2 * ad2s1200.c simple support for the ADI Resolver to Digital Converters:
5 * Copyright (c) 2010-2010 Analog Devices Inc.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/types.h>
13 #include <linux/mutex.h>
14 #include <linux/device.h>
15 #include <linux/spi/spi.h>
16 #include <linux/slab.h>
17 #include <linux/sysfs.h>
18 #include <linux/delay.h>
19 #include <linux/gpio.h>
20 #include <linux/module.h>
22 #include <linux/iio/iio.h>
23 #include <linux/iio/sysfs.h>
25 #define DRV_NAME "ad2s1200"
27 /* input pin sample and rdvel is controlled by driver */
30 /* input clock on serial interface */
31 #define AD2S1200_HZ 8192000
32 /* clock period in nano second */
33 #define AD2S1200_TSCLK (1000000000/AD2S1200_HZ)
35 struct ad2s1200_state {
37 struct spi_device *sdev;
40 u8 rx[2] ____cacheline_aligned;
43 static int ad2s1200_read_raw(struct iio_dev *indio_dev,
44 struct iio_chan_spec const *chan,
51 struct ad2s1200_state *st = iio_priv(indio_dev);
53 mutex_lock(&st->lock);
54 gpio_set_value(st->sample, 0);
55 /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */
57 gpio_set_value(st->sample, 1);
58 gpio_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
59 ret = spi_read(st->sdev, st->rx, 2);
61 mutex_unlock(&st->lock);
67 *val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
70 vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
71 vel = (vel << 4) >> 4;
75 mutex_unlock(&st->lock);
78 /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */
80 mutex_unlock(&st->lock);
84 static const struct iio_chan_spec ad2s1200_channels[] = {
89 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
94 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
98 static const struct iio_info ad2s1200_info = {
99 .read_raw = &ad2s1200_read_raw,
100 .driver_module = THIS_MODULE,
103 static int ad2s1200_probe(struct spi_device *spi)
105 struct ad2s1200_state *st;
106 struct iio_dev *indio_dev;
108 unsigned short *pins = spi->dev.platform_data;
110 for (pn = 0; pn < AD2S1200_PN; pn++)
111 ret = devm_gpio_request_one(&spi->dev, pins[pn], GPIOF_DIR_OUT,
114 dev_err(&spi->dev, "request gpio pin %d failed\n",
118 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
121 spi_set_drvdata(spi, indio_dev);
122 st = iio_priv(indio_dev);
123 mutex_init(&st->lock);
125 st->sample = pins[0];
128 indio_dev->dev.parent = &spi->dev;
129 indio_dev->info = &ad2s1200_info;
130 indio_dev->modes = INDIO_DIRECT_MODE;
131 indio_dev->channels = ad2s1200_channels;
132 indio_dev->num_channels = ARRAY_SIZE(ad2s1200_channels);
133 indio_dev->name = spi_get_device_id(spi)->name;
135 ret = devm_iio_device_register(&spi->dev, indio_dev);
139 spi->max_speed_hz = AD2S1200_HZ;
140 spi->mode = SPI_MODE_3;
146 static const struct spi_device_id ad2s1200_id[] = {
151 MODULE_DEVICE_TABLE(spi, ad2s1200_id);
153 static struct spi_driver ad2s1200_driver = {
156 .owner = THIS_MODULE,
158 .probe = ad2s1200_probe,
159 .id_table = ad2s1200_id,
161 module_spi_driver(ad2s1200_driver);
163 MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
164 MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver");
165 MODULE_LICENSE("GPL v2");