summaryrefslogtreecommitdiff
path: root/drivers/iio/pressure/hp03.c
blob: 406934ea6228f4292df2d3ff06774ffa76e31cc7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
/*
 * Copyright (c) 2016 Marek Vasut <marex@denx.de>
 *
 * Driver for Hope RF HP03 digital temperature and pressure sensor.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt) "hp03: " fmt

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

/*
 * The HP03 sensor occupies two fixed I2C addresses:
 *  0x50 ... read-only EEPROM with calibration data
 *  0x77 ... read-write ADC for pressure and temperature
 */
#define HP03_EEPROM_ADDR		0x50
#define HP03_ADC_ADDR			0x77

#define HP03_EEPROM_CX_OFFSET		0x10
#define HP03_EEPROM_AB_OFFSET		0x1e
#define HP03_EEPROM_CD_OFFSET		0x20

#define HP03_ADC_WRITE_REG		0xff
#define HP03_ADC_READ_REG		0xfd
#define HP03_ADC_READ_PRESSURE		0xf0	/* D1 in datasheet */
#define HP03_ADC_READ_TEMP		0xe8	/* D2 in datasheet */

struct hp03_priv {
	struct i2c_client	*client;
	struct mutex		lock;
	struct gpio_desc	*xclr_gpio;

	struct i2c_client	*eeprom_client;
	struct regmap		*eeprom_regmap;

	s32			pressure;	/* kPa */
	s32			temp;		/* Deg. C */
};

static const struct iio_chan_spec hp03_channels[] = {
	{
		.type = IIO_PRESSURE,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
	},
	{
		.type = IIO_TEMP,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
	},
};

static bool hp03_is_writeable_reg(struct device *dev, unsigned int reg)
{
	return false;
}

static bool hp03_is_volatile_reg(struct device *dev, unsigned int reg)
{
	return false;
}

static const struct regmap_config hp03_regmap_config = {
	.reg_bits	= 8,
	.val_bits	= 8,

	.max_register	= HP03_EEPROM_CD_OFFSET + 1,
	.cache_type	= REGCACHE_RBTREE,

	.writeable_reg	= hp03_is_writeable_reg,
	.volatile_reg	= hp03_is_volatile_reg,
};

static int hp03_get_temp_pressure(struct hp03_priv *priv, const u8 reg)
{
	int ret;

	ret = i2c_smbus_write_byte_data(priv->client, HP03_ADC_WRITE_REG, reg);
	if (ret < 0)
		return ret;

	msleep(50);	/* Wait for conversion to finish */

	return i2c_smbus_read_word_data(priv->client, HP03_ADC_READ_REG);
}

static int hp03_update_temp_pressure(struct hp03_priv *priv)
{
	struct device *dev = &priv->client->dev;
	u8 coefs[18];
	u16 cx_val[7];
	int ab_val, d1_val, d2_val, diff_val, dut, off, sens, x;
	int i, ret;

	/* Sample coefficients from EEPROM */
	ret = regmap_bulk_read(priv->eeprom_regmap, HP03_EEPROM_CX_OFFSET,
			       coefs, sizeof(coefs));
	if (ret < 0) {
		dev_err(dev, "Failed to read EEPROM (reg=%02x)\n",
			HP03_EEPROM_CX_OFFSET);
		return ret;
	}

	/* Sample Temperature and Pressure */
	gpiod_set_value_cansleep(priv->xclr_gpio, 1);

	ret = hp03_get_temp_pressure(priv, HP03_ADC_READ_PRESSURE);
	if (ret < 0) {
		dev_err(dev, "Failed to read pressure\n");
		goto err_adc;
	}
	d1_val = ret;

	ret = hp03_get_temp_pressure(priv, HP03_ADC_READ_TEMP);
	if (ret < 0) {
		dev_err(dev, "Failed to read temperature\n");
		goto err_adc;
	}
	d2_val = ret;

	gpiod_set_value_cansleep(priv->xclr_gpio, 0);

	/* The Cx coefficients and Temp/Pressure values are MSB first. */
	for (i = 0; i < 7; i++)
		cx_val[i] = (coefs[2 * i] << 8) | (coefs[(2 * i) + 1] << 0);
	d1_val = ((d1_val >> 8) & 0xff) | ((d1_val & 0xff) << 8);
	d2_val = ((d2_val >> 8) & 0xff) | ((d2_val & 0xff) << 8);

	/* Coefficient voodoo from the HP03 datasheet. */
	if (d2_val >= cx_val[4])
		ab_val = coefs[14];	/* A-value */
	else
		ab_val = coefs[15];	/* B-value */

	diff_val = d2_val - cx_val[4];
	dut = (ab_val * (diff_val >> 7) * (diff_val >> 7)) >> coefs[16];
	dut = diff_val - dut;

	off = (cx_val[1] + (((cx_val[3] - 1024) * dut) >> 14)) * 4;
	sens = cx_val[0] + ((cx_val[2] * dut) >> 10);
	x = ((sens * (d1_val - 7168)) >> 14) - off;

	priv->pressure = ((x * 100) >> 5) + (cx_val[6] * 10);
	priv->temp = 250 + ((dut * cx_val[5]) >> 16) - (dut >> coefs[17]);

	return 0;

err_adc:
	gpiod_set_value_cansleep(priv->xclr_gpio, 0);
	return ret;
}

static int hp03_read_raw(struct iio_dev *indio_dev,
			 struct iio_chan_spec const *chan,
			 int *val, int *val2, long mask)
{
	struct hp03_priv *priv = iio_priv(indio_dev);
	int ret;

	mutex_lock(&priv->lock);
	ret = hp03_update_temp_pressure(priv);
	mutex_unlock(&priv->lock);

	if (ret)
		return ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		switch (chan->type) {
		case IIO_PRESSURE:
			*val = priv->pressure;
			return IIO_VAL_INT;
		case IIO_TEMP:
			*val = priv->temp;
			return IIO_VAL_INT;
		default:
			return -EINVAL;
		}
		break;
	case IIO_CHAN_INFO_SCALE:
		switch (chan->type) {
		case IIO_PRESSURE:
			*val = 0;
			*val2 = 1000;
			return IIO_VAL_INT_PLUS_MICRO;
		case IIO_TEMP:
			*val = 10;
			return IIO_VAL_INT;
		default:
			return -EINVAL;
		}
		break;
	default:
		return -EINVAL;
	}

	return -EINVAL;
}

static const struct iio_info hp03_info = {
	.read_raw	= &hp03_read_raw,
};

static int hp03_probe(struct i2c_client *client,
		      const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct iio_dev *indio_dev;
	struct hp03_priv *priv;
	int ret;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
	if (!indio_dev)
		return -ENOMEM;

	priv = iio_priv(indio_dev);
	priv->client = client;
	mutex_init(&priv->lock);

	indio_dev->dev.parent = dev;
	indio_dev->name = id->name;
	indio_dev->channels = hp03_channels;
	indio_dev->num_channels = ARRAY_SIZE(hp03_channels);
	indio_dev->info = &hp03_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	priv->xclr_gpio = devm_gpiod_get_index(dev, "xclr", 0, GPIOD_OUT_HIGH);
	if (IS_ERR(priv->xclr_gpio)) {
		dev_err(dev, "Failed to claim XCLR GPIO\n");
		ret = PTR_ERR(priv->xclr_gpio);
		return ret;
	}

	/*
	 * Allocate another device for the on-sensor EEPROM,
	 * which has it's dedicated I2C address and contains
	 * the calibration constants for the sensor.
	 */
	priv->eeprom_client = i2c_new_dummy(client->adapter, HP03_EEPROM_ADDR);
	if (!priv->eeprom_client) {
		dev_err(dev, "New EEPROM I2C device failed\n");
		return -ENODEV;
	}

	priv->eeprom_regmap = regmap_init_i2c(priv->eeprom_client,
					      &hp03_regmap_config);
	if (IS_ERR(priv->eeprom_regmap)) {
		dev_err(dev, "Failed to allocate EEPROM regmap\n");
		ret = PTR_ERR(priv->eeprom_regmap);
		goto err_cleanup_eeprom_client;
	}

	ret = iio_device_register(indio_dev);
	if (ret) {
		dev_err(dev, "Failed to register IIO device\n");
		goto err_cleanup_eeprom_regmap;
	}

	i2c_set_clientdata(client, indio_dev);

	return 0;

err_cleanup_eeprom_regmap:
	regmap_exit(priv->eeprom_regmap);

err_cleanup_eeprom_client:
	i2c_unregister_device(priv->eeprom_client);
	return ret;
}

static int hp03_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct hp03_priv *priv = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	regmap_exit(priv->eeprom_regmap);
	i2c_unregister_device(priv->eeprom_client);

	return 0;
}

static const struct i2c_device_id hp03_id[] = {
	{ "hp03", 0 },
	{ },
};
MODULE_DEVICE_TABLE(i2c, hp03_id);

static const struct of_device_id hp03_of_match[] = {
	{ .compatible = "hoperf,hp03" },
	{ },
};
MODULE_DEVICE_TABLE(of, hp03_of_match);

static struct i2c_driver hp03_driver = {
	.driver = {
		.name	= "hp03",
		.of_match_table = hp03_of_match,
	},
	.probe		= hp03_probe,
	.remove		= hp03_remove,
	.id_table	= hp03_id,
};
module_i2c_driver(hp03_driver);

MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_DESCRIPTION("Driver for Hope RF HP03 pressure and temperature sensor");
MODULE_LICENSE("GPL v2");