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authorWilliam Breathitt Gray <vilhelm.gray@gmail.com>2016-09-28 14:00:01 -0400
committerJonathan Cameron <jic23@kernel.org>2016-10-01 17:06:21 +0100
commit28e5d3bb0325e71ef9b53a9cb4242cdfb55fd8c5 (patch)
tree91bae3ac0c7da7137a7dc2f94cb6dcafc3b9fd81 /drivers/iio/counter
parent1a8f324aa1f2237caef1c6633734785bbdcffeed (diff)
iio: 104-quad-8: Add IIO support for the ACCES 104-QUAD-8
The ACCES 104-QUAD-8 is a general purpose quadrature encoder counter/interface board. The 104-QUAD-8 is capable of monitoring the outputs of eight encoders via four on-board LSI/CSI LS7266R1 24-bit dual-axis quadrature counter chips. Core functions handled by the LS7266R1, such as direction and total count, are available. Performing a write to a counter's IIO_CHAN_INFO_RAW sets the counter and also clears the counter's respective error flag. Although the counters have a 25-bit range, only the lower 24 bits may be set, either directly or via a counter's preset attribute. Interrupts are not supported by this driver. This driver adds IIO support for the ACCES 104-QUAD-8 and ACCES 104-QUAD-4. The base port addresses for the devices may be configured via the base array module parameter. Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio/counter')
-rw-r--r--drivers/iio/counter/104-quad-8.c593
-rw-r--r--drivers/iio/counter/Kconfig24
-rw-r--r--drivers/iio/counter/Makefile7
3 files changed, 624 insertions, 0 deletions
diff --git a/drivers/iio/counter/104-quad-8.c b/drivers/iio/counter/104-quad-8.c
new file mode 100644
index 000000000000..2d2ee353dde7
--- /dev/null
+++ b/drivers/iio/counter/104-quad-8.c
@@ -0,0 +1,593 @@
+/*
+ * IIO driver for the ACCES 104-QUAD-8
+ * Copyright (C) 2016 William Breathitt Gray
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * This driver supports the ACCES 104-QUAD-8 and ACCES 104-QUAD-4.
+ */
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/types.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/isa.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+
+#define QUAD8_EXTENT 32
+
+static unsigned int base[max_num_isa_dev(QUAD8_EXTENT)];
+static unsigned int num_quad8;
+module_param_array(base, uint, &num_quad8, 0);
+MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
+
+#define QUAD8_NUM_COUNTERS 8
+
+/**
+ * struct quad8_iio - IIO device private data structure
+ * @preset: array of preset values
+ * @count_mode: array of count mode configurations
+ * @quadrature_mode: array of quadrature mode configurations
+ * @quadrature_scale: array of quadrature mode scale configurations
+ * @ab_enable: array of A and B inputs enable configurations
+ * @preset_enable: array of set_to_preset_on_index attribute configurations
+ * @synchronous_mode: array of index function synchronous mode configurations
+ * @index_polarity: array of index function polarity configurations
+ * @base: base port address of the IIO device
+ */
+struct quad8_iio {
+ unsigned int preset[QUAD8_NUM_COUNTERS];
+ unsigned int count_mode[QUAD8_NUM_COUNTERS];
+ unsigned int quadrature_mode[QUAD8_NUM_COUNTERS];
+ unsigned int quadrature_scale[QUAD8_NUM_COUNTERS];
+ unsigned int ab_enable[QUAD8_NUM_COUNTERS];
+ unsigned int preset_enable[QUAD8_NUM_COUNTERS];
+ unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
+ unsigned int index_polarity[QUAD8_NUM_COUNTERS];
+ unsigned int base;
+};
+
+static int quad8_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val, int *val2, long mask)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ const int base_offset = priv->base + 2 * chan->channel;
+ unsigned int flags;
+ unsigned int borrow;
+ unsigned int carry;
+ int i;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (chan->type == IIO_INDEX) {
+ *val = !!(inb(priv->base + 0x16) & BIT(chan->channel));
+ return IIO_VAL_INT;
+ }
+
+ flags = inb(base_offset);
+ borrow = flags & BIT(0);
+ carry = !!(flags & BIT(1));
+
+ /* Borrow XOR Carry effectively doubles count range */
+ *val = (borrow ^ carry) << 24;
+
+ /* Reset Byte Pointer; transfer Counter to Output Latch */
+ outb(0x11, base_offset + 1);
+
+ for (i = 0; i < 3; i++)
+ *val |= (unsigned int)inb(base_offset) << (8 * i);
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_ENABLE:
+ *val = priv->ab_enable[chan->channel];
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = 1;
+ *val2 = priv->quadrature_scale[chan->channel];
+ return IIO_VAL_FRACTIONAL_LOG2;
+ }
+
+ return -EINVAL;
+}
+
+static int quad8_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int val, int val2, long mask)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ const int base_offset = priv->base + 2 * chan->channel;
+ int i;
+ unsigned int ior_cfg;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (chan->type == IIO_INDEX)
+ return -EINVAL;
+
+ /* Only 24-bit values are supported */
+ if ((unsigned int)val > 0xFFFFFF)
+ return -EINVAL;
+
+ /* Reset Byte Pointer */
+ outb(0x01, base_offset + 1);
+
+ /* Counter can only be set via Preset Register */
+ for (i = 0; i < 3; i++)
+ outb(val >> (8 * i), base_offset);
+
+ /* Transfer Preset Register to Counter */
+ outb(0x08, base_offset + 1);
+
+ /* Reset Byte Pointer */
+ outb(0x01, base_offset + 1);
+
+ /* Set Preset Register back to original value */
+ val = priv->preset[chan->channel];
+ for (i = 0; i < 3; i++)
+ outb(val >> (8 * i), base_offset);
+
+ /* Reset Borrow, Carry, Compare, and Sign flags */
+ outb(0x02, base_offset + 1);
+ /* Reset Error flag */
+ outb(0x06, base_offset + 1);
+
+ return 0;
+ case IIO_CHAN_INFO_ENABLE:
+ /* only boolean values accepted */
+ if (val < 0 || val > 1)
+ return -EINVAL;
+
+ priv->ab_enable[chan->channel] = val;
+
+ ior_cfg = val | priv->preset_enable[chan->channel] << 1;
+
+ /* Load I/O control configuration */
+ outb(0x40 | ior_cfg, base_offset);
+
+ return 0;
+ case IIO_CHAN_INFO_SCALE:
+ /* Quadrature scaling only available in quadrature mode */
+ if (!priv->quadrature_mode[chan->channel] && (val2 || val != 1))
+ return -EINVAL;
+
+ /* Only three gain states (1, 0.5, 0.25) */
+ if (val == 1 && !val2)
+ priv->quadrature_scale[chan->channel] = 0;
+ else if (!val)
+ switch (val2) {
+ case 500000:
+ priv->quadrature_scale[chan->channel] = 1;
+ break;
+ case 250000:
+ priv->quadrature_scale[chan->channel] = 2;
+ break;
+ default:
+ return -EINVAL;
+ }
+ else
+ return -EINVAL;
+
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info quad8_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = quad8_read_raw,
+ .write_raw = quad8_write_raw
+};
+
+static ssize_t quad8_read_preset(struct iio_dev *indio_dev, uintptr_t private,
+ const struct iio_chan_spec *chan, char *buf)
+{
+ const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+ return snprintf(buf, PAGE_SIZE, "%u\n", priv->preset[chan->channel]);
+}
+
+static ssize_t quad8_write_preset(struct iio_dev *indio_dev, uintptr_t private,
+ const struct iio_chan_spec *chan, const char *buf, size_t len)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ const int base_offset = priv->base + 2 * chan->channel;
+ unsigned int preset;
+ int ret;
+ int i;
+
+ ret = kstrtouint(buf, 0, &preset);
+ if (ret)
+ return ret;
+
+ /* Only 24-bit values are supported */
+ if (preset > 0xFFFFFF)
+ return -EINVAL;
+
+ priv->preset[chan->channel] = preset;
+
+ /* Reset Byte Pointer */
+ outb(0x01, base_offset + 1);
+
+ /* Set Preset Register */
+ for (i = 0; i < 3; i++)
+ outb(preset >> (8 * i), base_offset);
+
+ return len;
+}
+
+static ssize_t quad8_read_set_to_preset_on_index(struct iio_dev *indio_dev,
+ uintptr_t private, const struct iio_chan_spec *chan, char *buf)
+{
+ const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+ return snprintf(buf, PAGE_SIZE, "%u\n",
+ priv->preset_enable[chan->channel]);
+}
+
+static ssize_t quad8_write_set_to_preset_on_index(struct iio_dev *indio_dev,
+ uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
+ size_t len)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ const int base_offset = priv->base + 2 * chan->channel;
+ bool preset_enable;
+ int ret;
+ unsigned int ior_cfg;
+
+ ret = kstrtobool(buf, &preset_enable);
+ if (ret)
+ return ret;
+
+ priv->preset_enable[chan->channel] = preset_enable;
+
+ ior_cfg = priv->ab_enable[chan->channel] |
+ (unsigned int)preset_enable << 1;
+
+ /* Load I/O control configuration to Input / Output Control Register */
+ outb(0x40 | ior_cfg, base_offset);
+
+ return len;
+}
+
+static const char *const quad8_noise_error_states[] = {
+ "No excessive noise is present at the count inputs",
+ "Excessive noise is present at the count inputs"
+};
+
+static int quad8_get_noise_error(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ const int base_offset = priv->base + 2 * chan->channel + 1;
+
+ return !!(inb(base_offset) & BIT(4));
+}
+
+static const struct iio_enum quad8_noise_error_enum = {
+ .items = quad8_noise_error_states,
+ .num_items = ARRAY_SIZE(quad8_noise_error_states),
+ .get = quad8_get_noise_error
+};
+
+static const char *const quad8_count_direction_states[] = {
+ "down",
+ "up"
+};
+
+static int quad8_get_count_direction(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ const int base_offset = priv->base + 2 * chan->channel + 1;
+
+ return !!(inb(base_offset) & BIT(5));
+}
+
+static const struct iio_enum quad8_count_direction_enum = {
+ .items = quad8_count_direction_states,
+ .num_items = ARRAY_SIZE(quad8_count_direction_states),
+ .get = quad8_get_count_direction
+};
+
+static const char *const quad8_count_modes[] = {
+ "normal",
+ "range limit",
+ "non-recycle",
+ "modulo-n"
+};
+
+static int quad8_set_count_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, unsigned int count_mode)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ unsigned int mode_cfg = count_mode << 1;
+ const int base_offset = priv->base + 2 * chan->channel + 1;
+
+ priv->count_mode[chan->channel] = count_mode;
+
+ /* Add quadrature mode configuration */
+ if (priv->quadrature_mode[chan->channel])
+ mode_cfg |= (priv->quadrature_scale[chan->channel] + 1) << 3;
+
+ /* Load mode configuration to Counter Mode Register */
+ outb(0x20 | mode_cfg, base_offset);
+
+ return 0;
+}
+
+static int quad8_get_count_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+ return priv->count_mode[chan->channel];
+}
+
+static const struct iio_enum quad8_count_mode_enum = {
+ .items = quad8_count_modes,
+ .num_items = ARRAY_SIZE(quad8_count_modes),
+ .set = quad8_set_count_mode,
+ .get = quad8_get_count_mode
+};
+
+static const char *const quad8_synchronous_modes[] = {
+ "non-synchronous",
+ "synchronous"
+};
+
+static int quad8_set_synchronous_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, unsigned int synchronous_mode)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ const unsigned int idr_cfg = synchronous_mode |
+ priv->index_polarity[chan->channel] << 1;
+ const int base_offset = priv->base + 2 * chan->channel + 1;
+
+ /* Index function must be non-synchronous in non-quadrature mode */
+ if (synchronous_mode && !priv->quadrature_mode[chan->channel])
+ return -EINVAL;
+
+ priv->synchronous_mode[chan->channel] = synchronous_mode;
+
+ /* Load Index Control configuration to Index Control Register */
+ outb(0x40 | idr_cfg, base_offset);
+
+ return 0;
+}
+
+static int quad8_get_synchronous_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+ return priv->synchronous_mode[chan->channel];
+}
+
+static const struct iio_enum quad8_synchronous_mode_enum = {
+ .items = quad8_synchronous_modes,
+ .num_items = ARRAY_SIZE(quad8_synchronous_modes),
+ .set = quad8_set_synchronous_mode,
+ .get = quad8_get_synchronous_mode
+};
+
+static const char *const quad8_quadrature_modes[] = {
+ "non-quadrature",
+ "quadrature"
+};
+
+static int quad8_set_quadrature_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, unsigned int quadrature_mode)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ unsigned int mode_cfg = priv->count_mode[chan->channel] << 1;
+ const int base_offset = priv->base + 2 * chan->channel + 1;
+
+ if (quadrature_mode)
+ mode_cfg |= (priv->quadrature_scale[chan->channel] + 1) << 3;
+ else {
+ /* Quadrature scaling only available in quadrature mode */
+ priv->quadrature_scale[chan->channel] = 0;
+
+ /* Synchronous function not supported in non-quadrature mode */
+ if (priv->synchronous_mode[chan->channel])
+ quad8_set_synchronous_mode(indio_dev, chan, 0);
+ }
+
+ priv->quadrature_mode[chan->channel] = quadrature_mode;
+
+ /* Load mode configuration to Counter Mode Register */
+ outb(0x20 | mode_cfg, base_offset);
+
+ return 0;
+}
+
+static int quad8_get_quadrature_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+ return priv->quadrature_mode[chan->channel];
+}
+
+static const struct iio_enum quad8_quadrature_mode_enum = {
+ .items = quad8_quadrature_modes,
+ .num_items = ARRAY_SIZE(quad8_quadrature_modes),
+ .set = quad8_set_quadrature_mode,
+ .get = quad8_get_quadrature_mode
+};
+
+static const char *const quad8_index_polarity_modes[] = {
+ "negative",
+ "positive"
+};
+
+static int quad8_set_index_polarity(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, unsigned int index_polarity)
+{
+ struct quad8_iio *const priv = iio_priv(indio_dev);
+ const unsigned int idr_cfg = priv->synchronous_mode[chan->channel] |
+ index_polarity << 1;
+ const int base_offset = priv->base + 2 * chan->channel + 1;
+
+ priv->index_polarity[chan->channel] = index_polarity;
+
+ /* Load Index Control configuration to Index Control Register */
+ outb(0x40 | idr_cfg, base_offset);
+
+ return 0;
+}
+
+static int quad8_get_index_polarity(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ const struct quad8_iio *const priv = iio_priv(indio_dev);
+
+ return priv->index_polarity[chan->channel];
+}
+
+static const struct iio_enum quad8_index_polarity_enum = {
+ .items = quad8_index_polarity_modes,
+ .num_items = ARRAY_SIZE(quad8_index_polarity_modes),
+ .set = quad8_set_index_polarity,
+ .get = quad8_get_index_polarity
+};
+
+static const struct iio_chan_spec_ext_info quad8_count_ext_info[] = {
+ {
+ .name = "preset",
+ .shared = IIO_SEPARATE,
+ .read = quad8_read_preset,
+ .write = quad8_write_preset
+ },
+ {
+ .name = "set_to_preset_on_index",
+ .shared = IIO_SEPARATE,
+ .read = quad8_read_set_to_preset_on_index,
+ .write = quad8_write_set_to_preset_on_index
+ },
+ IIO_ENUM("noise_error", IIO_SEPARATE, &quad8_noise_error_enum),
+ IIO_ENUM_AVAILABLE("noise_error", &quad8_noise_error_enum),
+ IIO_ENUM("count_direction", IIO_SEPARATE, &quad8_count_direction_enum),
+ IIO_ENUM_AVAILABLE("count_direction", &quad8_count_direction_enum),
+ IIO_ENUM("count_mode", IIO_SEPARATE, &quad8_count_mode_enum),
+ IIO_ENUM_AVAILABLE("count_mode", &quad8_count_mode_enum),
+ IIO_ENUM("quadrature_mode", IIO_SEPARATE, &quad8_quadrature_mode_enum),
+ IIO_ENUM_AVAILABLE("quadrature_mode", &quad8_quadrature_mode_enum),
+ {}
+};
+
+static const struct iio_chan_spec_ext_info quad8_index_ext_info[] = {
+ IIO_ENUM("synchronous_mode", IIO_SEPARATE,
+ &quad8_synchronous_mode_enum),
+ IIO_ENUM_AVAILABLE("synchronous_mode", &quad8_synchronous_mode_enum),
+ IIO_ENUM("index_polarity", IIO_SEPARATE, &quad8_index_polarity_enum),
+ IIO_ENUM_AVAILABLE("index_polarity", &quad8_index_polarity_enum),
+ {}
+};
+
+#define QUAD8_COUNT_CHAN(_chan) { \
+ .type = IIO_COUNT, \
+ .channel = (_chan), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_ENABLE) | BIT(IIO_CHAN_INFO_SCALE), \
+ .ext_info = quad8_count_ext_info, \
+ .indexed = 1 \
+}
+
+#define QUAD8_INDEX_CHAN(_chan) { \
+ .type = IIO_INDEX, \
+ .channel = (_chan), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .ext_info = quad8_index_ext_info, \
+ .indexed = 1 \
+}
+
+static const struct iio_chan_spec quad8_channels[] = {
+ QUAD8_COUNT_CHAN(0), QUAD8_INDEX_CHAN(0),
+ QUAD8_COUNT_CHAN(1), QUAD8_INDEX_CHAN(1),
+ QUAD8_COUNT_CHAN(2), QUAD8_INDEX_CHAN(2),
+ QUAD8_COUNT_CHAN(3), QUAD8_INDEX_CHAN(3),
+ QUAD8_COUNT_CHAN(4), QUAD8_INDEX_CHAN(4),
+ QUAD8_COUNT_CHAN(5), QUAD8_INDEX_CHAN(5),
+ QUAD8_COUNT_CHAN(6), QUAD8_INDEX_CHAN(6),
+ QUAD8_COUNT_CHAN(7), QUAD8_INDEX_CHAN(7)
+};
+
+static int quad8_probe(struct device *dev, unsigned int id)
+{
+ struct iio_dev *indio_dev;
+ struct quad8_iio *priv;
+ int i, j;
+ unsigned int base_offset;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ if (!devm_request_region(dev, base[id], QUAD8_EXTENT,
+ dev_name(dev))) {
+ dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
+ base[id], base[id] + QUAD8_EXTENT);
+ return -EBUSY;
+ }
+
+ indio_dev->info = &quad8_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->num_channels = ARRAY_SIZE(quad8_channels);
+ indio_dev->channels = quad8_channels;
+ indio_dev->name = dev_name(dev);
+
+ priv = iio_priv(indio_dev);
+ priv->base = base[id];
+
+ /* Reset all counters and disable interrupt function */
+ outb(0x01, base[id] + 0x11);
+ /* Set initial configuration for all counters */
+ for (i = 0; i < QUAD8_NUM_COUNTERS; i++) {
+ base_offset = base[id] + 2 * i;
+ /* Reset Byte Pointer */
+ outb(0x01, base_offset + 1);
+ /* Reset Preset Register */
+ for (j = 0; j < 3; j++)
+ outb(0x00, base_offset);
+ /* Reset Borrow, Carry, Compare, and Sign flags */
+ outb(0x04, base_offset + 1);
+ /* Reset Error flag */
+ outb(0x06, base_offset + 1);
+ /* Binary encoding; Normal count; non-quadrature mode */
+ outb(0x20, base_offset + 1);
+ /* Disable A and B inputs; preset on index; FLG1 as Carry */
+ outb(0x40, base_offset + 1);
+ /* Disable index function; negative index polarity */
+ outb(0x60, base_offset + 1);
+ }
+ /* Enable all counters */
+ outb(0x00, base[id] + 0x11);
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static struct isa_driver quad8_driver = {
+ .probe = quad8_probe,
+ .driver = {
+ .name = "104-quad-8"
+ }
+};
+
+module_isa_driver(quad8_driver, num_quad8);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("ACCES 104-QUAD-8 IIO driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/counter/Kconfig b/drivers/iio/counter/Kconfig
new file mode 100644
index 000000000000..44627f6e4861
--- /dev/null
+++ b/drivers/iio/counter/Kconfig
@@ -0,0 +1,24 @@
+#
+# Counter devices
+#
+# When adding new entries keep the list in alphabetical order
+
+menu "Counters"
+
+config 104_QUAD_8
+ tristate "ACCES 104-QUAD-8 driver"
+ depends on X86 && ISA_BUS_API
+ help
+ Say yes here to build support for the ACCES 104-QUAD-8 quadrature
+ encoder counter/interface device family (104-QUAD-8, 104-QUAD-4).
+
+ Performing a write to a counter's IIO_CHAN_INFO_RAW sets the counter and
+ also clears the counter's respective error flag. Although the counters
+ have a 25-bit range, only the lower 24 bits may be set, either directly
+ or via a counter's preset attribute. Interrupts are not supported by
+ this driver.
+
+ The base port addresses for the devices may be configured via the base
+ array module parameter.
+
+endmenu
diff --git a/drivers/iio/counter/Makefile b/drivers/iio/counter/Makefile
new file mode 100644
index 000000000000..007e88411648
--- /dev/null
+++ b/drivers/iio/counter/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for IIO counter devices
+#
+
+# When adding new entries keep the list in alphabetical order
+
+obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o