltc4245_read, | |
420 | }; | |
5950ec8d | 421 | |
a584287c GR |
422 | static const struct hwmon_chip_info ltc4245_chip_info = { |
423 | .ops = <c4245_hwmon_ops, | |
424 | .info = ltc4245_info, | |
425 | }; | |
5950ec8d IS |
426 | |
427 | static bool ltc4245_use_extra_gpios(struct i2c_client *client) | |
428 | { | |
429 | struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev); | |
5950ec8d | 430 | struct device_node *np = client->dev.of_node; |
5950ec8d IS |
431 | |
432 | /* prefer platform data */ | |
433 | if (pdata) | |
434 | return pdata->use_extra_gpios; | |
435 | ||
5950ec8d IS |
436 | /* fallback on OF */ |
437 | if (of_find_property(np, "ltc4245,use-extra-gpios", NULL)) | |
438 | return true; | |
5950ec8d IS |
439 | |
440 | return false; | |
441 | } | |
442 | ||
6e34b187 IS |
443 | static int ltc4245_probe(struct i2c_client *client, |
444 | const struct i2c_device_id *id) | |
445 | { | |
2d2a7cff | 446 | struct i2c_adapter *adapter = client->adapter; |
6e34b187 | 447 | struct ltc4245_data *data; |
9a85d53c | 448 | struct device *hwmon_dev; |
6e34b187 | 449 | |
2d2a7cff JD |
450 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
451 | return -ENODEV; | |
452 | ||
effb8ab1 GR |
453 | data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); |
454 | if (!data) | |
455 | return -ENOMEM; | |
6e34b187 | 456 | |
9a85d53c | 457 | data->client = client; |
6e34b187 | 458 | mutex_init(&data->update_lock); |
5950ec8d | 459 | data->use_extra_gpios = ltc4245_use_extra_gpios(client); |
6e34b187 IS |
460 | |
461 | /* Initialize the LTC4245 chip */ | |
58f055e5 IS |
462 | i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00); |
463 | i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00); | |
6e34b187 | 464 | |
a584287c GR |
465 | hwmon_dev = devm_hwmon_device_register_with_info(&client->dev, |
466 | client->name, data, | |
467 | <c4245_chip_info, | |
468 | NULL); | |
94c42cf9 | 469 | return PTR_ERR_OR_ZERO(hwmon_dev); |
6e34b187 IS |
470 | } |
471 | ||
6e34b187 | 472 | static const struct i2c_device_id ltc4245_id[] = { |
2d2a7cff | 473 | { "ltc4245", 0 }, |
6e34b187 IS |
474 | { } |
475 | }; | |
476 | MODULE_DEVICE_TABLE(i2c, ltc4245_id); | |
477 | ||
478 | /* This is the driver that will be inserted */ | |
479 | static struct i2c_driver ltc4245_driver = { | |
6e34b187 IS |
480 | .driver = { |
481 | .name = "ltc4245", | |
482 | }, | |
483 | .probe = ltc4245_probe, | |
6e34b187 | 484 | .id_table = ltc4245_id, |
6e34b187 IS |
485 | }; |
486 | ||
f0967eea | 487 | module_i2c_driver(ltc4245_driver); |
6e34b187 IS |
488 | |
489 | MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>"); | |
490 | MODULE_DESCRIPTION("LTC4245 driver"); | |
491 | MODULE_LICENSE("GPL"); |