3 files changed, 421 insertions, 0 deletions

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index ef5200a6850e..cd5eed60be28 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -18,6 +18,18 @@ config AD7266
           Say yes here to build support for Analog Devices AD7265 and AD7266
           ADCs.
 
+config AD7298
+        tristate "Analog Devices AD7298 ADC driver"
+        depends on SPI
+        select IIO_BUFFER
+        select IIO_TRIGGERED_BUFFER
+        help
+          Say yes here to build support for Analog Devices AD7298
+          8 Channel ADC with temperature sensor.
+
+          To compile this driver as a module, choose M here: the
+          module will be called ad7298.
+
 config AD7791
         tristate "Analog Devices AD7791 ADC driver"
         depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 54ac7bbcd01b..3256dc64a466 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -4,6 +4,7 @@
 
 obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
 obj-$(CONFIG_AD7266) += ad7266.o
+obj-$(CONFIG_AD7298) += ad7298.o
 obj-$(CONFIG_AD7476) += ad7476.o
 obj-$(CONFIG_AD7791) += ad7791.o
 obj-$(CONFIG_AD7887) += ad7887.o
diff --git a/drivers/iio/adc/ad7298.c b/drivers/iio/adc/ad7298.c
new file mode 100644
index 000000000000..441a9a265c12
--- /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.
+         */
+        unsigned short                  rx_buf[12] ____cacheline_aligned;
+        unsigned short                  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");