1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * max1586.c  --  Voltage and current regulation for the Maxim 1586
4  *
5  * Copyright (C) 2008 Robert Jarzmik
6  */
7 #include <linux/module.h>
8 #include <linux/err.h>
9 #include <linux/i2c.h>
10 #include <linux/platform_device.h>
11 #include <linux/regulator/driver.h>
12 #include <linux/slab.h>
13 #include <linux/regulator/max1586.h>
14 #include <linux/of_device.h>
15 #include <linux/regulator/of_regulator.h>
16 
17 #define MAX1586_V3_MAX_VSEL 31
18 #define MAX1586_V6_MAX_VSEL 3
19 
20 #define MAX1586_V3_MIN_UV   700000
21 #define MAX1586_V3_MAX_UV  1475000
22 
23 #define MAX1586_V6_MIN_UV        0
24 #define MAX1586_V6_MAX_UV  3000000
25 
26 #define I2C_V3_SELECT (0 << 5)
27 #define I2C_V6_SELECT (1 << 5)
28 
29 struct max1586_data {
30 	struct i2c_client *client;
31 
32 	/* min/max V3 voltage */
33 	unsigned int min_uV;
34 	unsigned int max_uV;
35 
36 	unsigned int v3_curr_sel;
37 	unsigned int v6_curr_sel;
38 };
39 
40 /*
41  * V6 voltage
42  * On I2C bus, sending a "x" byte to the max1586 means :
43  *   set V6 to either 0V, 1.8V, 2.5V, 3V depending on (x & 0x3)
44  * As regulator framework doesn't accept voltages to be 0V, we use 1uV.
45  */
46 static const unsigned int v6_voltages_uv[] = { 1, 1800000, 2500000, 3000000 };
47 
48 /*
49  * V3 voltage
50  * On I2C bus, sending a "x" byte to the max1586 means :
51  *   set V3 to 0.700V + (x & 0x1f) * 0.025V
52  * This voltage can be increased by external resistors
53  * R24 and R25=100kOhm as described in the data sheet.
54  * The gain is approximately: 1 + R24/R25 + R24/185.5kOhm
55  */
max1586_v3_get_voltage_sel(struct regulator_dev * rdev)56 static int max1586_v3_get_voltage_sel(struct regulator_dev *rdev)
57 {
58 	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
59 
60 	return max1586->v3_curr_sel;
61 }
62 
max1586_v3_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)63 static int max1586_v3_set_voltage_sel(struct regulator_dev *rdev,
64 				      unsigned selector)
65 {
66 	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
67 	struct i2c_client *client = max1586->client;
68 	int ret;
69 	u8 v3_prog;
70 
71 	dev_dbg(&client->dev, "changing voltage v3 to %dmv\n",
72 		regulator_list_voltage_linear(rdev, selector) / 1000);
73 
74 	v3_prog = I2C_V3_SELECT | (u8) selector;
75 	ret = i2c_smbus_write_byte(client, v3_prog);
76 	if (ret)
77 		return ret;
78 
79 	max1586->v3_curr_sel = selector;
80 
81 	return 0;
82 }
83 
max1586_v6_get_voltage_sel(struct regulator_dev * rdev)84 static int max1586_v6_get_voltage_sel(struct regulator_dev *rdev)
85 {
86 	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
87 
88 	return max1586->v6_curr_sel;
89 }
90 
max1586_v6_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)91 static int max1586_v6_set_voltage_sel(struct regulator_dev *rdev,
92 				      unsigned int selector)
93 {
94 	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
95 	struct i2c_client *client = max1586->client;
96 	u8 v6_prog;
97 	int ret;
98 
99 	dev_dbg(&client->dev, "changing voltage v6 to %dmv\n",
100 		rdev->desc->volt_table[selector] / 1000);
101 
102 	v6_prog = I2C_V6_SELECT | (u8) selector;
103 	ret = i2c_smbus_write_byte(client, v6_prog);
104 	if (ret)
105 		return ret;
106 
107 	max1586->v6_curr_sel = selector;
108 
109 	return 0;
110 }
111 
112 /*
113  * The Maxim 1586 controls V3 and V6 voltages, but offers no way of reading back
114  * the set up value.
115  */
116 static const struct regulator_ops max1586_v3_ops = {
117 	.get_voltage_sel = max1586_v3_get_voltage_sel,
118 	.set_voltage_sel = max1586_v3_set_voltage_sel,
119 	.list_voltage = regulator_list_voltage_linear,
120 	.map_voltage = regulator_map_voltage_linear,
121 };
122 
123 static const struct regulator_ops max1586_v6_ops = {
124 	.get_voltage_sel = max1586_v6_get_voltage_sel,
125 	.set_voltage_sel = max1586_v6_set_voltage_sel,
126 	.list_voltage = regulator_list_voltage_table,
127 };
128 
129 static struct regulator_desc max1586_reg[] = {
130 	{
131 		.name = "Output_V3",
132 		.id = MAX1586_V3,
133 		.ops = &max1586_v3_ops,
134 		.type = REGULATOR_VOLTAGE,
135 		.n_voltages = MAX1586_V3_MAX_VSEL + 1,
136 		.owner = THIS_MODULE,
137 	},
138 	{
139 		.name = "Output_V6",
140 		.id = MAX1586_V6,
141 		.ops = &max1586_v6_ops,
142 		.type = REGULATOR_VOLTAGE,
143 		.n_voltages = MAX1586_V6_MAX_VSEL + 1,
144 		.volt_table = v6_voltages_uv,
145 		.owner = THIS_MODULE,
146 	},
147 };
148 
of_get_max1586_platform_data(struct device * dev,struct max1586_platform_data * pdata)149 static int of_get_max1586_platform_data(struct device *dev,
150 				 struct max1586_platform_data *pdata)
151 {
152 	struct max1586_subdev_data *sub;
153 	struct of_regulator_match rmatch[ARRAY_SIZE(max1586_reg)] = { };
154 	struct device_node *np = dev->of_node;
155 	int i, matched;
156 
157 	if (of_property_read_u32(np, "v3-gain",
158 				 &pdata->v3_gain) < 0) {
159 		dev_err(dev, "%pOF has no 'v3-gain' property\n", np);
160 		return -EINVAL;
161 	}
162 
163 	np = of_get_child_by_name(np, "regulators");
164 	if (!np) {
165 		dev_err(dev, "missing 'regulators' subnode in DT\n");
166 		return -EINVAL;
167 	}
168 
169 	for (i = 0; i < ARRAY_SIZE(rmatch); i++)
170 		rmatch[i].name = max1586_reg[i].name;
171 
172 	matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
173 	of_node_put(np);
174 	/*
175 	 * If matched is 0, ie. neither Output_V3 nor Output_V6 have been found,
176 	 * return 0, which signals the normal situation where no subregulator is
177 	 * available. This is normal because the max1586 doesn't provide any
178 	 * readback support, so the subregulators can't report any status
179 	 * anyway.  If matched < 0, return the error.
180 	 */
181 	if (matched <= 0)
182 		return matched;
183 
184 	pdata->subdevs = devm_kcalloc(dev,
185 				      matched,
186 				      sizeof(struct max1586_subdev_data),
187 				      GFP_KERNEL);
188 	if (!pdata->subdevs)
189 		return -ENOMEM;
190 
191 	pdata->num_subdevs = matched;
192 	sub = pdata->subdevs;
193 
194 	for (i = 0; i < matched; i++) {
195 		sub->id = i;
196 		sub->name = rmatch[i].of_node->name;
197 		sub->platform_data = rmatch[i].init_data;
198 		sub++;
199 	}
200 
201 	return 0;
202 }
203 
204 static const struct of_device_id __maybe_unused max1586_of_match[] = {
205 	{ .compatible = "maxim,max1586", },
206 	{},
207 };
208 MODULE_DEVICE_TABLE(of, max1586_of_match);
209 
max1586_pmic_probe(struct i2c_client * client,const struct i2c_device_id * i2c_id)210 static int max1586_pmic_probe(struct i2c_client *client,
211 					const struct i2c_device_id *i2c_id)
212 {
213 	struct max1586_platform_data *pdata, pdata_of;
214 	struct regulator_config config = { };
215 	struct max1586_data *max1586;
216 	int i, id, ret;
217 	const struct of_device_id *match;
218 
219 	pdata = dev_get_platdata(&client->dev);
220 	if (client->dev.of_node && !pdata) {
221 		match = of_match_device(of_match_ptr(max1586_of_match),
222 					&client->dev);
223 		if (!match) {
224 			dev_err(&client->dev, "Error: No device match found\n");
225 			return -ENODEV;
226 		}
227 		ret = of_get_max1586_platform_data(&client->dev, &pdata_of);
228 		if (ret < 0)
229 			return ret;
230 		pdata = &pdata_of;
231 	}
232 
233 	max1586 = devm_kzalloc(&client->dev, sizeof(struct max1586_data),
234 			GFP_KERNEL);
235 	if (!max1586)
236 		return -ENOMEM;
237 
238 	max1586->client = client;
239 
240 	if (!pdata->v3_gain)
241 		return -EINVAL;
242 
243 	max1586->min_uV = MAX1586_V3_MIN_UV / 1000 * pdata->v3_gain / 1000;
244 	max1586->max_uV = MAX1586_V3_MAX_UV / 1000 * pdata->v3_gain / 1000;
245 
246 	/* Set curr_sel to default voltage on power-up */
247 	max1586->v3_curr_sel = 24; /* 1.3V */
248 	max1586->v6_curr_sel = 0;
249 
250 	for (i = 0; i < pdata->num_subdevs && i <= MAX1586_V6; i++) {
251 		struct regulator_dev *rdev;
252 
253 		id = pdata->subdevs[i].id;
254 		if (!pdata->subdevs[i].platform_data)
255 			continue;
256 		if (id < MAX1586_V3 || id > MAX1586_V6) {
257 			dev_err(&client->dev, "invalid regulator id %d\n", id);
258 			return -EINVAL;
259 		}
260 
261 		if (id == MAX1586_V3) {
262 			max1586_reg[id].min_uV = max1586->min_uV;
263 			max1586_reg[id].uV_step =
264 					(max1586->max_uV - max1586->min_uV) /
265 					MAX1586_V3_MAX_VSEL;
266 		}
267 
268 		config.dev = &client->dev;
269 		config.init_data = pdata->subdevs[i].platform_data;
270 		config.driver_data = max1586;
271 
272 		rdev = devm_regulator_register(&client->dev,
273 						  &max1586_reg[id], &config);
274 		if (IS_ERR(rdev)) {
275 			dev_err(&client->dev, "failed to register %s\n",
276 				max1586_reg[id].name);
277 			return PTR_ERR(rdev);
278 		}
279 	}
280 
281 	i2c_set_clientdata(client, max1586);
282 	dev_info(&client->dev, "Maxim 1586 regulator driver loaded\n");
283 	return 0;
284 }
285 
286 static const struct i2c_device_id max1586_id[] = {
287 	{ "max1586", 0 },
288 	{ }
289 };
290 MODULE_DEVICE_TABLE(i2c, max1586_id);
291 
292 static struct i2c_driver max1586_pmic_driver = {
293 	.probe = max1586_pmic_probe,
294 	.driver		= {
295 		.name	= "max1586",
296 		.of_match_table = of_match_ptr(max1586_of_match),
297 	},
298 	.id_table	= max1586_id,
299 };
300 
max1586_pmic_init(void)301 static int __init max1586_pmic_init(void)
302 {
303 	return i2c_add_driver(&max1586_pmic_driver);
304 }
305 subsys_initcall(max1586_pmic_init);
306 
max1586_pmic_exit(void)307 static void __exit max1586_pmic_exit(void)
308 {
309 	i2c_del_driver(&max1586_pmic_driver);
310 }
311 module_exit(max1586_pmic_exit);
312 
313 /* Module information */
314 MODULE_DESCRIPTION("MAXIM 1586 voltage regulator driver");
315 MODULE_AUTHOR("Robert Jarzmik");
316 MODULE_LICENSE("GPL");
317