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17#include <linux/module.h>
18#include <linux/init.h>
19#include <linux/i2c.h>
20#include <linux/err.h>
21#include <linux/delay.h>
22
23#include <linux/iio/iio.h>
24#include <linux/iio/sysfs.h>
25
26#include <linux/iio/dac/mcp4725.h>
27
28#define MCP4725_DRV_NAME "mcp4725"
29
30struct mcp4725_data {
31 struct i2c_client *client;
32 u16 vref_mv;
33 u16 dac_value;
34 bool powerdown;
35 unsigned powerdown_mode;
36};
37
38static int mcp4725_suspend(struct device *dev)
39{
40 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
41 to_i2c_client(dev)));
42 u8 outbuf[2];
43
44 outbuf[0] = (data->powerdown_mode + 1) << 4;
45 outbuf[1] = 0;
46 data->powerdown = true;
47
48 return i2c_master_send(data->client, outbuf, 2);
49}
50
51static int mcp4725_resume(struct device *dev)
52{
53 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
54 to_i2c_client(dev)));
55 u8 outbuf[2];
56
57
58 outbuf[0] = (data->dac_value >> 8) & 0xf;
59 outbuf[1] = data->dac_value & 0xff;
60 data->powerdown = false;
61
62 return i2c_master_send(data->client, outbuf, 2);
63}
64
65#ifdef CONFIG_PM_SLEEP
66static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
67#define MCP4725_PM_OPS (&mcp4725_pm_ops)
68#else
69#define MCP4725_PM_OPS NULL
70#endif
71
72static ssize_t mcp4725_store_eeprom(struct device *dev,
73 struct device_attribute *attr, const char *buf, size_t len)
74{
75 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
76 struct mcp4725_data *data = iio_priv(indio_dev);
77 int tries = 20;
78 u8 inoutbuf[3];
79 bool state;
80 int ret;
81
82 ret = strtobool(buf, &state);
83 if (ret < 0)
84 return ret;
85
86 if (!state)
87 return 0;
88
89 inoutbuf[0] = 0x60;
90 inoutbuf[1] = data->dac_value >> 4;
91 inoutbuf[2] = (data->dac_value & 0xf) << 4;
92
93 ret = i2c_master_send(data->client, inoutbuf, 3);
94 if (ret < 0)
95 return ret;
96 else if (ret != 3)
97 return -EIO;
98
99
100 while (tries--) {
101 msleep(20);
102 ret = i2c_master_recv(data->client, inoutbuf, 3);
103 if (ret < 0)
104 return ret;
105 else if (ret != 3)
106 return -EIO;
107
108 if (inoutbuf[0] & 0x80)
109 break;
110 }
111
112 if (tries < 0) {
113 dev_err(&data->client->dev,
114 "mcp4725_store_eeprom() failed, incomplete\n");
115 return -EIO;
116 }
117
118 return len;
119}
120
121static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
122
123static struct attribute *mcp4725_attributes[] = {
124 &iio_dev_attr_store_eeprom.dev_attr.attr,
125 NULL,
126};
127
128static const struct attribute_group mcp4725_attribute_group = {
129 .attrs = mcp4725_attributes,
130};
131
132static const char * const mcp4725_powerdown_modes[] = {
133 "1kohm_to_gnd",
134 "100kohm_to_gnd",
135 "500kohm_to_gnd"
136};
137
138static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
139 const struct iio_chan_spec *chan)
140{
141 struct mcp4725_data *data = iio_priv(indio_dev);
142
143 return data->powerdown_mode;
144}
145
146static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
147 const struct iio_chan_spec *chan, unsigned mode)
148{
149 struct mcp4725_data *data = iio_priv(indio_dev);
150
151 data->powerdown_mode = mode;
152
153 return 0;
154}
155
156static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
157 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
158{
159 struct mcp4725_data *data = iio_priv(indio_dev);
160
161 return sprintf(buf, "%d\n", data->powerdown);
162}
163
164static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
165 uintptr_t private, const struct iio_chan_spec *chan,
166 const char *buf, size_t len)
167{
168 struct mcp4725_data *data = iio_priv(indio_dev);
169 bool state;
170 int ret;
171
172 ret = strtobool(buf, &state);
173 if (ret)
174 return ret;
175
176 if (state)
177 ret = mcp4725_suspend(&data->client->dev);
178 else
179 ret = mcp4725_resume(&data->client->dev);
180 if (ret < 0)
181 return ret;
182
183 return len;
184}
185
186static const struct iio_enum mcp4725_powerdown_mode_enum = {
187 .items = mcp4725_powerdown_modes,
188 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
189 .get = mcp4725_get_powerdown_mode,
190 .set = mcp4725_set_powerdown_mode,
191};
192
193static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
194 {
195 .name = "powerdown",
196 .read = mcp4725_read_powerdown,
197 .write = mcp4725_write_powerdown,
198 },
199 IIO_ENUM("powerdown_mode", false, &mcp4725_powerdown_mode_enum),
200 IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum),
201 { },
202};
203
204static const struct iio_chan_spec mcp4725_channel = {
205 .type = IIO_VOLTAGE,
206 .indexed = 1,
207 .output = 1,
208 .channel = 0,
209 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
210 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
211 .scan_type = IIO_ST('u', 12, 16, 0),
212 .ext_info = mcp4725_ext_info,
213};
214
215static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
216{
217 struct mcp4725_data *data = iio_priv(indio_dev);
218 u8 outbuf[2];
219 int ret;
220
221 if (val >= (1 << 12) || val < 0)
222 return -EINVAL;
223
224 outbuf[0] = (val >> 8) & 0xf;
225 outbuf[1] = val & 0xff;
226
227 ret = i2c_master_send(data->client, outbuf, 2);
228 if (ret < 0)
229 return ret;
230 else if (ret != 2)
231 return -EIO;
232 else
233 return 0;
234}
235
236static int mcp4725_read_raw(struct iio_dev *indio_dev,
237 struct iio_chan_spec const *chan,
238 int *val, int *val2, long mask)
239{
240 struct mcp4725_data *data = iio_priv(indio_dev);
241 unsigned long scale_uv;
242
243 switch (mask) {
244 case IIO_CHAN_INFO_RAW:
245 *val = data->dac_value;
246 return IIO_VAL_INT;
247 case IIO_CHAN_INFO_SCALE:
248 scale_uv = (data->vref_mv * 1000) >> 12;
249 *val = scale_uv / 1000000;
250 *val2 = scale_uv % 1000000;
251 return IIO_VAL_INT_PLUS_MICRO;
252 }
253 return -EINVAL;
254}
255
256static int mcp4725_write_raw(struct iio_dev *indio_dev,
257 struct iio_chan_spec const *chan,
258 int val, int val2, long mask)
259{
260 struct mcp4725_data *data = iio_priv(indio_dev);
261 int ret;
262
263 switch (mask) {
264 case IIO_CHAN_INFO_RAW:
265 ret = mcp4725_set_value(indio_dev, val);
266 data->dac_value = val;
267 break;
268 default:
269 ret = -EINVAL;
270 break;
271 }
272
273 return ret;
274}
275
276static const struct iio_info mcp4725_info = {
277 .read_raw = mcp4725_read_raw,
278 .write_raw = mcp4725_write_raw,
279 .attrs = &mcp4725_attribute_group,
280 .driver_module = THIS_MODULE,
281};
282
283static int mcp4725_probe(struct i2c_client *client,
284 const struct i2c_device_id *id)
285{
286 struct mcp4725_data *data;
287 struct iio_dev *indio_dev;
288 struct mcp4725_platform_data *platform_data = client->dev.platform_data;
289 u8 inbuf[3];
290 u8 pd;
291 int err;
292
293 if (!platform_data || !platform_data->vref_mv) {
294 dev_err(&client->dev, "invalid platform data");
295 return -EINVAL;
296 }
297
298 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
299 if (indio_dev == NULL)
300 return -ENOMEM;
301 data = iio_priv(indio_dev);
302 i2c_set_clientdata(client, indio_dev);
303 data->client = client;
304
305 indio_dev->dev.parent = &client->dev;
306 indio_dev->info = &mcp4725_info;
307 indio_dev->channels = &mcp4725_channel;
308 indio_dev->num_channels = 1;
309 indio_dev->modes = INDIO_DIRECT_MODE;
310
311 data->vref_mv = platform_data->vref_mv;
312
313
314 err = i2c_master_recv(client, inbuf, 3);
315 if (err < 0) {
316 dev_err(&client->dev, "failed to read DAC value");
317 return err;
318 }
319 pd = (inbuf[0] >> 1) & 0x3;
320 data->powerdown = pd > 0 ? true : false;
321 data->powerdown_mode = pd ? pd-1 : 2;
322 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
323
324 err = iio_device_register(indio_dev);
325 if (err)
326 return err;
327
328 dev_info(&client->dev, "MCP4725 DAC registered\n");
329
330 return 0;
331}
332
333static int mcp4725_remove(struct i2c_client *client)
334{
335 iio_device_unregister(i2c_get_clientdata(client));
336 return 0;
337}
338
339static const struct i2c_device_id mcp4725_id[] = {
340 { "mcp4725", 0 },
341 { }
342};
343MODULE_DEVICE_TABLE(i2c, mcp4725_id);
344
345static struct i2c_driver mcp4725_driver = {
346 .driver = {
347 .name = MCP4725_DRV_NAME,
348 .pm = MCP4725_PM_OPS,
349 },
350 .probe = mcp4725_probe,
351 .remove = mcp4725_remove,
352 .id_table = mcp4725_id,
353};
354module_i2c_driver(mcp4725_driver);
355
356MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
357MODULE_DESCRIPTION("MCP4725 12-bit DAC");
358MODULE_LICENSE("GPL");
359
