--- /dev/null
+/*
+ * AD7887 SPI ADC driver
+ *
+ * Copyright 2010-2011 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/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/ad7887.h>
+
+#define AD7887_REF_DIS BIT(5) /* on-chip reference disable */
+#define AD7887_DUAL BIT(4) /* dual-channel mode */
+#define AD7887_CH_AIN1 BIT(3) /* convert on channel 1, DUAL=1 */
+#define AD7887_CH_AIN0 0 /* convert on channel 0, DUAL=0,1 */
+#define AD7887_PM_MODE1 0 /* CS based shutdown */
+#define AD7887_PM_MODE2 1 /* full on */
+#define AD7887_PM_MODE3 2 /* auto shutdown after conversion */
+#define AD7887_PM_MODE4 3 /* standby mode */
+
+enum ad7887_channels {
+ AD7887_CH0,
+ AD7887_CH0_CH1,
+ AD7887_CH1,
+};
+
+/**
+ * struct ad7887_chip_info - chip specifc information
+ * @int_vref_mv: the internal reference voltage
+ * @channel: channel specification
+ */
+struct ad7887_chip_info {
+ u16 int_vref_mv;
+ struct iio_chan_spec channel[3];
+};
+
+struct ad7887_state {
+ struct spi_device *spi;
+ const struct ad7887_chip_info *chip_info;
+ struct regulator *reg;
+ struct spi_transfer xfer[4];
+ struct spi_message msg[3];
+ struct spi_message *ring_msg;
+ unsigned char tx_cmd_buf[4];
+
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ * Buffer needs to be large enough to hold two 16 bit samples and a
+ * 64 bit aligned 64 bit timestamp.
+ */
+ unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
+ ____cacheline_aligned;
+};
+
+enum ad7887_supported_device_ids {
+ ID_AD7887
+};
+
+static int ad7887_ring_preenable(struct iio_dev *indio_dev)
+{
+ struct ad7887_state *st = iio_priv(indio_dev);
+
+ /* We know this is a single long so can 'cheat' */
+ switch (*indio_dev->active_scan_mask) {
+ case (1 << 0):
+ st->ring_msg = &st->msg[AD7887_CH0];
+ break;
+ case (1 << 1):
+ st->ring_msg = &st->msg[AD7887_CH1];
+ /* Dummy read: push CH1 setting down to hardware */
+ spi_sync(st->spi, st->ring_msg);
+ break;
+ case ((1 << 1) | (1 << 0)):
+ st->ring_msg = &st->msg[AD7887_CH0_CH1];
+ break;
+ }
+
+ return 0;
+}
+
+static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
+{
+ struct ad7887_state *st = iio_priv(indio_dev);
+
+ /* dummy read: restore default CH0 settin */
+ return spi_sync(st->spi, &st->msg[AD7887_CH0]);
+}
+
+/**
+ * ad7887_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 ad7887_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct ad7887_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->data,
+ iio_get_time_ns());
+done:
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = {
+ .preenable = &ad7887_ring_preenable,
+ .postenable = &iio_triggered_buffer_postenable,
+ .predisable = &iio_triggered_buffer_predisable,
+ .postdisable = &ad7887_ring_postdisable,
+};
+
+static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
+{
+ int ret = spi_sync(st->spi, &st->msg[ch]);
+ if (ret)
+ return ret;
+
+ return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
+}
+
+static int ad7887_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long m)
+{
+ int ret;
+ struct ad7887_state *st = iio_priv(indio_dev);
+
+ switch (m) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&indio_dev->mlock);
+ if (iio_buffer_enabled(indio_dev))
+ ret = -EBUSY;
+ else
+ ret = ad7887_scan_direct(st, chan->address);
+ mutex_unlock(&indio_dev->mlock);
+
+ if (ret < 0)
+ return ret;
+ *val = ret >> chan->scan_type.shift;
+ *val &= GENMASK(chan->scan_type.realbits - 1, 0);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ if (st->reg) {
+ *val = regulator_get_voltage(st->reg);
+ if (*val < 0)
+ return *val;
+ *val /= 1000;
+ } else {
+ *val = st->chip_info->int_vref_mv;
+ }
+
+ *val2 = chan->scan_type.realbits;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ }
+ return -EINVAL;
+}
+
+
+static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
+ /*
+ * More devices added in future
+ */
+ [ID_AD7887] = {
+ .channel[0] = {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .channel = 1,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+ .address = 1,
+ .scan_index = 1,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 12,
+ .storagebits = 16,
+ .shift = 0,
+ .endianness = IIO_BE,
+ },
+ },
+ .channel[1] = {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .channel = 0,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+ .address = 0,
+ .scan_index = 0,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 12,
+ .storagebits = 16,
+ .shift = 0,
+ .endianness = IIO_BE,
+ },
+ },
+ .channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
+ .int_vref_mv = 2500,
+ },
+};
+
+static const struct iio_info ad7887_info = {
+ .read_raw = &ad7887_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int ad7887_probe(struct spi_device *spi)
+{
+ struct ad7887_platform_data *pdata = spi->dev.platform_data;
+ struct ad7887_state *st;
+ struct iio_dev *indio_dev;
+ uint8_t mode;
+ 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->use_onchip_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;
+ }
+
+ st->chip_info =
+ &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+ spi_set_drvdata(spi, indio_dev);
+ st->spi = spi;
+
+ /* Estabilish that the iio_dev is a child of the spi device */
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->info = &ad7887_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ /* Setup default message */
+
+ mode = AD7887_PM_MODE4;
+ if (!pdata || !pdata->use_onchip_ref)
+ mode |= AD7887_REF_DIS;
+ if (pdata && pdata->en_dual)
+ mode |= AD7887_DUAL;
+
+ st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;
+
+ st->xfer[0].rx_buf = &st->data[0];
+ st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
+ st->xfer[0].len = 2;
+
+ spi_message_init(&st->msg[AD7887_CH0]);
+ spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
+
+ if (pdata && pdata->en_dual) {
+ st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;
+
+ st->xfer[1].rx_buf = &st->data[0];
+ st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
+ st->xfer[1].len = 2;
+
+ st->xfer[2].rx_buf = &st->data[2];
+ st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
+ st->xfer[2].len = 2;
+
+ spi_message_init(&st->msg[AD7887_CH0_CH1]);
+ spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
+ spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
+
+ st->xfer[3].rx_buf = &st->data[2];
+ st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
+ st->xfer[3].len = 2;
+
+ spi_message_init(&st->msg[AD7887_CH1]);
+ spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
+
+ indio_dev->channels = st->chip_info->channel;
+ indio_dev->num_channels = 3;
+ } else {
+ indio_dev->channels = &st->chip_info->channel[1];
+ indio_dev->num_channels = 2;
+ }
+
+ ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+ &ad7887_trigger_handler, &ad7887_ring_setup_ops);
+ if (ret)
+ goto error_disable_reg;
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto error_unregister_ring;
+
+ return 0;
+error_unregister_ring:
+ iio_triggered_buffer_cleanup(indio_dev);
+error_disable_reg:
+ if (st->reg)
+ regulator_disable(st->reg);
+
+ return ret;
+}
+
+static int ad7887_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct ad7887_state *st = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ iio_triggered_buffer_cleanup(indio_dev);
+ if (st->reg)
+ regulator_disable(st->reg);
+
+ return 0;
+}
+
+static const struct spi_device_id ad7887_id[] = {
+ {"ad7887", ID_AD7887},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, ad7887_id);
+
+static struct spi_driver ad7887_driver = {
+ .driver = {
+ .name = "ad7887",
+ .owner = THIS_MODULE,
+ },
+ .probe = ad7887_probe,
+ .remove = ad7887_remove,
+ .id_table = ad7887_id,
+};
+module_spi_driver(ad7887_driver);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
+MODULE_LICENSE("GPL v2");
Code Review / kvmfornfv.git / blobdiff