--- /dev/null
+/*
+ * 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),
+};
+
+static __init int ad5421_init(void)
+{
+ return spi_register_driver(&ad5421_driver);
+}
+module_init(ad5421_init);
+
+static __exit void ad5421_exit(void)
+{
+ spi_unregister_driver(&ad5421_driver);
+}
+module_exit(ad5421_exit);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Analog Devices AD5421 DAC");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("spi:ad5421");
projects / GitHub / exynos8895 / android_kernel_samsung_universal8895.git / commitdiff