1 files changed, 301 insertions, 0 deletions
diff --git a/drivers/staging/iio/adc/ad7780.c b/drivers/staging/iio/adc/ad7780.c
new file mode 100644
index 000000000000..e0c7b6cc05c7
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7780.c
@@ -0,0 +1,301 @@
+/*
+ * AD7780/AD7781 SPI ADC driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/interrupt.h>
+#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/sched.h>
+#include <linux/gpio.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../ring_generic.h"
+#include "adc.h"
+
+#include "ad7780.h"
+
+#define AD7780_RDY	(1 << 7)
+#define AD7780_FILTER	(1 << 6)
+#define AD7780_ERR	(1 << 5)
+#define AD7780_ID1	(1 << 4)
+#define AD7780_ID0	(1 << 3)
+#define AD7780_GAIN	(1 << 2)
+#define AD7780_PAT1	(1 << 1)
+#define AD7780_PAT0	(1 << 0)
+
+struct ad7780_chip_info {
+	struct iio_chan_spec		channel;
+};
+
+struct ad7780_state {
+	struct spi_device		*spi;
+	const struct ad7780_chip_info	*chip_info;
+	struct regulator		*reg;
+	struct ad7780_platform_data	*pdata;
+	wait_queue_head_t		wq_data_avail;
+	bool				done;
+	u16				int_vref_mv;
+	struct spi_transfer		xfer;
+	struct spi_message		msg;
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	unsigned int			data ____cacheline_aligned;
+};
+
+enum ad7780_supported_device_ids {
+	ID_AD7780,
+	ID_AD7781,
+};
+
+static int ad7780_read(struct ad7780_state *st, int *val)
+{
+	int ret;
+
+	spi_bus_lock(st->spi->master);
+
+	enable_irq(st->spi->irq);
+	st->done = false;
+	gpio_set_value(st->pdata->gpio_pdrst, 1);
+
+	ret = wait_event_interruptible(st->wq_data_avail, st->done);
+	disable_irq_nosync(st->spi->irq);
+	if (ret)
+		goto out;
+
+	ret = spi_sync_locked(st->spi, &st->msg);
+	*val = be32_to_cpu(st->data);
+out:
+	gpio_set_value(st->pdata->gpio_pdrst, 0);
+	spi_bus_unlock(st->spi->master);
+
+	return ret;
+}
+
+static int ad7780_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	struct ad7780_state *st = iio_priv(indio_dev);
+	struct iio_chan_spec channel = st->chip_info->channel;
+	int ret, smpl = 0;
+	unsigned long scale_uv;
+
+	switch (m) {
+	case 0:
+		mutex_lock(&indio_dev->mlock);
+		ret = ad7780_read(st, &smpl);
+		mutex_unlock(&indio_dev->mlock);
+
+		if (ret < 0)
+			return ret;
+
+		if ((smpl & AD7780_ERR) ||
+			!((smpl & AD7780_PAT0) && !(smpl & AD7780_PAT1)))
+			return -EIO;
+
+		*val = (smpl >> channel.scan_type.shift) &
+			((1 << (channel.scan_type.realbits)) - 1);
+		*val -= (1 << (channel.scan_type.realbits - 1));
+
+		if (!(smpl & AD7780_GAIN))
+			*val *= 128;
+
+		return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_SCALE_SHARED):
+		scale_uv = (st->int_vref_mv * 100000)
+			>> (channel.scan_type.realbits - 1);
+		*val =  scale_uv / 100000;
+		*val2 = (scale_uv % 100000) * 10;
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+	return -EINVAL;
+}
+
+static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
+	[ID_AD7780] = {
+		.channel = IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    0, 0, IIO_ST('s', 24, 32, 8), 0),
+	},
+	[ID_AD7781] = {
+		.channel = IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
+				    (1 << IIO_CHAN_INFO_SCALE_SHARED),
+				    0, 0, IIO_ST('s', 20, 32, 12), 0),
+	},
+};
+
+/**
+ *  Interrupt handler
+ */
+static irqreturn_t ad7780_interrupt(int irq, void *dev_id)
+{
+	struct ad7780_state *st = dev_id;
+
+	st->done = true;
+	wake_up_interruptible(&st->wq_data_avail);
+
+	return IRQ_HANDLED;
+};
+
+static const struct iio_info ad7780_info = {
+	.read_raw = &ad7780_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int __devinit ad7780_probe(struct spi_device *spi)
+{
+	struct ad7780_platform_data *pdata = spi->dev.platform_data;
+	struct ad7780_state *st;
+	struct iio_dev *indio_dev;
+	int ret, voltage_uv = 0;
+
+	if (!pdata) {
+		dev_dbg(&spi->dev, "no platform data?\n");
+		return -ENODEV;
+	}
+
+	indio_dev = iio_allocate_device(sizeof(*st));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	st->reg = regulator_get(&spi->dev, "vcc");
+	if (!IS_ERR(st->reg)) {
+		ret = regulator_enable(st->reg);
+		if (ret)
+			goto error_put_reg;
+
+		voltage_uv = regulator_get_voltage(st->reg);
+	}
+
+	st->chip_info =
+		&ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+	st->pdata = pdata;
+
+	if (pdata && pdata->vref_mv)
+		st->int_vref_mv = pdata->vref_mv;
+	else if (voltage_uv)
+		st->int_vref_mv = voltage_uv / 1000;
+	else
+		dev_warn(&spi->dev, "reference voltage unspecified\n");
+
+	spi_set_drvdata(spi, indio_dev);
+	st->spi = spi;
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = &st->chip_info->channel;
+	indio_dev->num_channels = 1;
+	indio_dev->info = &ad7780_info;
+
+	init_waitqueue_head(&st->wq_data_avail);
+
+	/* Setup default message */
+
+	st->xfer.rx_buf = &st->data;
+	st->xfer.len = st->chip_info->channel.scan_type.storagebits / 8;
+
+	spi_message_init(&st->msg);
+	spi_message_add_tail(&st->xfer, &st->msg);
+
+	ret = gpio_request_one(st->pdata->gpio_pdrst, GPIOF_OUT_INIT_LOW,
+			       "AD7780 /PDRST");
+	if (ret) {
+		dev_err(&spi->dev, "failed to request GPIO PDRST\n");
+		goto error_disable_reg;
+	}
+
+	ret = request_irq(spi->irq, ad7780_interrupt,
+		IRQF_TRIGGER_FALLING, spi_get_device_id(spi)->name, st);
+	if (ret)
+		goto error_free_gpio;
+
+	disable_irq(spi->irq);
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_free_irq;
+
+	return 0;
+
+error_free_irq:
+	free_irq(spi->irq, st);
+error_free_gpio:
+	gpio_free(st->pdata->gpio_pdrst);
+error_disable_reg:
+	if (!IS_ERR(st->reg))
+		regulator_disable(st->reg);
+error_put_reg:
+	if (!IS_ERR(st->reg))
+		regulator_put(st->reg);
+
+	iio_free_device(indio_dev);
+
+	return ret;
+}
+
+static int ad7780_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ad7780_state *st = iio_priv(indio_dev);
+
+	free_irq(spi->irq, st);
+	gpio_free(st->pdata->gpio_pdrst);
+	if (!IS_ERR(st->reg)) {
+		regulator_disable(st->reg);
+		regulator_put(st->reg);
+	}
+	iio_device_unregister(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id ad7780_id[] = {
+	{"ad7780", ID_AD7780},
+	{"ad7781", ID_AD7781},
+	{}
+};
+
+static struct spi_driver ad7780_driver = {
+	.driver = {
+		.name	= "ad7780",
+		.bus	= &spi_bus_type,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= ad7780_probe,
+	.remove		= __devexit_p(ad7780_remove),
+	.id_table	= ad7780_id,
+};
+
+static int __init ad7780_init(void)
+{
+	return spi_register_driver(&ad7780_driver);
+}
+module_init(ad7780_init);
+
+static void __exit ad7780_exit(void)
+{
+	spi_unregister_driver(&ad7780_driver);
+}
+module_exit(ad7780_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD7780/1 ADC");
+MODULE_LICENSE("GPL v2");