2 * ad2s120x.c simple support for the ADI Resolver to Digital Converters: AD2S1200/1205
4 * Copyright (c) 2010-2010 Analog Devices Inc.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/types.h>
12 #include <linux/mutex.h>
13 #include <linux/device.h>
14 #include <linux/spi/spi.h>
15 #include <linux/slab.h>
16 #include <linux/sysfs.h>
17 #include <linux/delay.h>
18 #include <linux/gpio.h>
23 #define DRV_NAME "ad2s120x"
25 /* input pin sample and rdvel is controlled by driver */
28 /* input clock on serial interface */
29 #define AD2S120X_HZ 8192000
30 /* clock period in nano second */
31 #define AD2S120X_TSCLK (1000000000/AD2S120X_HZ)
33 struct ad2s120x_state {
36 struct spi_device *sdev;
37 unsigned short sample;
43 static ssize_t ad2s120x_show_pos_vel(struct device *dev,
44 struct device_attribute *attr, char *buf)
46 struct spi_message msg;
47 struct spi_transfer xfer;
53 struct iio_dev *idev = dev_get_drvdata(dev);
54 struct ad2s120x_state *st = idev->dev_data;
59 mutex_lock(&st->lock);
61 gpio_set_value(st->sample, 0);
62 /* delay (6 * AD2S120X_TSCLK + 20) nano seconds */
64 gpio_set_value(st->sample, 1);
66 spi_message_init(&msg);
67 spi_message_add_tail(&xfer, &msg);
68 ret = spi_sync(st->sdev, &msg);
72 pos = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
73 len = sprintf(buf, "%d %c%c%c%c ", pos,
74 (status & 0x8) ? 'P' : 'V',
75 (status & 0x4) ? 'd' : '_',
76 (status & 0x2) ? 'l' : '_',
77 (status & 0x1) ? '1' : '0');
82 gpio_set_value(st->rdvel, 0);
85 spi_message_init(&msg);
86 spi_message_add_tail(&xfer, &msg);
87 ret = spi_sync(st->sdev, &msg);
91 vel = (st->rx[0] & 0x80) ? 0xf000 : 0;
92 vel |= (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
93 len += sprintf(buf + len, "%d %c%c%c%c\n", vel,
94 (status & 0x8) ? 'P' : 'V',
95 (status & 0x4) ? 'd' : '_',
96 (status & 0x2) ? 'l' : '_',
97 (status & 0x1) ? '1' : '0');
99 gpio_set_value(st->rdvel, 1);
100 /* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */
102 mutex_unlock(&st->lock);
104 return ret ? ret : len;
107 static ssize_t ad2s120x_show_pos(struct device *dev,
108 struct device_attribute *attr, char *buf)
110 struct spi_message msg;
111 struct spi_transfer xfer;
116 struct iio_dev *idev = dev_get_drvdata(dev);
117 struct ad2s120x_state *st = idev->dev_data;
120 xfer.tx_buf = st->tx;
121 xfer.rx_buf = st->rx;
122 mutex_lock(&st->lock);
124 gpio_set_value(st->sample, 0);
125 /* delay (6 * AD2S120X_TSCLK + 20) nano seconds */
127 gpio_set_value(st->sample, 1);
128 gpio_set_value(st->rdvel, 1);
130 spi_message_init(&msg);
131 spi_message_add_tail(&xfer, &msg);
132 ret = spi_sync(st->sdev, &msg);
136 pos = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
137 len = sprintf(buf, "%d %c%c%c%c ", pos,
138 (status & 0x8) ? 'P' : 'V',
139 (status & 0x4) ? 'd' : '_',
140 (status & 0x2) ? 'l' : '_',
141 (status & 0x1) ? '1' : '0');
143 /* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */
145 mutex_unlock(&st->lock);
147 return ret ? ret : len;
150 static ssize_t ad2s120x_show_vel(struct device *dev,
151 struct device_attribute *attr, char *buf)
153 struct spi_message msg;
154 struct spi_transfer xfer;
159 struct iio_dev *idev = dev_get_drvdata(dev);
160 struct ad2s120x_state *st = idev->dev_data;
163 xfer.tx_buf = st->tx;
164 xfer.rx_buf = st->rx;
165 mutex_lock(&st->lock);
167 gpio_set_value(st->sample, 0);
168 /* delay (6 * AD2S120X_TSCLK + 20) nano seconds */
170 gpio_set_value(st->sample, 1);
172 gpio_set_value(st->rdvel, 0);
175 spi_message_init(&msg);
176 spi_message_add_tail(&xfer, &msg);
177 ret = spi_sync(st->sdev, &msg);
181 vel = (st->rx[0] & 0x80) ? 0xf000 : 0;
182 vel |= (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
183 len += sprintf(buf + len, "%d %c%c%c%c\n", vel,
184 (status & 0x8) ? 'P' : 'V',
185 (status & 0x4) ? 'd' : '_',
186 (status & 0x2) ? 'l' : '_',
187 (status & 0x1) ? '1' : '0');
189 gpio_set_value(st->rdvel, 1);
190 /* delay (2 * AD2S120X_TSCLK + 20) ns for sample pulse */
192 mutex_unlock(&st->lock);
194 return ret ? ret : len;
197 static IIO_CONST_ATTR(description,
198 "12-Bit R/D Converter with Reference Oscillator");
199 static IIO_DEVICE_ATTR(pos_vel, S_IRUGO, ad2s120x_show_pos_vel, NULL, 0);
200 static IIO_DEVICE_ATTR(pos, S_IRUGO, ad2s120x_show_pos, NULL, 0);
201 static IIO_DEVICE_ATTR(vel, S_IRUGO, ad2s120x_show_vel, NULL, 0);
203 static struct attribute *ad2s120x_attributes[] = {
204 &iio_const_attr_description.dev_attr.attr,
205 &iio_dev_attr_pos_vel.dev_attr.attr,
206 &iio_dev_attr_pos.dev_attr.attr,
207 &iio_dev_attr_vel.dev_attr.attr,
211 static const struct attribute_group ad2s120x_attribute_group = {
213 .attrs = ad2s120x_attributes,
216 static int __devinit ad2s120x_probe(struct spi_device *spi)
218 struct ad2s120x_state *st;
220 unsigned short *pins = spi->dev.platform_data;
222 for (pn = 0; pn < AD2S120X_PN; pn++) {
223 if (gpio_request(pins[pn], DRV_NAME)) {
224 pr_err("%s: request gpio pin %d failed\n",
228 gpio_direction_output(pins[pn], 1);
231 st = kzalloc(sizeof(*st), GFP_KERNEL);
236 spi_set_drvdata(spi, st);
238 mutex_init(&st->lock);
240 st->sample = pins[0];
243 st->idev = iio_allocate_device();
244 if (st->idev == NULL) {
248 st->idev->dev.parent = &spi->dev;
249 st->idev->num_interrupt_lines = 0;
250 st->idev->event_attrs = NULL;
252 st->idev->attrs = &ad2s120x_attribute_group;
253 st->idev->dev_data = (void *)(st);
254 st->idev->driver_module = THIS_MODULE;
255 st->idev->modes = INDIO_DIRECT_MODE;
257 ret = iio_device_register(st->idev);
261 spi->max_speed_hz = AD2S120X_HZ;
262 spi->mode = SPI_MODE_3;
268 iio_free_device(st->idev);
272 for (--pn; pn >= 0; pn--)
277 static int __devexit ad2s120x_remove(struct spi_device *spi)
279 struct ad2s120x_state *st = spi_get_drvdata(spi);
281 iio_device_unregister(st->idev);
287 static struct spi_driver ad2s120x_driver = {
290 .owner = THIS_MODULE,
292 .probe = ad2s120x_probe,
293 .remove = __devexit_p(ad2s120x_remove),
296 static __init int ad2s120x_spi_init(void)
298 return spi_register_driver(&ad2s120x_driver);
300 module_init(ad2s120x_spi_init);
302 static __exit void ad2s120x_spi_exit(void)
304 spi_unregister_driver(&ad2s120x_driver);
306 module_exit(ad2s120x_spi_exit);
308 MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
309 MODULE_DESCRIPTION("Analog Devices AD2S1200/1205 Resolver to Digital SPI driver");
310 MODULE_LICENSE("GPL v2");