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/gpio/consumer.h>
31 #include <linux/io.h>
32 #include <linux/of.h>
33 #include <linux/of_gpio.h>
34 #include <linux/regulator/of_regulator.h>
35 #include <linux/slab.h>
36 
37 /* Registers */
38 enum {
39 	MAX8952_REG_MODE0,
40 	MAX8952_REG_MODE1,
41 	MAX8952_REG_MODE2,
42 	MAX8952_REG_MODE3,
43 	MAX8952_REG_CONTROL,
44 	MAX8952_REG_SYNC,
45 	MAX8952_REG_RAMP,
46 	MAX8952_REG_CHIP_ID1,
47 	MAX8952_REG_CHIP_ID2,
48 };
49 
50 struct max8952_data {
51 	struct i2c_client	*client;
52 	struct max8952_platform_data *pdata;
53 
54 	bool vid0;
55 	bool vid1;
56 };
57 
max8952_read_reg(struct max8952_data * max8952,u8 reg)58 static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
59 {
60 	int ret = i2c_smbus_read_byte_data(max8952->client, reg);
61 
62 	if (ret > 0)
63 		ret &= 0xff;
64 
65 	return ret;
66 }
67 
max8952_write_reg(struct max8952_data * max8952,u8 reg,u8 value)68 static int max8952_write_reg(struct max8952_data *max8952,
69 		u8 reg, u8 value)
70 {
71 	return i2c_smbus_write_byte_data(max8952->client, reg, value);
72 }
73 
max8952_list_voltage(struct regulator_dev * rdev,unsigned int selector)74 static int max8952_list_voltage(struct regulator_dev *rdev,
75 		unsigned int selector)
76 {
77 	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
78 
79 	if (rdev_get_id(rdev) != 0)
80 		return -EINVAL;
81 
82 	return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
83 }
84 
max8952_get_voltage_sel(struct regulator_dev * rdev)85 static int max8952_get_voltage_sel(struct regulator_dev *rdev)
86 {
87 	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
88 	u8 vid = 0;
89 
90 	if (max8952->vid0)
91 		vid += 1;
92 	if (max8952->vid1)
93 		vid += 2;
94 
95 	return vid;
96 }
97 
max8952_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)98 static int max8952_set_voltage_sel(struct regulator_dev *rdev,
99 				   unsigned selector)
100 {
101 	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
102 
103 	if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
104 			!gpio_is_valid(max8952->pdata->gpio_vid1)) {
105 		/* DVS not supported */
106 		return -EPERM;
107 	}
108 
109 	max8952->vid0 = selector & 0x1;
110 	max8952->vid1 = (selector >> 1) & 0x1;
111 	gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
112 	gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
113 
114 	return 0;
115 }
116 
117 static const struct regulator_ops max8952_ops = {
118 	.list_voltage		= max8952_list_voltage,
119 	.get_voltage_sel	= max8952_get_voltage_sel,
120 	.set_voltage_sel	= max8952_set_voltage_sel,
121 };
122 
123 static const struct regulator_desc regulator = {
124 	.name		= "MAX8952_VOUT",
125 	.id		= 0,
126 	.n_voltages	= MAX8952_NUM_DVS_MODE,
127 	.ops		= &max8952_ops,
128 	.type		= REGULATOR_VOLTAGE,
129 	.owner		= THIS_MODULE,
130 };
131 
132 #ifdef CONFIG_OF
133 static const struct of_device_id max8952_dt_match[] = {
134 	{ .compatible = "maxim,max8952" },
135 	{},
136 };
137 MODULE_DEVICE_TABLE(of, max8952_dt_match);
138 
max8952_parse_dt(struct device * dev)139 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
140 {
141 	struct max8952_platform_data *pd;
142 	struct device_node *np = dev->of_node;
143 	int ret;
144 	int i;
145 
146 	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
147 	if (!pd)
148 		return NULL;
149 
150 	pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0);
151 	pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1);
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, &regulator);
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
max8952_parse_dt(struct device * dev)186 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
187 {
188 	return NULL;
189 }
190 #endif
191 
max8952_pmic_probe(struct i2c_client * client,const struct i2c_device_id * i2c_id)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 	struct gpio_desc *gpiod;
201 	enum gpiod_flags gflags;
202 
203 	int ret = 0, err = 0;
204 
205 	if (client->dev.of_node)
206 		pdata = max8952_parse_dt(&client->dev);
207 
208 	if (!pdata) {
209 		dev_err(&client->dev, "Require the platform data\n");
210 		return -EINVAL;
211 	}
212 
213 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
214 		return -EIO;
215 
216 	max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
217 			       GFP_KERNEL);
218 	if (!max8952)
219 		return -ENOMEM;
220 
221 	max8952->client = client;
222 	max8952->pdata = pdata;
223 
224 	config.dev = &client->dev;
225 	config.init_data = pdata->reg_data;
226 	config.driver_data = max8952;
227 	config.of_node = client->dev.of_node;
228 
229 	if (pdata->reg_data->constraints.boot_on)
230 		gflags = GPIOD_OUT_HIGH;
231 	else
232 		gflags = GPIOD_OUT_LOW;
233 	gpiod = devm_gpiod_get_optional(&client->dev,
234 					"max8952,en",
235 					gflags);
236 	if (IS_ERR(gpiod))
237 		return PTR_ERR(gpiod);
238 	if (gpiod)
239 		config.ena_gpiod = gpiod;
240 
241 	rdev = devm_regulator_register(&client->dev, &regulator, &config);
242 	if (IS_ERR(rdev)) {
243 		ret = PTR_ERR(rdev);
244 		dev_err(&client->dev, "regulator init failed (%d)\n", ret);
245 		return ret;
246 	}
247 
248 	max8952->vid0 = pdata->default_mode & 0x1;
249 	max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
250 
251 	if (gpio_is_valid(pdata->gpio_vid0) &&
252 			gpio_is_valid(pdata->gpio_vid1)) {
253 		unsigned long gpio_flags;
254 
255 		gpio_flags = max8952->vid0 ?
256 			     GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
257 		if (devm_gpio_request_one(&client->dev, pdata->gpio_vid0,
258 					  gpio_flags, "MAX8952 VID0"))
259 			err = 1;
260 
261 		gpio_flags = max8952->vid1 ?
262 			     GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
263 		if (devm_gpio_request_one(&client->dev, pdata->gpio_vid1,
264 					  gpio_flags, "MAX8952 VID1"))
265 			err = 2;
266 	} else
267 		err = 3;
268 
269 	if (err) {
270 		dev_warn(&client->dev, "VID0/1 gpio invalid: "
271 				"DVS not available.\n");
272 		max8952->vid0 = 0;
273 		max8952->vid1 = 0;
274 		/* Mark invalid */
275 		pdata->gpio_vid0 = -1;
276 		pdata->gpio_vid1 = -1;
277 
278 		/* Disable Pulldown of EN only */
279 		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
280 
281 		dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
282 				" do not have proper controls.\n");
283 	} else {
284 		/*
285 		 * Disable Pulldown on EN, VID0, VID1 to reduce
286 		 * leakage current of MAX8952 assuming that MAX8952
287 		 * is turned on (EN==1). Note that without having VID0/1
288 		 * properly connected, turning pulldown off can be
289 		 * problematic. Thus, turn this off only when they are
290 		 * controllable by GPIO.
291 		 */
292 		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
293 	}
294 
295 	max8952_write_reg(max8952, MAX8952_REG_MODE0,
296 			(max8952_read_reg(max8952,
297 					  MAX8952_REG_MODE0) & 0xC0) |
298 			(pdata->dvs_mode[0] & 0x3F));
299 	max8952_write_reg(max8952, MAX8952_REG_MODE1,
300 			(max8952_read_reg(max8952,
301 					  MAX8952_REG_MODE1) & 0xC0) |
302 			(pdata->dvs_mode[1] & 0x3F));
303 	max8952_write_reg(max8952, MAX8952_REG_MODE2,
304 			(max8952_read_reg(max8952,
305 					  MAX8952_REG_MODE2) & 0xC0) |
306 			(pdata->dvs_mode[2] & 0x3F));
307 	max8952_write_reg(max8952, MAX8952_REG_MODE3,
308 			(max8952_read_reg(max8952,
309 					  MAX8952_REG_MODE3) & 0xC0) |
310 			(pdata->dvs_mode[3] & 0x3F));
311 
312 	max8952_write_reg(max8952, MAX8952_REG_SYNC,
313 			(max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
314 			((pdata->sync_freq & 0x3) << 6));
315 	max8952_write_reg(max8952, MAX8952_REG_RAMP,
316 			(max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
317 			((pdata->ramp_speed & 0x7) << 5));
318 
319 	i2c_set_clientdata(client, max8952);
320 
321 	return 0;
322 }
323 
324 static const struct i2c_device_id max8952_ids[] = {
325 	{ "max8952", 0 },
326 	{ },
327 };
328 MODULE_DEVICE_TABLE(i2c, max8952_ids);
329 
330 static struct i2c_driver max8952_pmic_driver = {
331 	.probe		= max8952_pmic_probe,
332 	.driver		= {
333 		.name	= "max8952",
334 		.of_match_table = of_match_ptr(max8952_dt_match),
335 	},
336 	.id_table	= max8952_ids,
337 };
338 
max8952_pmic_init(void)339 static int __init max8952_pmic_init(void)
340 {
341 	return i2c_add_driver(&max8952_pmic_driver);
342 }
343 subsys_initcall(max8952_pmic_init);
344 
max8952_pmic_exit(void)345 static void __exit max8952_pmic_exit(void)
346 {
347 	i2c_del_driver(&max8952_pmic_driver);
348 }
349 module_exit(max8952_pmic_exit);
350 
351 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
352 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
353 MODULE_LICENSE("GPL");
354