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IIO ADC support for AD7923

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This patch adds support for Analog Devices AD7923 ADC in the IIO Subsystem.

Signed-off-by: Patrick Vasseur <patrick.vasseur@c-s.fr>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Christophe Leroy 2013-02-13 06:47:00 +00:00 committed by Jonathan Cameron
parent 17d82b47a2
commit 0eac259db2
3 changed files with 311 additions and 0 deletions
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12
drivers/iio/adc/Kconfig
View File

@ -30,6 +30,18 @@ config AD7298
To compile this driver as a module, choose M here: the
module will be called ad7298.
config AD7923
tristate "Analog Devices AD7923 ADC driver"
depends on SPI
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
help
Say yes here to build support for Analog Devices AD7923
4 Channel ADC with temperature sensor.
To compile this driver as a module, choose M here: the
module will be called ad7923.
config AD7791
tristate "Analog Devices AD7791 ADC driver"
depends on SPI

1
drivers/iio/adc/Makefile
View File

@ -5,6 +5,7 @@
obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
obj-$(CONFIG_AD7266) += ad7266.o
obj-$(CONFIG_AD7298) += ad7298.o
obj-$(CONFIG_AD7923) += ad7923.o
obj-$(CONFIG_AD7476) += ad7476.o
obj-$(CONFIG_AD7791) += ad7791.o
obj-$(CONFIG_AD7793) += ad7793.o

298
drivers/iio/adc/ad7923.c Normal file
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@ -0,0 +1,298 @@
/*
* AD7923 SPI ADC driver
*
* Copyright 2011 Analog Devices Inc (from AD7923 Driver)
* Copyright 2012 CS Systemes d'Information
*
* Licensed under the GPL-2.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#define AD7923_WRITE_CR (1 << 11) /* write control register */
#define AD7923_RANGE (1 << 1) /* range to REFin */
#define AD7923_CODING (1 << 0) /* coding is straight binary */
#define AD7923_PM_MODE_AS (1) /* auto shutdown */
#define AD7923_PM_MODE_FS (2) /* full shutdown */
#define AD7923_PM_MODE_OPS (3) /* normal operation */
#define AD7923_CHANNEL_0 (0) /* analog input 0 */
#define AD7923_CHANNEL_1 (1) /* analog input 1 */
#define AD7923_CHANNEL_2 (2) /* analog input 2 */
#define AD7923_CHANNEL_3 (3) /* analog input 3 */
#define AD7923_SEQUENCE_OFF (0) /* no sequence fonction */
#define AD7923_SEQUENCE_PROTECT (2) /* no interrupt write cycle */
#define AD7923_SEQUENCE_ON (3) /* continuous sequence */
#define AD7923_MAX_CHAN 4
#define AD7923_PM_MODE_WRITE(mode) (mode << 4) /* write mode */
#define AD7923_CHANNEL_WRITE(channel) (channel << 6) /* write channel */
#define AD7923_SEQUENCE_WRITE(sequence) (((sequence & 1) << 3) \
+ ((sequence & 2) << 9))
/* write sequence fonction */
/* left shift for CR : bit 11 transmit in first */
#define AD7923_SHIFT_REGISTER 4
/* val = value, dec = left shift, bits = number of bits of the mask */
#define EXTRACT(val, dec, bits) ((val >> dec) & ((1 << bits) - 1))
struct ad7923_state {
struct spi_device *spi;
struct spi_transfer ring_xfer[5];
struct spi_transfer scan_single_xfer[2];
struct spi_message ring_msg;
struct spi_message scan_single_msg;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
*/
__be16 rx_buf[4] ____cacheline_aligned;
__be16 tx_buf[4];
};
#define AD7923_V_CHAN(index) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = index, \
.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
IIO_CHAN_INFO_SCALE_SHARED_BIT, \
.address = index, \
.scan_index = index, \
.scan_type = { \
.sign = 'u', \
.realbits = 12, \
.storagebits = 16, \
.endianness = IIO_BE, \
}, \
}
static const struct iio_chan_spec ad7923_channels[] = {
AD7923_V_CHAN(0),
AD7923_V_CHAN(1),
AD7923_V_CHAN(2),
AD7923_V_CHAN(3),
IIO_CHAN_SOFT_TIMESTAMP(4),
};
/**
* ad7923_update_scan_mode() setup the spi transfer buffer for the new scan mask
**/
static int ad7923_update_scan_mode(struct iio_dev *indio_dev,
const unsigned long *active_scan_mask)
{
struct ad7923_state *st = iio_priv(indio_dev);
int i, cmd, len;
len = 0;
for_each_set_bit(i, active_scan_mask, AD7923_MAX_CHAN) {
cmd = AD7923_WRITE_CR | AD7923_CODING | AD7923_RANGE |
AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS) |
AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
AD7923_CHANNEL_WRITE(i);
cmd <<= AD7923_SHIFT_REGISTER;
st->tx_buf[len++] = cpu_to_be16(cmd);
}
/* build spi ring message */
st->ring_xfer[0].tx_buf = &st->tx_buf[0];
st->ring_xfer[0].len = len;
st->ring_xfer[0].cs_change = 1;
spi_message_init(&st->ring_msg);
spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
for (i = 0; i < len; i++) {
st->ring_xfer[i + 1].rx_buf = &st->rx_buf[i];
st->ring_xfer[i + 1].len = 2;
st->ring_xfer[i + 1].cs_change = 1;
spi_message_add_tail(&st->ring_xfer[i + 1], &st->ring_msg);
}
/* make sure last transfer cs_change is not set */
st->ring_xfer[i + 1].cs_change = 0;
return 0;
}
/**
* ad7923_trigger_handler() bh of trigger launched polling to ring buffer
*
* Currently there is no option in this driver to disable the saving of
* timestamps within the ring.
**/
static irqreturn_t ad7923_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ad7923_state *st = iio_priv(indio_dev);
s64 time_ns = 0;
int b_sent;
b_sent = spi_sync(st->spi, &st->ring_msg);
if (b_sent)
goto done;
if (indio_dev->scan_timestamp) {
time_ns = iio_get_time_ns();
memcpy((u8 *)st->rx_buf + indio_dev->scan_bytes - sizeof(s64),
&time_ns, sizeof(time_ns));
}
iio_push_to_buffers(indio_dev, (u8 *)st->rx_buf);
done:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int ad7923_scan_direct(struct ad7923_state *st, unsigned ch)
{
int ret, cmd;
cmd = AD7923_WRITE_CR | AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS) |
AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) | AD7923_CODING |
AD7923_CHANNEL_WRITE(ch) | AD7923_RANGE;
cmd <<= AD7923_SHIFT_REGISTER;
st->tx_buf[0] = cpu_to_be16(cmd);
ret = spi_sync(st->spi, &st->scan_single_msg);
if (ret)
return ret;
return be16_to_cpu(st->rx_buf[0]);
}
static int ad7923_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
int ret;
struct ad7923_state *st = iio_priv(indio_dev);
switch (m) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&indio_dev->mlock);
if (iio_buffer_enabled(indio_dev))
ret = -EBUSY;
else
ret = ad7923_scan_direct(st, chan->address);
mutex_unlock(&indio_dev->mlock);
if (ret < 0)
return ret;
if (chan->address == EXTRACT(ret, 12, 4))
*val = EXTRACT(ret, 0, 12);
return IIO_VAL_INT;
}
return -EINVAL;
}
static const struct iio_info ad7923_info = {
.read_raw = &ad7923_read_raw,
.update_scan_mode = ad7923_update_scan_mode,
.driver_module = THIS_MODULE,
};
static int ad7923_probe(struct spi_device *spi)
{
struct ad7923_state *st;
struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st));
int ret;
if (indio_dev == NULL)
return -ENOMEM;
st = iio_priv(indio_dev);
spi_set_drvdata(spi, indio_dev);
st->spi = spi;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ad7923_channels;
indio_dev->num_channels = ARRAY_SIZE(ad7923_channels);
indio_dev->info = &ad7923_info;
/* Setup default message */
st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
st->scan_single_xfer[0].len = 2;
st->scan_single_xfer[0].cs_change = 1;
st->scan_single_xfer[1].rx_buf = &st->rx_buf[0];
st->scan_single_xfer[1].len = 2;
spi_message_init(&st->scan_single_msg);
spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
ret = iio_triggered_buffer_setup(indio_dev, NULL,
&ad7923_trigger_handler, NULL);
if (ret)
goto error_free;
ret = iio_device_register(indio_dev);
if (ret)
goto error_cleanup_ring;
return 0;
error_cleanup_ring:
iio_triggered_buffer_cleanup(indio_dev);
error_free:
iio_device_free(indio_dev);
return ret;
}
static int ad7923_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
iio_device_free(indio_dev);
return 0;
}
static const struct spi_device_id ad7923_id[] = {
{"ad7923", 0},
{}
};
MODULE_DEVICE_TABLE(spi, ad7923_id);
static struct spi_driver ad7923_driver = {
.driver = {
.name = "ad7923",
.owner = THIS_MODULE,
},
.probe = ad7923_probe,
.remove = ad7923_remove,
.id_table = ad7923_id,
};
module_spi_driver(ad7923_driver);
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>");
MODULE_DESCRIPTION("Analog Devices AD7923 ADC");
MODULE_LICENSE("GPL v2");