1 /*
2  * max1586.c  --  Voltage and current regulation for the Maxim 1586
3  *
4  * Copyright (C) 2008 Robert Jarzmik
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20 #include <linux/module.h>
21 #include <linux/err.h>
22 #include <linux/i2c.h>
23 #include <linux/platform_device.h>
24 #include <linux/regulator/driver.h>
25 #include <linux/slab.h>
26 #include <linux/regulator/max1586.h>
27 #include <linux/of_device.h>
28 #include <linux/regulator/of_regulator.h>
29 
30 #define MAX1586_V3_MAX_VSEL 31
31 #define MAX1586_V6_MAX_VSEL 3
32 
33 #define MAX1586_V3_MIN_UV   700000
34 #define MAX1586_V3_MAX_UV  1475000
35 
36 #define MAX1586_V6_MIN_UV        0
37 #define MAX1586_V6_MAX_UV  3000000
38 
39 #define I2C_V3_SELECT (0 << 5)
40 #define I2C_V6_SELECT (1 << 5)
41 
42 struct max1586_data {
43 	struct i2c_client *client;
44 
45 	/* min/max V3 voltage */
46 	unsigned int min_uV;
47 	unsigned int max_uV;
48 
49 	unsigned int v3_curr_sel;
50 	unsigned int v6_curr_sel;
51 };
52 
53 /*
54  * V6 voltage
55  * On I2C bus, sending a "x" byte to the max1586 means :
56  *   set V6 to either 0V, 1.8V, 2.5V, 3V depending on (x & 0x3)
57  * As regulator framework doesn't accept voltages to be 0V, we use 1uV.
58  */
59 static const unsigned int v6_voltages_uv[] = { 1, 1800000, 2500000, 3000000 };
60 
61 /*
62  * V3 voltage
63  * On I2C bus, sending a "x" byte to the max1586 means :
64  *   set V3 to 0.700V + (x & 0x1f) * 0.025V
65  * This voltage can be increased by external resistors
66  * R24 and R25=100kOhm as described in the data sheet.
67  * The gain is approximately: 1 + R24/R25 + R24/185.5kOhm
68  */
max1586_v3_get_voltage_sel(struct regulator_dev * rdev)69 static int max1586_v3_get_voltage_sel(struct regulator_dev *rdev)
70 {
71 	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
72 
73 	return max1586->v3_curr_sel;
74 }
75 
max1586_v3_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)76 static int max1586_v3_set_voltage_sel(struct regulator_dev *rdev,
77 				      unsigned selector)
78 {
79 	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
80 	struct i2c_client *client = max1586->client;
81 	int ret;
82 	u8 v3_prog;
83 
84 	dev_dbg(&client->dev, "changing voltage v3 to %dmv\n",
85 		regulator_list_voltage_linear(rdev, selector) / 1000);
86 
87 	v3_prog = I2C_V3_SELECT | (u8) selector;
88 	ret = i2c_smbus_write_byte(client, v3_prog);
89 	if (ret)
90 		return ret;
91 
92 	max1586->v3_curr_sel = selector;
93 
94 	return 0;
95 }
96 
max1586_v6_get_voltage_sel(struct regulator_dev * rdev)97 static int max1586_v6_get_voltage_sel(struct regulator_dev *rdev)
98 {
99 	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
100 
101 	return max1586->v6_curr_sel;
102 }
103 
max1586_v6_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)104 static int max1586_v6_set_voltage_sel(struct regulator_dev *rdev,
105 				      unsigned int selector)
106 {
107 	struct max1586_data *max1586 = rdev_get_drvdata(rdev);
108 	struct i2c_client *client = max1586->client;
109 	u8 v6_prog;
110 	int ret;
111 
112 	dev_dbg(&client->dev, "changing voltage v6 to %dmv\n",
113 		rdev->desc->volt_table[selector] / 1000);
114 
115 	v6_prog = I2C_V6_SELECT | (u8) selector;
116 	ret = i2c_smbus_write_byte(client, v6_prog);
117 	if (ret)
118 		return ret;
119 
120 	max1586->v6_curr_sel = selector;
121 
122 	return 0;
123 }
124 
125 /*
126  * The Maxim 1586 controls V3 and V6 voltages, but offers no way of reading back
127  * the set up value.
128  */
129 static const struct regulator_ops max1586_v3_ops = {
130 	.get_voltage_sel = max1586_v3_get_voltage_sel,
131 	.set_voltage_sel = max1586_v3_set_voltage_sel,
132 	.list_voltage = regulator_list_voltage_linear,
133 	.map_voltage = regulator_map_voltage_linear,
134 };
135 
136 static const struct regulator_ops max1586_v6_ops = {
137 	.get_voltage_sel = max1586_v6_get_voltage_sel,
138 	.set_voltage_sel = max1586_v6_set_voltage_sel,
139 	.list_voltage = regulator_list_voltage_table,
140 };
141 
142 static struct regulator_desc max1586_reg[] = {
143 	{
144 		.name = "Output_V3",
145 		.id = MAX1586_V3,
146 		.ops = &max1586_v3_ops,
147 		.type = REGULATOR_VOLTAGE,
148 		.n_voltages = MAX1586_V3_MAX_VSEL + 1,
149 		.owner = THIS_MODULE,
150 	},
151 	{
152 		.name = "Output_V6",
153 		.id = MAX1586_V6,
154 		.ops = &max1586_v6_ops,
155 		.type = REGULATOR_VOLTAGE,
156 		.n_voltages = MAX1586_V6_MAX_VSEL + 1,
157 		.volt_table = v6_voltages_uv,
158 		.owner = THIS_MODULE,
159 	},
160 };
161 
of_get_max1586_platform_data(struct device * dev,struct max1586_platform_data * pdata)162 static int of_get_max1586_platform_data(struct device *dev,
163 				 struct max1586_platform_data *pdata)
164 {
165 	struct max1586_subdev_data *sub;
166 	struct of_regulator_match rmatch[ARRAY_SIZE(max1586_reg)] = { };
167 	struct device_node *np = dev->of_node;
168 	int i, matched;
169 
170 	if (of_property_read_u32(np, "v3-gain",
171 				 &pdata->v3_gain) < 0) {
172 		dev_err(dev, "%pOF has no 'v3-gain' property\n", np);
173 		return -EINVAL;
174 	}
175 
176 	np = of_get_child_by_name(np, "regulators");
177 	if (!np) {
178 		dev_err(dev, "missing 'regulators' subnode in DT\n");
179 		return -EINVAL;
180 	}
181 
182 	for (i = 0; i < ARRAY_SIZE(rmatch); i++)
183 		rmatch[i].name = max1586_reg[i].name;
184 
185 	matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
186 	of_node_put(np);
187 	/*
188 	 * If matched is 0, ie. neither Output_V3 nor Output_V6 have been found,
189 	 * return 0, which signals the normal situation where no subregulator is
190 	 * available. This is normal because the max1586 doesn't provide any
191 	 * readback support, so the subregulators can't report any status
192 	 * anyway.  If matched < 0, return the error.
193 	 */
194 	if (matched <= 0)
195 		return matched;
196 
197 	pdata->subdevs = devm_kcalloc(dev,
198 				      matched,
199 				      sizeof(struct max1586_subdev_data),
200 				      GFP_KERNEL);
201 	if (!pdata->subdevs)
202 		return -ENOMEM;
203 
204 	pdata->num_subdevs = matched;
205 	sub = pdata->subdevs;
206 
207 	for (i = 0; i < matched; i++) {
208 		sub->id = i;
209 		sub->name = rmatch[i].of_node->name;
210 		sub->platform_data = rmatch[i].init_data;
211 		sub++;
212 	}
213 
214 	return 0;
215 }
216 
217 static const struct of_device_id max1586_of_match[] = {
218 	{ .compatible = "maxim,max1586", },
219 	{},
220 };
221 MODULE_DEVICE_TABLE(of, max1586_of_match);
222 
max1586_pmic_probe(struct i2c_client * client,const struct i2c_device_id * i2c_id)223 static int max1586_pmic_probe(struct i2c_client *client,
224 					const struct i2c_device_id *i2c_id)
225 {
226 	struct max1586_platform_data *pdata, pdata_of;
227 	struct regulator_config config = { };
228 	struct max1586_data *max1586;
229 	int i, id, ret;
230 	const struct of_device_id *match;
231 
232 	pdata = dev_get_platdata(&client->dev);
233 	if (client->dev.of_node && !pdata) {
234 		match = of_match_device(of_match_ptr(max1586_of_match),
235 					&client->dev);
236 		if (!match) {
237 			dev_err(&client->dev, "Error: No device match found\n");
238 			return -ENODEV;
239 		}
240 		ret = of_get_max1586_platform_data(&client->dev, &pdata_of);
241 		if (ret < 0)
242 			return ret;
243 		pdata = &pdata_of;
244 	}
245 
246 	max1586 = devm_kzalloc(&client->dev, sizeof(struct max1586_data),
247 			GFP_KERNEL);
248 	if (!max1586)
249 		return -ENOMEM;
250 
251 	max1586->client = client;
252 
253 	if (!pdata->v3_gain)
254 		return -EINVAL;
255 
256 	max1586->min_uV = MAX1586_V3_MIN_UV / 1000 * pdata->v3_gain / 1000;
257 	max1586->max_uV = MAX1586_V3_MAX_UV / 1000 * pdata->v3_gain / 1000;
258 
259 	/* Set curr_sel to default voltage on power-up */
260 	max1586->v3_curr_sel = 24; /* 1.3V */
261 	max1586->v6_curr_sel = 0;
262 
263 	for (i = 0; i < pdata->num_subdevs && i <= MAX1586_V6; i++) {
264 		struct regulator_dev *rdev;
265 
266 		id = pdata->subdevs[i].id;
267 		if (!pdata->subdevs[i].platform_data)
268 			continue;
269 		if (id < MAX1586_V3 || id > MAX1586_V6) {
270 			dev_err(&client->dev, "invalid regulator id %d\n", id);
271 			return -EINVAL;
272 		}
273 
274 		if (id == MAX1586_V3) {
275 			max1586_reg[id].min_uV = max1586->min_uV;
276 			max1586_reg[id].uV_step =
277 					(max1586->max_uV - max1586->min_uV) /
278 					MAX1586_V3_MAX_VSEL;
279 		}
280 
281 		config.dev = &client->dev;
282 		config.init_data = pdata->subdevs[i].platform_data;
283 		config.driver_data = max1586;
284 
285 		rdev = devm_regulator_register(&client->dev,
286 						  &max1586_reg[id], &config);
287 		if (IS_ERR(rdev)) {
288 			dev_err(&client->dev, "failed to register %s\n",
289 				max1586_reg[id].name);
290 			return PTR_ERR(rdev);
291 		}
292 	}
293 
294 	i2c_set_clientdata(client, max1586);
295 	dev_info(&client->dev, "Maxim 1586 regulator driver loaded\n");
296 	return 0;
297 }
298 
299 static const struct i2c_device_id max1586_id[] = {
300 	{ "max1586", 0 },
301 	{ }
302 };
303 MODULE_DEVICE_TABLE(i2c, max1586_id);
304 
305 static struct i2c_driver max1586_pmic_driver = {
306 	.probe = max1586_pmic_probe,
307 	.driver		= {
308 		.name	= "max1586",
309 		.of_match_table = of_match_ptr(max1586_of_match),
310 	},
311 	.id_table	= max1586_id,
312 };
313 
max1586_pmic_init(void)314 static int __init max1586_pmic_init(void)
315 {
316 	return i2c_add_driver(&max1586_pmic_driver);
317 }
318 subsys_initcall(max1586_pmic_init);
319 
max1586_pmic_exit(void)320 static void __exit max1586_pmic_exit(void)
321 {
322 	i2c_del_driver(&max1586_pmic_driver);
323 }
324 module_exit(max1586_pmic_exit);
325 
326 /* Module information */
327 MODULE_DESCRIPTION("MAXIM 1586 voltage regulator driver");
328 MODULE_AUTHOR("Robert Jarzmik");
329 MODULE_LICENSE("GPL");
330