blob: e399bf04c73ad283702e1e1432bb7bbb4f1a65d0 [file] [log] [blame]
/*
* AD7298 SPI ADC driver
*
* Copyright 2011 Analog Devices Inc.
*
* 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/regulator/consumer.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/bitops.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>
#include <linux/platform_data/ad7298.h>
#define AD7298_WRITE BIT(15) /* write to the control register */
#define AD7298_REPEAT BIT(14) /* repeated conversion enable */
#define AD7298_CH(x) BIT(13 - (x)) /* channel select */
#define AD7298_TSENSE BIT(5) /* temperature conversion enable */
#define AD7298_EXTREF BIT(2) /* external reference enable */
#define AD7298_TAVG BIT(1) /* temperature sensor averaging enable */
#define AD7298_PDD BIT(0) /* partial power down enable */
#define AD7298_MAX_CHAN 8
#define AD7298_INTREF_mV 2500
#define AD7298_CH_TEMP 9
struct ad7298_state {
struct spi_device *spi;
struct regulator *reg;
unsigned ext_ref;
struct spi_transfer ring_xfer[10];
struct spi_transfer scan_single_xfer[3];
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[12] ____cacheline_aligned;
__be16 tx_buf[2];
};
#define AD7298_V_CHAN(index) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = index, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.address = index, \
.scan_index = index, \
.scan_type = { \
.sign = 'u', \
.realbits = 12, \
.storagebits = 16, \
.endianness = IIO_BE, \
}, \
}
static const struct iio_chan_spec ad7298_channels[] = {
{
.type = IIO_TEMP,
.indexed = 1,
.channel = 0,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OFFSET),
.address = AD7298_CH_TEMP,
.scan_index = -1,
.scan_type = {
.sign = 's',
.realbits = 32,
.storagebits = 32,
},
},
AD7298_V_CHAN(0),
AD7298_V_CHAN(1),
AD7298_V_CHAN(2),
AD7298_V_CHAN(3),
AD7298_V_CHAN(4),
AD7298_V_CHAN(5),
AD7298_V_CHAN(6),
AD7298_V_CHAN(7),
IIO_CHAN_SOFT_TIMESTAMP(8),
};
/**
* ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask
**/
static int ad7298_update_scan_mode(struct iio_dev *indio_dev,
const unsigned long *active_scan_mask)
{
struct ad7298_state *st = iio_priv(indio_dev);
int i, m;
unsigned short command;
int scan_count;
/* Now compute overall size */
scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength);
command = AD7298_WRITE | st->ext_ref;
for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1)
if (test_bit(i, active_scan_mask))
command |= m;
st->tx_buf[0] = cpu_to_be16(command);
/* build spi ring message */
st->ring_xfer[0].tx_buf = &st->tx_buf[0];
st->ring_xfer[0].len = 2;
st->ring_xfer[0].cs_change = 1;
st->ring_xfer[1].tx_buf = &st->tx_buf[1];
st->ring_xfer[1].len = 2;
st->ring_xfer[1].cs_change = 1;
spi_message_init(&st->ring_msg);
spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg);
for (i = 0; i < scan_count; i++) {
st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i];
st->ring_xfer[i + 2].len = 2;
st->ring_xfer[i + 2].cs_change = 1;
spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg);
}
/* make sure last transfer cs_change is not set */
st->ring_xfer[i + 1].cs_change = 0;
return 0;
}
/**
* ad7298_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 ad7298_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ad7298_state *st = iio_priv(indio_dev);
int b_sent;
b_sent = spi_sync(st->spi, &st->ring_msg);
if (b_sent)
goto done;
iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
iio_get_time_ns(indio_dev));
done:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
{
int ret;
st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
(AD7298_CH(0) >> ch));
ret = spi_sync(st->spi, &st->scan_single_msg);
if (ret)
return ret;
return be16_to_cpu(st->rx_buf[0]);
}
static int ad7298_scan_temp(struct ad7298_state *st, int *val)
{
int ret;
__be16 buf;
buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
AD7298_TAVG | st->ext_ref);
ret = spi_write(st->spi, (u8 *)&buf, 2);
if (ret)
return ret;
buf = cpu_to_be16(0);
ret = spi_write(st->spi, (u8 *)&buf, 2);
if (ret)
return ret;
usleep_range(101, 1000); /* sleep > 100us */
ret = spi_read(st->spi, (u8 *)&buf, 2);
if (ret)
return ret;
*val = sign_extend32(be16_to_cpu(buf), 11);
return 0;
}
static int ad7298_get_ref_voltage(struct ad7298_state *st)
{
int vref;
if (st->ext_ref) {
vref = regulator_get_voltage(st->reg);
if (vref < 0)
return vref;
return vref / 1000;
} else {
return AD7298_INTREF_mV;
}
}
static int ad7298_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
int ret;
struct ad7298_state *st = iio_priv(indio_dev);
switch (m) {
case IIO_CHAN_INFO_RAW:
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
if (chan->address == AD7298_CH_TEMP)
ret = ad7298_scan_temp(st, val);
else
ret = ad7298_scan_direct(st, chan->address);
iio_device_release_direct_mode(indio_dev);
if (ret < 0)
return ret;
if (chan->address != AD7298_CH_TEMP)
*val = ret & GENMASK(chan->scan_type.realbits - 1, 0);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_VOLTAGE:
*val = ad7298_get_ref_voltage(st);
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_TEMP:
*val = ad7298_get_ref_voltage(st);
*val2 = 10;
return IIO_VAL_FRACTIONAL;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_OFFSET:
*val = 1093 - 2732500 / ad7298_get_ref_voltage(st);
return IIO_VAL_INT;
}
return -EINVAL;
}
static const struct iio_info ad7298_info = {
.read_raw = &ad7298_read_raw,
.update_scan_mode = ad7298_update_scan_mode,
.driver_module = THIS_MODULE,
};
static int ad7298_probe(struct spi_device *spi)
{
struct ad7298_platform_data *pdata = spi->dev.platform_data;
struct ad7298_state *st;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (indio_dev == NULL)
return -ENOMEM;
st = iio_priv(indio_dev);
if (pdata && pdata->ext_ref)
st->ext_ref = AD7298_EXTREF;
if (st->ext_ref) {
st->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(st->reg))
return PTR_ERR(st->reg);
ret = regulator_enable(st->reg);
if (ret)
return ret;
}
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->dev.of_node = spi->dev.of_node;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ad7298_channels;
indio_dev->num_channels = ARRAY_SIZE(ad7298_channels);
indio_dev->info = &ad7298_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].tx_buf = &st->tx_buf[1];
st->scan_single_xfer[1].len = 2;
st->scan_single_xfer[1].cs_change = 1;
st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
st->scan_single_xfer[2].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);
spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
ret = iio_triggered_buffer_setup(indio_dev, NULL,
&ad7298_trigger_handler, NULL);
if (ret)
goto error_disable_reg;
ret = iio_device_register(indio_dev);
if (ret)
goto error_cleanup_ring;
return 0;
error_cleanup_ring:
iio_triggered_buffer_cleanup(indio_dev);
error_disable_reg:
if (st->ext_ref)
regulator_disable(st->reg);
return ret;
}
static int ad7298_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ad7298_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
if (st->ext_ref)
regulator_disable(st->reg);
return 0;
}
static const struct spi_device_id ad7298_id[] = {
{"ad7298", 0},
{}
};
MODULE_DEVICE_TABLE(spi, ad7298_id);
static struct spi_driver ad7298_driver = {
.driver = {
.name = "ad7298",
},
.probe = ad7298_probe,
.remove = ad7298_remove,
.id_table = ad7298_id,
};
module_spi_driver(ad7298_driver);
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
MODULE_LICENSE("GPL v2");