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 * The ATXP1 can reside on I2C addresses 0x37 or 0x4e. The chip is
16 * not auto-detected by the driver and must be instantiated explicitly.
17 * See Documentation/i2c/instantiating-devices for more information.
18 */
19
20#include <linux/kernel.h>
21#include <linux/init.h>
22#include <linux/module.h>
23#include <linux/jiffies.h>
24#include <linux/i2c.h>
25#include <linux/hwmon.h>
26#include <linux/hwmon-vid.h>
27#include <linux/err.h>
28#include <linux/mutex.h>
29#include <linux/sysfs.h>
30#include <linux/slab.h>
31
32MODULE_LICENSE("GPL");
33MODULE_DESCRIPTION("System voltages control via Attansic ATXP1");
34MODULE_VERSION("0.6.3");
35MODULE_AUTHOR("Sebastian Witt <se.witt@gmx.net>");
36
37#define ATXP1_VID 0x00
38#define ATXP1_CVID 0x01
39#define ATXP1_GPIO1 0x06
40#define ATXP1_GPIO2 0x0a
41#define ATXP1_VIDENA 0x20
42#define ATXP1_VIDMASK 0x1f
43#define ATXP1_GPIO1MASK 0x0f
44
45struct atxp1_data {
46 struct i2c_client *client;
47 struct mutex update_lock;
48 unsigned long last_updated;
49 u8 valid;
50 struct {
51 u8 vid; /* VID output register */
52 u8 cpu_vid; /* VID input from CPU */
53 u8 gpio1; /* General purpose I/O register 1 */
54 u8 gpio2; /* General purpose I/O register 2 */
55 } reg;
56 u8 vrm; /* Detected CPU VRM */
57};
58
59static struct atxp1_data *atxp1_update_device(struct device *dev)
60{
61 struct atxp1_data *data = dev_get_drvdata(dev);
62 struct i2c_client *client = data->client;
63
64 mutex_lock(&data->update_lock);
65
66 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
67
68 /* Update local register data */
69 data->reg.vid = i2c_smbus_read_byte_data(client, ATXP1_VID);
70 data->reg.cpu_vid = i2c_smbus_read_byte_data(client,
71 ATXP1_CVID);
72 data->reg.gpio1 = i2c_smbus_read_byte_data(client, ATXP1_GPIO1);
73 data->reg.gpio2 = i2c_smbus_read_byte_data(client, ATXP1_GPIO2);
74
75 data->valid = 1;
76 }
77
78 mutex_unlock(&data->update_lock);
79
80 return data;
81}
82
83/* sys file functions for cpu0_vid */
84static ssize_t cpu0_vid_show(struct device *dev,
85 struct device_attribute *attr, char *buf)
86{
87 int size;
88 struct atxp1_data *data;
89
90 data = atxp1_update_device(dev);
91
92 size = sprintf(buf, "%d\n", vid_from_reg(data->reg.vid & ATXP1_VIDMASK,
93 data->vrm));
94
95 return size;
96}
97
98static ssize_t cpu0_vid_store(struct device *dev,
99 struct device_attribute *attr, const char *buf,
100 size_t count)
101{
102 struct atxp1_data *data = atxp1_update_device(dev);
103 struct i2c_client *client = data->client;
104 int vid, cvid;
105 unsigned long vcore;
106 int err;
107
108 err = kstrtoul(buf, 10, &vcore);
109 if (err)
110 return err;
111
112 vcore /= 25;
113 vcore *= 25;
114
115 /* Calculate VID */
116 vid = vid_to_reg(vcore, data->vrm);
117 if (vid < 0) {
118 dev_err(dev, "VID calculation failed.\n");
119 return vid;
120 }
121
122 /*
123 * If output enabled, use control register value.
124 * Otherwise original CPU VID
125 */
126 if (data->reg.vid & ATXP1_VIDENA)
127 cvid = data->reg.vid & ATXP1_VIDMASK;
128 else
129 cvid = data->reg.cpu_vid;
130
131 /* Nothing changed, aborting */
132 if (vid == cvid)
133 return count;
134
135 dev_dbg(dev, "Setting VCore to %d mV (0x%02x)\n", (int)vcore, vid);
136
137 /* Write every 25 mV step to increase stability */
138 if (cvid > vid) {
139 for (; cvid >= vid; cvid--)
140 i2c_smbus_write_byte_data(client,
141 ATXP1_VID, cvid | ATXP1_VIDENA);
142 } else {
143 for (; cvid <= vid; cvid++)
144 i2c_smbus_write_byte_data(client,
145 ATXP1_VID, cvid | ATXP1_VIDENA);
146 }
147
148 data->valid = 0;
149
150 return count;
151}
152
153/*
154 * CPU core reference voltage
155 * unit: millivolt
156 */
157static DEVICE_ATTR_RW(cpu0_vid);
158
159/* sys file functions for GPIO1 */
160static ssize_t gpio1_show(struct device *dev, struct device_attribute *attr,
161 char *buf)
162{
163 int size;
164 struct atxp1_data *data;
165
166 data = atxp1_update_device(dev);
167
168 size = sprintf(buf, "0x%02x\n", data->reg.gpio1 & ATXP1_GPIO1MASK);
169
170 return size;
171}
172
173static ssize_t gpio1_store(struct device *dev, struct device_attribute *attr,
174 const char *buf, size_t count)
175{
176 struct atxp1_data *data = atxp1_update_device(dev);
177 struct i2c_client *client = data->client;
178 unsigned long value;
179 int err;
180
181 err = kstrtoul(buf, 16, &value);
182 if (err)
183 return err;
184
185 value &= ATXP1_GPIO1MASK;
186
187 if (value != (data->reg.gpio1 & ATXP1_GPIO1MASK)) {
188 dev_info(dev, "Writing 0x%x to GPIO1.\n", (unsigned int)value);
189
190 i2c_smbus_write_byte_data(client, ATXP1_GPIO1, value);
191
192 data->valid = 0;
193 }
194
195 return count;
196}
197
198/*
199 * GPIO1 data register
200 * unit: Four bit as hex (e.g. 0x0f)
201 */
202static DEVICE_ATTR_RW(gpio1);
203
204/* sys file functions for GPIO2 */
205static ssize_t gpio2_show(struct device *dev, struct device_attribute *attr,
206 char *buf)
207{
208 int size;
209 struct atxp1_data *data;
210
211 data = atxp1_update_device(dev);
212
213 size = sprintf(buf, "0x%02x\n", data->reg.gpio2);
214
215 return size;
216}
217
218static ssize_t gpio2_store(struct device *dev, struct device_attribute *attr,
219 const char *buf, size_t count)
220{
221 struct atxp1_data *data = atxp1_update_device(dev);
222 struct i2c_client *client = data->client;
223 unsigned long value;
224 int err;
225
226 err = kstrtoul(buf, 16, &value);
227 if (err)
228 return err;
229 value &= 0xff;
230
231 if (value != data->reg.gpio2) {
232 dev_info(dev, "Writing 0x%x to GPIO1.\n", (unsigned int)value);
233
234 i2c_smbus_write_byte_data(client, ATXP1_GPIO2, value);
235
236 data->valid = 0;
237 }
238
239 return count;
240}
241
242/*
243 * GPIO2 data register
244 * unit: Eight bit as hex (e.g. 0xff)
245 */
246static DEVICE_ATTR_RW(gpio2);
247
248static struct attribute *atxp1_attrs[] = {
249 &dev_attr_gpio1.attr,
250 &dev_attr_gpio2.attr,
251 &dev_attr_cpu0_vid.attr,
252 NULL
253};
254ATTRIBUTE_GROUPS(atxp1);
255
256static int atxp1_probe(struct i2c_client *client,
257 const struct i2c_device_id *id)
258{
259 struct device *dev = &client->dev;
260 struct atxp1_data *data;
261 struct device *hwmon_dev;
262
263 data = devm_kzalloc(dev, sizeof(struct atxp1_data), GFP_KERNEL);
264 if (!data)
265 return -ENOMEM;
266
267 /* Get VRM */
268 data->vrm = vid_which_vrm();
269 if (data->vrm != 90 && data->vrm != 91) {
270 dev_err(dev, "atxp1: Not supporting VRM %d.%d\n",
271 data->vrm / 10, data->vrm % 10);
272 return -ENODEV;
273 }
274
275 data->client = client;
276 mutex_init(&data->update_lock);
277
278 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
279 data,
280 atxp1_groups);
281 if (IS_ERR(hwmon_dev))
282 return PTR_ERR(hwmon_dev);
283
284 dev_info(dev, "Using VRM: %d.%d\n", data->vrm / 10, data->vrm % 10);
285
286 return 0;
287};
288
289static const struct i2c_device_id atxp1_id[] = {
290 { "atxp1", 0 },
291 { }
292};
293MODULE_DEVICE_TABLE(i2c, atxp1_id);
294
295static struct i2c_driver atxp1_driver = {
296 .class = I2C_CLASS_HWMON,
297 .driver = {
298 .name = "atxp1",
299 },
300 .probe = atxp1_probe,
301 .id_table = atxp1_id,
302};
303
304module_i2c_driver(atxp1_driver);
305