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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * atxp1.c - kernel module for setting CPU VID and general purpose
4 * I/Os using the Attansic ATXP1 chip.
5 *
6 * The ATXP1 can reside on I2C addresses 0x37 or 0x4e. The chip is
7 * not auto-detected by the driver and must be instantiated explicitly.
8 * See Documentation/i2c/instantiating-devices.rst for more information.
9 */
10
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/jiffies.h>
15#include <linux/i2c.h>
16#include <linux/hwmon.h>
17#include <linux/hwmon-vid.h>
18#include <linux/err.h>
19#include <linux/kstrtox.h>
20#include <linux/mutex.h>
21#include <linux/sysfs.h>
22#include <linux/slab.h>
23
24MODULE_LICENSE("GPL");
25MODULE_DESCRIPTION("System voltages control via Attansic ATXP1");
26MODULE_VERSION("0.6.3");
27MODULE_AUTHOR("Sebastian Witt <[email protected]>");
28
29#define ATXP1_VID 0x00
30#define ATXP1_CVID 0x01
31#define ATXP1_GPIO1 0x06
32#define ATXP1_GPIO2 0x0a
33#define ATXP1_VIDENA 0x20
34#define ATXP1_VIDMASK 0x1f
35#define ATXP1_GPIO1MASK 0x0f
36
37struct atxp1_data {
38 struct i2c_client *client;
39 struct mutex update_lock;
40 unsigned long last_updated;
41 bool valid;
42 struct {
43 u8 vid; /* VID output register */
44 u8 cpu_vid; /* VID input from CPU */
45 u8 gpio1; /* General purpose I/O register 1 */
46 u8 gpio2; /* General purpose I/O register 2 */
47 } reg;
48 u8 vrm; /* Detected CPU VRM */
49};
50
51static struct atxp1_data *atxp1_update_device(struct device *dev)
52{
53 struct atxp1_data *data = dev_get_drvdata(dev);
54 struct i2c_client *client = data->client;
55
56 mutex_lock(&data->update_lock);
57
58 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
59
60 /* Update local register data */
61 data->reg.vid = i2c_smbus_read_byte_data(client, ATXP1_VID);
62 data->reg.cpu_vid = i2c_smbus_read_byte_data(client,
63 ATXP1_CVID);
64 data->reg.gpio1 = i2c_smbus_read_byte_data(client, ATXP1_GPIO1);
65 data->reg.gpio2 = i2c_smbus_read_byte_data(client, ATXP1_GPIO2);
66
67 data->valid = true;
68 }
69
70 mutex_unlock(&data->update_lock);
71
72 return data;
73}
74
75/* sys file functions for cpu0_vid */
76static ssize_t cpu0_vid_show(struct device *dev,
77 struct device_attribute *attr, char *buf)
78{
79 int size;
80 struct atxp1_data *data;
81
82 data = atxp1_update_device(dev);
83
84 size = sprintf(buf, "%d\n", vid_from_reg(data->reg.vid & ATXP1_VIDMASK,
85 data->vrm));
86
87 return size;
88}
89
90static ssize_t cpu0_vid_store(struct device *dev,
91 struct device_attribute *attr, const char *buf,
92 size_t count)
93{
94 struct atxp1_data *data = atxp1_update_device(dev);
95 struct i2c_client *client = data->client;
96 int vid, cvid;
97 unsigned long vcore;
98 int err;
99
100 err = kstrtoul(buf, 10, &vcore);
101 if (err)
102 return err;
103
104 vcore /= 25;
105 vcore *= 25;
106
107 /* Calculate VID */
108 vid = vid_to_reg(vcore, data->vrm);
109 if (vid < 0) {
110 dev_err(dev, "VID calculation failed.\n");
111 return vid;
112 }
113
114 /*
115 * If output enabled, use control register value.
116 * Otherwise original CPU VID
117 */
118 if (data->reg.vid & ATXP1_VIDENA)
119 cvid = data->reg.vid & ATXP1_VIDMASK;
120 else
121 cvid = data->reg.cpu_vid;
122
123 /* Nothing changed, aborting */
124 if (vid == cvid)
125 return count;
126
127 dev_dbg(dev, "Setting VCore to %d mV (0x%02x)\n", (int)vcore, vid);
128
129 /* Write every 25 mV step to increase stability */
130 if (cvid > vid) {
131 for (; cvid >= vid; cvid--)
132 i2c_smbus_write_byte_data(client,
133 ATXP1_VID, cvid | ATXP1_VIDENA);
134 } else {
135 for (; cvid <= vid; cvid++)
136 i2c_smbus_write_byte_data(client,
137 ATXP1_VID, cvid | ATXP1_VIDENA);
138 }
139
140 data->valid = false;
141
142 return count;
143}
144
145/*
146 * CPU core reference voltage
147 * unit: millivolt
148 */
149static DEVICE_ATTR_RW(cpu0_vid);
150
151/* sys file functions for GPIO1 */
152static ssize_t gpio1_show(struct device *dev, struct device_attribute *attr,
153 char *buf)
154{
155 int size;
156 struct atxp1_data *data;
157
158 data = atxp1_update_device(dev);
159
160 size = sprintf(buf, "0x%02x\n", data->reg.gpio1 & ATXP1_GPIO1MASK);
161
162 return size;
163}
164
165static ssize_t gpio1_store(struct device *dev, struct device_attribute *attr,
166 const char *buf, size_t count)
167{
168 struct atxp1_data *data = atxp1_update_device(dev);
169 struct i2c_client *client = data->client;
170 unsigned long value;
171 int err;
172
173 err = kstrtoul(buf, 16, &value);
174 if (err)
175 return err;
176
177 value &= ATXP1_GPIO1MASK;
178
179 if (value != (data->reg.gpio1 & ATXP1_GPIO1MASK)) {
180 dev_info(dev, "Writing 0x%x to GPIO1.\n", (unsigned int)value);
181
182 i2c_smbus_write_byte_data(client, ATXP1_GPIO1, value);
183
184 data->valid = false;
185 }
186
187 return count;
188}
189
190/*
191 * GPIO1 data register
192 * unit: Four bit as hex (e.g. 0x0f)
193 */
194static DEVICE_ATTR_RW(gpio1);
195
196/* sys file functions for GPIO2 */
197static ssize_t gpio2_show(struct device *dev, struct device_attribute *attr,
198 char *buf)
199{
200 int size;
201 struct atxp1_data *data;
202
203 data = atxp1_update_device(dev);
204
205 size = sprintf(buf, "0x%02x\n", data->reg.gpio2);
206
207 return size;
208}
209
210static ssize_t gpio2_store(struct device *dev, struct device_attribute *attr,
211 const char *buf, size_t count)
212{
213 struct atxp1_data *data = atxp1_update_device(dev);
214 struct i2c_client *client = data->client;
215 unsigned long value;
216 int err;
217
218 err = kstrtoul(buf, 16, &value);
219 if (err)
220 return err;
221 value &= 0xff;
222
223 if (value != data->reg.gpio2) {
224 dev_info(dev, "Writing 0x%x to GPIO1.\n", (unsigned int)value);
225
226 i2c_smbus_write_byte_data(client, ATXP1_GPIO2, value);
227
228 data->valid = false;
229 }
230
231 return count;
232}
233
234/*
235 * GPIO2 data register
236 * unit: Eight bit as hex (e.g. 0xff)
237 */
238static DEVICE_ATTR_RW(gpio2);
239
240static struct attribute *atxp1_attrs[] = {
241 &dev_attr_gpio1.attr,
242 &dev_attr_gpio2.attr,
243 &dev_attr_cpu0_vid.attr,
244 NULL
245};
246ATTRIBUTE_GROUPS(atxp1);
247
248static int atxp1_probe(struct i2c_client *client)
249{
250 struct device *dev = &client->dev;
251 struct atxp1_data *data;
252 struct device *hwmon_dev;
253
254 data = devm_kzalloc(dev, sizeof(struct atxp1_data), GFP_KERNEL);
255 if (!data)
256 return -ENOMEM;
257
258 /* Get VRM */
259 data->vrm = vid_which_vrm();
260 if (data->vrm != 90 && data->vrm != 91) {
261 dev_err(dev, "atxp1: Not supporting VRM %d.%d\n",
262 data->vrm / 10, data->vrm % 10);
263 return -ENODEV;
264 }
265
266 data->client = client;
267 mutex_init(&data->update_lock);
268
269 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
270 data,
271 atxp1_groups);
272 if (IS_ERR(hwmon_dev))
273 return PTR_ERR(hwmon_dev);
274
275 dev_info(dev, "Using VRM: %d.%d\n", data->vrm / 10, data->vrm % 10);
276
277 return 0;
278};
279
280static const struct i2c_device_id atxp1_id[] = {
281 { .name = "atxp1" },
282 { }
283};
284MODULE_DEVICE_TABLE(i2c, atxp1_id);
285
286static struct i2c_driver atxp1_driver = {
287 .class = I2C_CLASS_HWMON,
288 .driver = {
289 .name = "atxp1",
290 },
291 .probe = atxp1_probe,
292 .id_table = atxp1_id,
293};
294
295module_i2c_driver(atxp1_driver);