This patch adds support for Diolan DLN2 ADC via IIO's ADC interface.
ADC is the fourth and final component of the DLN2 for the kernel.

Signed-off-by: Jack Andersen <jackoa...@gmail.com>
---
 drivers/iio/adc/Kconfig    |   9 +
 drivers/iio/adc/Makefile   |   1 +
 drivers/iio/adc/dln2-adc.c | 648 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/mfd/dln2.c         |  12 +
 4 files changed, 670 insertions(+)
 create mode 100644 drivers/iio/adc/dln2-adc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 401f47b..78d7455 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -239,6 +239,15 @@ config DA9150_GPADC
          To compile this driver as a module, choose M here: the module will be
          called berlin2-adc.
 
+config DLN2_ADC
+       tristate "Diolan DLN-2 ADC driver support"
+       depends on MFD_DLN2
+       help
+         Say yes here to build support for Diolan DLN-2 ADC.
+
+         This driver can also be built as a module. If so, the module will be
+         called adc_dln2.
+
 config ENVELOPE_DETECTOR
        tristate "Envelope detector using a DAC and a comparator"
        depends on OF
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 9339bec..378bc65 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
 obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
 obj-$(CONFIG_CPCAP_ADC) += cpcap-adc.o
 obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
+obj-$(CONFIG_DLN2_ADC) += dln2-adc.o
 obj-$(CONFIG_ENVELOPE_DETECTOR) += envelope-detector.o
 obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
 obj-$(CONFIG_FSL_MX25_ADC) += fsl-imx25-gcq.o
diff --git a/drivers/iio/adc/dln2-adc.c b/drivers/iio/adc/dln2-adc.c
new file mode 100644
index 0000000..7900e2c
--- /dev/null
+++ b/drivers/iio/adc/dln2-adc.c
@@ -0,0 +1,648 @@
+/*
+ * Driver for the Diolan DLN-2 USB-ADC adapter
+ *
+ * Copyright (c) 2017 Jack Andersen
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/dln2.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/kfifo_buf.h>
+#include <linux/virtio.h>
+#include <linux/version.h>
+
+#define DLN2_ADC_MOD_NAME "dln2-adc"
+
+#define DLN2_ADC_ID             0x06
+
+#define DLN2_ADC_GET_CHANNEL_COUNT     DLN2_CMD(0x01, DLN2_ADC_ID)
+#define DLN2_ADC_ENABLE                        DLN2_CMD(0x02, DLN2_ADC_ID)
+#define DLN2_ADC_DISABLE               DLN2_CMD(0x03, DLN2_ADC_ID)
+#define DLN2_ADC_CHANNEL_ENABLE                DLN2_CMD(0x05, DLN2_ADC_ID)
+#define DLN2_ADC_CHANNEL_DISABLE       DLN2_CMD(0x06, DLN2_ADC_ID)
+#define DLN2_ADC_SET_RESOLUTION                DLN2_CMD(0x08, DLN2_ADC_ID)
+#define DLN2_ADC_CHANNEL_GET_VAL       DLN2_CMD(0x0A, DLN2_ADC_ID)
+#define DLN2_ADC_CHANNEL_GET_ALL_VAL   DLN2_CMD(0x0B, DLN2_ADC_ID)
+#define DLN2_ADC_CHANNEL_SET_CFG       DLN2_CMD(0x0C, DLN2_ADC_ID)
+#define DLN2_ADC_CHANNEL_GET_CFG       DLN2_CMD(0x0D, DLN2_ADC_ID)
+#define DLN2_ADC_CONDITION_MET_EV      DLN2_CMD(0x10, DLN2_ADC_ID)
+
+#define DLN2_ADC_EVENT_NONE            0
+#define DLN2_ADC_EVENT_BELOW           1
+#define DLN2_ADC_EVENT_LEVEL_ABOVE     2
+#define DLN2_ADC_EVENT_OUTSIDE         3
+#define DLN2_ADC_EVENT_INSIDE          4
+#define DLN2_ADC_EVENT_ALWAYS          5
+
+#define DLN2_ADC_MAX_CHANNELS 8
+#define DLN2_ADC_DATA_BITS 10
+
+struct dln2_adc {
+       struct platform_device *pdev;
+       int port;
+       struct iio_trigger *trig;
+       /* Set once initialized */
+       u8 port_enabled;
+       /* Set once resolution request made to HW */
+       u8 resolution_set;
+       /* Bitmask requesting enabled channels */
+       unsigned long chans_requested;
+       /* Bitmask indicating enabled channels on HW */
+       unsigned long chans_enabled;
+       /* Channel that is arbitrated for event trigger */
+       int trigger_chan;
+};
+
+struct dln2_adc_port_chan {
+       u8 port;
+       u8 chan;
+};
+
+struct dln2_adc_get_all_vals {
+       __le16 channel_mask;
+       __le16 values[DLN2_ADC_MAX_CHANNELS];
+};
+
+static int dln2_adc_get_chan_count(struct dln2_adc *dln2)
+{
+       int ret;
+       u8 port = dln2->port;
+       int ilen = sizeof(port);
+       u8 count;
+       int olen = sizeof(count);
+
+       ret = dln2_transfer(dln2->pdev, DLN2_ADC_GET_CHANNEL_COUNT,
+                           &port, ilen, &count, &olen);
+       if (ret < 0) {
+               dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
+               return ret;
+       }
+       if (olen < sizeof(count))
+               return -EPROTO;
+
+       return count;
+}
+
+static int dln2_adc_set_port_resolution(struct dln2_adc *dln2)
+{
+       int ret;
+       struct dln2_adc_port_chan port_chan = {
+               .port = dln2->port,
+               .chan = DLN2_ADC_DATA_BITS,
+       };
+       int ilen = sizeof(port_chan);
+
+       ret = dln2_transfer_tx(dln2->pdev, DLN2_ADC_SET_RESOLUTION,
+                              &port_chan, ilen);
+       if (ret < 0) {
+               dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
+               return ret;
+       }
+
+       return 0;
+}
+
+static int dln2_adc_set_chan_enabled(struct dln2_adc *dln2,
+                                    int channel, bool enable)
+{
+       int ret;
+       struct dln2_adc_port_chan port_chan = {
+               .port = dln2->port,
+               .chan = channel,
+       };
+       int ilen = sizeof(port_chan);
+
+       u16 cmd = enable ? DLN2_ADC_CHANNEL_ENABLE : DLN2_ADC_CHANNEL_DISABLE;
+
+       ret = dln2_transfer_tx(dln2->pdev, cmd, &port_chan, ilen);
+       if (ret < 0) {
+               dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
+               return ret;
+       }
+
+       return 0;
+}
+
+static int dln2_adc_set_port_enabled(struct dln2_adc *dln2, bool enable)
+{
+       int ret;
+       u8 port = dln2->port;
+       int ilen = sizeof(port);
+       __le16 conflict;
+       int olen = sizeof(conflict);
+
+       u16 cmd = enable ? DLN2_ADC_ENABLE : DLN2_ADC_DISABLE;
+
+       ret = dln2_transfer(dln2->pdev, cmd, &port, ilen, &conflict, &olen);
+       if (ret < 0) {
+               dev_dbg(&dln2->pdev->dev, "Problem in %s(%d)\n",
+                       __func__, (int)enable);
+               return ret;
+       }
+       if (enable && olen < sizeof(conflict))
+               return -EPROTO;
+
+       return 0;
+}
+
+/*
+ * ADC channels are lazily enabled due to the pins being shared with GPIO
+ * channels. Enabling channels requires taking the ADC port offline, specifying
+ * the resolution, individually enabling channels, then putting the port back
+ * online. If GPIO pins have already been exported by gpio_dln2, EINVAL is
+ * reported.
+ */
+static int dln2_adc_update_enabled_chans(struct dln2_adc *dln2)
+{
+       int ret, i, chan_count;
+       struct iio_dev *indio_dev;
+
+       if (dln2->chans_enabled == dln2->chans_requested)
+               return 0;
+
+       indio_dev = platform_get_drvdata(dln2->pdev);
+       chan_count = indio_dev->num_channels;
+
+       if (dln2->port_enabled) {
+               ret = dln2_adc_set_port_enabled(dln2, false);
+               if (ret < 0)
+                       return ret;
+               dln2->port_enabled = false;
+       }
+
+       if (!dln2->resolution_set) {
+               ret = dln2_adc_set_port_resolution(dln2);
+               if (ret < 0)
+                       return ret;
+               dln2->resolution_set = true;
+       }
+
+       for (i = 0; i < chan_count; ++i) {
+               bool requested = (dln2->chans_requested & (1 << i));
+               bool enabled = (dln2->chans_enabled & (1 << i));
+
+               if (requested == enabled)
+                       continue;
+               ret = dln2_adc_set_chan_enabled(dln2, i, requested);
+               if (ret < 0)
+                       return ret;
+       }
+
+       dln2->chans_enabled = dln2->chans_requested;
+
+       ret = dln2_adc_set_port_enabled(dln2, true);
+       if (ret < 0)
+               return ret;
+       dln2->port_enabled = true;
+
+       return ret;
+}
+
+static int dln2_adc_get_chan_freq(struct dln2_adc *dln2, unsigned int channel)
+{
+       int ret;
+       struct dln2_adc_port_chan port_chan = {
+               .port = dln2->port,
+               .chan = channel,
+       };
+       int ilen = sizeof(port_chan);
+       struct {
+               __u8 type;
+               __le16 period;
+               __le16 low;
+               __le16 high;
+       } __packed get_cfg;
+       int olen = sizeof(get_cfg);
+
+       ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_CFG,
+                           &port_chan, ilen, &get_cfg, &olen);
+       if (ret < 0) {
+               dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
+               return ret;
+       }
+       if (olen < sizeof(get_cfg))
+               return -EPROTO;
+
+       return get_cfg.period;
+}
+
+static int dln2_adc_set_chan_freq(struct dln2_adc *dln2, unsigned int channel,
+                                 unsigned int freq)
+{
+       int ret;
+       struct {
+               struct dln2_adc_port_chan port_chan;
+               __u8 type;
+               __le16 period;
+               __le16 low;
+               __le16 high;
+       } __packed set_cfg = {
+               .port_chan.port = dln2->port,
+               .port_chan.chan = channel,
+               .type = freq ? DLN2_ADC_EVENT_ALWAYS : DLN2_ADC_EVENT_NONE,
+               .period = freq
+       };
+
+       ret = dln2_transfer_tx(dln2->pdev, DLN2_ADC_CHANNEL_SET_CFG,
+                              &set_cfg, sizeof(set_cfg));
+       return ret;
+}
+
+static int dln2_adc_read(struct dln2_adc *dln2, unsigned int channel)
+{
+       int ret;
+
+       dln2->chans_requested |= (1 << channel);
+       ret = dln2_adc_update_enabled_chans(dln2);
+       if (ret < 0)
+               return ret;
+       dln2->port_enabled = 1;
+
+       struct dln2_adc_port_chan port_chan = {
+               .port = dln2->port,
+               .chan = channel,
+       };
+       int ilen = sizeof(port_chan);
+       __le16 value;
+       int olen = sizeof(value);
+
+       ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_VAL,
+                           &port_chan, ilen, &value, &olen);
+       if (ret < 0) {
+               dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
+               return ret;
+       }
+       if (olen < sizeof(value))
+               return -EPROTO;
+
+       return le16_to_cpu(value);
+}
+
+static int dln2_adc_read_all(struct dln2_adc *dln2,
+                            struct dln2_adc_get_all_vals *get_all_vals)
+{
+       int ret;
+       __u8 port = dln2->port;
+       int olen = sizeof(struct dln2_adc_get_all_vals);
+
+       ret = dln2_transfer(dln2->pdev, DLN2_ADC_CHANNEL_GET_ALL_VAL,
+                           &port, sizeof(port), get_all_vals, &olen);
+       if (ret < 0) {
+               dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
+               return ret;
+       }
+       if (olen < sizeof(struct dln2_adc_get_all_vals))
+               return -EPROTO;
+
+       return 0;
+}
+
+static int dln2_adc_read_raw(struct iio_dev *indio_dev,
+                            struct iio_chan_spec const *chan,
+                            int *val,
+                            int *val2,
+                            long mask)
+{
+       int ret;
+       struct dln2_adc *dln2 = iio_priv(indio_dev);
+
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW:
+               mutex_lock(&indio_dev->mlock);
+               ret = dln2_adc_read(dln2, chan->channel);
+               mutex_unlock(&indio_dev->mlock);
+
+               if (ret < 0)
+                       break;
+
+               *val = ret;
+               return IIO_VAL_INT;
+
+       case IIO_CHAN_INFO_SCALE:
+               *val = 0;
+               // 3.3 / (1 << 10) * 1000000;
+               *val2 = 3222656;
+               return IIO_VAL_INT_PLUS_NANO;
+
+       case IIO_CHAN_INFO_SAMP_FREQ:
+               mutex_lock(&indio_dev->mlock);
+               if (dln2->trigger_chan == -1)
+                       ret = 0;
+               else
+                       ret = dln2_adc_get_chan_freq(dln2, dln2->trigger_chan);
+               mutex_unlock(&indio_dev->mlock);
+
+               if (ret < 0)
+                       break;
+
+               *val = ret / 1000;
+               *val2 = (ret % 1000) * 1000;
+               return IIO_VAL_INT_PLUS_MICRO;
+
+       default:
+               break;
+       }
+
+       return -EINVAL;
+}
+
+static int dln2_adc_write_raw(struct iio_dev *indio_dev,
+                             struct iio_chan_spec const *chan,
+                             int val,
+                             int val2,
+                             long mask)
+{
+       int ret = 0;
+       unsigned int freq;
+       struct dln2_adc *dln2 = iio_priv(indio_dev);
+
+       switch (mask) {
+       case IIO_CHAN_INFO_SAMP_FREQ:
+               freq = val * 1000 + val2 / 1000;
+               if (freq > 65535) {
+                       freq = 65535;
+                       dev_warn(&dln2->pdev->dev,
+                                "clamping freq to 65535ms\n");
+               }
+               mutex_lock(&indio_dev->mlock);
+
+               /*
+                * The first requested channel is arbitrated as a shared
+                * trigger source, so only one event is registered with the DLN.
+                * The event handler will then read all enabled channel values
+                * using DLN2_ADC_CHANNEL_GET_ALL_VAL to maintain
+                * synchronization between ADC readings.
+                */
+               if (dln2->trigger_chan == -1)
+                       dln2->trigger_chan = chan->channel;
+               ret = dln2_adc_set_chan_freq(dln2, dln2->trigger_chan, freq);
+
+               mutex_unlock(&indio_dev->mlock);
+
+               if (ret < 0)
+                       break;
+
+               return 0;
+
+       default:
+               break;
+       }
+
+       return -EINVAL;
+}
+
+#define DLN2_ADC_CHAN(idx) {                                   \
+       .type = IIO_VOLTAGE,                                    \
+       .indexed = 1,                                           \
+       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
+       .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE) |   \
+                                  BIT(IIO_CHAN_INFO_SAMP_FREQ),\
+       .scan_type.sign = 'u',                                  \
+       .scan_type.realbits = DLN2_ADC_DATA_BITS,               \
+       .scan_type.storagebits = 16,                            \
+       .scan_type.endianness = IIO_LE,                         \
+       .channel = idx,                                         \
+       .scan_index = idx,                                      \
+}
+
+static const struct iio_chan_spec dln2_adc_iio_channels[] = {
+       DLN2_ADC_CHAN(0),
+       DLN2_ADC_CHAN(1),
+       DLN2_ADC_CHAN(2),
+       DLN2_ADC_CHAN(3),
+       DLN2_ADC_CHAN(4),
+       DLN2_ADC_CHAN(5),
+       DLN2_ADC_CHAN(6),
+       DLN2_ADC_CHAN(7),
+};
+
+static const struct iio_info dln2_adc_info = {
+       .read_raw = &dln2_adc_read_raw,
+       .write_raw = &dln2_adc_write_raw,
+       .driver_module = THIS_MODULE,
+};
+
+static irqreturn_t dln2_adc_trigger_h(int irq, void *p)
+{
+       struct iio_poll_func *pf = p;
+       struct iio_dev *indio_dev = pf->indio_dev;
+       int len = 0;
+       u16 *data;
+       struct dln2_adc_get_all_vals dev_data;
+       struct dln2_adc *dln2 = iio_priv(indio_dev);
+
+       mutex_lock(&indio_dev->mlock);
+
+       dln2->chans_requested |= *indio_dev->active_scan_mask;
+       if (dln2_adc_update_enabled_chans(dln2) < 0) {
+               mutex_unlock(&indio_dev->mlock);
+               goto done;
+       }
+
+       if (dln2_adc_read_all(dln2, &dev_data) < 0) {
+               mutex_unlock(&indio_dev->mlock);
+               goto done;
+       }
+
+       mutex_unlock(&indio_dev->mlock);
+
+       data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
+       if (!data)
+               goto done;
+
+       if (!bitmap_empty(indio_dev->active_scan_mask,
+                         indio_dev->masklength)) {
+               int i, j;
+
+               for (i = 0, j = 0;
+                    i < bitmap_weight(indio_dev->active_scan_mask,
+                                      indio_dev->masklength);
+                    i++, j++) {
+                       j = find_next_bit(indio_dev->active_scan_mask,
+                                         indio_dev->masklength, j);
+                       data[i] = dev_data.values[j];
+                       len += 2;
+               }
+       }
+
+       iio_push_to_buffers_with_timestamp(indio_dev, data,
+                                          iio_get_time_ns(indio_dev));
+
+       kfree(data);
+
+done:
+       iio_trigger_notify_done(indio_dev->trig);
+       return IRQ_HANDLED;
+}
+
+static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev)
+{
+       struct dln2_adc *dln2 = iio_priv(indio_dev);
+
+       dln2->chans_requested |= *indio_dev->active_scan_mask;
+       dln2_adc_update_enabled_chans(dln2);
+
+       return iio_triggered_buffer_postenable(indio_dev);
+}
+
+static const struct iio_buffer_setup_ops dln2_adc_buffer_setup_ops = {
+       .postenable = &dln2_adc_triggered_buffer_postenable,
+       .predisable = &iio_triggered_buffer_predisable,
+};
+
+static void dln2_adc_event(struct platform_device *pdev, u16 echo,
+                          const void *data, int len)
+{
+       struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+       struct dln2_adc *dln2 = iio_priv(indio_dev);
+
+       iio_trigger_poll(dln2->trig);
+}
+
+static const struct iio_trigger_ops dln2_adc_trigger_ops = {
+       .owner = THIS_MODULE,
+};
+
+static int dln2_adc_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct dln2_adc *dln2;
+       struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
+       struct iio_dev *indio_dev = NULL;
+       struct iio_buffer *buffer;
+       int ret = -ENODEV;
+       int chans;
+
+       indio_dev = devm_iio_device_alloc(dev, sizeof(struct dln2_adc));
+       if (!indio_dev) {
+               dev_err(dev, "failed allocating iio device\n");
+               return -ENOMEM;
+       }
+
+       dln2 = iio_priv(indio_dev);
+       dln2->pdev = pdev;
+       dln2->port = pdata->port;
+       dln2->port_enabled = 0;
+       dln2->resolution_set = 0;
+       dln2->chans_requested = 0;
+       dln2->chans_enabled = 0;
+       dln2->trigger_chan = -1;
+
+       platform_set_drvdata(pdev, indio_dev);
+
+       chans = dln2_adc_get_chan_count(dln2);
+       if (chans < 0) {
+               dev_err(dev, "failed to get channel count: %d\n", chans);
+               ret = chans;
+               goto dealloc_dev;
+       }
+       if (chans > DLN2_ADC_MAX_CHANNELS) {
+               chans = DLN2_ADC_MAX_CHANNELS;
+               dev_warn(dev, "clamping channels to %d\n",
+                        DLN2_ADC_MAX_CHANNELS);
+       }
+
+       indio_dev->name = DLN2_ADC_MOD_NAME;
+       indio_dev->dev.parent = dev;
+       indio_dev->info = &dln2_adc_info;
+       indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
+       indio_dev->channels = dln2_adc_iio_channels;
+       indio_dev->num_channels = chans;
+       indio_dev->setup_ops = &dln2_adc_buffer_setup_ops;
+
+       dln2->trig = devm_iio_trigger_alloc(dev, "samplerate");
+       if (!dln2->trig) {
+               dev_err(dev, "failed to allocate trigger\n");
+               goto dealloc_dev;
+       }
+       dln2->trig->ops = &dln2_adc_trigger_ops;
+       iio_trigger_set_drvdata(dln2->trig, dln2);
+       iio_trigger_register(dln2->trig);
+       iio_trigger_set_immutable(indio_dev, dln2->trig);
+
+       buffer = devm_iio_kfifo_allocate(dev);
+       if (!buffer) {
+               dev_err(dev, "failed to allocate kfifo\n");
+               ret = -ENOMEM;
+               goto dealloc_trigger;
+       }
+
+       iio_device_attach_buffer(indio_dev, buffer);
+
+       indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
+                                                &dln2_adc_trigger_h,
+                                                IRQF_ONESHOT,
+                                                indio_dev,
+                                                "samplerate");
+
+       if (!indio_dev->pollfunc) {
+               ret = -ENOMEM;
+               goto dealloc_kfifo;
+       }
+
+       ret = dln2_register_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV,
+                                    dln2_adc_event);
+       if (ret) {
+               dev_err(dev, "failed to register event cb: %d\n", ret);
+               goto dealloc_pollfunc;
+       }
+
+       ret = iio_device_register(indio_dev);
+       if (ret) {
+               dev_err(dev, "failed to register iio device: %d\n", ret);
+               goto dealloc_pollfunc;
+       }
+
+       dev_info(dev, "DLN2 ADC driver loaded\n");
+
+       return 0;
+
+dealloc_pollfunc:
+       iio_dealloc_pollfunc(indio_dev->pollfunc);
+dealloc_kfifo:
+dealloc_trigger:
+       iio_trigger_unregister(dln2->trig);
+dealloc_dev:
+
+       return ret;
+}
+
+static int dln2_adc_remove(struct platform_device *pdev)
+{
+       struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+       struct dln2_adc *dln2 = iio_priv(indio_dev);
+
+       dev_info(&indio_dev->dev, "DLN2 ADC driver unloaded\n");
+
+       dln2_unregister_event_cb(pdev, DLN2_ADC_CONDITION_MET_EV);
+       iio_device_unregister(indio_dev);
+       iio_trigger_unregister(dln2->trig);
+       iio_dealloc_pollfunc(indio_dev->pollfunc);
+
+       return 0;
+}
+
+static struct platform_driver dln2_adc_driver = {
+       .driver.name    = DLN2_ADC_MOD_NAME,
+       .probe          = dln2_adc_probe,
+       .remove         = dln2_adc_remove,
+};
+
+module_platform_driver(dln2_adc_driver);
+
+MODULE_AUTHOR("Jack Andersen <jackoa...@gmail.com");
+MODULE_DESCRIPTION("Driver for the Diolan DLN2 ADC interface");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:dln2-adc");
diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
index 704e189..a22ab8c 100644
--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -53,6 +53,7 @@ enum dln2_handle {
        DLN2_HANDLE_GPIO,
        DLN2_HANDLE_I2C,
        DLN2_HANDLE_SPI,
+       DLN2_HANDLE_ADC,
        DLN2_HANDLES
 };
 
@@ -663,6 +664,12 @@ static int dln2_start_rx_urbs(struct dln2_dev *dln2, gfp_t 
gfp)
        .port = 0,
 };
 
+/* Only one ADC port supported */
+static struct dln2_platform_data dln2_pdata_adc = {
+       .handle = DLN2_HANDLE_ADC,
+       .port = 0,
+};
+
 static const struct mfd_cell dln2_devs[] = {
        {
                .name = "dln2-gpio",
@@ -679,6 +686,11 @@ static int dln2_start_rx_urbs(struct dln2_dev *dln2, gfp_t 
gfp)
                .platform_data = &dln2_pdata_spi,
                .pdata_size = sizeof(struct dln2_platform_data),
        },
+       {
+               .name = "dln2-adc",
+               .platform_data = &dln2_pdata_adc,
+               .pdata_size = sizeof(struct dln2_platform_data),
+       },
 };
 
 static void dln2_stop(struct dln2_dev *dln2)
-- 
1.9.1

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