diff options
Diffstat (limited to 'drivers/iio/adc/ad7923.c')
| -rw-r--r-- | drivers/iio/adc/ad7923.c | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7923.c b/drivers/iio/adc/ad7923.c new file mode 100644 index 0000000..28b2bda --- /dev/null +++ b/drivers/iio/adc/ad7923.c @@ -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"); |