1 files changed, 408 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7298.c b/drivers/iio/adc/ad7298.c
new file mode 100644
index 000000000000..2364807a5d6c
--- /dev/null
+++ b/drivers/iio/adc/ad7298.c
@@ -0,0 +1,408 @@
+/*
+ * 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/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	(1 << 15) /* write to the control register */
+#define AD7298_REPEAT	(1 << 14) /* repeated conversion enable */
+#define AD7298_CH(x)	(1 << (13 - (x))) /* channel select */
+#define AD7298_TSENSE	(1 << 5) /* temperature conversion enable */
+#define AD7298_EXTREF	(1 << 2) /* external reference enable */
+#define AD7298_TAVG	(1 << 1) /* temperature sensor averaging enable */
+#define AD7298_PDD	(1 << 0) /* partial power down enable */
+
+#define AD7298_MAX_CHAN		8
+#define AD7298_BITS		12
+#define AD7298_STORAGE_BITS	16
+#define AD7298_INTREF_mV	2500
+
+#define AD7298_CH_TEMP		9
+
+#define RES_MASK(bits)	((1 << (bits)) - 1)
+
+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 = IIO_CHAN_INFO_RAW_SEPARATE_BIT |		\
+		IIO_CHAN_INFO_SCALE_SHARED_BIT,				\
+		.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 = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
+			IIO_CHAN_INFO_SCALE_SEPARATE_BIT |
+			IIO_CHAN_INFO_OFFSET_SEPARATE_BIT,
+		.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);
+	s64 time_ns = 0;
+	int b_sent;
+
+	b_sent = spi_sync(st->spi, &st->ring_msg);
+	if (b_sent)
+		goto done;
+
+	if (indio_dev->scan_timestamp) {
+		time_ns = iio_get_time_ns();
+		memcpy((u8 *)st->rx_buf + indio_dev->scan_bytes - sizeof(s64),
+			&time_ns, sizeof(time_ns));
+	}
+
+	iio_push_to_buffers(indio_dev, (u8 *)st->rx_buf);
+
+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 & RES_MASK(AD7298_BITS);
+
+		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 __devinit ad7298_probe(struct spi_device *spi)
+{
+	struct ad7298_platform_data *pdata = spi->dev.platform_data;
+	struct ad7298_state *st;
+	struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st));
+	int ret;
+
+	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 = regulator_get(&spi->dev, "vref");
+		if (IS_ERR(st->reg)) {
+			ret = PTR_ERR(st->reg);
+			goto error_free;
+		}
+		ret = regulator_enable(st->reg);
+		if (ret)
+			goto error_put_reg;
+	}
+
+	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);
+error_put_reg:
+	if (st->ext_ref)
+		regulator_put(st->reg);
+error_free:
+	iio_device_free(indio_dev);
+
+	return ret;
+}
+
+static int __devexit 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);
+		regulator_put(st->reg);
+	}
+	iio_device_free(indio_dev);
+
+	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		= __devexit_p(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");