2 * AD7298 SPI ADC driver
4 * Copyright 2011 Analog Devices Inc.
6 * Licensed under the GPL-2.
9 #include <linux/device.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/sysfs.h>
13 #include <linux/spi/spi.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/err.h>
16 #include <linux/delay.h>
17 #include <linux/module.h>
18 #include <linux/interrupt.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/buffer.h>
23 #include <linux/iio/trigger_consumer.h>
24 #include <linux/iio/triggered_buffer.h>
26 #include <linux/platform_data/ad7298.h>
28 #define AD7298_WRITE (1 << 15) /* write to the control register */
29 #define AD7298_REPEAT (1 << 14) /* repeated conversion enable */
30 #define AD7298_CH(x) (1 << (13 - (x))) /* channel select */
31 #define AD7298_TSENSE (1 << 5) /* temperature conversion enable */
32 #define AD7298_EXTREF (1 << 2) /* external reference enable */
33 #define AD7298_TAVG (1 << 1) /* temperature sensor averaging enable */
34 #define AD7298_PDD (1 << 0) /* partial power down enable */
36 #define AD7298_MAX_CHAN 8
37 #define AD7298_BITS 12
38 #define AD7298_STORAGE_BITS 16
39 #define AD7298_INTREF_mV 2500
41 #define AD7298_CH_TEMP 9
43 #define RES_MASK(bits) ((1 << (bits)) - 1)
46 struct spi_device
*spi
;
47 struct regulator
*reg
;
49 struct spi_transfer ring_xfer
[10];
50 struct spi_transfer scan_single_xfer
[3];
51 struct spi_message ring_msg
;
52 struct spi_message scan_single_msg
;
54 * DMA (thus cache coherency maintenance) requires the
55 * transfer buffers to live in their own cache lines.
57 __be16 rx_buf
[12] ____cacheline_aligned
;
61 #define AD7298_V_CHAN(index) \
63 .type = IIO_VOLTAGE, \
66 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
67 IIO_CHAN_INFO_SCALE_SHARED_BIT, \
69 .scan_index = index, \
74 .endianness = IIO_BE, \
78 static const struct iio_chan_spec ad7298_channels
[] = {
83 .info_mask
= IIO_CHAN_INFO_RAW_SEPARATE_BIT
|
84 IIO_CHAN_INFO_SCALE_SEPARATE_BIT
|
85 IIO_CHAN_INFO_OFFSET_SEPARATE_BIT
,
86 .address
= AD7298_CH_TEMP
,
102 IIO_CHAN_SOFT_TIMESTAMP(8),
106 * ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask
108 static int ad7298_update_scan_mode(struct iio_dev
*indio_dev
,
109 const unsigned long *active_scan_mask
)
111 struct ad7298_state
*st
= iio_priv(indio_dev
);
113 unsigned short command
;
116 /* Now compute overall size */
117 scan_count
= bitmap_weight(active_scan_mask
, indio_dev
->masklength
);
119 command
= AD7298_WRITE
| st
->ext_ref
;
121 for (i
= 0, m
= AD7298_CH(0); i
< AD7298_MAX_CHAN
; i
++, m
>>= 1)
122 if (test_bit(i
, active_scan_mask
))
125 st
->tx_buf
[0] = cpu_to_be16(command
);
127 /* build spi ring message */
128 st
->ring_xfer
[0].tx_buf
= &st
->tx_buf
[0];
129 st
->ring_xfer
[0].len
= 2;
130 st
->ring_xfer
[0].cs_change
= 1;
131 st
->ring_xfer
[1].tx_buf
= &st
->tx_buf
[1];
132 st
->ring_xfer
[1].len
= 2;
133 st
->ring_xfer
[1].cs_change
= 1;
135 spi_message_init(&st
->ring_msg
);
136 spi_message_add_tail(&st
->ring_xfer
[0], &st
->ring_msg
);
137 spi_message_add_tail(&st
->ring_xfer
[1], &st
->ring_msg
);
139 for (i
= 0; i
< scan_count
; i
++) {
140 st
->ring_xfer
[i
+ 2].rx_buf
= &st
->rx_buf
[i
];
141 st
->ring_xfer
[i
+ 2].len
= 2;
142 st
->ring_xfer
[i
+ 2].cs_change
= 1;
143 spi_message_add_tail(&st
->ring_xfer
[i
+ 2], &st
->ring_msg
);
145 /* make sure last transfer cs_change is not set */
146 st
->ring_xfer
[i
+ 1].cs_change
= 0;
152 * ad7298_trigger_handler() bh of trigger launched polling to ring buffer
154 * Currently there is no option in this driver to disable the saving of
155 * timestamps within the ring.
157 static irqreturn_t
ad7298_trigger_handler(int irq
, void *p
)
159 struct iio_poll_func
*pf
= p
;
160 struct iio_dev
*indio_dev
= pf
->indio_dev
;
161 struct ad7298_state
*st
= iio_priv(indio_dev
);
165 b_sent
= spi_sync(st
->spi
, &st
->ring_msg
);
169 if (indio_dev
->scan_timestamp
) {
170 time_ns
= iio_get_time_ns();
171 memcpy((u8
*)st
->rx_buf
+ indio_dev
->scan_bytes
- sizeof(s64
),
172 &time_ns
, sizeof(time_ns
));
175 iio_push_to_buffers(indio_dev
, (u8
*)st
->rx_buf
);
178 iio_trigger_notify_done(indio_dev
->trig
);
183 static int ad7298_scan_direct(struct ad7298_state
*st
, unsigned ch
)
186 st
->tx_buf
[0] = cpu_to_be16(AD7298_WRITE
| st
->ext_ref
|
187 (AD7298_CH(0) >> ch
));
189 ret
= spi_sync(st
->spi
, &st
->scan_single_msg
);
193 return be16_to_cpu(st
->rx_buf
[0]);
196 static int ad7298_scan_temp(struct ad7298_state
*st
, int *val
)
201 buf
= cpu_to_be16(AD7298_WRITE
| AD7298_TSENSE
|
202 AD7298_TAVG
| st
->ext_ref
);
204 ret
= spi_write(st
->spi
, (u8
*)&buf
, 2);
208 buf
= cpu_to_be16(0);
210 ret
= spi_write(st
->spi
, (u8
*)&buf
, 2);
214 usleep_range(101, 1000); /* sleep > 100us */
216 ret
= spi_read(st
->spi
, (u8
*)&buf
, 2);
220 *val
= sign_extend32(be16_to_cpu(buf
), 11);
225 static int ad7298_get_ref_voltage(struct ad7298_state
*st
)
230 vref
= regulator_get_voltage(st
->reg
);
236 return AD7298_INTREF_mV
;
240 static int ad7298_read_raw(struct iio_dev
*indio_dev
,
241 struct iio_chan_spec
const *chan
,
247 struct ad7298_state
*st
= iio_priv(indio_dev
);
250 case IIO_CHAN_INFO_RAW
:
251 mutex_lock(&indio_dev
->mlock
);
252 if (indio_dev
->currentmode
== INDIO_BUFFER_TRIGGERED
) {
255 if (chan
->address
== AD7298_CH_TEMP
)
256 ret
= ad7298_scan_temp(st
, val
);
258 ret
= ad7298_scan_direct(st
, chan
->address
);
260 mutex_unlock(&indio_dev
->mlock
);
265 if (chan
->address
!= AD7298_CH_TEMP
)
266 *val
= ret
& RES_MASK(AD7298_BITS
);
269 case IIO_CHAN_INFO_SCALE
:
270 switch (chan
->type
) {
272 *val
= ad7298_get_ref_voltage(st
);
273 *val2
= chan
->scan_type
.realbits
;
274 return IIO_VAL_FRACTIONAL_LOG2
;
276 *val
= ad7298_get_ref_voltage(st
);
278 return IIO_VAL_FRACTIONAL
;
282 case IIO_CHAN_INFO_OFFSET
:
283 *val
= 1093 - 2732500 / ad7298_get_ref_voltage(st
);
289 static const struct iio_info ad7298_info
= {
290 .read_raw
= &ad7298_read_raw
,
291 .update_scan_mode
= ad7298_update_scan_mode
,
292 .driver_module
= THIS_MODULE
,
295 static int ad7298_probe(struct spi_device
*spi
)
297 struct ad7298_platform_data
*pdata
= spi
->dev
.platform_data
;
298 struct ad7298_state
*st
;
299 struct iio_dev
*indio_dev
= iio_device_alloc(sizeof(*st
));
302 if (indio_dev
== NULL
)
305 st
= iio_priv(indio_dev
);
307 if (pdata
&& pdata
->ext_ref
)
308 st
->ext_ref
= AD7298_EXTREF
;
311 st
->reg
= regulator_get(&spi
->dev
, "vref");
312 if (IS_ERR(st
->reg
)) {
313 ret
= PTR_ERR(st
->reg
);
316 ret
= regulator_enable(st
->reg
);
321 spi_set_drvdata(spi
, indio_dev
);
325 indio_dev
->name
= spi_get_device_id(spi
)->name
;
326 indio_dev
->dev
.parent
= &spi
->dev
;
327 indio_dev
->modes
= INDIO_DIRECT_MODE
;
328 indio_dev
->channels
= ad7298_channels
;
329 indio_dev
->num_channels
= ARRAY_SIZE(ad7298_channels
);
330 indio_dev
->info
= &ad7298_info
;
332 /* Setup default message */
334 st
->scan_single_xfer
[0].tx_buf
= &st
->tx_buf
[0];
335 st
->scan_single_xfer
[0].len
= 2;
336 st
->scan_single_xfer
[0].cs_change
= 1;
337 st
->scan_single_xfer
[1].tx_buf
= &st
->tx_buf
[1];
338 st
->scan_single_xfer
[1].len
= 2;
339 st
->scan_single_xfer
[1].cs_change
= 1;
340 st
->scan_single_xfer
[2].rx_buf
= &st
->rx_buf
[0];
341 st
->scan_single_xfer
[2].len
= 2;
343 spi_message_init(&st
->scan_single_msg
);
344 spi_message_add_tail(&st
->scan_single_xfer
[0], &st
->scan_single_msg
);
345 spi_message_add_tail(&st
->scan_single_xfer
[1], &st
->scan_single_msg
);
346 spi_message_add_tail(&st
->scan_single_xfer
[2], &st
->scan_single_msg
);
348 ret
= iio_triggered_buffer_setup(indio_dev
, NULL
,
349 &ad7298_trigger_handler
, NULL
);
351 goto error_disable_reg
;
353 ret
= iio_device_register(indio_dev
);
355 goto error_cleanup_ring
;
360 iio_triggered_buffer_cleanup(indio_dev
);
363 regulator_disable(st
->reg
);
366 regulator_put(st
->reg
);
368 iio_device_free(indio_dev
);
373 static int ad7298_remove(struct spi_device
*spi
)
375 struct iio_dev
*indio_dev
= spi_get_drvdata(spi
);
376 struct ad7298_state
*st
= iio_priv(indio_dev
);
378 iio_device_unregister(indio_dev
);
379 iio_triggered_buffer_cleanup(indio_dev
);
381 regulator_disable(st
->reg
);
382 regulator_put(st
->reg
);
384 iio_device_free(indio_dev
);
389 static const struct spi_device_id ad7298_id
[] = {
393 MODULE_DEVICE_TABLE(spi
, ad7298_id
);
395 static struct spi_driver ad7298_driver
= {
398 .owner
= THIS_MODULE
,
400 .probe
= ad7298_probe
,
401 .remove
= ad7298_remove
,
402 .id_table
= ad7298_id
,
404 module_spi_driver(ad7298_driver
);
406 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
407 MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
408 MODULE_LICENSE("GPL v2");