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
54enum 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
66struct 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
73static 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
90static 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
118static 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
135static 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
145static 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 */
173static 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 */
185static const struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
186};
187
188/* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
189static 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
224static 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
235static 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
246static 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
255static 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_MAPLE,
265};
266
267static 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
298static 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
359static const struct i2c_device_id ltc3676_i2c_id[] = {
360	{ "ltc3676" },
361	{ }
362};
363MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
364
365static const struct of_device_id __maybe_unused ltc3676_of_match[] = {
366	{ .compatible = "lltc,ltc3676" },
367	{ },
368};
369MODULE_DEVICE_TABLE(of, ltc3676_of_match);
370
371static struct i2c_driver ltc3676_driver = {
372	.driver = {
373		.name = DRIVER_NAME,
374		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
375		.of_match_table = of_match_ptr(ltc3676_of_match),
376	},
377	.probe = ltc3676_regulator_probe,
378	.id_table = ltc3676_i2c_id,
379};
380module_i2c_driver(ltc3676_driver);
381
382MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
383MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC3676");
384MODULE_LICENSE("GPL v2");
385