1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2016 Gateworks Corporation, Inc. All Rights Reserved.
4  */
5 #include <linux/i2c.h>
6 #include <linux/init.h>
7 #include <linux/interrupt.h>
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/of.h>
11 #include <linux/regmap.h>
12 #include <linux/regulator/driver.h>
13 #include <linux/regulator/machine.h>
14 #include <linux/regulator/of_regulator.h>
15 
16 #define DRIVER_NAME		"ltc3676"
17 
18 /* LTC3676 Registers */
19 #define LTC3676_BUCK1     0x01
20 #define LTC3676_BUCK2     0x02
21 #define LTC3676_BUCK3     0x03
22 #define LTC3676_BUCK4     0x04
23 #define LTC3676_LDOA      0x05
24 #define LTC3676_LDOB      0x06
25 #define LTC3676_SQD1      0x07
26 #define LTC3676_SQD2      0x08
27 #define LTC3676_CNTRL     0x09
28 #define LTC3676_DVB1A     0x0A
29 #define LTC3676_DVB1B     0x0B
30 #define LTC3676_DVB2A     0x0C
31 #define LTC3676_DVB2B     0x0D
32 #define LTC3676_DVB3A     0x0E
33 #define LTC3676_DVB3B     0x0F
34 #define LTC3676_DVB4A     0x10
35 #define LTC3676_DVB4B     0x11
36 #define LTC3676_MSKIRQ    0x12
37 #define LTC3676_MSKPG     0x13
38 #define LTC3676_USER      0x14
39 #define LTC3676_IRQSTAT   0x15
40 #define LTC3676_PGSTATL   0x16
41 #define LTC3676_PGSTATRT  0x17
42 #define LTC3676_HRST      0x1E
43 #define LTC3676_CLIRQ     0x1F
44 
45 #define LTC3676_DVBxA_REF_SELECT	BIT(5)
46 #define LTC3676_DVBxB_PGOOD_MASK	BIT(5)
47 
48 #define LTC3676_IRQSTAT_PGOOD_TIMEOUT	BIT(3)
49 #define LTC3676_IRQSTAT_UNDERVOLT_WARN	BIT(4)
50 #define LTC3676_IRQSTAT_UNDERVOLT_FAULT	BIT(5)
51 #define LTC3676_IRQSTAT_THERMAL_WARN	BIT(6)
52 #define LTC3676_IRQSTAT_THERMAL_FAULT	BIT(7)
53 
54 enum ltc3676_reg {
55 	LTC3676_SW1,
56 	LTC3676_SW2,
57 	LTC3676_SW3,
58 	LTC3676_SW4,
59 	LTC3676_LDO1,
60 	LTC3676_LDO2,
61 	LTC3676_LDO3,
62 	LTC3676_LDO4,
63 	LTC3676_NUM_REGULATORS,
64 };
65 
66 struct ltc3676 {
67 	struct regmap *regmap;
68 	struct device *dev;
69 	struct regulator_desc regulator_descs[LTC3676_NUM_REGULATORS];
70 	struct regulator_dev *regulators[LTC3676_NUM_REGULATORS];
71 };
72 
ltc3676_set_suspend_voltage(struct regulator_dev * rdev,int uV)73 static int ltc3676_set_suspend_voltage(struct regulator_dev *rdev, int uV)
74 {
75 	struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
76 	struct device *dev = ltc3676->dev;
77 	int dcdc = rdev_get_id(rdev);
78 	int sel;
79 
80 	dev_dbg(dev, "%s id=%d uV=%d\n", __func__, dcdc, uV);
81 	sel = regulator_map_voltage_linear(rdev, uV, uV);
82 	if (sel < 0)
83 		return sel;
84 
85 	/* DVBB register follows right after the corresponding DVBA register */
86 	return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
87 				  rdev->desc->vsel_mask, sel);
88 }
89 
ltc3676_set_suspend_mode(struct regulator_dev * rdev,unsigned int mode)90 static int ltc3676_set_suspend_mode(struct regulator_dev *rdev,
91 				    unsigned int mode)
92 {
93 	struct ltc3676 *ltc3676= rdev_get_drvdata(rdev);
94 	struct device *dev = ltc3676->dev;
95 	int mask, val;
96 	int dcdc = rdev_get_id(rdev);
97 
98 	dev_dbg(dev, "%s id=%d mode=%d\n", __func__, dcdc, mode);
99 
100 	mask = LTC3676_DVBxA_REF_SELECT;
101 	switch (mode) {
102 	case REGULATOR_MODE_STANDBY:
103 		val = 0; /* select DVBxA */
104 		break;
105 	case REGULATOR_MODE_NORMAL:
106 		val = LTC3676_DVBxA_REF_SELECT; /* select DVBxB */
107 		break;
108 	default:
109 		dev_warn(&rdev->dev, "%s: regulator mode: 0x%x not supported\n",
110 			 rdev->desc->name, mode);
111 		return -EINVAL;
112 	}
113 
114 	return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg,
115 				  mask, val);
116 }
117 
ltc3676_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)118 static int ltc3676_set_voltage_sel(struct regulator_dev *rdev, unsigned selector)
119 {
120 	struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
121 	struct device *dev = ltc3676->dev;
122 	int ret, dcdc = rdev_get_id(rdev);
123 
124 	dev_dbg(dev, "%s id=%d selector=%d\n", __func__, dcdc, selector);
125 
126 	ret = regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
127 				 LTC3676_DVBxB_PGOOD_MASK,
128 				 LTC3676_DVBxB_PGOOD_MASK);
129 	if (ret)
130 		return ret;
131 
132 	return regulator_set_voltage_sel_regmap(rdev, selector);
133 }
134 
ltc3676_scale(unsigned int uV,u32 r1,u32 r2)135 static inline unsigned int ltc3676_scale(unsigned int uV, u32 r1, u32 r2)
136 {
137 	uint64_t tmp;
138 	if (uV == 0)
139 		return 0;
140 	tmp = (uint64_t)uV * r1;
141 	do_div(tmp, r2);
142 	return uV + (unsigned int)tmp;
143 }
144 
ltc3676_of_parse_cb(struct device_node * np,const struct regulator_desc * desc,struct regulator_config * config)145 static int ltc3676_of_parse_cb(struct device_node *np,
146 			       const struct regulator_desc *desc,
147 			       struct regulator_config *config)
148 {
149 	struct ltc3676 *ltc3676 = config->driver_data;
150 	struct regulator_desc *rdesc = &ltc3676->regulator_descs[desc->id];
151 	u32 r[2];
152 	int ret;
153 
154 	/* LDO3 has a fixed output */
155 	if (desc->id == LTC3676_LDO3)
156 		return 0;
157 
158 	ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider", r, 2);
159 	if (ret) {
160 		dev_err(ltc3676->dev, "Failed to parse voltage divider: %d\n",
161 			ret);
162 		return ret;
163 	}
164 
165 	rdesc->min_uV = ltc3676_scale(desc->min_uV, r[0], r[1]);
166 	rdesc->uV_step = ltc3676_scale(desc->uV_step, r[0], r[1]);
167 	rdesc->fixed_uV = ltc3676_scale(desc->fixed_uV, r[0], r[1]);
168 
169 	return 0;
170 }
171 
172 /* SW1, SW2, SW3, SW4 linear 0.8V-3.3V with scalar via R1/R2 feeback res */
173 static const struct regulator_ops ltc3676_linear_regulator_ops = {
174 	.enable = regulator_enable_regmap,
175 	.disable = regulator_disable_regmap,
176 	.is_enabled = regulator_is_enabled_regmap,
177 	.list_voltage = regulator_list_voltage_linear,
178 	.set_voltage_sel = ltc3676_set_voltage_sel,
179 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
180 	.set_suspend_voltage = ltc3676_set_suspend_voltage,
181 	.set_suspend_mode = ltc3676_set_suspend_mode,
182 };
183 
184 /* LDO1 always on fixed 0.8V-3.3V via scalar via R1/R2 feeback res */
185 static const struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
186 };
187 
188 /* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
189 static const struct regulator_ops ltc3676_fixed_regulator_ops = {
190 	.enable = regulator_enable_regmap,
191 	.disable = regulator_disable_regmap,
192 	.is_enabled = regulator_is_enabled_regmap,
193 };
194 
195 #define LTC3676_REG(_id, _name, _ops, en_reg, en_bit, dvba_reg, dvb_mask)   \
196 	[LTC3676_ ## _id] = {                                        \
197 		.name = #_name,                                \
198 		.of_match = of_match_ptr(#_name),              \
199 		.regulators_node = of_match_ptr("regulators"), \
200 		.of_parse_cb = ltc3676_of_parse_cb,            \
201 		.n_voltages = (dvb_mask) + 1,                  \
202 		.min_uV = (dvba_reg) ? 412500 : 0,             \
203 		.uV_step = (dvba_reg) ? 12500 : 0,             \
204 		.ramp_delay = (dvba_reg) ? 800 : 0,            \
205 		.fixed_uV = (dvb_mask) ? 0 : 725000,           \
206 		.ops = &ltc3676_ ## _ops ## _regulator_ops,    \
207 		.type = REGULATOR_VOLTAGE,                     \
208 		.id = LTC3676_ ## _id,                         \
209 		.owner = THIS_MODULE,                          \
210 		.vsel_reg = (dvba_reg),                        \
211 		.vsel_mask = (dvb_mask),                       \
212 		.enable_reg = (en_reg),                        \
213 		.enable_mask = (1 << en_bit),                  \
214 	}
215 
216 #define LTC3676_LINEAR_REG(_id, _name, _en, _dvba)                     \
217 	LTC3676_REG(_id, _name, linear,                                \
218 		    LTC3676_ ## _en, 7,                                \
219 		    LTC3676_ ## _dvba, 0x1f)
220 
221 #define LTC3676_FIXED_REG(_id, _name, _en_reg, _en_bit)                \
222 	LTC3676_REG(_id, _name, fixed, LTC3676_ ## _en_reg, _en_bit, 0, 0)
223 
224 static const struct regulator_desc ltc3676_regulators[LTC3676_NUM_REGULATORS] = {
225 	LTC3676_LINEAR_REG(SW1, sw1, BUCK1, DVB1A),
226 	LTC3676_LINEAR_REG(SW2, sw2, BUCK2, DVB2A),
227 	LTC3676_LINEAR_REG(SW3, sw3, BUCK3, DVB3A),
228 	LTC3676_LINEAR_REG(SW4, sw4, BUCK4, DVB4A),
229 	LTC3676_REG(LDO1, ldo1, fixed_standby, 0, 0, 0, 0),
230 	LTC3676_FIXED_REG(LDO2, ldo2, LDOA, 2),
231 	LTC3676_FIXED_REG(LDO3, ldo3, LDOA, 5),
232 	LTC3676_FIXED_REG(LDO4, ldo4, LDOB, 2),
233 };
234 
ltc3676_readable_writeable_reg(struct device * dev,unsigned int reg)235 static bool ltc3676_readable_writeable_reg(struct device *dev, unsigned int reg)
236 {
237 	switch (reg) {
238 	case LTC3676_BUCK1 ... LTC3676_IRQSTAT:
239 	case LTC3676_HRST:
240 	case LTC3676_CLIRQ:
241 		return true;
242 	}
243 	return false;
244 }
245 
ltc3676_volatile_reg(struct device * dev,unsigned int reg)246 static bool ltc3676_volatile_reg(struct device *dev, unsigned int reg)
247 {
248 	switch (reg) {
249 	case LTC3676_IRQSTAT ... LTC3676_PGSTATRT:
250 		return true;
251 	}
252 	return false;
253 }
254 
255 static const struct regmap_config ltc3676_regmap_config = {
256 	.reg_bits = 8,
257 	.val_bits = 8,
258 	.writeable_reg = ltc3676_readable_writeable_reg,
259 	.readable_reg = ltc3676_readable_writeable_reg,
260 	.volatile_reg = ltc3676_volatile_reg,
261 	.max_register = LTC3676_CLIRQ,
262 	.use_single_read = true,
263 	.use_single_write = true,
264 	.cache_type = REGCACHE_RBTREE,
265 };
266 
ltc3676_isr(int irq,void * dev_id)267 static irqreturn_t ltc3676_isr(int irq, void *dev_id)
268 {
269 	struct ltc3676 *ltc3676 = dev_id;
270 	struct device *dev = ltc3676->dev;
271 	unsigned int i, irqstat, event;
272 
273 	regmap_read(ltc3676->regmap, LTC3676_IRQSTAT, &irqstat);
274 
275 	dev_dbg(dev, "irq%d irqstat=0x%02x\n", irq, irqstat);
276 	if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) {
277 		dev_warn(dev, "Over-temperature Warning\n");
278 		event = REGULATOR_EVENT_OVER_TEMP;
279 		for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
280 			regulator_notifier_call_chain(ltc3676->regulators[i],
281 						      event, NULL);
282 	}
283 
284 	if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) {
285 		dev_info(dev, "Undervoltage Warning\n");
286 		event = REGULATOR_EVENT_UNDER_VOLTAGE;
287 		for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
288 			regulator_notifier_call_chain(ltc3676->regulators[i],
289 						      event, NULL);
290 	}
291 
292 	/* Clear warning condition */
293 	regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
294 
295 	return IRQ_HANDLED;
296 }
297 
ltc3676_regulator_probe(struct i2c_client * client)298 static int ltc3676_regulator_probe(struct i2c_client *client)
299 {
300 	struct device *dev = &client->dev;
301 	struct regulator_init_data *init_data = dev_get_platdata(dev);
302 	struct regulator_desc *descs;
303 	struct ltc3676 *ltc3676;
304 	int i, ret;
305 
306 	ltc3676 = devm_kzalloc(dev, sizeof(*ltc3676), GFP_KERNEL);
307 	if (!ltc3676)
308 		return -ENOMEM;
309 
310 	i2c_set_clientdata(client, ltc3676);
311 	ltc3676->dev = dev;
312 
313 	descs = ltc3676->regulator_descs;
314 	memcpy(descs, ltc3676_regulators, sizeof(ltc3676_regulators));
315 	descs[LTC3676_LDO3].fixed_uV = 1800000; /* LDO3 is fixed 1.8V */
316 
317 	ltc3676->regmap = devm_regmap_init_i2c(client, &ltc3676_regmap_config);
318 	if (IS_ERR(ltc3676->regmap)) {
319 		ret = PTR_ERR(ltc3676->regmap);
320 		dev_err(dev, "failed to initialize regmap: %d\n", ret);
321 		return ret;
322 	}
323 
324 	for (i = 0; i < LTC3676_NUM_REGULATORS; i++) {
325 		struct regulator_desc *desc = &ltc3676->regulator_descs[i];
326 		struct regulator_config config = { };
327 
328 		if (init_data)
329 			config.init_data = &init_data[i];
330 
331 		config.dev = dev;
332 		config.driver_data = ltc3676;
333 
334 		ltc3676->regulators[i] = devm_regulator_register(dev, desc,
335 								 &config);
336 		if (IS_ERR(ltc3676->regulators[i])) {
337 			ret = PTR_ERR(ltc3676->regulators[i]);
338 			dev_err(dev, "failed to register regulator %s: %d\n",
339 				desc->name, ret);
340 			return ret;
341 		}
342 	}
343 
344 	regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
345 	if (client->irq) {
346 		ret = devm_request_threaded_irq(dev, client->irq, NULL,
347 						ltc3676_isr,
348 						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
349 						client->name, ltc3676);
350 		if (ret) {
351 			dev_err(dev, "Failed to request IRQ: %d\n", ret);
352 			return ret;
353 		}
354 	}
355 
356 	return 0;
357 }
358 
359 static const struct i2c_device_id ltc3676_i2c_id[] = {
360 	{ "ltc3676" },
361 	{ }
362 };
363 MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
364 
365 static const struct of_device_id __maybe_unused ltc3676_of_match[] = {
366 	{ .compatible = "lltc,ltc3676" },
367 	{ },
368 };
369 MODULE_DEVICE_TABLE(of, ltc3676_of_match);
370 
371 static struct i2c_driver ltc3676_driver = {
372 	.driver = {
373 		.name = DRIVER_NAME,
374 		.of_match_table = of_match_ptr(ltc3676_of_match),
375 	},
376 	.probe_new = ltc3676_regulator_probe,
377 	.id_table = ltc3676_i2c_id,
378 };
379 module_i2c_driver(ltc3676_driver);
380 
381 MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
382 MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC3676");
383 MODULE_LICENSE("GPL v2");
384