3 files changed, 392 insertions, 0 deletions

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 492758120338..706386ba02e3 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -45,6 +45,19 @@ config AD7476
           To compile this driver as a module, choose M here: the
           module will be called ad7476.
 
+config AD7887
+        tristate "Analog Devices AD7887 ADC driver"
+        depends on SPI
+        select IIO_BUFFER
+        select IIO_TRIGGERED_BUFFER
+        help
+          Say yes here to build support for Analog Devices
+          AD7887 SPI analog to digital converter (ADC).
+          If unsure, say N (but it's safe to say "Y").
+
+          To compile this driver as a module, choose M here: the
+          module will be called ad7887.
+
 config AT91_ADC
         tristate "Atmel AT91 ADC"
         depends on ARCH_AT91
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 900995d5e179..034eacb8f7c9 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -6,5 +6,6 @@ obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
 obj-$(CONFIG_AD7266) += ad7266.o
 obj-$(CONFIG_AD7476) += ad7476.o
 obj-$(CONFIG_AD7791) += ad7791.o
+obj-$(CONFIG_AD7887) += ad7887.o
 obj-$(CONFIG_AT91_ADC) += at91_adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
diff --git a/drivers/iio/adc/ad7887.c b/drivers/iio/adc/ad7887.c
new file mode 100644
index 000000000000..fd62309b4d3d
--- /dev/null
+++ b/drivers/iio/adc/ad7887.c
@@ -0,0 +1,378 @@
+/*
+ * 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/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          (1 << 5) /* on-chip reference disable */
+#define AD7887_DUAL             (1 << 4) /* dual-channel mode */
+#define AD7887_CH_AIN1          (1 << 3) /* convert on channel 1, DUAL=1 */
+#define AD7887_CH_AIN0          (0 << 3) /* 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,
+};
+
+#define RES_MASK(bits)  ((1 << (bits)) - 1)
+
+/**
+ * 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);
+        int ret;
+
+        ret = iio_sw_buffer_preenable(indio_dev);
+        if (ret < 0)
+                return ret;
+
+        /* 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);
+        s64 time_ns;
+        int b_sent;
+
+        b_sent = spi_sync(st->spi, st->ring_msg);
+        if (b_sent)
+                goto done;
+
+        time_ns = iio_get_time_ns();
+
+        if (indio_dev->scan_timestamp)
+                memcpy(st->data + indio_dev->scan_bytes - sizeof(s64),
+                       &time_ns, sizeof(time_ns));
+
+        iio_push_to_buffer(indio_dev->buffer, st->data);
+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 &= RES_MASK(chan->scan_type.realbits);
+                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 = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
+                        IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                        .address = 1,
+                        .scan_index = 1,
+                        .scan_type = IIO_ST('u', 12, 16, 0),
+                },
+                .channel[1] = {
+                        .type = IIO_VOLTAGE,
+                        .indexed = 1,
+                        .channel = 0,
+                        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
+                        IIO_CHAN_INFO_SCALE_SHARED_BIT,
+                        .address = 0,
+                        .scan_index = 0,
+                        .scan_type = IIO_ST('u', 12, 16, 0),
+                },
+                .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 __devinit ad7887_probe(struct spi_device *spi)
+{
+        struct ad7887_platform_data *pdata = spi->dev.platform_data;
+        struct ad7887_state *st;
+        struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st));
+        uint8_t mode;
+        int ret;
+
+        if (indio_dev == NULL)
+                return -ENOMEM;
+
+        st = iio_priv(indio_dev);
+
+        if (!pdata || !pdata->use_onchip_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;
+        }
+
+        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);
+error_put_reg:
+        if (st->reg)
+                regulator_put(st->reg);
+error_free:
+        iio_device_free(indio_dev);
+
+        return ret;
+}
+
+static int __devexit 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);
+                regulator_put(st->reg);
+        }
+        iio_device_free(indio_dev);
+
+        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         = __devexit_p(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");