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11#include <linux/module.h>
12#include <linux/spi/spi.h>
13#include <linux/acpi.h>
14
15#include <linux/iio/sysfs.h>
16#include <linux/iio/iio.h>
17
18#define MAX5487_WRITE_WIPER_A (0x01 << 8)
19#define MAX5487_WRITE_WIPER_B (0x02 << 8)
20
21
22#define MAX5487_COPY_AB_TO_NV (0x23 << 8)
23
24#define MAX5487_COPY_NV_TO_AB (0x33 << 8)
25
26#define MAX5487_MAX_POS 255
27
28struct max5487_data {
29 struct spi_device *spi;
30 int kohms;
31};
32
33#define MAX5487_CHANNEL(ch, addr) { \
34 .type = IIO_RESISTANCE, \
35 .indexed = 1, \
36 .output = 1, \
37 .channel = ch, \
38 .address = addr, \
39 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
40 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
41}
42
43static const struct iio_chan_spec max5487_channels[] = {
44 MAX5487_CHANNEL(0, MAX5487_WRITE_WIPER_A),
45 MAX5487_CHANNEL(1, MAX5487_WRITE_WIPER_B),
46};
47
48static int max5487_write_cmd(struct spi_device *spi, u16 cmd)
49{
50 return spi_write(spi, (const void *) &cmd, sizeof(u16));
51}
52
53static int max5487_read_raw(struct iio_dev *indio_dev,
54 struct iio_chan_spec const *chan,
55 int *val, int *val2, long mask)
56{
57 struct max5487_data *data = iio_priv(indio_dev);
58
59 if (mask != IIO_CHAN_INFO_SCALE)
60 return -EINVAL;
61
62 *val = 1000 * data->kohms;
63 *val2 = MAX5487_MAX_POS;
64
65 return IIO_VAL_FRACTIONAL;
66}
67
68static int max5487_write_raw(struct iio_dev *indio_dev,
69 struct iio_chan_spec const *chan,
70 int val, int val2, long mask)
71{
72 struct max5487_data *data = iio_priv(indio_dev);
73
74 if (mask != IIO_CHAN_INFO_RAW)
75 return -EINVAL;
76
77 if (val < 0 || val > MAX5487_MAX_POS)
78 return -EINVAL;
79
80 return max5487_write_cmd(data->spi, chan->address | val);
81}
82
83static const struct iio_info max5487_info = {
84 .read_raw = max5487_read_raw,
85 .write_raw = max5487_write_raw,
86};
87
88static int max5487_spi_probe(struct spi_device *spi)
89{
90 struct iio_dev *indio_dev;
91 struct max5487_data *data;
92 const struct spi_device_id *id = spi_get_device_id(spi);
93 int ret;
94
95 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
96 if (!indio_dev)
97 return -ENOMEM;
98
99 dev_set_drvdata(&spi->dev, indio_dev);
100 data = iio_priv(indio_dev);
101
102 data->spi = spi;
103 data->kohms = id->driver_data;
104
105 indio_dev->info = &max5487_info;
106 indio_dev->name = id->name;
107 indio_dev->dev.parent = &spi->dev;
108 indio_dev->modes = INDIO_DIRECT_MODE;
109 indio_dev->channels = max5487_channels;
110 indio_dev->num_channels = ARRAY_SIZE(max5487_channels);
111
112
113 ret = max5487_write_cmd(data->spi, MAX5487_COPY_NV_TO_AB);
114 if (ret < 0)
115 return ret;
116
117 return iio_device_register(indio_dev);
118}
119
120static int max5487_spi_remove(struct spi_device *spi)
121{
122 struct iio_dev *indio_dev = dev_get_drvdata(&spi->dev);
123
124 iio_device_unregister(indio_dev);
125
126
127 return max5487_write_cmd(spi, MAX5487_COPY_AB_TO_NV);
128}
129
130static const struct spi_device_id max5487_id[] = {
131 { "MAX5487", 10 },
132 { "MAX5488", 50 },
133 { "MAX5489", 100 },
134 { }
135};
136MODULE_DEVICE_TABLE(spi, max5487_id);
137
138static const struct acpi_device_id max5487_acpi_match[] = {
139 { "MAX5487", 10 },
140 { "MAX5488", 50 },
141 { "MAX5489", 100 },
142 { },
143};
144MODULE_DEVICE_TABLE(acpi, max5487_acpi_match);
145
146static struct spi_driver max5487_driver = {
147 .driver = {
148 .name = "max5487",
149 .acpi_match_table = ACPI_PTR(max5487_acpi_match),
150 },
151 .id_table = max5487_id,
152 .probe = max5487_spi_probe,
153 .remove = max5487_spi_remove
154};
155module_spi_driver(max5487_driver);
156
157MODULE_AUTHOR("Cristina-Gabriela Moraru <cristina.moraru09@gmail.com>");
158MODULE_DESCRIPTION("max5487 SPI driver");
159MODULE_LICENSE("GPL v2");
160
