diff options
Diffstat (limited to 'kernel/drivers/iio/adc/ad7266.c')
| -rw-r--r-- | kernel/drivers/iio/adc/ad7266.c | 522 |
1 files changed, 522 insertions, 0 deletions
diff --git a/kernel/drivers/iio/adc/ad7266.c b/kernel/drivers/iio/adc/ad7266.c new file mode 100644 index 000000000..70f78c306 --- /dev/null +++ b/kernel/drivers/iio/adc/ad7266.c @@ -0,0 +1,522 @@ +/* + * AD7266/65 SPI ADC driver + * + * Copyright 2012 Analog Devices Inc. + * + * Licensed under the GPL-2. + */ + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> +#include <linux/regulator/consumer.h> +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/module.h> + +#include <linux/interrupt.h> + +#include <linux/iio/iio.h> +#include <linux/iio/buffer.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> + +#include <linux/platform_data/ad7266.h> + +struct ad7266_state { + struct spi_device *spi; + struct regulator *reg; + unsigned long vref_mv; + + struct spi_transfer single_xfer[3]; + struct spi_message single_msg; + + enum ad7266_range range; + enum ad7266_mode mode; + bool fixed_addr; + struct gpio gpios[3]; + + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + * The buffer needs to be large enough to hold two samples (4 bytes) and + * the naturally aligned timestamp (8 bytes). + */ + struct { + __be16 sample[2]; + s64 timestamp; + } data ____cacheline_aligned; +}; + +static int ad7266_wakeup(struct ad7266_state *st) +{ + /* Any read with >= 2 bytes will wake the device */ + return spi_read(st->spi, &st->data.sample[0], 2); +} + +static int ad7266_powerdown(struct ad7266_state *st) +{ + /* Any read with < 2 bytes will powerdown the device */ + return spi_read(st->spi, &st->data.sample[0], 1); +} + +static int ad7266_preenable(struct iio_dev *indio_dev) +{ + struct ad7266_state *st = iio_priv(indio_dev); + return ad7266_wakeup(st); +} + +static int ad7266_postdisable(struct iio_dev *indio_dev) +{ + struct ad7266_state *st = iio_priv(indio_dev); + return ad7266_powerdown(st); +} + +static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = { + .preenable = &ad7266_preenable, + .postenable = &iio_triggered_buffer_postenable, + .predisable = &iio_triggered_buffer_predisable, + .postdisable = &ad7266_postdisable, +}; + +static irqreturn_t ad7266_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct ad7266_state *st = iio_priv(indio_dev); + int ret; + + ret = spi_read(st->spi, st->data.sample, 4); + if (ret == 0) { + iio_push_to_buffers_with_timestamp(indio_dev, &st->data, + pf->timestamp); + } + + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static void ad7266_select_input(struct ad7266_state *st, unsigned int nr) +{ + unsigned int i; + + if (st->fixed_addr) + return; + + switch (st->mode) { + case AD7266_MODE_SINGLE_ENDED: + nr >>= 1; + break; + case AD7266_MODE_PSEUDO_DIFF: + nr |= 1; + break; + case AD7266_MODE_DIFF: + nr &= ~1; + break; + } + + for (i = 0; i < 3; ++i) + gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i))); +} + +static int ad7266_update_scan_mode(struct iio_dev *indio_dev, + const unsigned long *scan_mask) +{ + struct ad7266_state *st = iio_priv(indio_dev); + unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength); + + ad7266_select_input(st, nr); + + return 0; +} + +static int ad7266_read_single(struct ad7266_state *st, int *val, + unsigned int address) +{ + int ret; + + ad7266_select_input(st, address); + + ret = spi_sync(st->spi, &st->single_msg); + *val = be16_to_cpu(st->data.sample[address % 2]); + + return ret; +} + +static int ad7266_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, int *val2, long m) +{ + struct ad7266_state *st = iio_priv(indio_dev); + unsigned long scale_mv; + int ret; + + switch (m) { + case IIO_CHAN_INFO_RAW: + if (iio_buffer_enabled(indio_dev)) + return -EBUSY; + + ret = ad7266_read_single(st, val, chan->address); + if (ret) + return ret; + + *val = (*val >> 2) & 0xfff; + if (chan->scan_type.sign == 's') + *val = sign_extend32(*val, 11); + + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + scale_mv = st->vref_mv; + if (st->mode == AD7266_MODE_DIFF) + scale_mv *= 2; + if (st->range == AD7266_RANGE_2VREF) + scale_mv *= 2; + + *val = scale_mv; + *val2 = chan->scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; + case IIO_CHAN_INFO_OFFSET: + if (st->range == AD7266_RANGE_2VREF && + st->mode != AD7266_MODE_DIFF) + *val = 2048; + else + *val = 0; + return IIO_VAL_INT; + } + return -EINVAL; +} + +#define AD7266_CHAN(_chan, _sign) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (_chan), \ + .address = (_chan), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ + | BIT(IIO_CHAN_INFO_OFFSET), \ + .scan_index = (_chan), \ + .scan_type = { \ + .sign = (_sign), \ + .realbits = 12, \ + .storagebits = 16, \ + .shift = 2, \ + .endianness = IIO_BE, \ + }, \ +} + +#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \ +const struct iio_chan_spec ad7266_channels_##_name[] = { \ + AD7266_CHAN(0, (_sign)), \ + AD7266_CHAN(1, (_sign)), \ + AD7266_CHAN(2, (_sign)), \ + AD7266_CHAN(3, (_sign)), \ + AD7266_CHAN(4, (_sign)), \ + AD7266_CHAN(5, (_sign)), \ + AD7266_CHAN(6, (_sign)), \ + AD7266_CHAN(7, (_sign)), \ + AD7266_CHAN(8, (_sign)), \ + AD7266_CHAN(9, (_sign)), \ + AD7266_CHAN(10, (_sign)), \ + AD7266_CHAN(11, (_sign)), \ + IIO_CHAN_SOFT_TIMESTAMP(13), \ +} + +#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \ +const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \ + AD7266_CHAN(0, (_sign)), \ + AD7266_CHAN(1, (_sign)), \ + IIO_CHAN_SOFT_TIMESTAMP(2), \ +} + +static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u'); +static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's'); +static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u'); +static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's'); + +#define AD7266_CHAN_DIFF(_chan, _sign) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (_chan) * 2, \ + .channel2 = (_chan) * 2 + 1, \ + .address = (_chan), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ + | BIT(IIO_CHAN_INFO_OFFSET), \ + .scan_index = (_chan), \ + .scan_type = { \ + .sign = _sign, \ + .realbits = 12, \ + .storagebits = 16, \ + .shift = 2, \ + .endianness = IIO_BE, \ + }, \ + .differential = 1, \ +} + +#define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \ +const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \ + AD7266_CHAN_DIFF(0, (_sign)), \ + AD7266_CHAN_DIFF(1, (_sign)), \ + AD7266_CHAN_DIFF(2, (_sign)), \ + AD7266_CHAN_DIFF(3, (_sign)), \ + AD7266_CHAN_DIFF(4, (_sign)), \ + AD7266_CHAN_DIFF(5, (_sign)), \ + IIO_CHAN_SOFT_TIMESTAMP(6), \ +} + +static AD7266_DECLARE_DIFF_CHANNELS(s, 's'); +static AD7266_DECLARE_DIFF_CHANNELS(u, 'u'); + +#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \ +const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \ + AD7266_CHAN_DIFF(0, (_sign)), \ + AD7266_CHAN_DIFF(1, (_sign)), \ + IIO_CHAN_SOFT_TIMESTAMP(2), \ +} + +static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's'); +static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u'); + +static const struct iio_info ad7266_info = { + .read_raw = &ad7266_read_raw, + .update_scan_mode = &ad7266_update_scan_mode, + .driver_module = THIS_MODULE, +}; + +static const unsigned long ad7266_available_scan_masks[] = { + 0x003, + 0x00c, + 0x030, + 0x0c0, + 0x300, + 0xc00, + 0x000, +}; + +static const unsigned long ad7266_available_scan_masks_diff[] = { + 0x003, + 0x00c, + 0x030, + 0x000, +}; + +static const unsigned long ad7266_available_scan_masks_fixed[] = { + 0x003, + 0x000, +}; + +struct ad7266_chan_info { + const struct iio_chan_spec *channels; + unsigned int num_channels; + const unsigned long *scan_masks; +}; + +#define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \ + (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0)) + +static const struct ad7266_chan_info ad7266_chan_infos[] = { + [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = { + .channels = ad7266_channels_u, + .num_channels = ARRAY_SIZE(ad7266_channels_u), + .scan_masks = ad7266_available_scan_masks, + }, + [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = { + .channels = ad7266_channels_u_fixed, + .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed), + .scan_masks = ad7266_available_scan_masks_fixed, + }, + [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = { + .channels = ad7266_channels_s, + .num_channels = ARRAY_SIZE(ad7266_channels_s), + .scan_masks = ad7266_available_scan_masks, + }, + [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = { + .channels = ad7266_channels_s_fixed, + .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed), + .scan_masks = ad7266_available_scan_masks_fixed, + }, + [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = { + .channels = ad7266_channels_diff_u, + .num_channels = ARRAY_SIZE(ad7266_channels_diff_u), + .scan_masks = ad7266_available_scan_masks_diff, + }, + [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = { + .channels = ad7266_channels_diff_fixed_u, + .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u), + .scan_masks = ad7266_available_scan_masks_fixed, + }, + [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = { + .channels = ad7266_channels_diff_s, + .num_channels = ARRAY_SIZE(ad7266_channels_diff_s), + .scan_masks = ad7266_available_scan_masks_diff, + }, + [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = { + .channels = ad7266_channels_diff_fixed_s, + .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s), + .scan_masks = ad7266_available_scan_masks_fixed, + }, +}; + +static void ad7266_init_channels(struct iio_dev *indio_dev) +{ + struct ad7266_state *st = iio_priv(indio_dev); + bool is_differential, is_signed; + const struct ad7266_chan_info *chan_info; + int i; + + is_differential = st->mode != AD7266_MODE_SINGLE_ENDED; + is_signed = (st->range == AD7266_RANGE_2VREF) | + (st->mode == AD7266_MODE_DIFF); + + i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr); + chan_info = &ad7266_chan_infos[i]; + + indio_dev->channels = chan_info->channels; + indio_dev->num_channels = chan_info->num_channels; + indio_dev->available_scan_masks = chan_info->scan_masks; + indio_dev->masklength = chan_info->num_channels - 1; +} + +static const char * const ad7266_gpio_labels[] = { + "AD0", "AD1", "AD2", +}; + +static int ad7266_probe(struct spi_device *spi) +{ + struct ad7266_platform_data *pdata = spi->dev.platform_data; + struct iio_dev *indio_dev; + struct ad7266_state *st; + unsigned int i; + 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(&spi->dev, "vref"); + if (!IS_ERR_OR_NULL(st->reg)) { + ret = regulator_enable(st->reg); + if (ret) + return ret; + + ret = regulator_get_voltage(st->reg); + if (ret < 0) + goto error_disable_reg; + + st->vref_mv = ret / 1000; + } else { + /* Use internal reference */ + st->vref_mv = 2500; + } + + if (pdata) { + st->fixed_addr = pdata->fixed_addr; + st->mode = pdata->mode; + st->range = pdata->range; + + if (!st->fixed_addr) { + for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) { + st->gpios[i].gpio = pdata->addr_gpios[i]; + st->gpios[i].flags = GPIOF_OUT_INIT_LOW; + st->gpios[i].label = ad7266_gpio_labels[i]; + } + ret = gpio_request_array(st->gpios, + ARRAY_SIZE(st->gpios)); + if (ret) + goto error_disable_reg; + } + } else { + st->fixed_addr = true; + st->range = AD7266_RANGE_VREF; + st->mode = AD7266_MODE_DIFF; + } + + spi_set_drvdata(spi, indio_dev); + st->spi = spi; + + indio_dev->dev.parent = &spi->dev; + indio_dev->name = spi_get_device_id(spi)->name; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &ad7266_info; + + ad7266_init_channels(indio_dev); + + /* wakeup */ + st->single_xfer[0].rx_buf = &st->data.sample[0]; + st->single_xfer[0].len = 2; + st->single_xfer[0].cs_change = 1; + /* conversion */ + st->single_xfer[1].rx_buf = st->data.sample; + st->single_xfer[1].len = 4; + st->single_xfer[1].cs_change = 1; + /* powerdown */ + st->single_xfer[2].tx_buf = &st->data.sample[0]; + st->single_xfer[2].len = 1; + + spi_message_init(&st->single_msg); + spi_message_add_tail(&st->single_xfer[0], &st->single_msg); + spi_message_add_tail(&st->single_xfer[1], &st->single_msg); + spi_message_add_tail(&st->single_xfer[2], &st->single_msg); + + ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, + &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops); + if (ret) + goto error_free_gpios; + + ret = iio_device_register(indio_dev); + if (ret) + goto error_buffer_cleanup; + + return 0; + +error_buffer_cleanup: + iio_triggered_buffer_cleanup(indio_dev); +error_free_gpios: + if (!st->fixed_addr) + gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios)); +error_disable_reg: + if (!IS_ERR_OR_NULL(st->reg)) + regulator_disable(st->reg); + + return ret; +} + +static int ad7266_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + struct ad7266_state *st = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + iio_triggered_buffer_cleanup(indio_dev); + if (!st->fixed_addr) + gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios)); + if (!IS_ERR_OR_NULL(st->reg)) + regulator_disable(st->reg); + + return 0; +} + +static const struct spi_device_id ad7266_id[] = { + {"ad7265", 0}, + {"ad7266", 0}, + { } +}; +MODULE_DEVICE_TABLE(spi, ad7266_id); + +static struct spi_driver ad7266_driver = { + .driver = { + .name = "ad7266", + .owner = THIS_MODULE, + }, + .probe = ad7266_probe, + .remove = ad7266_remove, + .id_table = ad7266_id, +}; +module_spi_driver(ad7266_driver); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC"); +MODULE_LICENSE("GPL v2"); |