1 | // SPDX-License-Identifier: GPL-2.0-only |
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 | * |
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> |
16 | #include <linux/bitops.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> |
22 | #include <linux/jiffies.h> |
23 | #include <linux/platform_data/ltc4245.h> |
24 | |
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, |
48 | LTC4245_GPIOADC = 0x1c, |
49 | }; |
50 | |
51 | struct ltc4245_data { |
52 | struct i2c_client *client; |
53 | |
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 */ |
62 | u8 vregs[0x0d]; |
63 | |
64 | /* GPIO ADC registers */ |
65 | bool ; |
66 | int gpios[3]; |
67 | }; |
68 | |
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 | { |
78 | struct ltc4245_data *data = dev_get_drvdata(dev); |
79 | struct i2c_client *client = data->client; |
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)) { |
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, command: LTC4245_GPIO, value: gpio_reg); |
123 | |
124 | /* Update saved data */ |
125 | data->cregs[LTC4245_GPIO] = gpio_reg; |
126 | } |
127 | |
128 | static struct ltc4245_data *ltc4245_update_device(struct device *dev) |
129 | { |
130 | struct ltc4245_data *data = dev_get_drvdata(dev); |
131 | struct i2c_client *client = data->client; |
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 | |
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, command: i); |
142 | if (unlikely(val < 0)) |
143 | data->cregs[i] = 0; |
144 | else |
145 | data->cregs[i] = val; |
146 | } |
147 | |
148 | /* Read voltage registers -- 0x10 to 0x1c */ |
149 | for (i = 0; i < ARRAY_SIZE(data->vregs); i++) { |
150 | val = i2c_smbus_read_byte_data(client, command: i+0x10); |
151 | if (unlikely(val < 0)) |
152 | data->vregs[i] = 0; |
153 | else |
154 | data->vregs[i] = val; |
155 | } |
156 | |
157 | /* Update GPIO readings */ |
158 | ltc4245_update_gpios(dev); |
159 | |
160 | data->last_updated = jiffies; |
161 | data->valid = true; |
162 | } |
163 | |
164 | mutex_unlock(lock: &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; |
193 | case LTC4245_GPIOADC: |
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 | |
213 | /* |
214 | * The strange looking conversions that follow are fixed-point |
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 | |
255 | /* Map from voltage channel index to voltage register */ |
256 | |
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 */ |
263 | |
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) |
270 | { |
271 | struct ltc4245_data *data = ltc4245_update_device(dev); |
272 | |
273 | switch (attr) { |
274 | case hwmon_curr_input: |
275 | *val = ltc4245_get_current(dev, reg: 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 | } |
283 | } |
284 | |
285 | static int ltc4245_read_in(struct device *dev, u32 attr, int channel, long *val) |
286 | { |
287 | struct ltc4245_data *data = ltc4245_update_device(dev); |
288 | |
289 | switch (attr) { |
290 | case hwmon_in_input: |
291 | if (channel < 8) { |
292 | *val = ltc4245_get_voltage(dev, |
293 | reg: 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 | } |
313 | |
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, reg: ltc4245_curr_regs[channel]); |
324 | voltage = ltc4245_get_voltage(dev, reg: ltc4245_in_regs[channel]); |
325 | *val = abs(curr * voltage); |
326 | return 0; |
327 | default: |
328 | return -EOPNOTSUPP; |
329 | } |
330 | } |
331 | |
332 | static int ltc4245_read(struct device *dev, enum hwmon_sensor_types type, |
333 | u32 attr, int channel, long *val) |
334 | { |
335 | |
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: channel - 1, val); |
343 | default: |
344 | return -EOPNOTSUPP; |
345 | } |
346 | } |
347 | |
348 | static umode_t ltc4245_is_visible(const void *_data, |
349 | enum hwmon_sensor_types type, |
350 | u32 attr, int channel) |
351 | { |
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; |
362 | return 0444; |
363 | case hwmon_in_min_alarm: |
364 | if (channel > 8) |
365 | return 0; |
366 | return 0444; |
367 | default: |
368 | return 0; |
369 | } |
370 | case hwmon_curr: |
371 | switch (attr) { |
372 | case hwmon_curr_input: |
373 | case hwmon_curr_max_alarm: |
374 | return 0444; |
375 | default: |
376 | return 0; |
377 | } |
378 | case hwmon_power: |
379 | switch (attr) { |
380 | case hwmon_power_input: |
381 | return 0444; |
382 | default: |
383 | return 0; |
384 | } |
385 | default: |
386 | return 0; |
387 | } |
388 | } |
389 | |
390 | static const struct hwmon_channel_info * const ltc4245_info[] = { |
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), |
414 | NULL |
415 | }; |
416 | |
417 | static const struct hwmon_ops ltc4245_hwmon_ops = { |
418 | .is_visible = ltc4245_is_visible, |
419 | .read = ltc4245_read, |
420 | }; |
421 | |
422 | static const struct hwmon_chip_info ltc4245_chip_info = { |
423 | .ops = <c4245_hwmon_ops, |
424 | .info = ltc4245_info, |
425 | }; |
426 | |
427 | static bool (struct i2c_client *client) |
428 | { |
429 | struct ltc4245_platform_data *pdata = dev_get_platdata(dev: &client->dev); |
430 | struct device_node *np = client->dev.of_node; |
431 | |
432 | /* prefer platform data */ |
433 | if (pdata) |
434 | return pdata->use_extra_gpios; |
435 | |
436 | /* fallback on OF */ |
437 | if (of_property_read_bool(np, propname: "ltc4245,use-extra-gpios" )) |
438 | return true; |
439 | |
440 | return false; |
441 | } |
442 | |
443 | static int ltc4245_probe(struct i2c_client *client) |
444 | { |
445 | struct i2c_adapter *adapter = client->adapter; |
446 | struct ltc4245_data *data; |
447 | struct device *hwmon_dev; |
448 | |
449 | if (!i2c_check_functionality(adap: adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
450 | return -ENODEV; |
451 | |
452 | data = devm_kzalloc(dev: &client->dev, size: sizeof(*data), GFP_KERNEL); |
453 | if (!data) |
454 | return -ENOMEM; |
455 | |
456 | data->client = client; |
457 | mutex_init(&data->update_lock); |
458 | data->use_extra_gpios = ltc4245_use_extra_gpios(client); |
459 | |
460 | /* Initialize the LTC4245 chip */ |
461 | i2c_smbus_write_byte_data(client, command: LTC4245_FAULT1, value: 0x00); |
462 | i2c_smbus_write_byte_data(client, command: LTC4245_FAULT2, value: 0x00); |
463 | |
464 | hwmon_dev = devm_hwmon_device_register_with_info(dev: &client->dev, |
465 | name: client->name, drvdata: data, |
466 | info: <c4245_chip_info, |
467 | NULL); |
468 | return PTR_ERR_OR_ZERO(ptr: hwmon_dev); |
469 | } |
470 | |
471 | static const struct i2c_device_id ltc4245_id[] = { |
472 | { "ltc4245" , 0 }, |
473 | { } |
474 | }; |
475 | MODULE_DEVICE_TABLE(i2c, ltc4245_id); |
476 | |
477 | /* This is the driver that will be inserted */ |
478 | static struct i2c_driver ltc4245_driver = { |
479 | .driver = { |
480 | .name = "ltc4245" , |
481 | }, |
482 | .probe = ltc4245_probe, |
483 | .id_table = ltc4245_id, |
484 | }; |
485 | |
486 | module_i2c_driver(ltc4245_driver); |
487 | |
488 | MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>" ); |
489 | MODULE_DESCRIPTION("LTC4245 driver" ); |
490 | MODULE_LICENSE("GPL" ); |
491 | |