--- /dev/null
+/*
+ * AD7298 SPI ADC driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/spi/spi.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/bitops.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#include <linux/platform_data/ad7298.h>
+
+#define AD7298_WRITE BIT(15) /* write to the control register */
+#define AD7298_REPEAT BIT(14) /* repeated conversion enable */
+#define AD7298_CH(x) BIT(13 - (x)) /* channel select */
+#define AD7298_TSENSE BIT(5) /* temperature conversion enable */
+#define AD7298_EXTREF BIT(2) /* external reference enable */
+#define AD7298_TAVG BIT(1) /* temperature sensor averaging enable */
+#define AD7298_PDD BIT(0) /* partial power down enable */
+
+#define AD7298_MAX_CHAN 8
+#define AD7298_INTREF_mV 2500
+
+#define AD7298_CH_TEMP 9
+
+struct ad7298_state {
+ struct spi_device *spi;
+ struct regulator *reg;
+ unsigned ext_ref;
+ struct spi_transfer ring_xfer[10];
+ struct spi_transfer scan_single_xfer[3];
+ struct spi_message ring_msg;
+ struct spi_message scan_single_msg;
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ */
+ __be16 rx_buf[12] ____cacheline_aligned;
+ __be16 tx_buf[2];
+};
+
+#define AD7298_V_CHAN(index) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .address = index, \
+ .scan_index = index, \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 12, \
+ .storagebits = 16, \
+ .endianness = IIO_BE, \
+ }, \
+ }
+
+static const struct iio_chan_spec ad7298_channels[] = {
+ {
+ .type = IIO_TEMP,
+ .indexed = 1,
+ .channel = 0,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_OFFSET),
+ .address = AD7298_CH_TEMP,
+ .scan_index = -1,
+ .scan_type = {
+ .sign = 's',
+ .realbits = 32,
+ .storagebits = 32,
+ },
+ },
+ AD7298_V_CHAN(0),
+ AD7298_V_CHAN(1),
+ AD7298_V_CHAN(2),
+ AD7298_V_CHAN(3),
+ AD7298_V_CHAN(4),
+ AD7298_V_CHAN(5),
+ AD7298_V_CHAN(6),
+ AD7298_V_CHAN(7),
+ IIO_CHAN_SOFT_TIMESTAMP(8),
+};
+
+/**
+ * ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask
+ **/
+static int ad7298_update_scan_mode(struct iio_dev *indio_dev,
+ const unsigned long *active_scan_mask)
+{
+ struct ad7298_state *st = iio_priv(indio_dev);
+ int i, m;
+ unsigned short command;
+ int scan_count;
+
+ /* Now compute overall size */
+ scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength);
+
+ command = AD7298_WRITE | st->ext_ref;
+
+ for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1)
+ if (test_bit(i, active_scan_mask))
+ command |= m;
+
+ st->tx_buf[0] = cpu_to_be16(command);
+
+ /* build spi ring message */
+ st->ring_xfer[0].tx_buf = &st->tx_buf[0];
+ st->ring_xfer[0].len = 2;
+ st->ring_xfer[0].cs_change = 1;
+ st->ring_xfer[1].tx_buf = &st->tx_buf[1];
+ st->ring_xfer[1].len = 2;
+ st->ring_xfer[1].cs_change = 1;
+
+ spi_message_init(&st->ring_msg);
+ spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
+ spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg);
+
+ for (i = 0; i < scan_count; i++) {
+ st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i];
+ st->ring_xfer[i + 2].len = 2;
+ st->ring_xfer[i + 2].cs_change = 1;
+ spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg);
+ }
+ /* make sure last transfer cs_change is not set */
+ st->ring_xfer[i + 1].cs_change = 0;
+
+ return 0;
+}
+
+/**
+ * ad7298_trigger_handler() bh of trigger launched polling to ring buffer
+ *
+ * Currently there is no option in this driver to disable the saving of
+ * timestamps within the ring.
+ **/
+static irqreturn_t ad7298_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct ad7298_state *st = iio_priv(indio_dev);
+ int b_sent;
+
+ b_sent = spi_sync(st->spi, &st->ring_msg);
+ if (b_sent)
+ goto done;
+
+ iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
+ iio_get_time_ns());
+
+done:
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
+{
+ int ret;
+ st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
+ (AD7298_CH(0) >> ch));
+
+ ret = spi_sync(st->spi, &st->scan_single_msg);
+ if (ret)
+ return ret;
+
+ return be16_to_cpu(st->rx_buf[0]);
+}
+
+static int ad7298_scan_temp(struct ad7298_state *st, int *val)
+{
+ int ret;
+ __be16 buf;
+
+ buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
+ AD7298_TAVG | st->ext_ref);
+
+ ret = spi_write(st->spi, (u8 *)&buf, 2);
+ if (ret)
+ return ret;
+
+ buf = cpu_to_be16(0);
+
+ ret = spi_write(st->spi, (u8 *)&buf, 2);
+ if (ret)
+ return ret;
+
+ usleep_range(101, 1000); /* sleep > 100us */
+
+ ret = spi_read(st->spi, (u8 *)&buf, 2);
+ if (ret)
+ return ret;
+
+ *val = sign_extend32(be16_to_cpu(buf), 11);
+
+ return 0;
+}
+
+static int ad7298_get_ref_voltage(struct ad7298_state *st)
+{
+ int vref;
+
+ if (st->ext_ref) {
+ vref = regulator_get_voltage(st->reg);
+ if (vref < 0)
+ return vref;
+
+ return vref / 1000;
+ } else {
+ return AD7298_INTREF_mV;
+ }
+}
+
+static int ad7298_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long m)
+{
+ int ret;
+ struct ad7298_state *st = iio_priv(indio_dev);
+
+ switch (m) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&indio_dev->mlock);
+ if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+ ret = -EBUSY;
+ } else {
+ if (chan->address == AD7298_CH_TEMP)
+ ret = ad7298_scan_temp(st, val);
+ else
+ ret = ad7298_scan_direct(st, chan->address);
+ }
+ mutex_unlock(&indio_dev->mlock);
+
+ if (ret < 0)
+ return ret;
+
+ if (chan->address != AD7298_CH_TEMP)
+ *val = ret & GENMASK(chan->scan_type.realbits - 1, 0);
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ *val = ad7298_get_ref_voltage(st);
+ *val2 = chan->scan_type.realbits;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_TEMP:
+ *val = ad7298_get_ref_voltage(st);
+ *val2 = 10;
+ return IIO_VAL_FRACTIONAL;
+ default:
+ return -EINVAL;
+ }
+ case IIO_CHAN_INFO_OFFSET:
+ *val = 1093 - 2732500 / ad7298_get_ref_voltage(st);
+ return IIO_VAL_INT;
+ }
+ return -EINVAL;
+}
+
+static const struct iio_info ad7298_info = {
+ .read_raw = &ad7298_read_raw,
+ .update_scan_mode = ad7298_update_scan_mode,
+ .driver_module = THIS_MODULE,
+};
+
+static int ad7298_probe(struct spi_device *spi)
+{
+ struct ad7298_platform_data *pdata = spi->dev.platform_data;
+ struct ad7298_state *st;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (indio_dev == NULL)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+
+ if (pdata && pdata->ext_ref)
+ st->ext_ref = AD7298_EXTREF;
+
+ if (st->ext_ref) {
+ st->reg = devm_regulator_get(&spi->dev, "vref");
+ if (IS_ERR(st->reg))
+ return PTR_ERR(st->reg);
+
+ ret = regulator_enable(st->reg);
+ if (ret)
+ return ret;
+ }
+
+ spi_set_drvdata(spi, indio_dev);
+
+ st->spi = spi;
+
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = ad7298_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ad7298_channels);
+ indio_dev->info = &ad7298_info;
+
+ /* Setup default message */
+
+ st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
+ st->scan_single_xfer[0].len = 2;
+ st->scan_single_xfer[0].cs_change = 1;
+ st->scan_single_xfer[1].tx_buf = &st->tx_buf[1];
+ st->scan_single_xfer[1].len = 2;
+ st->scan_single_xfer[1].cs_change = 1;
+ st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
+ st->scan_single_xfer[2].len = 2;
+
+ spi_message_init(&st->scan_single_msg);
+ spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
+ spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
+ spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
+
+ ret = iio_triggered_buffer_setup(indio_dev, NULL,
+ &ad7298_trigger_handler, NULL);
+ if (ret)
+ goto error_disable_reg;
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto error_cleanup_ring;
+
+ return 0;
+
+error_cleanup_ring:
+ iio_triggered_buffer_cleanup(indio_dev);
+error_disable_reg:
+ if (st->ext_ref)
+ regulator_disable(st->reg);
+
+ return ret;
+}
+
+static int ad7298_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct ad7298_state *st = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ iio_triggered_buffer_cleanup(indio_dev);
+ if (st->ext_ref)
+ regulator_disable(st->reg);
+
+ return 0;
+}
+
+static const struct spi_device_id ad7298_id[] = {
+ {"ad7298", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, ad7298_id);
+
+static struct spi_driver ad7298_driver = {
+ .driver = {
+ .name = "ad7298",
+ .owner = THIS_MODULE,
+ },
+ .probe = ad7298_probe,
+ .remove = ad7298_remove,
+ .id_table = ad7298_id,
+};
+module_spi_driver(ad7298_driver);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
+MODULE_LICENSE("GPL v2");
Code Review / kvmfornfv.git / blobdiff