diff options
Diffstat (limited to 'drivers/iio/adc/ad7887.c')
| -rw-r--r-- | drivers/iio/adc/ad7887.c | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7887.c b/drivers/iio/adc/ad7887.c new file mode 100644 index 00000000000..81153fafac7 --- /dev/null +++ b/drivers/iio/adc/ad7887.c @@ -0,0 +1,378 @@ +/* + * AD7887 SPI ADC driver + * + * Copyright 2010-2011 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/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> + +#include <linux/platform_data/ad7887.h> + +#define AD7887_REF_DIS (1 << 5) /* on-chip reference disable */ +#define AD7887_DUAL (1 << 4) /* dual-channel mode */ +#define AD7887_CH_AIN1 (1 << 3) /* convert on channel 1, DUAL=1 */ +#define AD7887_CH_AIN0 (0 << 3) /* 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, +}; + +#define RES_MASK(bits) ((1 << (bits)) - 1) + +/** + * struct ad7887_chip_info - chip specifc information + * @int_vref_mv: the internal reference voltage + * @channel: channel specification + */ +struct ad7887_chip_info { + u16 int_vref_mv; + struct iio_chan_spec channel[3]; +}; + +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) requires 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)] + ____cacheline_aligned; +}; + +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); + int ret; + + ret = iio_sw_buffer_preenable(indio_dev); + if (ret < 0) + return ret; + + /* 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]); +} + +/** + * ad7887_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 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); + s64 time_ns; + int b_sent; + + b_sent = spi_sync(st->spi, st->ring_msg); + if (b_sent) + goto done; + + time_ns = iio_get_time_ns(); + + if (indio_dev->scan_timestamp) + memcpy(st->data + indio_dev->scan_bytes - sizeof(s64), + &time_ns, sizeof(time_ns)); + + iio_push_to_buffers(indio_dev, st->data); +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, + .postenable = &iio_triggered_buffer_postenable, + .predisable = &iio_triggered_buffer_predisable, + .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: + mutex_lock(&indio_dev->mlock); + if (iio_buffer_enabled(indio_dev)) + ret = -EBUSY; + else + ret = ad7887_scan_direct(st, chan->address); + mutex_unlock(&indio_dev->mlock); + + if (ret < 0) + return ret; + *val = ret >> chan->scan_type.shift; + *val &= RES_MASK(chan->scan_type.realbits); + 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; +} + + +static const struct ad7887_chip_info ad7887_chip_info_tbl[] = { + /* + * More devices added in future + */ + [ID_AD7887] = { + .channel[0] = { + .type = IIO_VOLTAGE, + .indexed = 1, + .channel = 1, + .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | + IIO_CHAN_INFO_SCALE_SHARED_BIT, + .address = 1, + .scan_index = 1, + .scan_type = IIO_ST('u', 12, 16, 0), + }, + .channel[1] = { + .type = IIO_VOLTAGE, + .indexed = 1, + .channel = 0, + .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | + IIO_CHAN_INFO_SCALE_SHARED_BIT, + .address = 0, + .scan_index = 0, + .scan_type = IIO_ST('u', 12, 16, 0), + }, + .channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2), + .int_vref_mv = 2500, + }, +}; + +static const struct iio_info ad7887_info = { + .read_raw = &ad7887_read_raw, + .driver_module = THIS_MODULE, +}; + +static int __devinit ad7887_probe(struct spi_device *spi) +{ + struct ad7887_platform_data *pdata = spi->dev.platform_data; + struct ad7887_state *st; + struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st)); + uint8_t mode; + int ret; + + if (indio_dev == NULL) + return -ENOMEM; + + st = iio_priv(indio_dev); + + if (!pdata || !pdata->use_onchip_ref) { + st->reg = regulator_get(&spi->dev, "vref"); + if (IS_ERR(st->reg)) { + ret = PTR_ERR(st->reg); + goto error_free; + } + + ret = regulator_enable(st->reg); + if (ret) + goto error_put_reg; + } + + st->chip_info = + &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data]; + + spi_set_drvdata(spi, indio_dev); + st->spi = spi; + + /* Estabilish that the iio_dev is a child of the spi device */ + indio_dev->dev.parent = &spi->dev; + 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 (!pdata || !pdata->use_onchip_ref) + 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->channel; + indio_dev->num_channels = 3; + } else { + indio_dev->channels = &st->chip_info->channel[1]; + indio_dev->num_channels = 2; + } + + ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, + &ad7887_trigger_handler, &ad7887_ring_setup_ops); + if (ret) + goto error_disable_reg; + + ret = iio_device_register(indio_dev); + if (ret) + goto error_unregister_ring; + + return 0; +error_unregister_ring: + iio_triggered_buffer_cleanup(indio_dev); +error_disable_reg: + if (st->reg) + regulator_disable(st->reg); +error_put_reg: + if (st->reg) + regulator_put(st->reg); +error_free: + iio_device_free(indio_dev); + + return ret; +} + +static int __devexit ad7887_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + struct ad7887_state *st = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + iio_triggered_buffer_cleanup(indio_dev); + if (st->reg) { + regulator_disable(st->reg); + regulator_put(st->reg); + } + iio_device_free(indio_dev); + + return 0; +} + +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", + .owner = THIS_MODULE, + }, + .probe = ad7887_probe, + .remove = __devexit_p(ad7887_remove), + .id_table = ad7887_id, +}; +module_spi_driver(ad7887_driver); + +MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); +MODULE_DESCRIPTION("Analog Devices AD7887 ADC"); +MODULE_LICENSE("GPL v2"); |