| /* |
| * 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 "../iio.h" |
| #include "../sysfs.h" |
| #include "../events.h" |
| #include "dac.h" |
| #include "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 { |
| u32 d32; |
| u8 d8[4]; |
| } data[2] ____cacheline_aligned; |
| }; |
| |
| static const struct iio_chan_spec ad5421_channels[] = { |
| { |
| .type = IIO_CURRENT, |
| .indexed = 1, |
| .output = 1, |
| .channel = 0, |
| .info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT | |
| IIO_CHAN_INFO_OFFSET_SHARED_BIT | |
| IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT | |
| IIO_CHAN_INFO_CALIBBIAS_SEPARATE_BIT, |
| .scan_type = IIO_ST('u', 16, 16, 0), |
| .event_mask = IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING) | |
| IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_FALLING), |
| }, |
| { |
| .type = IIO_TEMP, |
| .channel = -1, |
| .event_mask = IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING), |
| }, |
| }; |
| |
| 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); |
| struct spi_message m; |
| 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, |
| }, |
| }; |
| |
| spi_message_init(&m); |
| spi_message_add_tail(&t[0], &m); |
| spi_message_add_tail(&t[1], &m); |
| |
| mutex_lock(&indio_dev->mlock); |
| |
| st->data[0].d32 = cpu_to_be32((1 << 23) | (reg << 16)); |
| |
| ret = spi_sync(st->spi, &m); |
| 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()); |
| } |
| |
| 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()); |
| } |
| |
| 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()); |
| } |
| |
| 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 inline unsigned int ad5421_get_scale(struct ad5421_state *st) |
| { |
| unsigned int min, max; |
| |
| ad5421_get_current_min_max(st, &min, &max); |
| return ((max - min) * 1000) / (1 << 16); |
| } |
| |
| 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); |
| int ret; |
| |
| if (chan->type != IIO_CURRENT) |
| return -EINVAL; |
| |
| switch (m) { |
| case 0: |
| 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: |
| *val = 0; |
| *val2 = ad5421_get_scale(st); |
| return IIO_VAL_INT_PLUS_MICRO; |
| 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 0: |
| 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, |
| u64 event_code, int state) |
| { |
| struct ad5421_state *st = iio_priv(indio_dev); |
| unsigned int mask; |
| |
| switch (IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event_code)) { |
| case IIO_CURRENT: |
| if (IIO_EVENT_CODE_EXTRACT_DIR(event_code) == |
| 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, |
| u64 event_code) |
| { |
| struct ad5421_state *st = iio_priv(indio_dev); |
| unsigned int mask; |
| |
| switch (IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event_code)) { |
| case IIO_CURRENT: |
| if (IIO_EVENT_CODE_EXTRACT_DIR(event_code) == |
| 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, u64 event_code, |
| int *val) |
| { |
| int ret; |
| |
| switch (IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event_code)) { |
| 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 0; |
| } |
| |
| 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, |
| .driver_module = THIS_MODULE, |
| }; |
| |
| static int __devinit 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 = iio_allocate_device(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 = request_threaded_irq(spi->irq, |
| NULL, |
| ad5421_fault_handler, |
| IRQF_TRIGGER_HIGH | IRQF_ONESHOT, |
| "ad5421 fault", |
| indio_dev); |
| if (ret) |
| goto error_free; |
| } |
| |
| ret = iio_device_register(indio_dev); |
| if (ret) { |
| dev_err(&spi->dev, "Failed to register iio device: %d\n", ret); |
| goto error_free_irq; |
| } |
| |
| return 0; |
| |
| error_free_irq: |
| if (spi->irq) |
| free_irq(spi->irq, indio_dev); |
| error_free: |
| iio_free_device(indio_dev); |
| |
| return ret; |
| } |
| |
| static int __devexit ad5421_remove(struct spi_device *spi) |
| { |
| struct iio_dev *indio_dev = spi_get_drvdata(spi); |
| |
| iio_device_unregister(indio_dev); |
| if (spi->irq) |
| free_irq(spi->irq, indio_dev); |
| iio_free_device(indio_dev); |
| |
| return 0; |
| } |
| |
| static struct spi_driver ad5421_driver = { |
| .driver = { |
| .name = "ad5421", |
| .owner = THIS_MODULE, |
| }, |
| .probe = ad5421_probe, |
| .remove = __devexit_p(ad5421_remove), |
| }; |
| 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"); |