aboutsummaryrefslogtreecommitdiff
path: root/drivers/hwmon/max1111.c
blob: b4eb0889c465a95edd815b64e5d6666d53b8eeac (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
/*
 * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs
 *
 * Based on arch/arm/mach-pxa/corgi_ssp.c
 *
 * Copyright (C) 2004-2005 Richard Purdie
 *
 * Copyright (C) 2008 Marvell International Ltd.
 *	Eric Miao <eric.miao@marvell.com>
 *
 *  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
 *  publishhed by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>

enum chips { max1110, max1111, max1112, max1113 };

#define MAX1111_TX_BUF_SIZE	1
#define MAX1111_RX_BUF_SIZE	2

/* MAX1111 Commands */
#define MAX1111_CTRL_PD0      (1u << 0)
#define MAX1111_CTRL_PD1      (1u << 1)
#define MAX1111_CTRL_SGL      (1u << 2)
#define MAX1111_CTRL_UNI      (1u << 3)
#define MAX1110_CTRL_SEL_SH   (4)
#define MAX1111_CTRL_SEL_SH   (5)	/* NOTE: bit 4 is ignored */
#define MAX1111_CTRL_STR      (1u << 7)

struct max1111_data {
	struct spi_device	*spi;
	struct device		*hwmon_dev;
	struct spi_message	msg;
	struct spi_transfer	xfer[2];
	uint8_t tx_buf[MAX1111_TX_BUF_SIZE];
	uint8_t rx_buf[MAX1111_RX_BUF_SIZE];
	struct mutex		drvdata_lock;
	/* protect msg, xfer and buffers from multiple access */
	int			sel_sh;
	int			lsb;
};

static int max1111_read(struct device *dev, int channel)
{
	struct max1111_data *data = dev_get_drvdata(dev);
	uint8_t v1, v2;
	int err;

	/* writing to drvdata struct is not thread safe, wait on mutex */
	mutex_lock(&data->drvdata_lock);

	data->tx_buf[0] = (channel << data->sel_sh) |
		MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
		MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;

	err = spi_sync(data->spi, &data->msg);
	if (err < 0) {
		dev_err(dev, "spi_sync failed with %d\n", err);
		mutex_unlock(&data->drvdata_lock);
		return err;
	}

	v1 = data->rx_buf[0];
	v2 = data->rx_buf[1];

	mutex_unlock(&data->drvdata_lock);

	if ((v1 & 0xc0) || (v2 & 0x3f))
		return -EINVAL;

	return (v1 << 2) | (v2 >> 6);
}

#ifdef CONFIG_SHARPSL_PM
static struct max1111_data *the_max1111;

int max1111_read_channel(int channel)
{
	return max1111_read(&the_max1111->spi->dev, channel);
}
EXPORT_SYMBOL(max1111_read_channel);
#endif

/*
 * NOTE: SPI devices do not have a default 'name' attribute, which is
 * likely to be used by hwmon applications to distinguish between
 * different devices, explicitly add a name attribute here.
 */
static ssize_t show_name(struct device *dev,
			 struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
}

static ssize_t show_adc(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct max1111_data *data = dev_get_drvdata(dev);
	int channel = to_sensor_dev_attr(attr)->index;
	int ret;

	ret = max1111_read(dev, channel);
	if (ret < 0)
		return ret;

	/*
	 * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit
	 * sample. The LSB weight is 8mV or 16mV depending on the chip type.
	 */
	return sprintf(buf, "%d\n", ret * data->lsb);
}

#define MAX1111_ADC_ATTR(_id)		\
	SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id)

static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
static MAX1111_ADC_ATTR(0);
static MAX1111_ADC_ATTR(1);
static MAX1111_ADC_ATTR(2);
static MAX1111_ADC_ATTR(3);
static MAX1111_ADC_ATTR(4);
static MAX1111_ADC_ATTR(5);
static MAX1111_ADC_ATTR(6);
static MAX1111_ADC_ATTR(7);

static struct attribute *max1111_attributes[] = {
	&dev_attr_name.attr,
	&sensor_dev_attr_in0_input.dev_attr.attr,
	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_in2_input.dev_attr.attr,
	&sensor_dev_attr_in3_input.dev_attr.attr,
	NULL,
};

static const struct attribute_group max1111_attr_group = {
	.attrs	= max1111_attributes,
};

static struct attribute *max1110_attributes[] = {
	&sensor_dev_attr_in4_input.dev_attr.attr,
	&sensor_dev_attr_in5_input.dev_attr.attr,
	&sensor_dev_attr_in6_input.dev_attr.attr,
	&sensor_dev_attr_in7_input.dev_attr.attr,
	NULL,
};

static const struct attribute_group max1110_attr_group = {
	.attrs	= max1110_attributes,
};

static int __devinit setup_transfer(struct max1111_data *data)
{
	struct spi_message *m;
	struct spi_transfer *x;

	m = &data->msg;
	x = &data->xfer[0];

	spi_message_init(m);

	x->tx_buf = &data->tx_buf[0];
	x->len = MAX1111_TX_BUF_SIZE;
	spi_message_add_tail(x, m);

	x++;
	x->rx_buf = &data->rx_buf[0];
	x->len = MAX1111_RX_BUF_SIZE;
	spi_message_add_tail(x, m);

	return 0;
}

static int __devinit max1111_probe(struct spi_device *spi)
{
	enum chips chip = spi_get_device_id(spi)->driver_data;
	struct max1111_data *data;
	int err;

	spi->bits_per_word = 8;
	spi->mode = SPI_MODE_0;
	err = spi_setup(spi);
	if (err < 0)
		return err;

	data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL);
	if (data == NULL) {
		dev_err(&spi->dev, "failed to allocate memory\n");
		return -ENOMEM;
	}

	switch (chip) {
	case max1110:
		data->lsb = 8;
		data->sel_sh = MAX1110_CTRL_SEL_SH;
		break;
	case max1111:
		data->lsb = 8;
		data->sel_sh = MAX1111_CTRL_SEL_SH;
		break;
	case max1112:
		data->lsb = 16;
		data->sel_sh = MAX1110_CTRL_SEL_SH;
		break;
	case max1113:
		data->lsb = 16;
		data->sel_sh = MAX1111_CTRL_SEL_SH;
		break;
	}
	err = setup_transfer(data);
	if (err)
		return err;

	mutex_init(&data->drvdata_lock);

	data->spi = spi;
	spi_set_drvdata(spi, data);

	err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
	if (err) {
		dev_err(&spi->dev, "failed to create attribute group\n");
		return err;
	}
	if (chip == max1110 || chip == max1112) {
		err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group);
		if (err) {
			dev_err(&spi->dev,
				"failed to create extended attribute group\n");
			goto err_remove;
		}
	}

	data->hwmon_dev = hwmon_device_register(&spi->dev);
	if (IS_ERR(data->hwmon_dev)) {
		dev_err(&spi->dev, "failed to create hwmon device\n");
		err = PTR_ERR(data->hwmon_dev);
		goto err_remove;
	}

#ifdef CONFIG_SHARPSL_PM
	the_max1111 = data;
#endif
	return 0;

err_remove:
	sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
	sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
	return err;
}

static int __devexit max1111_remove(struct spi_device *spi)
{
	struct max1111_data *data = spi_get_drvdata(spi);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
	sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
	mutex_destroy(&data->drvdata_lock);
	return 0;
}

static const struct spi_device_id max1111_ids[] = {
	{ "max1110", max1110 },
	{ "max1111", max1111 },
	{ "max1112", max1112 },
	{ "max1113", max1113 },
	{ },
};
MODULE_DEVICE_TABLE(spi, max1111_ids);

static struct spi_driver max1111_driver = {
	.driver		= {
		.name	= "max1111",
		.owner	= THIS_MODULE,
	},
	.id_table	= max1111_ids,
	.probe		= max1111_probe,
	.remove		= __devexit_p(max1111_remove),
};

module_spi_driver(max1111_driver);

MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver");
MODULE_LICENSE("GPL");