xref: /openbmc/linux/drivers/hwmon/atxp1.c (revision d2999e1b)
1 /*
2  * atxp1.c - kernel module for setting CPU VID and general purpose
3  *	     I/Os using the Attansic ATXP1 chip.
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18  *
19  */
20 
21 #include <linux/kernel.h>
22 #include <linux/init.h>
23 #include <linux/module.h>
24 #include <linux/jiffies.h>
25 #include <linux/i2c.h>
26 #include <linux/hwmon.h>
27 #include <linux/hwmon-vid.h>
28 #include <linux/err.h>
29 #include <linux/mutex.h>
30 #include <linux/sysfs.h>
31 #include <linux/slab.h>
32 
33 MODULE_LICENSE("GPL");
34 MODULE_DESCRIPTION("System voltages control via Attansic ATXP1");
35 MODULE_VERSION("0.6.3");
36 MODULE_AUTHOR("Sebastian Witt <se.witt@gmx.net>");
37 
38 #define ATXP1_VID	0x00
39 #define ATXP1_CVID	0x01
40 #define ATXP1_GPIO1	0x06
41 #define ATXP1_GPIO2	0x0a
42 #define ATXP1_VIDENA	0x20
43 #define ATXP1_VIDMASK	0x1f
44 #define ATXP1_GPIO1MASK	0x0f
45 
46 static const unsigned short normal_i2c[] = { 0x37, 0x4e, I2C_CLIENT_END };
47 
48 struct atxp1_data {
49 	struct device *hwmon_dev;
50 	struct mutex update_lock;
51 	unsigned long last_updated;
52 	u8 valid;
53 	struct {
54 		u8 vid;		/* VID output register */
55 		u8 cpu_vid; /* VID input from CPU */
56 		u8 gpio1;   /* General purpose I/O register 1 */
57 		u8 gpio2;   /* General purpose I/O register 2 */
58 	} reg;
59 	u8 vrm;			/* Detected CPU VRM */
60 };
61 
62 static struct atxp1_data *atxp1_update_device(struct device *dev)
63 {
64 	struct i2c_client *client;
65 	struct atxp1_data *data;
66 
67 	client = to_i2c_client(dev);
68 	data = i2c_get_clientdata(client);
69 
70 	mutex_lock(&data->update_lock);
71 
72 	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
73 
74 		/* Update local register data */
75 		data->reg.vid = i2c_smbus_read_byte_data(client, ATXP1_VID);
76 		data->reg.cpu_vid = i2c_smbus_read_byte_data(client,
77 							     ATXP1_CVID);
78 		data->reg.gpio1 = i2c_smbus_read_byte_data(client, ATXP1_GPIO1);
79 		data->reg.gpio2 = i2c_smbus_read_byte_data(client, ATXP1_GPIO2);
80 
81 		data->valid = 1;
82 	}
83 
84 	mutex_unlock(&data->update_lock);
85 
86 	return data;
87 }
88 
89 /* sys file functions for cpu0_vid */
90 static ssize_t atxp1_showvcore(struct device *dev,
91 			       struct device_attribute *attr, char *buf)
92 {
93 	int size;
94 	struct atxp1_data *data;
95 
96 	data = atxp1_update_device(dev);
97 
98 	size = sprintf(buf, "%d\n", vid_from_reg(data->reg.vid & ATXP1_VIDMASK,
99 						 data->vrm));
100 
101 	return size;
102 }
103 
104 static ssize_t atxp1_storevcore(struct device *dev,
105 				struct device_attribute *attr,
106 				const char *buf, size_t count)
107 {
108 	struct atxp1_data *data;
109 	struct i2c_client *client;
110 	int vid, cvid;
111 	unsigned long vcore;
112 	int err;
113 
114 	client = to_i2c_client(dev);
115 	data = atxp1_update_device(dev);
116 
117 	err = kstrtoul(buf, 10, &vcore);
118 	if (err)
119 		return err;
120 
121 	vcore /= 25;
122 	vcore *= 25;
123 
124 	/* Calculate VID */
125 	vid = vid_to_reg(vcore, data->vrm);
126 	if (vid < 0) {
127 		dev_err(dev, "VID calculation failed.\n");
128 		return vid;
129 	}
130 
131 	/*
132 	 * If output enabled, use control register value.
133 	 * Otherwise original CPU VID
134 	 */
135 	if (data->reg.vid & ATXP1_VIDENA)
136 		cvid = data->reg.vid & ATXP1_VIDMASK;
137 	else
138 		cvid = data->reg.cpu_vid;
139 
140 	/* Nothing changed, aborting */
141 	if (vid == cvid)
142 		return count;
143 
144 	dev_dbg(dev, "Setting VCore to %d mV (0x%02x)\n", (int)vcore, vid);
145 
146 	/* Write every 25 mV step to increase stability */
147 	if (cvid > vid) {
148 		for (; cvid >= vid; cvid--)
149 			i2c_smbus_write_byte_data(client,
150 						ATXP1_VID, cvid | ATXP1_VIDENA);
151 	} else {
152 		for (; cvid <= vid; cvid++)
153 			i2c_smbus_write_byte_data(client,
154 						ATXP1_VID, cvid | ATXP1_VIDENA);
155 	}
156 
157 	data->valid = 0;
158 
159 	return count;
160 }
161 
162 /*
163  * CPU core reference voltage
164  * unit: millivolt
165  */
166 static DEVICE_ATTR(cpu0_vid, S_IRUGO | S_IWUSR, atxp1_showvcore,
167 		   atxp1_storevcore);
168 
169 /* sys file functions for GPIO1 */
170 static ssize_t atxp1_showgpio1(struct device *dev,
171 			       struct device_attribute *attr, char *buf)
172 {
173 	int size;
174 	struct atxp1_data *data;
175 
176 	data = atxp1_update_device(dev);
177 
178 	size = sprintf(buf, "0x%02x\n", data->reg.gpio1 & ATXP1_GPIO1MASK);
179 
180 	return size;
181 }
182 
183 static ssize_t atxp1_storegpio1(struct device *dev,
184 				struct device_attribute *attr, const char *buf,
185 				size_t count)
186 {
187 	struct atxp1_data *data;
188 	struct i2c_client *client;
189 	unsigned long value;
190 	int err;
191 
192 	client = to_i2c_client(dev);
193 	data = atxp1_update_device(dev);
194 
195 	err = kstrtoul(buf, 16, &value);
196 	if (err)
197 		return err;
198 
199 	value &= ATXP1_GPIO1MASK;
200 
201 	if (value != (data->reg.gpio1 & ATXP1_GPIO1MASK)) {
202 		dev_info(dev, "Writing 0x%x to GPIO1.\n", (unsigned int)value);
203 
204 		i2c_smbus_write_byte_data(client, ATXP1_GPIO1, value);
205 
206 		data->valid = 0;
207 	}
208 
209 	return count;
210 }
211 
212 /*
213  * GPIO1 data register
214  * unit: Four bit as hex (e.g. 0x0f)
215  */
216 static DEVICE_ATTR(gpio1, S_IRUGO | S_IWUSR, atxp1_showgpio1, atxp1_storegpio1);
217 
218 /* sys file functions for GPIO2 */
219 static ssize_t atxp1_showgpio2(struct device *dev,
220 			       struct device_attribute *attr, char *buf)
221 {
222 	int size;
223 	struct atxp1_data *data;
224 
225 	data = atxp1_update_device(dev);
226 
227 	size = sprintf(buf, "0x%02x\n", data->reg.gpio2);
228 
229 	return size;
230 }
231 
232 static ssize_t atxp1_storegpio2(struct device *dev,
233 				struct device_attribute *attr,
234 				const char *buf, size_t count)
235 {
236 	struct atxp1_data *data = atxp1_update_device(dev);
237 	struct i2c_client *client = to_i2c_client(dev);
238 	unsigned long value;
239 	int err;
240 
241 	err = kstrtoul(buf, 16, &value);
242 	if (err)
243 		return err;
244 	value &= 0xff;
245 
246 	if (value != data->reg.gpio2) {
247 		dev_info(dev, "Writing 0x%x to GPIO1.\n", (unsigned int)value);
248 
249 		i2c_smbus_write_byte_data(client, ATXP1_GPIO2, value);
250 
251 		data->valid = 0;
252 	}
253 
254 	return count;
255 }
256 
257 /*
258  * GPIO2 data register
259  * unit: Eight bit as hex (e.g. 0xff)
260  */
261 static DEVICE_ATTR(gpio2, S_IRUGO | S_IWUSR, atxp1_showgpio2, atxp1_storegpio2);
262 
263 static struct attribute *atxp1_attributes[] = {
264 	&dev_attr_gpio1.attr,
265 	&dev_attr_gpio2.attr,
266 	&dev_attr_cpu0_vid.attr,
267 	NULL
268 };
269 
270 static const struct attribute_group atxp1_group = {
271 	.attrs = atxp1_attributes,
272 };
273 
274 
275 /* Return 0 if detection is successful, -ENODEV otherwise */
276 static int atxp1_detect(struct i2c_client *new_client,
277 			struct i2c_board_info *info)
278 {
279 	struct i2c_adapter *adapter = new_client->adapter;
280 
281 	u8 temp;
282 
283 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
284 		return -ENODEV;
285 
286 	/* Detect ATXP1, checking if vendor ID registers are all zero */
287 	if (!((i2c_smbus_read_byte_data(new_client, 0x3e) == 0) &&
288 	     (i2c_smbus_read_byte_data(new_client, 0x3f) == 0) &&
289 	     (i2c_smbus_read_byte_data(new_client, 0xfe) == 0) &&
290 	     (i2c_smbus_read_byte_data(new_client, 0xff) == 0)))
291 		return -ENODEV;
292 
293 	/*
294 	 * No vendor ID, now checking if registers 0x10,0x11 (non-existent)
295 	 * showing the same as register 0x00
296 	 */
297 	temp = i2c_smbus_read_byte_data(new_client, 0x00);
298 
299 	if (!((i2c_smbus_read_byte_data(new_client, 0x10) == temp) &&
300 	      (i2c_smbus_read_byte_data(new_client, 0x11) == temp)))
301 		return -ENODEV;
302 
303 	/* Get VRM */
304 	temp = vid_which_vrm();
305 
306 	if ((temp != 90) && (temp != 91)) {
307 		dev_err(&adapter->dev, "atxp1: Not supporting VRM %d.%d\n",
308 				temp / 10, temp % 10);
309 		return -ENODEV;
310 	}
311 
312 	strlcpy(info->type, "atxp1", I2C_NAME_SIZE);
313 
314 	return 0;
315 }
316 
317 static int atxp1_probe(struct i2c_client *new_client,
318 		       const struct i2c_device_id *id)
319 {
320 	struct atxp1_data *data;
321 	int err;
322 
323 	data = devm_kzalloc(&new_client->dev, sizeof(struct atxp1_data),
324 			    GFP_KERNEL);
325 	if (!data)
326 		return -ENOMEM;
327 
328 	/* Get VRM */
329 	data->vrm = vid_which_vrm();
330 
331 	i2c_set_clientdata(new_client, data);
332 	mutex_init(&data->update_lock);
333 
334 	/* Register sysfs hooks */
335 	err = sysfs_create_group(&new_client->dev.kobj, &atxp1_group);
336 	if (err)
337 		return err;
338 
339 	data->hwmon_dev = hwmon_device_register(&new_client->dev);
340 	if (IS_ERR(data->hwmon_dev)) {
341 		err = PTR_ERR(data->hwmon_dev);
342 		goto exit_remove_files;
343 	}
344 
345 	dev_info(&new_client->dev, "Using VRM: %d.%d\n",
346 			 data->vrm / 10, data->vrm % 10);
347 
348 	return 0;
349 
350 exit_remove_files:
351 	sysfs_remove_group(&new_client->dev.kobj, &atxp1_group);
352 	return err;
353 };
354 
355 static int atxp1_remove(struct i2c_client *client)
356 {
357 	struct atxp1_data *data = i2c_get_clientdata(client);
358 
359 	hwmon_device_unregister(data->hwmon_dev);
360 	sysfs_remove_group(&client->dev.kobj, &atxp1_group);
361 
362 	return 0;
363 };
364 
365 static const struct i2c_device_id atxp1_id[] = {
366 	{ "atxp1", 0 },
367 	{ }
368 };
369 MODULE_DEVICE_TABLE(i2c, atxp1_id);
370 
371 static struct i2c_driver atxp1_driver = {
372 	.class		= I2C_CLASS_HWMON,
373 	.driver = {
374 		.name	= "atxp1",
375 	},
376 	.probe		= atxp1_probe,
377 	.remove		= atxp1_remove,
378 	.id_table	= atxp1_id,
379 	.detect		= atxp1_detect,
380 	.address_list	= normal_i2c,
381 };
382 
383 module_i2c_driver(atxp1_driver);
384