1 /*
2  * Copyright (C) 2016 Gateworks Corporation, Inc. All Rights Reserved.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2
6  * as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  */
14 #include <linux/i2c.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/module.h>
18 #include <linux/kernel.h>
19 #include <linux/of.h>
20 #include <linux/regmap.h>
21 #include <linux/regulator/driver.h>
22 #include <linux/regulator/machine.h>
23 #include <linux/regulator/of_regulator.h>
24 
25 #define DRIVER_NAME		"ltc3676"
26 
27 /* LTC3676 Registers */
28 #define LTC3676_BUCK1     0x01
29 #define LTC3676_BUCK2     0x02
30 #define LTC3676_BUCK3     0x03
31 #define LTC3676_BUCK4     0x04
32 #define LTC3676_LDOA      0x05
33 #define LTC3676_LDOB      0x06
34 #define LTC3676_SQD1      0x07
35 #define LTC3676_SQD2      0x08
36 #define LTC3676_CNTRL     0x09
37 #define LTC3676_DVB1A     0x0A
38 #define LTC3676_DVB1B     0x0B
39 #define LTC3676_DVB2A     0x0C
40 #define LTC3676_DVB2B     0x0D
41 #define LTC3676_DVB3A     0x0E
42 #define LTC3676_DVB3B     0x0F
43 #define LTC3676_DVB4A     0x10
44 #define LTC3676_DVB4B     0x11
45 #define LTC3676_MSKIRQ    0x12
46 #define LTC3676_MSKPG     0x13
47 #define LTC3676_USER      0x14
48 #define LTC3676_IRQSTAT   0x15
49 #define LTC3676_PGSTATL   0x16
50 #define LTC3676_PGSTATRT  0x17
51 #define LTC3676_HRST      0x1E
52 #define LTC3676_CLIRQ     0x1F
53 
54 #define LTC3676_DVBxA_REF_SELECT	BIT(5)
55 #define LTC3676_DVBxB_PGOOD_MASK	BIT(5)
56 
57 #define LTC3676_IRQSTAT_PGOOD_TIMEOUT	BIT(3)
58 #define LTC3676_IRQSTAT_UNDERVOLT_WARN	BIT(4)
59 #define LTC3676_IRQSTAT_UNDERVOLT_FAULT	BIT(5)
60 #define LTC3676_IRQSTAT_THERMAL_WARN	BIT(6)
61 #define LTC3676_IRQSTAT_THERMAL_FAULT	BIT(7)
62 
63 enum ltc3676_reg {
64 	LTC3676_SW1,
65 	LTC3676_SW2,
66 	LTC3676_SW3,
67 	LTC3676_SW4,
68 	LTC3676_LDO1,
69 	LTC3676_LDO2,
70 	LTC3676_LDO3,
71 	LTC3676_LDO4,
72 	LTC3676_NUM_REGULATORS,
73 };
74 
75 struct ltc3676 {
76 	struct regmap *regmap;
77 	struct device *dev;
78 	struct regulator_desc regulator_descs[LTC3676_NUM_REGULATORS];
79 	struct regulator_dev *regulators[LTC3676_NUM_REGULATORS];
80 };
81 
ltc3676_set_suspend_voltage(struct regulator_dev * rdev,int uV)82 static int ltc3676_set_suspend_voltage(struct regulator_dev *rdev, int uV)
83 {
84 	struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
85 	struct device *dev = ltc3676->dev;
86 	int dcdc = rdev_get_id(rdev);
87 	int sel;
88 
89 	dev_dbg(dev, "%s id=%d uV=%d\n", __func__, dcdc, uV);
90 	sel = regulator_map_voltage_linear(rdev, uV, uV);
91 	if (sel < 0)
92 		return sel;
93 
94 	/* DVBB register follows right after the corresponding DVBA register */
95 	return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
96 				  rdev->desc->vsel_mask, sel);
97 }
98 
ltc3676_set_suspend_mode(struct regulator_dev * rdev,unsigned int mode)99 static int ltc3676_set_suspend_mode(struct regulator_dev *rdev,
100 				    unsigned int mode)
101 {
102 	struct ltc3676 *ltc3676= rdev_get_drvdata(rdev);
103 	struct device *dev = ltc3676->dev;
104 	int mask, val;
105 	int dcdc = rdev_get_id(rdev);
106 
107 	dev_dbg(dev, "%s id=%d mode=%d\n", __func__, dcdc, mode);
108 
109 	mask = LTC3676_DVBxA_REF_SELECT;
110 	switch (mode) {
111 	case REGULATOR_MODE_STANDBY:
112 		val = 0; /* select DVBxA */
113 		break;
114 	case REGULATOR_MODE_NORMAL:
115 		val = LTC3676_DVBxA_REF_SELECT; /* select DVBxB */
116 		break;
117 	default:
118 		dev_warn(&rdev->dev, "%s: regulator mode: 0x%x not supported\n",
119 			 rdev->desc->name, mode);
120 		return -EINVAL;
121 	}
122 
123 	return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg,
124 				  mask, val);
125 }
126 
ltc3676_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)127 static int ltc3676_set_voltage_sel(struct regulator_dev *rdev, unsigned selector)
128 {
129 	struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
130 	struct device *dev = ltc3676->dev;
131 	int ret, dcdc = rdev_get_id(rdev);
132 
133 	dev_dbg(dev, "%s id=%d selector=%d\n", __func__, dcdc, selector);
134 
135 	ret = regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
136 				 LTC3676_DVBxB_PGOOD_MASK,
137 				 LTC3676_DVBxB_PGOOD_MASK);
138 	if (ret)
139 		return ret;
140 
141 	return regulator_set_voltage_sel_regmap(rdev, selector);
142 }
143 
ltc3676_scale(unsigned int uV,u32 r1,u32 r2)144 static inline unsigned int ltc3676_scale(unsigned int uV, u32 r1, u32 r2)
145 {
146 	uint64_t tmp;
147 	if (uV == 0)
148 		return 0;
149 	tmp = (uint64_t)uV * r1;
150 	do_div(tmp, r2);
151 	return uV + (unsigned int)tmp;
152 }
153 
ltc3676_of_parse_cb(struct device_node * np,const struct regulator_desc * desc,struct regulator_config * config)154 static int ltc3676_of_parse_cb(struct device_node *np,
155 			       const struct regulator_desc *desc,
156 			       struct regulator_config *config)
157 {
158 	struct ltc3676 *ltc3676 = config->driver_data;
159 	struct regulator_desc *rdesc = &ltc3676->regulator_descs[desc->id];
160 	u32 r[2];
161 	int ret;
162 
163 	/* LDO3 has a fixed output */
164 	if (desc->id == LTC3676_LDO3)
165 		return 0;
166 
167 	ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider", r, 2);
168 	if (ret) {
169 		dev_err(ltc3676->dev, "Failed to parse voltage divider: %d\n",
170 			ret);
171 		return ret;
172 	}
173 
174 	rdesc->min_uV = ltc3676_scale(desc->min_uV, r[0], r[1]);
175 	rdesc->uV_step = ltc3676_scale(desc->uV_step, r[0], r[1]);
176 	rdesc->fixed_uV = ltc3676_scale(desc->fixed_uV, r[0], r[1]);
177 
178 	return 0;
179 }
180 
181 /* SW1, SW2, SW3, SW4 linear 0.8V-3.3V with scalar via R1/R2 feeback res */
182 static const struct regulator_ops ltc3676_linear_regulator_ops = {
183 	.enable = regulator_enable_regmap,
184 	.disable = regulator_disable_regmap,
185 	.is_enabled = regulator_is_enabled_regmap,
186 	.list_voltage = regulator_list_voltage_linear,
187 	.set_voltage_sel = ltc3676_set_voltage_sel,
188 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
189 	.set_suspend_voltage = ltc3676_set_suspend_voltage,
190 	.set_suspend_mode = ltc3676_set_suspend_mode,
191 };
192 
193 /* LDO1 always on fixed 0.8V-3.3V via scalar via R1/R2 feeback res */
194 static const struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
195 };
196 
197 /* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
198 static const struct regulator_ops ltc3676_fixed_regulator_ops = {
199 	.enable = regulator_enable_regmap,
200 	.disable = regulator_disable_regmap,
201 	.is_enabled = regulator_is_enabled_regmap,
202 };
203 
204 #define LTC3676_REG(_id, _name, _ops, en_reg, en_bit, dvba_reg, dvb_mask)   \
205 	[LTC3676_ ## _id] = {                                        \
206 		.name = #_name,                                \
207 		.of_match = of_match_ptr(#_name),              \
208 		.regulators_node = of_match_ptr("regulators"), \
209 		.of_parse_cb = ltc3676_of_parse_cb,            \
210 		.n_voltages = (dvb_mask) + 1,                  \
211 		.min_uV = (dvba_reg) ? 412500 : 0,             \
212 		.uV_step = (dvba_reg) ? 12500 : 0,             \
213 		.ramp_delay = (dvba_reg) ? 800 : 0,            \
214 		.fixed_uV = (dvb_mask) ? 0 : 725000,           \
215 		.ops = &ltc3676_ ## _ops ## _regulator_ops,    \
216 		.type = REGULATOR_VOLTAGE,                     \
217 		.id = LTC3676_ ## _id,                         \
218 		.owner = THIS_MODULE,                          \
219 		.vsel_reg = (dvba_reg),                        \
220 		.vsel_mask = (dvb_mask),                       \
221 		.enable_reg = (en_reg),                        \
222 		.enable_mask = (1 << en_bit),                  \
223 	}
224 
225 #define LTC3676_LINEAR_REG(_id, _name, _en, _dvba)                     \
226 	LTC3676_REG(_id, _name, linear,                                \
227 		    LTC3676_ ## _en, 7,                                \
228 		    LTC3676_ ## _dvba, 0x1f)
229 
230 #define LTC3676_FIXED_REG(_id, _name, _en_reg, _en_bit)                \
231 	LTC3676_REG(_id, _name, fixed, LTC3676_ ## _en_reg, _en_bit, 0, 0)
232 
233 static struct regulator_desc ltc3676_regulators[LTC3676_NUM_REGULATORS] = {
234 	LTC3676_LINEAR_REG(SW1, sw1, BUCK1, DVB1A),
235 	LTC3676_LINEAR_REG(SW2, sw2, BUCK2, DVB2A),
236 	LTC3676_LINEAR_REG(SW3, sw3, BUCK3, DVB3A),
237 	LTC3676_LINEAR_REG(SW4, sw4, BUCK4, DVB4A),
238 	LTC3676_REG(LDO1, ldo1, fixed_standby, 0, 0, 0, 0),
239 	LTC3676_FIXED_REG(LDO2, ldo2, LDOA, 2),
240 	LTC3676_FIXED_REG(LDO3, ldo3, LDOA, 5),
241 	LTC3676_FIXED_REG(LDO4, ldo4, LDOB, 2),
242 };
243 
ltc3676_writeable_reg(struct device * dev,unsigned int reg)244 static bool ltc3676_writeable_reg(struct device *dev, unsigned int reg)
245 {
246 	switch (reg) {
247 	case LTC3676_IRQSTAT:
248 	case LTC3676_BUCK1:
249 	case LTC3676_BUCK2:
250 	case LTC3676_BUCK3:
251 	case LTC3676_BUCK4:
252 	case LTC3676_LDOA:
253 	case LTC3676_LDOB:
254 	case LTC3676_SQD1:
255 	case LTC3676_SQD2:
256 	case LTC3676_CNTRL:
257 	case LTC3676_DVB1A:
258 	case LTC3676_DVB1B:
259 	case LTC3676_DVB2A:
260 	case LTC3676_DVB2B:
261 	case LTC3676_DVB3A:
262 	case LTC3676_DVB3B:
263 	case LTC3676_DVB4A:
264 	case LTC3676_DVB4B:
265 	case LTC3676_MSKIRQ:
266 	case LTC3676_MSKPG:
267 	case LTC3676_USER:
268 	case LTC3676_HRST:
269 	case LTC3676_CLIRQ:
270 		return true;
271 	}
272 	return false;
273 }
274 
ltc3676_readable_reg(struct device * dev,unsigned int reg)275 static bool ltc3676_readable_reg(struct device *dev, unsigned int reg)
276 {
277 	switch (reg) {
278 	case LTC3676_IRQSTAT:
279 	case LTC3676_BUCK1:
280 	case LTC3676_BUCK2:
281 	case LTC3676_BUCK3:
282 	case LTC3676_BUCK4:
283 	case LTC3676_LDOA:
284 	case LTC3676_LDOB:
285 	case LTC3676_SQD1:
286 	case LTC3676_SQD2:
287 	case LTC3676_CNTRL:
288 	case LTC3676_DVB1A:
289 	case LTC3676_DVB1B:
290 	case LTC3676_DVB2A:
291 	case LTC3676_DVB2B:
292 	case LTC3676_DVB3A:
293 	case LTC3676_DVB3B:
294 	case LTC3676_DVB4A:
295 	case LTC3676_DVB4B:
296 	case LTC3676_MSKIRQ:
297 	case LTC3676_MSKPG:
298 	case LTC3676_USER:
299 	case LTC3676_HRST:
300 	case LTC3676_CLIRQ:
301 		return true;
302 	}
303 	return false;
304 }
305 
ltc3676_volatile_reg(struct device * dev,unsigned int reg)306 static bool ltc3676_volatile_reg(struct device *dev, unsigned int reg)
307 {
308 	switch (reg) {
309 	case LTC3676_IRQSTAT:
310 	case LTC3676_PGSTATL:
311 	case LTC3676_PGSTATRT:
312 		return true;
313 	}
314 	return false;
315 }
316 
317 static const struct regmap_config ltc3676_regmap_config = {
318 	.reg_bits = 8,
319 	.val_bits = 8,
320 	.writeable_reg = ltc3676_writeable_reg,
321 	.readable_reg = ltc3676_readable_reg,
322 	.volatile_reg = ltc3676_volatile_reg,
323 	.max_register = LTC3676_CLIRQ,
324 	.use_single_rw = true,
325 	.cache_type = REGCACHE_RBTREE,
326 };
327 
ltc3676_isr(int irq,void * dev_id)328 static irqreturn_t ltc3676_isr(int irq, void *dev_id)
329 {
330 	struct ltc3676 *ltc3676 = dev_id;
331 	struct device *dev = ltc3676->dev;
332 	unsigned int i, irqstat, event;
333 
334 	regmap_read(ltc3676->regmap, LTC3676_IRQSTAT, &irqstat);
335 
336 	dev_dbg(dev, "irq%d irqstat=0x%02x\n", irq, irqstat);
337 	if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) {
338 		dev_warn(dev, "Over-temperature Warning\n");
339 		event = REGULATOR_EVENT_OVER_TEMP;
340 		for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
341 			regulator_notifier_call_chain(ltc3676->regulators[i],
342 						      event, NULL);
343 	}
344 
345 	if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) {
346 		dev_info(dev, "Undervoltage Warning\n");
347 		event = REGULATOR_EVENT_UNDER_VOLTAGE;
348 		for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
349 			regulator_notifier_call_chain(ltc3676->regulators[i],
350 						      event, NULL);
351 	}
352 
353 	/* Clear warning condition */
354 	regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
355 
356 	return IRQ_HANDLED;
357 }
358 
ltc3676_regulator_probe(struct i2c_client * client,const struct i2c_device_id * id)359 static int ltc3676_regulator_probe(struct i2c_client *client,
360 				    const struct i2c_device_id *id)
361 {
362 	struct device *dev = &client->dev;
363 	struct regulator_init_data *init_data = dev_get_platdata(dev);
364 	struct regulator_desc *descs;
365 	struct ltc3676 *ltc3676;
366 	int i, ret;
367 
368 	ltc3676 = devm_kzalloc(dev, sizeof(*ltc3676), GFP_KERNEL);
369 	if (!ltc3676)
370 		return -ENOMEM;
371 
372 	i2c_set_clientdata(client, ltc3676);
373 	ltc3676->dev = dev;
374 
375 	descs = ltc3676->regulator_descs;
376 	memcpy(descs, ltc3676_regulators, sizeof(ltc3676_regulators));
377 	descs[LTC3676_LDO3].fixed_uV = 1800000; /* LDO3 is fixed 1.8V */
378 
379 	ltc3676->regmap = devm_regmap_init_i2c(client, &ltc3676_regmap_config);
380 	if (IS_ERR(ltc3676->regmap)) {
381 		ret = PTR_ERR(ltc3676->regmap);
382 		dev_err(dev, "failed to initialize regmap: %d\n", ret);
383 		return ret;
384 	}
385 
386 	for (i = 0; i < LTC3676_NUM_REGULATORS; i++) {
387 		struct regulator_desc *desc = &ltc3676->regulator_descs[i];
388 		struct regulator_config config = { };
389 
390 		if (init_data)
391 			config.init_data = &init_data[i];
392 
393 		config.dev = dev;
394 		config.driver_data = ltc3676;
395 
396 		ltc3676->regulators[i] = devm_regulator_register(dev, desc,
397 								 &config);
398 		if (IS_ERR(ltc3676->regulators[i])) {
399 			ret = PTR_ERR(ltc3676->regulators[i]);
400 			dev_err(dev, "failed to register regulator %s: %d\n",
401 				desc->name, ret);
402 			return ret;
403 		}
404 	}
405 
406 	regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
407 	if (client->irq) {
408 		ret = devm_request_threaded_irq(dev, client->irq, NULL,
409 						ltc3676_isr,
410 						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
411 						client->name, ltc3676);
412 		if (ret) {
413 			dev_err(dev, "Failed to request IRQ: %d\n", ret);
414 			return ret;
415 		}
416 	}
417 
418 	return 0;
419 }
420 
421 static const struct i2c_device_id ltc3676_i2c_id[] = {
422 	{ "ltc3676" },
423 	{ }
424 };
425 MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
426 
427 static const struct of_device_id ltc3676_of_match[] = {
428 	{ .compatible = "lltc,ltc3676" },
429 	{ },
430 };
431 MODULE_DEVICE_TABLE(of, ltc3676_of_match);
432 
433 static struct i2c_driver ltc3676_driver = {
434 	.driver = {
435 		.name = DRIVER_NAME,
436 		.of_match_table = of_match_ptr(ltc3676_of_match),
437 	},
438 	.probe = ltc3676_regulator_probe,
439 	.id_table = ltc3676_i2c_id,
440 };
441 module_i2c_driver(ltc3676_driver);
442 
443 MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
444 MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC1376");
445 MODULE_LICENSE("GPL v2");
446