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
63enum 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
75struct 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
82static 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
99static 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
127static 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
144static 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
154static 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 */
182static 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 */
194static const struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
195};
196
197/* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
198static 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
233static 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
244static bool ltc3676_readable_writeable_reg(struct device *dev, unsigned int reg)
245{
246 switch (reg) {
247 case LTC3676_BUCK1 ... LTC3676_IRQSTAT:
248 case LTC3676_HRST:
249 case LTC3676_CLIRQ:
250 return true;
251 }
252 return false;
253}
254
255static bool ltc3676_volatile_reg(struct device *dev, unsigned int reg)
256{
257 switch (reg) {
258 case LTC3676_IRQSTAT ... LTC3676_PGSTATRT:
259 return true;
260 }
261 return false;
262}
263
264static const struct regmap_config ltc3676_regmap_config = {
265 .reg_bits = 8,
266 .val_bits = 8,
267 .writeable_reg = ltc3676_readable_writeable_reg,
268 .readable_reg = ltc3676_readable_writeable_reg,
269 .volatile_reg = ltc3676_volatile_reg,
270 .max_register = LTC3676_CLIRQ,
271 .use_single_read = true,
272 .use_single_write = true,
273 .cache_type = REGCACHE_RBTREE,
274};
275
276static irqreturn_t ltc3676_isr(int irq, void *dev_id)
277{
278 struct ltc3676 *ltc3676 = dev_id;
279 struct device *dev = ltc3676->dev;
280 unsigned int i, irqstat, event;
281
282 regmap_read(ltc3676->regmap, LTC3676_IRQSTAT, &irqstat);
283
284 dev_dbg(dev, "irq%d irqstat=0x%02x\n", irq, irqstat);
285 if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) {
286 dev_warn(dev, "Over-temperature Warning\n");
287 event = REGULATOR_EVENT_OVER_TEMP;
288 for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
289 regulator_notifier_call_chain(ltc3676->regulators[i],
290 event, NULL);
291 }
292
293 if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) {
294 dev_info(dev, "Undervoltage Warning\n");
295 event = REGULATOR_EVENT_UNDER_VOLTAGE;
296 for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
297 regulator_notifier_call_chain(ltc3676->regulators[i],
298 event, NULL);
299 }
300
301 /* Clear warning condition */
302 regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
303
304 return IRQ_HANDLED;
305}
306
307static int ltc3676_regulator_probe(struct i2c_client *client,
308 const struct i2c_device_id *id)
309{
310 struct device *dev = &client->dev;
311 struct regulator_init_data *init_data = dev_get_platdata(dev);
312 struct regulator_desc *descs;
313 struct ltc3676 *ltc3676;
314 int i, ret;
315
316 ltc3676 = devm_kzalloc(dev, sizeof(*ltc3676), GFP_KERNEL);
317 if (!ltc3676)
318 return -ENOMEM;
319
320 i2c_set_clientdata(client, ltc3676);
321 ltc3676->dev = dev;
322
323 descs = ltc3676->regulator_descs;
324 memcpy(descs, ltc3676_regulators, sizeof(ltc3676_regulators));
325 descs[LTC3676_LDO3].fixed_uV = 1800000; /* LDO3 is fixed 1.8V */
326
327 ltc3676->regmap = devm_regmap_init_i2c(client, &ltc3676_regmap_config);
328 if (IS_ERR(ltc3676->regmap)) {
329 ret = PTR_ERR(ltc3676->regmap);
330 dev_err(dev, "failed to initialize regmap: %d\n", ret);
331 return ret;
332 }
333
334 for (i = 0; i < LTC3676_NUM_REGULATORS; i++) {
335 struct regulator_desc *desc = &ltc3676->regulator_descs[i];
336 struct regulator_config config = { };
337
338 if (init_data)
339 config.init_data = &init_data[i];
340
341 config.dev = dev;
342 config.driver_data = ltc3676;
343
344 ltc3676->regulators[i] = devm_regulator_register(dev, desc,
345 &config);
346 if (IS_ERR(ltc3676->regulators[i])) {
347 ret = PTR_ERR(ltc3676->regulators[i]);
348 dev_err(dev, "failed to register regulator %s: %d\n",
349 desc->name, ret);
350 return ret;
351 }
352 }
353
354 regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
355 if (client->irq) {
356 ret = devm_request_threaded_irq(dev, client->irq, NULL,
357 ltc3676_isr,
358 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
359 client->name, ltc3676);
360 if (ret) {
361 dev_err(dev, "Failed to request IRQ: %d\n", ret);
362 return ret;
363 }
364 }
365
366 return 0;
367}
368
369static const struct i2c_device_id ltc3676_i2c_id[] = {
370 { "ltc3676" },
371 { }
372};
373MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
374
375static const struct of_device_id ltc3676_of_match[] = {
376 { .compatible = "lltc,ltc3676" },
377 { },
378};
379MODULE_DEVICE_TABLE(of, ltc3676_of_match);
380
381static struct i2c_driver ltc3676_driver = {
382 .driver = {
383 .name = DRIVER_NAME,
384 .of_match_table = of_match_ptr(ltc3676_of_match),
385 },
386 .probe = ltc3676_regulator_probe,
387 .id_table = ltc3676_i2c_id,
388};
389module_i2c_driver(ltc3676_driver);
390
391MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
392MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC3676");
393MODULE_LICENSE("GPL v2");
394