diff options
Diffstat (limited to 'drivers/iio/dac/ad5421.c')
| -rw-r--r-- | drivers/iio/dac/ad5421.c | 534 |
1 files changed, 534 insertions, 0 deletions
diff --git a/drivers/iio/dac/ad5421.c b/drivers/iio/dac/ad5421.c new file mode 100644 index 000000000..8e9633d8d --- /dev/null +++ b/drivers/iio/dac/ad5421.c @@ -0,0 +1,534 @@ +/* + * AD5421 Digital to analog converters driver + * + * Copyright 2011 Analog Devices Inc. + * + * Licensed under the GPL-2. + */ + +#include <linux/device.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/spi/spi.h> +#include <linux/slab.h> +#include <linux/sysfs.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/events.h> +#include <linux/iio/dac/ad5421.h> + + +#define AD5421_REG_DAC_DATA 0x1 +#define AD5421_REG_CTRL 0x2 +#define AD5421_REG_OFFSET 0x3 +#define AD5421_REG_GAIN 0x4 +/* load dac and fault shared the same register number. Writing to it will cause + * a dac load command, reading from it will return the fault status register */ +#define AD5421_REG_LOAD_DAC 0x5 +#define AD5421_REG_FAULT 0x5 +#define AD5421_REG_FORCE_ALARM_CURRENT 0x6 +#define AD5421_REG_RESET 0x7 +#define AD5421_REG_START_CONVERSION 0x8 +#define AD5421_REG_NOOP 0x9 + +#define AD5421_CTRL_WATCHDOG_DISABLE BIT(12) +#define AD5421_CTRL_AUTO_FAULT_READBACK BIT(11) +#define AD5421_CTRL_MIN_CURRENT BIT(9) +#define AD5421_CTRL_ADC_SOURCE_TEMP BIT(8) +#define AD5421_CTRL_ADC_ENABLE BIT(7) +#define AD5421_CTRL_PWR_DOWN_INT_VREF BIT(6) + +#define AD5421_FAULT_SPI BIT(15) +#define AD5421_FAULT_PEC BIT(14) +#define AD5421_FAULT_OVER_CURRENT BIT(13) +#define AD5421_FAULT_UNDER_CURRENT BIT(12) +#define AD5421_FAULT_TEMP_OVER_140 BIT(11) +#define AD5421_FAULT_TEMP_OVER_100 BIT(10) +#define AD5421_FAULT_UNDER_VOLTAGE_6V BIT(9) +#define AD5421_FAULT_UNDER_VOLTAGE_12V BIT(8) + +/* These bits will cause the fault pin to go high */ +#define AD5421_FAULT_TRIGGER_IRQ \ + (AD5421_FAULT_SPI | AD5421_FAULT_PEC | AD5421_FAULT_OVER_CURRENT | \ + AD5421_FAULT_UNDER_CURRENT | AD5421_FAULT_TEMP_OVER_140) + +/** + * struct ad5421_state - driver instance specific data + * @spi: spi_device + * @ctrl: control register cache + * @current_range: current range which the device is configured for + * @data: spi transfer buffers + * @fault_mask: software masking of events + */ +struct ad5421_state { + struct spi_device *spi; + unsigned int ctrl; + enum ad5421_current_range current_range; + unsigned int fault_mask; + + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + */ + union { + __be32 d32; + u8 d8[4]; + } data[2] ____cacheline_aligned; +}; + +static const struct iio_event_spec ad5421_current_event[] = { + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_RISING, + .mask_separate = BIT(IIO_EV_INFO_VALUE) | + BIT(IIO_EV_INFO_ENABLE), + }, { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_FALLING, + .mask_separate = BIT(IIO_EV_INFO_VALUE) | + BIT(IIO_EV_INFO_ENABLE), + }, +}; + +static const struct iio_event_spec ad5421_temp_event[] = { + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_RISING, + .mask_separate = BIT(IIO_EV_INFO_VALUE) | + BIT(IIO_EV_INFO_ENABLE), + }, +}; + +static const struct iio_chan_spec ad5421_channels[] = { + { + .type = IIO_CURRENT, + .indexed = 1, + .output = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_CALIBSCALE) | + BIT(IIO_CHAN_INFO_CALIBBIAS), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_OFFSET), + .scan_type = { + .sign = 'u', + .realbits = 16, + .storagebits = 16, + }, + .event_spec = ad5421_current_event, + .num_event_specs = ARRAY_SIZE(ad5421_current_event), + }, + { + .type = IIO_TEMP, + .channel = -1, + .event_spec = ad5421_temp_event, + .num_event_specs = ARRAY_SIZE(ad5421_temp_event), + }, +}; + +static int ad5421_write_unlocked(struct iio_dev *indio_dev, + unsigned int reg, unsigned int val) +{ + struct ad5421_state *st = iio_priv(indio_dev); + + st->data[0].d32 = cpu_to_be32((reg << 16) | val); + + return spi_write(st->spi, &st->data[0].d8[1], 3); +} + +static int ad5421_write(struct iio_dev *indio_dev, unsigned int reg, + unsigned int val) +{ + int ret; + + mutex_lock(&indio_dev->mlock); + ret = ad5421_write_unlocked(indio_dev, reg, val); + mutex_unlock(&indio_dev->mlock); + + return ret; +} + +static int ad5421_read(struct iio_dev *indio_dev, unsigned int reg) +{ + struct ad5421_state *st = iio_priv(indio_dev); + int ret; + struct spi_transfer t[] = { + { + .tx_buf = &st->data[0].d8[1], + .len = 3, + .cs_change = 1, + }, { + .rx_buf = &st->data[1].d8[1], + .len = 3, + }, + }; + + mutex_lock(&indio_dev->mlock); + + st->data[0].d32 = cpu_to_be32((1 << 23) | (reg << 16)); + + ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t)); + if (ret >= 0) + ret = be32_to_cpu(st->data[1].d32) & 0xffff; + + mutex_unlock(&indio_dev->mlock); + + return ret; +} + +static int ad5421_update_ctrl(struct iio_dev *indio_dev, unsigned int set, + unsigned int clr) +{ + struct ad5421_state *st = iio_priv(indio_dev); + unsigned int ret; + + mutex_lock(&indio_dev->mlock); + + st->ctrl &= ~clr; + st->ctrl |= set; + + ret = ad5421_write_unlocked(indio_dev, AD5421_REG_CTRL, st->ctrl); + + mutex_unlock(&indio_dev->mlock); + + return ret; +} + +static irqreturn_t ad5421_fault_handler(int irq, void *data) +{ + struct iio_dev *indio_dev = data; + struct ad5421_state *st = iio_priv(indio_dev); + unsigned int fault; + unsigned int old_fault = 0; + unsigned int events; + + fault = ad5421_read(indio_dev, AD5421_REG_FAULT); + if (!fault) + return IRQ_NONE; + + /* If we had a fault, this might mean that the DAC has lost its state + * and has been reset. Make sure that the control register actually + * contains what we expect it to contain. Otherwise the watchdog might + * be enabled and we get watchdog timeout faults, which will render the + * DAC unusable. */ + ad5421_update_ctrl(indio_dev, 0, 0); + + + /* The fault pin stays high as long as a fault condition is present and + * it is not possible to mask fault conditions. For certain fault + * conditions for example like over-temperature it takes some time + * until the fault condition disappears. If we would exit the interrupt + * handler immediately after handling the event it would be entered + * again instantly. Thus we fall back to polling in case we detect that + * a interrupt condition is still present. + */ + do { + /* 0xffff is a invalid value for the register and will only be + * read if there has been a communication error */ + if (fault == 0xffff) + fault = 0; + + /* we are only interested in new events */ + events = (old_fault ^ fault) & fault; + events &= st->fault_mask; + + if (events & AD5421_FAULT_OVER_CURRENT) { + iio_push_event(indio_dev, + IIO_UNMOD_EVENT_CODE(IIO_CURRENT, + 0, + IIO_EV_TYPE_THRESH, + IIO_EV_DIR_RISING), + iio_get_time_ns(indio_dev)); + } + + if (events & AD5421_FAULT_UNDER_CURRENT) { + iio_push_event(indio_dev, + IIO_UNMOD_EVENT_CODE(IIO_CURRENT, + 0, + IIO_EV_TYPE_THRESH, + IIO_EV_DIR_FALLING), + iio_get_time_ns(indio_dev)); + } + + if (events & AD5421_FAULT_TEMP_OVER_140) { + iio_push_event(indio_dev, + IIO_UNMOD_EVENT_CODE(IIO_TEMP, + 0, + IIO_EV_TYPE_MAG, + IIO_EV_DIR_RISING), + iio_get_time_ns(indio_dev)); + } + + old_fault = fault; + fault = ad5421_read(indio_dev, AD5421_REG_FAULT); + + /* still active? go to sleep for some time */ + if (fault & AD5421_FAULT_TRIGGER_IRQ) + msleep(1000); + + } while (fault & AD5421_FAULT_TRIGGER_IRQ); + + + return IRQ_HANDLED; +} + +static void ad5421_get_current_min_max(struct ad5421_state *st, + unsigned int *min, unsigned int *max) +{ + /* The current range is configured using external pins, which are + * usually hard-wired and not run-time switchable. */ + switch (st->current_range) { + case AD5421_CURRENT_RANGE_4mA_20mA: + *min = 4000; + *max = 20000; + break; + case AD5421_CURRENT_RANGE_3mA8_21mA: + *min = 3800; + *max = 21000; + break; + case AD5421_CURRENT_RANGE_3mA2_24mA: + *min = 3200; + *max = 24000; + break; + default: + *min = 0; + *max = 1; + break; + } +} + +static inline unsigned int ad5421_get_offset(struct ad5421_state *st) +{ + unsigned int min, max; + + ad5421_get_current_min_max(st, &min, &max); + return (min * (1 << 16)) / (max - min); +} + +static int ad5421_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, int *val2, long m) +{ + struct ad5421_state *st = iio_priv(indio_dev); + unsigned int min, max; + int ret; + + if (chan->type != IIO_CURRENT) + return -EINVAL; + + switch (m) { + case IIO_CHAN_INFO_RAW: + ret = ad5421_read(indio_dev, AD5421_REG_DAC_DATA); + if (ret < 0) + return ret; + *val = ret; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + ad5421_get_current_min_max(st, &min, &max); + *val = max - min; + *val2 = (1 << 16) * 1000; + return IIO_VAL_FRACTIONAL; + case IIO_CHAN_INFO_OFFSET: + *val = ad5421_get_offset(st); + return IIO_VAL_INT; + case IIO_CHAN_INFO_CALIBBIAS: + ret = ad5421_read(indio_dev, AD5421_REG_OFFSET); + if (ret < 0) + return ret; + *val = ret - 32768; + return IIO_VAL_INT; + case IIO_CHAN_INFO_CALIBSCALE: + ret = ad5421_read(indio_dev, AD5421_REG_GAIN); + if (ret < 0) + return ret; + *val = ret; + return IIO_VAL_INT; + } + + return -EINVAL; +} + +static int ad5421_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int val, int val2, long mask) +{ + const unsigned int max_val = 1 << 16; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (val >= max_val || val < 0) + return -EINVAL; + + return ad5421_write(indio_dev, AD5421_REG_DAC_DATA, val); + case IIO_CHAN_INFO_CALIBBIAS: + val += 32768; + if (val >= max_val || val < 0) + return -EINVAL; + + return ad5421_write(indio_dev, AD5421_REG_OFFSET, val); + case IIO_CHAN_INFO_CALIBSCALE: + if (val >= max_val || val < 0) + return -EINVAL; + + return ad5421_write(indio_dev, AD5421_REG_GAIN, val); + default: + break; + } + + return -EINVAL; +} + +static int ad5421_write_event_config(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, enum iio_event_type type, + enum iio_event_direction dir, int state) +{ + struct ad5421_state *st = iio_priv(indio_dev); + unsigned int mask; + + switch (chan->type) { + case IIO_CURRENT: + if (dir == IIO_EV_DIR_RISING) + mask = AD5421_FAULT_OVER_CURRENT; + else + mask = AD5421_FAULT_UNDER_CURRENT; + break; + case IIO_TEMP: + mask = AD5421_FAULT_TEMP_OVER_140; + break; + default: + return -EINVAL; + } + + mutex_lock(&indio_dev->mlock); + if (state) + st->fault_mask |= mask; + else + st->fault_mask &= ~mask; + mutex_unlock(&indio_dev->mlock); + + return 0; +} + +static int ad5421_read_event_config(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, enum iio_event_type type, + enum iio_event_direction dir) +{ + struct ad5421_state *st = iio_priv(indio_dev); + unsigned int mask; + + switch (chan->type) { + case IIO_CURRENT: + if (dir == IIO_EV_DIR_RISING) + mask = AD5421_FAULT_OVER_CURRENT; + else + mask = AD5421_FAULT_UNDER_CURRENT; + break; + case IIO_TEMP: + mask = AD5421_FAULT_TEMP_OVER_140; + break; + default: + return -EINVAL; + } + + return (bool)(st->fault_mask & mask); +} + +static int ad5421_read_event_value(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, enum iio_event_type type, + enum iio_event_direction dir, enum iio_event_info info, int *val, + int *val2) +{ + int ret; + + switch (chan->type) { + case IIO_CURRENT: + ret = ad5421_read(indio_dev, AD5421_REG_DAC_DATA); + if (ret < 0) + return ret; + *val = ret; + break; + case IIO_TEMP: + *val = 140000; + break; + default: + return -EINVAL; + } + + return IIO_VAL_INT; +} + +static const struct iio_info ad5421_info = { + .read_raw = ad5421_read_raw, + .write_raw = ad5421_write_raw, + .read_event_config = ad5421_read_event_config, + .write_event_config = ad5421_write_event_config, + .read_event_value = ad5421_read_event_value, +}; + +static int ad5421_probe(struct spi_device *spi) +{ + struct ad5421_platform_data *pdata = dev_get_platdata(&spi->dev); + struct iio_dev *indio_dev; + struct ad5421_state *st; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); + if (indio_dev == NULL) { + dev_err(&spi->dev, "Failed to allocate iio device\n"); + return -ENOMEM; + } + + st = iio_priv(indio_dev); + spi_set_drvdata(spi, indio_dev); + + st->spi = spi; + + indio_dev->dev.parent = &spi->dev; + indio_dev->name = "ad5421"; + indio_dev->info = &ad5421_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = ad5421_channels; + indio_dev->num_channels = ARRAY_SIZE(ad5421_channels); + + st->ctrl = AD5421_CTRL_WATCHDOG_DISABLE | + AD5421_CTRL_AUTO_FAULT_READBACK; + + if (pdata) { + st->current_range = pdata->current_range; + if (pdata->external_vref) + st->ctrl |= AD5421_CTRL_PWR_DOWN_INT_VREF; + } else { + st->current_range = AD5421_CURRENT_RANGE_4mA_20mA; + } + + /* write initial ctrl register value */ + ad5421_update_ctrl(indio_dev, 0, 0); + + if (spi->irq) { + ret = devm_request_threaded_irq(&spi->dev, spi->irq, + NULL, + ad5421_fault_handler, + IRQF_TRIGGER_HIGH | IRQF_ONESHOT, + "ad5421 fault", + indio_dev); + if (ret) + return ret; + } + + return devm_iio_device_register(&spi->dev, indio_dev); +} + +static struct spi_driver ad5421_driver = { + .driver = { + .name = "ad5421", + }, + .probe = ad5421_probe, +}; +module_spi_driver(ad5421_driver); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_DESCRIPTION("Analog Devices AD5421 DAC"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("spi:ad5421"); |