xref: /openbmc/linux/drivers/regulator/max8952.c (revision b34e08d5)
1 /*
2  * max8952.c - Voltage and current regulation for the Maxim 8952
3  *
4  * Copyright (C) 2010 Samsung Electronics
5  * MyungJoo Ham <myungjoo.ham@samsung.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  */
21 
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/i2c.h>
25 #include <linux/err.h>
26 #include <linux/platform_device.h>
27 #include <linux/regulator/driver.h>
28 #include <linux/regulator/max8952.h>
29 #include <linux/gpio.h>
30 #include <linux/io.h>
31 #include <linux/of.h>
32 #include <linux/of_gpio.h>
33 #include <linux/regulator/of_regulator.h>
34 #include <linux/slab.h>
35 
36 /* Registers */
37 enum {
38 	MAX8952_REG_MODE0,
39 	MAX8952_REG_MODE1,
40 	MAX8952_REG_MODE2,
41 	MAX8952_REG_MODE3,
42 	MAX8952_REG_CONTROL,
43 	MAX8952_REG_SYNC,
44 	MAX8952_REG_RAMP,
45 	MAX8952_REG_CHIP_ID1,
46 	MAX8952_REG_CHIP_ID2,
47 };
48 
49 struct max8952_data {
50 	struct i2c_client	*client;
51 	struct max8952_platform_data *pdata;
52 
53 	bool vid0;
54 	bool vid1;
55 };
56 
57 static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
58 {
59 	int ret = i2c_smbus_read_byte_data(max8952->client, reg);
60 
61 	if (ret > 0)
62 		ret &= 0xff;
63 
64 	return ret;
65 }
66 
67 static int max8952_write_reg(struct max8952_data *max8952,
68 		u8 reg, u8 value)
69 {
70 	return i2c_smbus_write_byte_data(max8952->client, reg, value);
71 }
72 
73 static int max8952_list_voltage(struct regulator_dev *rdev,
74 		unsigned int selector)
75 {
76 	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
77 
78 	if (rdev_get_id(rdev) != 0)
79 		return -EINVAL;
80 
81 	return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
82 }
83 
84 static int max8952_get_voltage_sel(struct regulator_dev *rdev)
85 {
86 	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
87 	u8 vid = 0;
88 
89 	if (max8952->vid0)
90 		vid += 1;
91 	if (max8952->vid1)
92 		vid += 2;
93 
94 	return vid;
95 }
96 
97 static int max8952_set_voltage_sel(struct regulator_dev *rdev,
98 				   unsigned selector)
99 {
100 	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
101 
102 	if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
103 			!gpio_is_valid(max8952->pdata->gpio_vid1)) {
104 		/* DVS not supported */
105 		return -EPERM;
106 	}
107 
108 	max8952->vid0 = selector & 0x1;
109 	max8952->vid1 = (selector >> 1) & 0x1;
110 	gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
111 	gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
112 
113 	return 0;
114 }
115 
116 static struct regulator_ops max8952_ops = {
117 	.list_voltage		= max8952_list_voltage,
118 	.get_voltage_sel	= max8952_get_voltage_sel,
119 	.set_voltage_sel	= max8952_set_voltage_sel,
120 };
121 
122 static const struct regulator_desc regulator = {
123 	.name		= "MAX8952_VOUT",
124 	.id		= 0,
125 	.n_voltages	= MAX8952_NUM_DVS_MODE,
126 	.ops		= &max8952_ops,
127 	.type		= REGULATOR_VOLTAGE,
128 	.owner		= THIS_MODULE,
129 };
130 
131 #ifdef CONFIG_OF
132 static struct of_device_id max8952_dt_match[] = {
133 	{ .compatible = "maxim,max8952" },
134 	{},
135 };
136 MODULE_DEVICE_TABLE(of, max8952_dt_match);
137 
138 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
139 {
140 	struct max8952_platform_data *pd;
141 	struct device_node *np = dev->of_node;
142 	int ret;
143 	int i;
144 
145 	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
146 	if (!pd)
147 		return NULL;
148 
149 	pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0);
150 	pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1);
151 	pd->gpio_en = of_get_named_gpio(np, "max8952,en-gpio", 0);
152 
153 	if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode))
154 		dev_warn(dev, "Default mode not specified, assuming 0\n");
155 
156 	ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt",
157 					pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode));
158 	if (ret) {
159 		dev_err(dev, "max8952,dvs-mode-microvolt property not specified");
160 		return NULL;
161 	}
162 
163 	for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) {
164 		if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) {
165 			dev_err(dev, "DVS voltage %d out of range\n", i);
166 			return NULL;
167 		}
168 		pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000;
169 	}
170 
171 	if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq))
172 		dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n");
173 
174 	if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed))
175 		dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n");
176 
177 	pd->reg_data = of_get_regulator_init_data(dev, np);
178 	if (!pd->reg_data) {
179 		dev_err(dev, "Failed to parse regulator init data\n");
180 		return NULL;
181 	}
182 
183 	return pd;
184 }
185 #else
186 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
187 {
188 	return NULL;
189 }
190 #endif
191 
192 static int max8952_pmic_probe(struct i2c_client *client,
193 		const struct i2c_device_id *i2c_id)
194 {
195 	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
196 	struct max8952_platform_data *pdata = dev_get_platdata(&client->dev);
197 	struct regulator_config config = { };
198 	struct max8952_data *max8952;
199 	struct regulator_dev *rdev;
200 
201 	int ret = 0, err = 0;
202 
203 	if (client->dev.of_node)
204 		pdata = max8952_parse_dt(&client->dev);
205 
206 	if (!pdata) {
207 		dev_err(&client->dev, "Require the platform data\n");
208 		return -EINVAL;
209 	}
210 
211 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
212 		return -EIO;
213 
214 	max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
215 			       GFP_KERNEL);
216 	if (!max8952)
217 		return -ENOMEM;
218 
219 	max8952->client = client;
220 	max8952->pdata = pdata;
221 
222 	config.dev = &client->dev;
223 	config.init_data = pdata->reg_data;
224 	config.driver_data = max8952;
225 	config.of_node = client->dev.of_node;
226 
227 	config.ena_gpio = pdata->gpio_en;
228 	if (pdata->reg_data->constraints.boot_on)
229 		config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
230 
231 	rdev = devm_regulator_register(&client->dev, &regulator, &config);
232 
233 	if (IS_ERR(rdev)) {
234 		ret = PTR_ERR(rdev);
235 		dev_err(&client->dev, "regulator init failed (%d)\n", ret);
236 		return ret;
237 	}
238 
239 	max8952->vid0 = pdata->default_mode & 0x1;
240 	max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
241 
242 	if (gpio_is_valid(pdata->gpio_vid0) &&
243 			gpio_is_valid(pdata->gpio_vid1)) {
244 		if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
245 			gpio_direction_output(pdata->gpio_vid0,
246 					(pdata->default_mode) & 0x1);
247 		else
248 			err = 1;
249 
250 		if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
251 			gpio_direction_output(pdata->gpio_vid1,
252 				(pdata->default_mode >> 1) & 0x1);
253 		else {
254 			if (!err)
255 				gpio_free(pdata->gpio_vid0);
256 			err = 2;
257 		}
258 
259 	} else
260 		err = 3;
261 
262 	if (err) {
263 		dev_warn(&client->dev, "VID0/1 gpio invalid: "
264 				"DVS not available.\n");
265 		max8952->vid0 = 0;
266 		max8952->vid1 = 0;
267 		/* Mark invalid */
268 		pdata->gpio_vid0 = -1;
269 		pdata->gpio_vid1 = -1;
270 
271 		/* Disable Pulldown of EN only */
272 		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
273 
274 		dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
275 				" do not have proper controls.\n");
276 	} else {
277 		/*
278 		 * Disable Pulldown on EN, VID0, VID1 to reduce
279 		 * leakage current of MAX8952 assuming that MAX8952
280 		 * is turned on (EN==1). Note that without having VID0/1
281 		 * properly connected, turning pulldown off can be
282 		 * problematic. Thus, turn this off only when they are
283 		 * controllable by GPIO.
284 		 */
285 		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
286 	}
287 
288 	max8952_write_reg(max8952, MAX8952_REG_MODE0,
289 			(max8952_read_reg(max8952,
290 					  MAX8952_REG_MODE0) & 0xC0) |
291 			(pdata->dvs_mode[0] & 0x3F));
292 	max8952_write_reg(max8952, MAX8952_REG_MODE1,
293 			(max8952_read_reg(max8952,
294 					  MAX8952_REG_MODE1) & 0xC0) |
295 			(pdata->dvs_mode[1] & 0x3F));
296 	max8952_write_reg(max8952, MAX8952_REG_MODE2,
297 			(max8952_read_reg(max8952,
298 					  MAX8952_REG_MODE2) & 0xC0) |
299 			(pdata->dvs_mode[2] & 0x3F));
300 	max8952_write_reg(max8952, MAX8952_REG_MODE3,
301 			(max8952_read_reg(max8952,
302 					  MAX8952_REG_MODE3) & 0xC0) |
303 			(pdata->dvs_mode[3] & 0x3F));
304 
305 	max8952_write_reg(max8952, MAX8952_REG_SYNC,
306 			(max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
307 			((pdata->sync_freq & 0x3) << 6));
308 	max8952_write_reg(max8952, MAX8952_REG_RAMP,
309 			(max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
310 			((pdata->ramp_speed & 0x7) << 5));
311 
312 	i2c_set_clientdata(client, max8952);
313 
314 	return 0;
315 }
316 
317 static int max8952_pmic_remove(struct i2c_client *client)
318 {
319 	struct max8952_data *max8952 = i2c_get_clientdata(client);
320 	struct max8952_platform_data *pdata = max8952->pdata;
321 
322 	gpio_free(pdata->gpio_vid0);
323 	gpio_free(pdata->gpio_vid1);
324 	return 0;
325 }
326 
327 static const struct i2c_device_id max8952_ids[] = {
328 	{ "max8952", 0 },
329 	{ },
330 };
331 MODULE_DEVICE_TABLE(i2c, max8952_ids);
332 
333 static struct i2c_driver max8952_pmic_driver = {
334 	.probe		= max8952_pmic_probe,
335 	.remove		= max8952_pmic_remove,
336 	.driver		= {
337 		.name	= "max8952",
338 		.of_match_table = of_match_ptr(max8952_dt_match),
339 	},
340 	.id_table	= max8952_ids,
341 };
342 
343 static int __init max8952_pmic_init(void)
344 {
345 	return i2c_add_driver(&max8952_pmic_driver);
346 }
347 subsys_initcall(max8952_pmic_init);
348 
349 static void __exit max8952_pmic_exit(void)
350 {
351 	i2c_del_driver(&max8952_pmic_driver);
352 }
353 module_exit(max8952_pmic_exit);
354 
355 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
356 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
357 MODULE_LICENSE("GPL");
358