diff options
Diffstat (limited to 'drivers/iio/adc/ad7887.c')
| -rw-r--r-- | drivers/iio/adc/ad7887.c | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7887.c b/drivers/iio/adc/ad7887.c new file mode 100644 index 000000000..965bdc8aa --- /dev/null +++ b/drivers/iio/adc/ad7887.c @@ -0,0 +1,348 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AD7887 SPI ADC driver + * + * Copyright 2010-2011 Analog Devices Inc. + */ + +#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/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/ad7887.h> + +#define AD7887_REF_DIS BIT(5) /* on-chip reference disable */ +#define AD7887_DUAL BIT(4) /* dual-channel mode */ +#define AD7887_CH_AIN1 BIT(3) /* convert on channel 1, DUAL=1 */ +#define AD7887_CH_AIN0 0 /* convert on channel 0, DUAL=0,1 */ +#define AD7887_PM_MODE1 0 /* CS based shutdown */ +#define AD7887_PM_MODE2 1 /* full on */ +#define AD7887_PM_MODE3 2 /* auto shutdown after conversion */ +#define AD7887_PM_MODE4 3 /* standby mode */ + +enum ad7887_channels { + AD7887_CH0, + AD7887_CH0_CH1, + AD7887_CH1, +}; + +/** + * struct ad7887_chip_info - chip specifc information + * @int_vref_mv: the internal reference voltage + * @channels: channels specification + * @num_channels: number of channels + * @dual_channels: channels specification in dual mode + * @num_dual_channels: number of channels in dual mode + */ +struct ad7887_chip_info { + u16 int_vref_mv; + const struct iio_chan_spec *channels; + unsigned int num_channels; + const struct iio_chan_spec *dual_channels; + unsigned int num_dual_channels; +}; + +struct ad7887_state { + struct spi_device *spi; + const struct ad7887_chip_info *chip_info; + struct regulator *reg; + struct spi_transfer xfer[4]; + struct spi_message msg[3]; + struct spi_message *ring_msg; + unsigned char tx_cmd_buf[4]; + + /* + * DMA (thus cache coherency maintenance) may require the + * transfer buffers to live in their own cache lines. + * Buffer needs to be large enough to hold two 16 bit samples and a + * 64 bit aligned 64 bit timestamp. + */ + unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)] __aligned(IIO_DMA_MINALIGN); +}; + +enum ad7887_supported_device_ids { + ID_AD7887 +}; + +static int ad7887_ring_preenable(struct iio_dev *indio_dev) +{ + struct ad7887_state *st = iio_priv(indio_dev); + + /* We know this is a single long so can 'cheat' */ + switch (*indio_dev->active_scan_mask) { + case (1 << 0): + st->ring_msg = &st->msg[AD7887_CH0]; + break; + case (1 << 1): + st->ring_msg = &st->msg[AD7887_CH1]; + /* Dummy read: push CH1 setting down to hardware */ + spi_sync(st->spi, st->ring_msg); + break; + case ((1 << 1) | (1 << 0)): + st->ring_msg = &st->msg[AD7887_CH0_CH1]; + break; + } + + return 0; +} + +static int ad7887_ring_postdisable(struct iio_dev *indio_dev) +{ + struct ad7887_state *st = iio_priv(indio_dev); + + /* dummy read: restore default CH0 settin */ + return spi_sync(st->spi, &st->msg[AD7887_CH0]); +} + +static irqreturn_t ad7887_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct ad7887_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->data, + iio_get_time_ns(indio_dev)); +done: + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = { + .preenable = &ad7887_ring_preenable, + .postdisable = &ad7887_ring_postdisable, +}; + +static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch) +{ + int ret = spi_sync(st->spi, &st->msg[ch]); + if (ret) + return ret; + + return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1]; +} + +static int ad7887_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long m) +{ + int ret; + struct ad7887_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; + ret = ad7887_scan_direct(st, chan->address); + iio_device_release_direct_mode(indio_dev); + + if (ret < 0) + return ret; + *val = ret >> chan->scan_type.shift; + *val &= GENMASK(chan->scan_type.realbits - 1, 0); + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + if (st->reg) { + *val = regulator_get_voltage(st->reg); + if (*val < 0) + return *val; + *val /= 1000; + } else { + *val = st->chip_info->int_vref_mv; + } + + *val2 = chan->scan_type.realbits; + + return IIO_VAL_FRACTIONAL_LOG2; + } + return -EINVAL; +} + +#define AD7887_CHANNEL(x) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (x), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .address = (x), \ + .scan_index = (x), \ + .scan_type = { \ + .sign = 'u', \ + .realbits = 12, \ + .storagebits = 16, \ + .shift = 0, \ + .endianness = IIO_BE, \ + }, \ +} + +static const struct iio_chan_spec ad7887_channels[] = { + AD7887_CHANNEL(0), + IIO_CHAN_SOFT_TIMESTAMP(1), +}; + +static const struct iio_chan_spec ad7887_dual_channels[] = { + AD7887_CHANNEL(0), + AD7887_CHANNEL(1), + IIO_CHAN_SOFT_TIMESTAMP(2), +}; + +static const struct ad7887_chip_info ad7887_chip_info_tbl[] = { + /* + * More devices added in future + */ + [ID_AD7887] = { + .channels = ad7887_channels, + .num_channels = ARRAY_SIZE(ad7887_channels), + .dual_channels = ad7887_dual_channels, + .num_dual_channels = ARRAY_SIZE(ad7887_dual_channels), + .int_vref_mv = 2500, + }, +}; + +static const struct iio_info ad7887_info = { + .read_raw = &ad7887_read_raw, +}; + +static void ad7887_reg_disable(void *data) +{ + struct regulator *reg = data; + + regulator_disable(reg); +} + +static int ad7887_probe(struct spi_device *spi) +{ + struct ad7887_platform_data *pdata = spi->dev.platform_data; + struct ad7887_state *st; + struct iio_dev *indio_dev; + uint8_t mode; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); + if (indio_dev == NULL) + return -ENOMEM; + + st = iio_priv(indio_dev); + + st->reg = devm_regulator_get_optional(&spi->dev, "vref"); + if (IS_ERR(st->reg)) { + if (PTR_ERR(st->reg) != -ENODEV) + return PTR_ERR(st->reg); + + st->reg = NULL; + } + + if (st->reg) { + ret = regulator_enable(st->reg); + if (ret) + return ret; + + ret = devm_add_action_or_reset(&spi->dev, ad7887_reg_disable, st->reg); + if (ret) + return ret; + } + + st->chip_info = + &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data]; + + st->spi = spi; + + indio_dev->name = spi_get_device_id(spi)->name; + indio_dev->info = &ad7887_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + /* Setup default message */ + + mode = AD7887_PM_MODE4; + if (!st->reg) + mode |= AD7887_REF_DIS; + if (pdata && pdata->en_dual) + mode |= AD7887_DUAL; + + st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode; + + st->xfer[0].rx_buf = &st->data[0]; + st->xfer[0].tx_buf = &st->tx_cmd_buf[0]; + st->xfer[0].len = 2; + + spi_message_init(&st->msg[AD7887_CH0]); + spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]); + + if (pdata && pdata->en_dual) { + st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode; + + st->xfer[1].rx_buf = &st->data[0]; + st->xfer[1].tx_buf = &st->tx_cmd_buf[2]; + st->xfer[1].len = 2; + + st->xfer[2].rx_buf = &st->data[2]; + st->xfer[2].tx_buf = &st->tx_cmd_buf[0]; + st->xfer[2].len = 2; + + spi_message_init(&st->msg[AD7887_CH0_CH1]); + spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]); + spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]); + + st->xfer[3].rx_buf = &st->data[2]; + st->xfer[3].tx_buf = &st->tx_cmd_buf[2]; + st->xfer[3].len = 2; + + spi_message_init(&st->msg[AD7887_CH1]); + spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]); + + indio_dev->channels = st->chip_info->dual_channels; + indio_dev->num_channels = st->chip_info->num_dual_channels; + } else { + indio_dev->channels = st->chip_info->channels; + indio_dev->num_channels = st->chip_info->num_channels; + } + + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, + &iio_pollfunc_store_time, + &ad7887_trigger_handler, &ad7887_ring_setup_ops); + if (ret) + return ret; + + return devm_iio_device_register(&spi->dev, indio_dev); +} + +static const struct spi_device_id ad7887_id[] = { + {"ad7887", ID_AD7887}, + {} +}; +MODULE_DEVICE_TABLE(spi, ad7887_id); + +static struct spi_driver ad7887_driver = { + .driver = { + .name = "ad7887", + }, + .probe = ad7887_probe, + .id_table = ad7887_id, +}; +module_spi_driver(ad7887_driver); + +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); +MODULE_DESCRIPTION("Analog Devices AD7887 ADC"); +MODULE_LICENSE("GPL v2"); |