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-rw-r--r--drivers/iio/dac/ad5421.c537
1 files changed, 537 insertions, 0 deletions
diff --git a/drivers/iio/dac/ad5421.c b/drivers/iio/dac/ad5421.c
new file mode 100644
index 000000000..7644acfd8
--- /dev/null
+++ b/drivers/iio/dac/ad5421.c
@@ -0,0 +1,537 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AD5421 Digital to analog converters driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ */
+
+#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
+ * @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, 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(&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 <lars@metafoo.de>");
+MODULE_DESCRIPTION("Analog Devices AD5421 DAC");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("spi:ad5421");
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