1 files changed, 369 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7887.c b/drivers/iio/adc/ad7887.c
new file mode 100644
index 000000000..2fd012ee9
--- /dev/null
+++ b/drivers/iio/adc/ad7887.c
@@ -0,0 +1,369 @@
+/*
+ * 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");