1 /*
2 * t5403.c - Support for EPCOS T5403 pressure/temperature sensor
3 *
4 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
5 *
6 * This file is subject to the terms and conditions of version 2 of
7 * the GNU General Public License. See the file COPYING in the main
8 * directory of this archive for more details.
9 *
10 * (7-bit I2C slave address 0x77)
11 *
12 * TODO: end-of-conversion irq
13 */
14
15 #include <linux/module.h>
16 #include <linux/i2c.h>
17 #include <linux/iio/iio.h>
18 #include <linux/iio/sysfs.h>
19 #include <linux/delay.h>
20
21 #define T5403_DATA 0xf5 /* data, LSB first, 16 bit */
22 #define T5403_CALIB_DATA 0x8e /* 10 calibration coeff., LSB first, 16 bit */
23 #define T5403_SLAVE_ADDR 0x88 /* I2C slave address, 0x77 */
24 #define T5403_COMMAND 0xf1
25
26 /* command bits */
27 #define T5403_MODE_SHIFT 3 /* conversion time: 2, 8, 16, 66 ms */
28 #define T5403_PT BIT(1) /* 0 .. pressure, 1 .. temperature measurement */
29 #define T5403_SCO BIT(0) /* start conversion */
30
31 #define T5403_MODE_LOW 0
32 #define T5403_MODE_STANDARD 1
33 #define T5403_MODE_HIGH 2
34 #define T5403_MODE_ULTRA_HIGH 3
35
36 #define T5403_I2C_MASK (~BIT(7))
37 #define T5403_I2C_ADDR 0x77
38
39 static const int t5403_pressure_conv_ms[] = {2, 8, 16, 66};
40
41 struct t5403_data {
42 struct i2c_client *client;
43 struct mutex lock;
44 int mode;
45 __le16 c[10];
46 };
47
48 #define T5403_C_U16(i) le16_to_cpu(data->c[(i) - 1])
49 #define T5403_C(i) sign_extend32(T5403_C_U16(i), 15)
50
t5403_read(struct t5403_data * data,bool pressure)51 static int t5403_read(struct t5403_data *data, bool pressure)
52 {
53 int wait_time = 3; /* wakeup time in ms */
54
55 int ret = i2c_smbus_write_byte_data(data->client, T5403_COMMAND,
56 (pressure ? (data->mode << T5403_MODE_SHIFT) : T5403_PT) |
57 T5403_SCO);
58 if (ret < 0)
59 return ret;
60
61 wait_time += pressure ? t5403_pressure_conv_ms[data->mode] : 2;
62
63 msleep(wait_time);
64
65 return i2c_smbus_read_word_data(data->client, T5403_DATA);
66 }
67
t5403_comp_pressure(struct t5403_data * data,int * val,int * val2)68 static int t5403_comp_pressure(struct t5403_data *data, int *val, int *val2)
69 {
70 int ret;
71 s16 t_r;
72 u16 p_r;
73 s32 S, O, X;
74
75 mutex_lock(&data->lock);
76
77 ret = t5403_read(data, false);
78 if (ret < 0)
79 goto done;
80 t_r = ret;
81
82 ret = t5403_read(data, true);
83 if (ret < 0)
84 goto done;
85 p_r = ret;
86
87 /* see EPCOS application note */
88 S = T5403_C_U16(3) + (s32) T5403_C_U16(4) * t_r / 0x20000 +
89 T5403_C(5) * t_r / 0x8000 * t_r / 0x80000 +
90 T5403_C(9) * t_r / 0x8000 * t_r / 0x8000 * t_r / 0x10000;
91
92 O = T5403_C(6) * 0x4000 + T5403_C(7) * t_r / 8 +
93 T5403_C(8) * t_r / 0x8000 * t_r / 16 +
94 T5403_C(9) * t_r / 0x8000 * t_r / 0x10000 * t_r;
95
96 X = (S * p_r + O) / 0x4000;
97
98 X += ((X - 75000) * (X - 75000) / 0x10000 - 9537) *
99 T5403_C(10) / 0x10000;
100
101 *val = X / 1000;
102 *val2 = (X % 1000) * 1000;
103
104 done:
105 mutex_unlock(&data->lock);
106 return ret;
107 }
108
t5403_comp_temp(struct t5403_data * data,int * val)109 static int t5403_comp_temp(struct t5403_data *data, int *val)
110 {
111 int ret;
112 s16 t_r;
113
114 mutex_lock(&data->lock);
115 ret = t5403_read(data, false);
116 if (ret < 0)
117 goto done;
118 t_r = ret;
119
120 /* see EPCOS application note */
121 *val = ((s32) T5403_C_U16(1) * t_r / 0x100 +
122 (s32) T5403_C_U16(2) * 0x40) * 1000 / 0x10000;
123
124 done:
125 mutex_unlock(&data->lock);
126 return ret;
127 }
128
t5403_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)129 static int t5403_read_raw(struct iio_dev *indio_dev,
130 struct iio_chan_spec const *chan,
131 int *val, int *val2, long mask)
132 {
133 struct t5403_data *data = iio_priv(indio_dev);
134 int ret;
135
136 switch (mask) {
137 case IIO_CHAN_INFO_PROCESSED:
138 switch (chan->type) {
139 case IIO_PRESSURE:
140 ret = t5403_comp_pressure(data, val, val2);
141 if (ret < 0)
142 return ret;
143 return IIO_VAL_INT_PLUS_MICRO;
144 case IIO_TEMP:
145 ret = t5403_comp_temp(data, val);
146 if (ret < 0)
147 return ret;
148 return IIO_VAL_INT;
149 default:
150 return -EINVAL;
151 }
152 case IIO_CHAN_INFO_INT_TIME:
153 *val = 0;
154 *val2 = t5403_pressure_conv_ms[data->mode] * 1000;
155 return IIO_VAL_INT_PLUS_MICRO;
156 default:
157 return -EINVAL;
158 }
159 }
160
t5403_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)161 static int t5403_write_raw(struct iio_dev *indio_dev,
162 struct iio_chan_spec const *chan,
163 int val, int val2, long mask)
164 {
165 struct t5403_data *data = iio_priv(indio_dev);
166 int i;
167
168 switch (mask) {
169 case IIO_CHAN_INFO_INT_TIME:
170 if (val != 0)
171 return -EINVAL;
172 for (i = 0; i < ARRAY_SIZE(t5403_pressure_conv_ms); i++)
173 if (val2 == t5403_pressure_conv_ms[i] * 1000) {
174 mutex_lock(&data->lock);
175 data->mode = i;
176 mutex_unlock(&data->lock);
177 return 0;
178 }
179 return -EINVAL;
180 default:
181 return -EINVAL;
182 }
183 }
184
185 static const struct iio_chan_spec t5403_channels[] = {
186 {
187 .type = IIO_PRESSURE,
188 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
189 BIT(IIO_CHAN_INFO_INT_TIME),
190 },
191 {
192 .type = IIO_TEMP,
193 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
194 },
195 };
196
197 static IIO_CONST_ATTR_INT_TIME_AVAIL("0.002 0.008 0.016 0.066");
198
199 static struct attribute *t5403_attributes[] = {
200 &iio_const_attr_integration_time_available.dev_attr.attr,
201 NULL
202 };
203
204 static const struct attribute_group t5403_attribute_group = {
205 .attrs = t5403_attributes,
206 };
207
208 static const struct iio_info t5403_info = {
209 .read_raw = &t5403_read_raw,
210 .write_raw = &t5403_write_raw,
211 .attrs = &t5403_attribute_group,
212 };
213
t5403_probe(struct i2c_client * client,const struct i2c_device_id * id)214 static int t5403_probe(struct i2c_client *client,
215 const struct i2c_device_id *id)
216 {
217 struct t5403_data *data;
218 struct iio_dev *indio_dev;
219 int ret;
220
221 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
222 I2C_FUNC_SMBUS_I2C_BLOCK))
223 return -EOPNOTSUPP;
224
225 ret = i2c_smbus_read_byte_data(client, T5403_SLAVE_ADDR);
226 if (ret < 0)
227 return ret;
228 if ((ret & T5403_I2C_MASK) != T5403_I2C_ADDR)
229 return -ENODEV;
230
231 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
232 if (!indio_dev)
233 return -ENOMEM;
234
235 data = iio_priv(indio_dev);
236 data->client = client;
237 mutex_init(&data->lock);
238
239 i2c_set_clientdata(client, indio_dev);
240 indio_dev->info = &t5403_info;
241 indio_dev->name = id->name;
242 indio_dev->dev.parent = &client->dev;
243 indio_dev->modes = INDIO_DIRECT_MODE;
244 indio_dev->channels = t5403_channels;
245 indio_dev->num_channels = ARRAY_SIZE(t5403_channels);
246
247 data->mode = T5403_MODE_STANDARD;
248
249 ret = i2c_smbus_read_i2c_block_data(data->client, T5403_CALIB_DATA,
250 sizeof(data->c), (u8 *) data->c);
251 if (ret < 0)
252 return ret;
253
254 return devm_iio_device_register(&client->dev, indio_dev);
255 }
256
257 static const struct i2c_device_id t5403_id[] = {
258 { "t5403", 0 },
259 { }
260 };
261 MODULE_DEVICE_TABLE(i2c, t5403_id);
262
263 static struct i2c_driver t5403_driver = {
264 .driver = {
265 .name = "t5403",
266 },
267 .probe = t5403_probe,
268 .id_table = t5403_id,
269 };
270 module_i2c_driver(t5403_driver);
271
272 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
273 MODULE_DESCRIPTION("EPCOS T5403 pressure/temperature sensor driver");
274 MODULE_LICENSE("GPL");
275