xref: /openbmc/linux/drivers/regulator/ltc3676.c (revision 2d96b44f)
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 
56 #define LTC3676_IRQSTAT_PGOOD_TIMEOUT	BIT(3)
57 #define LTC3676_IRQSTAT_UNDERVOLT_WARN	BIT(4)
58 #define LTC3676_IRQSTAT_UNDERVOLT_FAULT	BIT(5)
59 #define LTC3676_IRQSTAT_THERMAL_WARN	BIT(6)
60 #define LTC3676_IRQSTAT_THERMAL_FAULT	BIT(7)
61 
62 enum ltc3676_reg {
63 	LTC3676_SW1,
64 	LTC3676_SW2,
65 	LTC3676_SW3,
66 	LTC3676_SW4,
67 	LTC3676_LDO1,
68 	LTC3676_LDO2,
69 	LTC3676_LDO3,
70 	LTC3676_LDO4,
71 	LTC3676_NUM_REGULATORS,
72 };
73 
74 struct ltc3676 {
75 	struct regmap *regmap;
76 	struct device *dev;
77 	struct regulator_desc regulator_descs[LTC3676_NUM_REGULATORS];
78 	struct regulator_dev *regulators[LTC3676_NUM_REGULATORS];
79 };
80 
81 static int ltc3676_set_suspend_voltage(struct regulator_dev *rdev, int uV)
82 {
83 	struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
84 	struct device *dev = ltc3676->dev;
85 	int dcdc = rdev_get_id(rdev);
86 	int sel;
87 
88 	dev_dbg(dev, "%s id=%d uV=%d\n", __func__, dcdc, uV);
89 	sel = regulator_map_voltage_linear(rdev, uV, uV);
90 	if (sel < 0)
91 		return sel;
92 
93 	/* DVBB register follows right after the corresponding DVBA register */
94 	return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
95 				  rdev->desc->vsel_mask, sel);
96 }
97 
98 static int ltc3676_set_suspend_mode(struct regulator_dev *rdev,
99 				    unsigned int mode)
100 {
101 	struct ltc3676 *ltc3676= rdev_get_drvdata(rdev);
102 	struct device *dev = ltc3676->dev;
103 	int mask, val;
104 	int dcdc = rdev_get_id(rdev);
105 
106 	dev_dbg(dev, "%s id=%d mode=%d\n", __func__, dcdc, mode);
107 
108 	mask = LTC3676_DVBxA_REF_SELECT;
109 	switch (mode) {
110 	case REGULATOR_MODE_STANDBY:
111 		val = 0; /* select DVBxA */
112 		break;
113 	case REGULATOR_MODE_NORMAL:
114 		val = LTC3676_DVBxA_REF_SELECT; /* select DVBxB */
115 		break;
116 	default:
117 		dev_warn(&rdev->dev, "%s: regulator mode: 0x%x not supported\n",
118 			 rdev->desc->name, mode);
119 		return -EINVAL;
120 	}
121 
122 	return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg,
123 				  mask, val);
124 }
125 
126 static inline unsigned int ltc3676_scale(unsigned int uV, u32 r1, u32 r2)
127 {
128 	uint64_t tmp;
129 	if (uV == 0)
130 		return 0;
131 	tmp = (uint64_t)uV * r1;
132 	do_div(tmp, r2);
133 	return uV + (unsigned int)tmp;
134 }
135 
136 static int ltc3676_of_parse_cb(struct device_node *np,
137 			       const struct regulator_desc *desc,
138 			       struct regulator_config *config)
139 {
140 	struct ltc3676 *ltc3676 = config->driver_data;
141 	struct regulator_desc *rdesc = &ltc3676->regulator_descs[desc->id];
142 	u32 r[2];
143 	int ret;
144 
145 	/* LDO3 has a fixed output */
146 	if (desc->id == LTC3676_LDO3)
147 		return 0;
148 
149 	ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider", r, 2);
150 	if (ret) {
151 		dev_err(ltc3676->dev, "Failed to parse voltage divider: %d\n",
152 			ret);
153 		return ret;
154 	}
155 
156 	rdesc->min_uV = ltc3676_scale(desc->min_uV, r[0], r[1]);
157 	rdesc->uV_step = ltc3676_scale(desc->uV_step, r[0], r[1]);
158 	rdesc->fixed_uV = ltc3676_scale(desc->fixed_uV, r[0], r[1]);
159 
160 	return 0;
161 }
162 
163 /* SW1, SW2, SW3, SW4 linear 0.8V-3.3V with scalar via R1/R2 feeback res */
164 static struct regulator_ops ltc3676_linear_regulator_ops = {
165 	.enable = regulator_enable_regmap,
166 	.disable = regulator_disable_regmap,
167 	.is_enabled = regulator_is_enabled_regmap,
168 	.list_voltage = regulator_list_voltage_linear,
169 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
170 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
171 	.set_suspend_voltage = ltc3676_set_suspend_voltage,
172 	.set_suspend_mode = ltc3676_set_suspend_mode,
173 };
174 
175 /* LDO1 always on fixed 0.8V-3.3V via scalar via R1/R2 feeback res */
176 static struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
177 };
178 
179 /* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
180 static struct regulator_ops ltc3676_fixed_regulator_ops = {
181 	.enable = regulator_enable_regmap,
182 	.disable = regulator_disable_regmap,
183 	.is_enabled = regulator_is_enabled_regmap,
184 };
185 
186 #define LTC3676_REG(_id, _name, _ops, en_reg, en_bit, dvba_reg, dvb_mask)   \
187 	[LTC3676_ ## _id] = {                                        \
188 		.name = #_name,                                \
189 		.of_match = of_match_ptr(#_name),              \
190 		.regulators_node = of_match_ptr("regulators"), \
191 		.of_parse_cb = ltc3676_of_parse_cb,            \
192 		.n_voltages = (dvb_mask) + 1,                  \
193 		.min_uV = (dvba_reg) ? 412500 : 0,             \
194 		.uV_step = (dvba_reg) ? 12500 : 0,             \
195 		.ramp_delay = (dvba_reg) ? 800 : 0,            \
196 		.fixed_uV = (dvb_mask) ? 0 : 725000,           \
197 		.ops = &ltc3676_ ## _ops ## _regulator_ops,    \
198 		.type = REGULATOR_VOLTAGE,                     \
199 		.id = LTC3676_ ## _id,                         \
200 		.owner = THIS_MODULE,                          \
201 		.vsel_reg = (dvba_reg),                        \
202 		.vsel_mask = (dvb_mask),                       \
203 		.enable_reg = (en_reg),                        \
204 		.enable_mask = (1 << en_bit),                  \
205 	}
206 
207 #define LTC3676_LINEAR_REG(_id, _name, _en, _dvba)                     \
208 	LTC3676_REG(_id, _name, linear,                                \
209 		    LTC3676_ ## _en, 7,                                \
210 		    LTC3676_ ## _dvba, 0x1f)
211 
212 #define LTC3676_FIXED_REG(_id, _name, _en_reg, _en_bit)                \
213 	LTC3676_REG(_id, _name, fixed, LTC3676_ ## _en_reg, _en_bit, 0, 0)
214 
215 static struct regulator_desc ltc3676_regulators[LTC3676_NUM_REGULATORS] = {
216 	LTC3676_LINEAR_REG(SW1, sw1, BUCK1, DVB1A),
217 	LTC3676_LINEAR_REG(SW2, sw2, BUCK2, DVB2A),
218 	LTC3676_LINEAR_REG(SW3, sw3, BUCK3, DVB3A),
219 	LTC3676_LINEAR_REG(SW4, sw4, BUCK4, DVB4A),
220 	LTC3676_REG(LDO1, ldo1, fixed_standby, 0, 0, 0, 0),
221 	LTC3676_FIXED_REG(LDO2, ldo2, LDOA, 2),
222 	LTC3676_FIXED_REG(LDO3, ldo3, LDOA, 5),
223 	LTC3676_FIXED_REG(LDO4, ldo4, LDOB, 2),
224 };
225 
226 static bool ltc3676_writeable_reg(struct device *dev, unsigned int reg)
227 {
228 	switch (reg) {
229 	case LTC3676_IRQSTAT:
230 	case LTC3676_BUCK1:
231 	case LTC3676_BUCK2:
232 	case LTC3676_BUCK3:
233 	case LTC3676_BUCK4:
234 	case LTC3676_LDOA:
235 	case LTC3676_LDOB:
236 	case LTC3676_SQD1:
237 	case LTC3676_SQD2:
238 	case LTC3676_CNTRL:
239 	case LTC3676_DVB1A:
240 	case LTC3676_DVB1B:
241 	case LTC3676_DVB2A:
242 	case LTC3676_DVB2B:
243 	case LTC3676_DVB3A:
244 	case LTC3676_DVB3B:
245 	case LTC3676_DVB4A:
246 	case LTC3676_DVB4B:
247 	case LTC3676_MSKIRQ:
248 	case LTC3676_MSKPG:
249 	case LTC3676_USER:
250 	case LTC3676_HRST:
251 	case LTC3676_CLIRQ:
252 		return true;
253 	}
254 	return false;
255 }
256 
257 static bool ltc3676_readable_reg(struct device *dev, unsigned int reg)
258 {
259 	switch (reg) {
260 	case LTC3676_IRQSTAT:
261 	case LTC3676_BUCK1:
262 	case LTC3676_BUCK2:
263 	case LTC3676_BUCK3:
264 	case LTC3676_BUCK4:
265 	case LTC3676_LDOA:
266 	case LTC3676_LDOB:
267 	case LTC3676_SQD1:
268 	case LTC3676_SQD2:
269 	case LTC3676_CNTRL:
270 	case LTC3676_DVB1A:
271 	case LTC3676_DVB1B:
272 	case LTC3676_DVB2A:
273 	case LTC3676_DVB2B:
274 	case LTC3676_DVB3A:
275 	case LTC3676_DVB3B:
276 	case LTC3676_DVB4A:
277 	case LTC3676_DVB4B:
278 	case LTC3676_MSKIRQ:
279 	case LTC3676_MSKPG:
280 	case LTC3676_USER:
281 	case LTC3676_HRST:
282 	case LTC3676_CLIRQ:
283 		return true;
284 	}
285 	return false;
286 }
287 
288 static bool ltc3676_volatile_reg(struct device *dev, unsigned int reg)
289 {
290 	switch (reg) {
291 	case LTC3676_IRQSTAT:
292 	case LTC3676_PGSTATL:
293 	case LTC3676_PGSTATRT:
294 		return true;
295 	}
296 	return false;
297 }
298 
299 static const struct regmap_config ltc3676_regmap_config = {
300 	.reg_bits = 8,
301 	.val_bits = 8,
302 	.writeable_reg = ltc3676_writeable_reg,
303 	.readable_reg = ltc3676_readable_reg,
304 	.volatile_reg = ltc3676_volatile_reg,
305 	.max_register = LTC3676_CLIRQ,
306 	.use_single_rw = true,
307 	.cache_type = REGCACHE_RBTREE,
308 };
309 
310 static irqreturn_t ltc3676_isr(int irq, void *dev_id)
311 {
312 	struct ltc3676 *ltc3676 = dev_id;
313 	struct device *dev = ltc3676->dev;
314 	unsigned int i, irqstat, event;
315 
316 	regmap_read(ltc3676->regmap, LTC3676_IRQSTAT, &irqstat);
317 
318 	dev_dbg(dev, "irq%d irqstat=0x%02x\n", irq, irqstat);
319 	if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) {
320 		dev_warn(dev, "Over-temperature Warning\n");
321 		event = REGULATOR_EVENT_OVER_TEMP;
322 		for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
323 			regulator_notifier_call_chain(ltc3676->regulators[i],
324 						      event, NULL);
325 	}
326 
327 	if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) {
328 		dev_info(dev, "Undervoltage Warning\n");
329 		event = REGULATOR_EVENT_UNDER_VOLTAGE;
330 		for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
331 			regulator_notifier_call_chain(ltc3676->regulators[i],
332 						      event, NULL);
333 	}
334 
335 	/* Clear warning condition */
336 	regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
337 
338 	return IRQ_HANDLED;
339 }
340 
341 static int ltc3676_regulator_probe(struct i2c_client *client,
342 				    const struct i2c_device_id *id)
343 {
344 	struct device *dev = &client->dev;
345 	struct regulator_init_data *init_data = dev_get_platdata(dev);
346 	struct regulator_desc *descs;
347 	struct ltc3676 *ltc3676;
348 	int i, ret;
349 
350 	ltc3676 = devm_kzalloc(dev, sizeof(*ltc3676), GFP_KERNEL);
351 	if (!ltc3676)
352 		return -ENOMEM;
353 
354 	i2c_set_clientdata(client, ltc3676);
355 	ltc3676->dev = dev;
356 
357 	descs = ltc3676->regulator_descs;
358 	memcpy(descs, ltc3676_regulators, sizeof(ltc3676_regulators));
359 	descs[LTC3676_LDO3].fixed_uV = 1800000; /* LDO3 is fixed 1.8V */
360 
361 	ltc3676->regmap = devm_regmap_init_i2c(client, &ltc3676_regmap_config);
362 	if (IS_ERR(ltc3676->regmap)) {
363 		ret = PTR_ERR(ltc3676->regmap);
364 		dev_err(dev, "failed to initialize regmap: %d\n", ret);
365 		return ret;
366 	}
367 
368 	for (i = 0; i < LTC3676_NUM_REGULATORS; i++) {
369 		struct regulator_desc *desc = &ltc3676->regulator_descs[i];
370 		struct regulator_config config = { };
371 
372 		if (init_data)
373 			config.init_data = &init_data[i];
374 
375 		config.dev = dev;
376 		config.driver_data = ltc3676;
377 
378 		ltc3676->regulators[i] = devm_regulator_register(dev, desc,
379 								 &config);
380 		if (IS_ERR(ltc3676->regulators[i])) {
381 			ret = PTR_ERR(ltc3676->regulators[i]);
382 			dev_err(dev, "failed to register regulator %s: %d\n",
383 				desc->name, ret);
384 			return ret;
385 		}
386 	}
387 
388 	regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
389 	if (client->irq) {
390 		ret = devm_request_threaded_irq(dev, client->irq, NULL,
391 						ltc3676_isr,
392 						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
393 						client->name, ltc3676);
394 		if (ret) {
395 			dev_err(dev, "Failed to request IRQ: %d\n", ret);
396 			return ret;
397 		}
398 	}
399 
400 	return 0;
401 }
402 
403 static const struct i2c_device_id ltc3676_i2c_id[] = {
404 	{ "ltc3676" },
405 	{ }
406 };
407 MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
408 
409 static struct i2c_driver ltc3676_driver = {
410 	.driver = {
411 		.name = DRIVER_NAME,
412 	},
413 	.probe = ltc3676_regulator_probe,
414 	.id_table = ltc3676_i2c_id,
415 };
416 module_i2c_driver(ltc3676_driver);
417 
418 MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
419 MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC1376");
420 MODULE_LICENSE("GPL v2");
421