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
33MODULE_LICENSE("GPL");
34MODULE_DESCRIPTION("System voltages control via Attansic ATXP1");
35MODULE_VERSION("0.6.3");
36MODULE_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
46static const unsigned short normal_i2c[] = { 0x37, 0x4e, I2C_CLIENT_END };
47
48struct atxp1_data {
49	struct i2c_client *client;
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
62static struct atxp1_data *atxp1_update_device(struct device *dev)
63{
64	struct atxp1_data *data = dev_get_drvdata(dev);
65	struct i2c_client *client = data->client;
66
67	mutex_lock(&data->update_lock);
68
69	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
70
71		/* Update local register data */
72		data->reg.vid = i2c_smbus_read_byte_data(client, ATXP1_VID);
73		data->reg.cpu_vid = i2c_smbus_read_byte_data(client,
74							     ATXP1_CVID);
75		data->reg.gpio1 = i2c_smbus_read_byte_data(client, ATXP1_GPIO1);
76		data->reg.gpio2 = i2c_smbus_read_byte_data(client, ATXP1_GPIO2);
77
78		data->valid = 1;
79	}
80
81	mutex_unlock(&data->update_lock);
82
83	return data;
84}
85
86/* sys file functions for cpu0_vid */
87static ssize_t atxp1_showvcore(struct device *dev,
88			       struct device_attribute *attr, char *buf)
89{
90	int size;
91	struct atxp1_data *data;
92
93	data = atxp1_update_device(dev);
94
95	size = sprintf(buf, "%d\n", vid_from_reg(data->reg.vid & ATXP1_VIDMASK,
96						 data->vrm));
97
98	return size;
99}
100
101static ssize_t atxp1_storevcore(struct device *dev,
102				struct device_attribute *attr,
103				const char *buf, size_t count)
104{
105	struct atxp1_data *data = atxp1_update_device(dev);
106	struct i2c_client *client = data->client;
107	int vid, cvid;
108	unsigned long vcore;
109	int err;
110
111	err = kstrtoul(buf, 10, &vcore);
112	if (err)
113		return err;
114
115	vcore /= 25;
116	vcore *= 25;
117
118	/* Calculate VID */
119	vid = vid_to_reg(vcore, data->vrm);
120	if (vid < 0) {
121		dev_err(dev, "VID calculation failed.\n");
122		return vid;
123	}
124
125	/*
126	 * If output enabled, use control register value.
127	 * Otherwise original CPU VID
128	 */
129	if (data->reg.vid & ATXP1_VIDENA)
130		cvid = data->reg.vid & ATXP1_VIDMASK;
131	else
132		cvid = data->reg.cpu_vid;
133
134	/* Nothing changed, aborting */
135	if (vid == cvid)
136		return count;
137
138	dev_dbg(dev, "Setting VCore to %d mV (0x%02x)\n", (int)vcore, vid);
139
140	/* Write every 25 mV step to increase stability */
141	if (cvid > vid) {
142		for (; cvid >= vid; cvid--)
143			i2c_smbus_write_byte_data(client,
144						ATXP1_VID, cvid | ATXP1_VIDENA);
145	} else {
146		for (; cvid <= vid; cvid++)
147			i2c_smbus_write_byte_data(client,
148						ATXP1_VID, cvid | ATXP1_VIDENA);
149	}
150
151	data->valid = 0;
152
153	return count;
154}
155
156/*
157 * CPU core reference voltage
158 * unit: millivolt
159 */
160static DEVICE_ATTR(cpu0_vid, S_IRUGO | S_IWUSR, atxp1_showvcore,
161		   atxp1_storevcore);
162
163/* sys file functions for GPIO1 */
164static ssize_t atxp1_showgpio1(struct device *dev,
165			       struct device_attribute *attr, char *buf)
166{
167	int size;
168	struct atxp1_data *data;
169
170	data = atxp1_update_device(dev);
171
172	size = sprintf(buf, "0x%02x\n", data->reg.gpio1 & ATXP1_GPIO1MASK);
173
174	return size;
175}
176
177static ssize_t atxp1_storegpio1(struct device *dev,
178				struct device_attribute *attr, const char *buf,
179				size_t count)
180{
181	struct atxp1_data *data = atxp1_update_device(dev);
182	struct i2c_client *client = data->client;
183	unsigned long value;
184	int err;
185
186	err = kstrtoul(buf, 16, &value);
187	if (err)
188		return err;
189
190	value &= ATXP1_GPIO1MASK;
191
192	if (value != (data->reg.gpio1 & ATXP1_GPIO1MASK)) {
193		dev_info(dev, "Writing 0x%x to GPIO1.\n", (unsigned int)value);
194
195		i2c_smbus_write_byte_data(client, ATXP1_GPIO1, value);
196
197		data->valid = 0;
198	}
199
200	return count;
201}
202
203/*
204 * GPIO1 data register
205 * unit: Four bit as hex (e.g. 0x0f)
206 */
207static DEVICE_ATTR(gpio1, S_IRUGO | S_IWUSR, atxp1_showgpio1, atxp1_storegpio1);
208
209/* sys file functions for GPIO2 */
210static ssize_t atxp1_showgpio2(struct device *dev,
211			       struct device_attribute *attr, char *buf)
212{
213	int size;
214	struct atxp1_data *data;
215
216	data = atxp1_update_device(dev);
217
218	size = sprintf(buf, "0x%02x\n", data->reg.gpio2);
219
220	return size;
221}
222
223static ssize_t atxp1_storegpio2(struct device *dev,
224				struct device_attribute *attr,
225				const char *buf, size_t count)
226{
227	struct atxp1_data *data = atxp1_update_device(dev);
228	struct i2c_client *client = data->client;
229	unsigned long value;
230	int err;
231
232	err = kstrtoul(buf, 16, &value);
233	if (err)
234		return err;
235	value &= 0xff;
236
237	if (value != data->reg.gpio2) {
238		dev_info(dev, "Writing 0x%x to GPIO1.\n", (unsigned int)value);
239
240		i2c_smbus_write_byte_data(client, ATXP1_GPIO2, value);
241
242		data->valid = 0;
243	}
244
245	return count;
246}
247
248/*
249 * GPIO2 data register
250 * unit: Eight bit as hex (e.g. 0xff)
251 */
252static DEVICE_ATTR(gpio2, S_IRUGO | S_IWUSR, atxp1_showgpio2, atxp1_storegpio2);
253
254static struct attribute *atxp1_attrs[] = {
255	&dev_attr_gpio1.attr,
256	&dev_attr_gpio2.attr,
257	&dev_attr_cpu0_vid.attr,
258	NULL
259};
260ATTRIBUTE_GROUPS(atxp1);
261
262/* Return 0 if detection is successful, -ENODEV otherwise */
263static int atxp1_detect(struct i2c_client *new_client,
264			struct i2c_board_info *info)
265{
266	struct i2c_adapter *adapter = new_client->adapter;
267
268	u8 temp;
269
270	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
271		return -ENODEV;
272
273	/* Detect ATXP1, checking if vendor ID registers are all zero */
274	if (!((i2c_smbus_read_byte_data(new_client, 0x3e) == 0) &&
275	     (i2c_smbus_read_byte_data(new_client, 0x3f) == 0) &&
276	     (i2c_smbus_read_byte_data(new_client, 0xfe) == 0) &&
277	     (i2c_smbus_read_byte_data(new_client, 0xff) == 0)))
278		return -ENODEV;
279
280	/*
281	 * No vendor ID, now checking if registers 0x10,0x11 (non-existent)
282	 * showing the same as register 0x00
283	 */
284	temp = i2c_smbus_read_byte_data(new_client, 0x00);
285
286	if (!((i2c_smbus_read_byte_data(new_client, 0x10) == temp) &&
287	      (i2c_smbus_read_byte_data(new_client, 0x11) == temp)))
288		return -ENODEV;
289
290	/* Get VRM */
291	temp = vid_which_vrm();
292
293	if ((temp != 90) && (temp != 91)) {
294		dev_err(&adapter->dev, "atxp1: Not supporting VRM %d.%d\n",
295				temp / 10, temp % 10);
296		return -ENODEV;
297	}
298
299	strlcpy(info->type, "atxp1", I2C_NAME_SIZE);
300
301	return 0;
302}
303
304static int atxp1_probe(struct i2c_client *client,
305		       const struct i2c_device_id *id)
306{
307	struct device *dev = &client->dev;
308	struct atxp1_data *data;
309	struct device *hwmon_dev;
310
311	data = devm_kzalloc(dev, sizeof(struct atxp1_data), GFP_KERNEL);
312	if (!data)
313		return -ENOMEM;
314
315	/* Get VRM */
316	data->vrm = vid_which_vrm();
317
318	data->client = client;
319	mutex_init(&data->update_lock);
320
321	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
322							   data,
323							   atxp1_groups);
324	if (IS_ERR(hwmon_dev))
325		return PTR_ERR(hwmon_dev);
326
327	dev_info(dev, "Using VRM: %d.%d\n", data->vrm / 10, data->vrm % 10);
328
329	return 0;
330};
331
332static const struct i2c_device_id atxp1_id[] = {
333	{ "atxp1", 0 },
334	{ }
335};
336MODULE_DEVICE_TABLE(i2c, atxp1_id);
337
338static struct i2c_driver atxp1_driver = {
339	.class		= I2C_CLASS_HWMON,
340	.driver = {
341		.name	= "atxp1",
342	},
343	.probe		= atxp1_probe,
344	.id_table	= atxp1_id,
345	.detect		= atxp1_detect,
346	.address_list	= normal_i2c,
347};
348
349module_i2c_driver(atxp1_driver);
350