1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * max8952.c - Voltage and current regulation for the Maxim 8952
4 *
5 * Copyright (C) 2010 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 */
8
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/i2c.h>
12#include <linux/err.h>
13#include <linux/platform_device.h>
14#include <linux/regulator/driver.h>
15#include <linux/regulator/max8952.h>
16#include <linux/gpio/consumer.h>
17#include <linux/io.h>
18#include <linux/of.h>
19#include <linux/regulator/of_regulator.h>
20#include <linux/slab.h>
21
22/* Registers */
23enum {
24	MAX8952_REG_MODE0,
25	MAX8952_REG_MODE1,
26	MAX8952_REG_MODE2,
27	MAX8952_REG_MODE3,
28	MAX8952_REG_CONTROL,
29	MAX8952_REG_SYNC,
30	MAX8952_REG_RAMP,
31	MAX8952_REG_CHIP_ID1,
32	MAX8952_REG_CHIP_ID2,
33};
34
35struct max8952_data {
36	struct i2c_client	*client;
37	struct max8952_platform_data *pdata;
38	struct gpio_desc *vid0_gpiod;
39	struct gpio_desc *vid1_gpiod;
40	bool vid0;
41	bool vid1;
42};
43
44static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
45{
46	int ret = i2c_smbus_read_byte_data(max8952->client, reg);
47
48	if (ret > 0)
49		ret &= 0xff;
50
51	return ret;
52}
53
54static int max8952_write_reg(struct max8952_data *max8952,
55		u8 reg, u8 value)
56{
57	return i2c_smbus_write_byte_data(max8952->client, reg, value);
58}
59
60static int max8952_list_voltage(struct regulator_dev *rdev,
61		unsigned int selector)
62{
63	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
64
65	if (rdev_get_id(rdev) != 0)
66		return -EINVAL;
67
68	return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
69}
70
71static int max8952_get_voltage_sel(struct regulator_dev *rdev)
72{
73	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
74	u8 vid = 0;
75
76	if (max8952->vid0)
77		vid += 1;
78	if (max8952->vid1)
79		vid += 2;
80
81	return vid;
82}
83
84static int max8952_set_voltage_sel(struct regulator_dev *rdev,
85				   unsigned selector)
86{
87	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
88
89	if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) {
90		/* DVS not supported */
91		return -EPERM;
92	}
93
94	max8952->vid0 = selector & 0x1;
95	max8952->vid1 = (selector >> 1) & 0x1;
96	gpiod_set_value(max8952->vid0_gpiod, max8952->vid0);
97	gpiod_set_value(max8952->vid1_gpiod, max8952->vid1);
98
99	return 0;
100}
101
102static const struct regulator_ops max8952_ops = {
103	.list_voltage		= max8952_list_voltage,
104	.get_voltage_sel	= max8952_get_voltage_sel,
105	.set_voltage_sel	= max8952_set_voltage_sel,
106};
107
108static const struct regulator_desc regulator = {
109	.name		= "MAX8952_VOUT",
110	.id		= 0,
111	.n_voltages	= MAX8952_NUM_DVS_MODE,
112	.ops		= &max8952_ops,
113	.type		= REGULATOR_VOLTAGE,
114	.owner		= THIS_MODULE,
115};
116
117#ifdef CONFIG_OF
118static const struct of_device_id max8952_dt_match[] = {
119	{ .compatible = "maxim,max8952" },
120	{},
121};
122MODULE_DEVICE_TABLE(of, max8952_dt_match);
123
124static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
125{
126	struct max8952_platform_data *pd;
127	struct device_node *np = dev->of_node;
128	int ret;
129	int i;
130
131	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
132	if (!pd)
133		return NULL;
134
135	if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode))
136		dev_warn(dev, "Default mode not specified, assuming 0\n");
137
138	ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt",
139					pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode));
140	if (ret) {
141		dev_err(dev, "max8952,dvs-mode-microvolt property not specified");
142		return NULL;
143	}
144
145	for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) {
146		if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) {
147			dev_err(dev, "DVS voltage %d out of range\n", i);
148			return NULL;
149		}
150		pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000;
151	}
152
153	if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq))
154		dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n");
155
156	if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed))
157		dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n");
158
159	pd->reg_data = of_get_regulator_init_data(dev, np, &regulator);
160	if (!pd->reg_data) {
161		dev_err(dev, "Failed to parse regulator init data\n");
162		return NULL;
163	}
164
165	return pd;
166}
167#else
168static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
169{
170	return NULL;
171}
172#endif
173
174static int max8952_pmic_probe(struct i2c_client *client)
175{
176	struct i2c_adapter *adapter = client->adapter;
177	struct max8952_platform_data *pdata = dev_get_platdata(&client->dev);
178	struct regulator_config config = { };
179	struct max8952_data *max8952;
180	struct regulator_dev *rdev;
181	struct gpio_desc *gpiod;
182	enum gpiod_flags gflags;
183
184	int ret = 0;
185
186	if (client->dev.of_node)
187		pdata = max8952_parse_dt(&client->dev);
188
189	if (!pdata) {
190		dev_err(&client->dev, "Require the platform data\n");
191		return -EINVAL;
192	}
193
194	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
195		return -EIO;
196
197	max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
198			       GFP_KERNEL);
199	if (!max8952)
200		return -ENOMEM;
201
202	max8952->client = client;
203	max8952->pdata = pdata;
204
205	config.dev = &client->dev;
206	config.init_data = pdata->reg_data;
207	config.driver_data = max8952;
208	config.of_node = client->dev.of_node;
209
210	if (pdata->reg_data->constraints.boot_on)
211		gflags = GPIOD_OUT_HIGH;
212	else
213		gflags = GPIOD_OUT_LOW;
214	gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
215	/*
216	 * Do not use devm* here: the regulator core takes over the
217	 * lifecycle management of the GPIO descriptor.
218	 */
219	gpiod = gpiod_get_optional(&client->dev,
220				   "max8952,en",
221				   gflags);
222	if (IS_ERR(gpiod))
223		return PTR_ERR(gpiod);
224	if (gpiod)
225		config.ena_gpiod = gpiod;
226
227	rdev = devm_regulator_register(&client->dev, &regulator, &config);
228	if (IS_ERR(rdev)) {
229		ret = PTR_ERR(rdev);
230		dev_err(&client->dev, "regulator init failed (%d)\n", ret);
231		return ret;
232	}
233
234	max8952->vid0 = pdata->default_mode & 0x1;
235	max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
236
237	/* Fetch vid0 and vid1 GPIOs if available */
238	gflags = max8952->vid0 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
239	max8952->vid0_gpiod = devm_gpiod_get_index_optional(&client->dev,
240							    "max8952,vid",
241							    0, gflags);
242	if (IS_ERR(max8952->vid0_gpiod))
243		return PTR_ERR(max8952->vid0_gpiod);
244	gflags = max8952->vid1 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
245	max8952->vid1_gpiod = devm_gpiod_get_index_optional(&client->dev,
246							    "max8952,vid",
247							    1, gflags);
248	if (IS_ERR(max8952->vid1_gpiod))
249		return PTR_ERR(max8952->vid1_gpiod);
250
251	/* If either VID GPIO is missing just disable this */
252	if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) {
253		dev_warn(&client->dev, "VID0/1 gpio invalid: "
254			 "DVS not available.\n");
255		max8952->vid0 = 0;
256		max8952->vid1 = 0;
257		/* Make sure if we have any descriptors they get set to low */
258		if (max8952->vid0_gpiod)
259			gpiod_set_value(max8952->vid0_gpiod, 0);
260		if (max8952->vid1_gpiod)
261			gpiod_set_value(max8952->vid1_gpiod, 0);
262
263		/* Disable Pulldown of EN only */
264		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
265
266		dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
267				" do not have proper controls.\n");
268	} else {
269		/*
270		 * Disable Pulldown on EN, VID0, VID1 to reduce
271		 * leakage current of MAX8952 assuming that MAX8952
272		 * is turned on (EN==1). Note that without having VID0/1
273		 * properly connected, turning pulldown off can be
274		 * problematic. Thus, turn this off only when they are
275		 * controllable by GPIO.
276		 */
277		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
278	}
279
280	max8952_write_reg(max8952, MAX8952_REG_MODE0,
281			(max8952_read_reg(max8952,
282					  MAX8952_REG_MODE0) & 0xC0) |
283			(pdata->dvs_mode[0] & 0x3F));
284	max8952_write_reg(max8952, MAX8952_REG_MODE1,
285			(max8952_read_reg(max8952,
286					  MAX8952_REG_MODE1) & 0xC0) |
287			(pdata->dvs_mode[1] & 0x3F));
288	max8952_write_reg(max8952, MAX8952_REG_MODE2,
289			(max8952_read_reg(max8952,
290					  MAX8952_REG_MODE2) & 0xC0) |
291			(pdata->dvs_mode[2] & 0x3F));
292	max8952_write_reg(max8952, MAX8952_REG_MODE3,
293			(max8952_read_reg(max8952,
294					  MAX8952_REG_MODE3) & 0xC0) |
295			(pdata->dvs_mode[3] & 0x3F));
296
297	max8952_write_reg(max8952, MAX8952_REG_SYNC,
298			(max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
299			((pdata->sync_freq & 0x3) << 6));
300	max8952_write_reg(max8952, MAX8952_REG_RAMP,
301			(max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
302			((pdata->ramp_speed & 0x7) << 5));
303
304	i2c_set_clientdata(client, max8952);
305
306	return 0;
307}
308
309static const struct i2c_device_id max8952_ids[] = {
310	{ "max8952", 0 },
311	{ },
312};
313MODULE_DEVICE_TABLE(i2c, max8952_ids);
314
315static struct i2c_driver max8952_pmic_driver = {
316	.probe		= max8952_pmic_probe,
317	.driver		= {
318		.name	= "max8952",
319		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
320		.of_match_table = of_match_ptr(max8952_dt_match),
321	},
322	.id_table	= max8952_ids,
323};
324
325static int __init max8952_pmic_init(void)
326{
327	return i2c_add_driver(&max8952_pmic_driver);
328}
329subsys_initcall(max8952_pmic_init);
330
331static void __exit max8952_pmic_exit(void)
332{
333	i2c_del_driver(&max8952_pmic_driver);
334}
335module_exit(max8952_pmic_exit);
336
337MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
338MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
339MODULE_LICENSE("GPL");
340