// SPDX-License-Identifier: GPL-2.0-only /* * AD5421 Digital to analog converters driver * * Copyright 2011 Analog Devices Inc. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #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 * @lock: lock to protect the data buffer during SPI ops */ struct ad5421_state { struct spi_device *spi; unsigned int ctrl; enum ad5421_current_range current_range; unsigned int fault_mask; struct mutex lock; /* * DMA (thus cache coherency maintenance) may require the * transfer buffers to live in their own cache lines. */ union { __be32 d32; u8 d8[4]; } data[2] __aligned(IIO_DMA_MINALIGN); }; 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) { struct ad5421_state *st = iio_priv(indio_dev); int ret; mutex_lock(&st->lock); ret = ad5421_write_unlocked(indio_dev, reg, val); mutex_unlock(&st->lock); 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(&st->lock); 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(&st->lock); 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(&st->lock); st->ctrl &= ~clr; st->ctrl |= set; ret = ad5421_write_unlocked(indio_dev, AD5421_REG_CTRL, st->ctrl); mutex_unlock(&st->lock); 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, bool 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(&st->lock); if (state) st->fault_mask |= mask; else st->fault_mask &= ~mask; mutex_unlock(&st->lock); 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->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); mutex_init(&st->lock); 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 "); MODULE_DESCRIPTION("Analog Devices AD5421 DAC"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("spi:ad5421");