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 */
23 enum {
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
35 struct 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
max8952_read_reg(struct max8952_data * max8952,u8 reg)44 static 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
max8952_write_reg(struct max8952_data * max8952,u8 reg,u8 value)54 static 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
max8952_list_voltage(struct regulator_dev * rdev,unsigned int selector)60 static 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
max8952_get_voltage_sel(struct regulator_dev * rdev)71 static 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
max8952_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)84 static 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
102 static 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
108 static 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
118 static const struct of_device_id max8952_dt_match[] = {
119 { .compatible = "maxim,max8952" },
120 {},
121 };
122 MODULE_DEVICE_TABLE(of, max8952_dt_match);
123
max8952_parse_dt(struct device * dev)124 static 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, ®ulator);
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
max8952_parse_dt(struct device * dev)168 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
169 {
170 return NULL;
171 }
172 #endif
173
max8952_pmic_probe(struct i2c_client * client)174 static 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, ®ulator, &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
309 static const struct i2c_device_id max8952_ids[] = {
310 { "max8952" },
311 { }
312 };
313 MODULE_DEVICE_TABLE(i2c, max8952_ids);
314
315 static 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
max8952_pmic_init(void)325 static int __init max8952_pmic_init(void)
326 {
327 return i2c_add_driver(&max8952_pmic_driver);
328 }
329 subsys_initcall(max8952_pmic_init);
330
max8952_pmic_exit(void)331 static void __exit max8952_pmic_exit(void)
332 {
333 i2c_del_driver(&max8952_pmic_driver);
334 }
335 module_exit(max8952_pmic_exit);
336
337 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
338 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
339 MODULE_LICENSE("GPL");
340