3 files changed, 489 insertions, 0 deletions
diff --git a/drivers/iio/multiplexer/Kconfig b/drivers/iio/multiplexer/Kconfig
new file mode 100644
index 000000000..735a7b0e6
--- /dev/null
+++ b/drivers/iio/multiplexer/Kconfig
@@ -0,0 +1,18 @@
+#
+# Multiplexer drivers
+#
+# When adding new entries keep the list in alphabetical order
+
+menu "Multiplexers"
+
+config IIO_MUX
+	tristate "IIO multiplexer driver"
+	select MULTIPLEXER
+	depends on OF || COMPILE_TEST
+	help
+	  Say yes here to build support for the IIO multiplexer.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called iio-mux.
+
+endmenu
diff --git a/drivers/iio/multiplexer/Makefile b/drivers/iio/multiplexer/Makefile
new file mode 100644
index 000000000..68be3c4ab
--- /dev/null
+++ b/drivers/iio/multiplexer/Makefile
@@ -0,0 +1,6 @@
+#
+# Makefile for industrial I/O multiplexer drivers
+#
+
+# When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_IIO_MUX) += iio-mux.o
diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/iio-mux.c
new file mode 100644
index 000000000..e1f44cecd
--- /dev/null
+++ b/drivers/iio/multiplexer/iio-mux.c
@@ -0,0 +1,465 @@
+/*
+ * IIO multiplexer driver
+ *
+ * Copyright (C) 2017 Axentia Technologies AB
+ *
+ * Author: Peter Rosin <peda@axentia.se>
+ *
+ * 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.
+ */
+
+#include <linux/err.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/mux/consumer.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+struct mux_ext_info_cache {
+	char *data;
+	ssize_t size;
+};
+
+struct mux_child {
+	struct mux_ext_info_cache *ext_info_cache;
+};
+
+struct mux {
+	int cached_state;
+	struct mux_control *control;
+	struct iio_channel *parent;
+	struct iio_dev *indio_dev;
+	struct iio_chan_spec *chan;
+	struct iio_chan_spec_ext_info *ext_info;
+	struct mux_child *child;
+};
+
+static int iio_mux_select(struct mux *mux, int idx)
+{
+	struct mux_child *child = &mux->child[idx];
+	struct iio_chan_spec const *chan = &mux->chan[idx];
+	int ret;
+	int i;
+
+	ret = mux_control_select(mux->control, chan->channel);
+	if (ret < 0) {
+		mux->cached_state = -1;
+		return ret;
+	}
+
+	if (mux->cached_state == chan->channel)
+		return 0;
+
+	if (chan->ext_info) {
+		for (i = 0; chan->ext_info[i].name; ++i) {
+			const char *attr = chan->ext_info[i].name;
+			struct mux_ext_info_cache *cache;
+
+			cache = &child->ext_info_cache[i];
+
+			if (cache->size < 0)
+				continue;
+
+			ret = iio_write_channel_ext_info(mux->parent, attr,
+							 cache->data,
+							 cache->size);
+
+			if (ret < 0) {
+				mux_control_deselect(mux->control);
+				mux->cached_state = -1;
+				return ret;
+			}
+		}
+	}
+	mux->cached_state = chan->channel;
+
+	return 0;
+}
+
+static void iio_mux_deselect(struct mux *mux)
+{
+	mux_control_deselect(mux->control);
+}
+
+static int mux_read_raw(struct iio_dev *indio_dev,
+			struct iio_chan_spec const *chan,
+			int *val, int *val2, long mask)
+{
+	struct mux *mux = iio_priv(indio_dev);
+	int idx = chan - mux->chan;
+	int ret;
+
+	ret = iio_mux_select(mux, idx);
+	if (ret < 0)
+		return ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_read_channel_raw(mux->parent, val);
+		break;
+
+	case IIO_CHAN_INFO_SCALE:
+		ret = iio_read_channel_scale(mux->parent, val, val2);
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+
+	iio_mux_deselect(mux);
+
+	return ret;
+}
+
+static int mux_read_avail(struct iio_dev *indio_dev,
+			  struct iio_chan_spec const *chan,
+			  const int **vals, int *type, int *length,
+			  long mask)
+{
+	struct mux *mux = iio_priv(indio_dev);
+	int idx = chan - mux->chan;
+	int ret;
+
+	ret = iio_mux_select(mux, idx);
+	if (ret < 0)
+		return ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		*type = IIO_VAL_INT;
+		ret = iio_read_avail_channel_raw(mux->parent, vals, length);
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+
+	iio_mux_deselect(mux);
+
+	return ret;
+}
+
+static int mux_write_raw(struct iio_dev *indio_dev,
+			 struct iio_chan_spec const *chan,
+			 int val, int val2, long mask)
+{
+	struct mux *mux = iio_priv(indio_dev);
+	int idx = chan - mux->chan;
+	int ret;
+
+	ret = iio_mux_select(mux, idx);
+	if (ret < 0)
+		return ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_write_channel_raw(mux->parent, val);
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+
+	iio_mux_deselect(mux);
+
+	return ret;
+}
+
+static const struct iio_info mux_info = {
+	.read_raw = mux_read_raw,
+	.read_avail = mux_read_avail,
+	.write_raw = mux_write_raw,
+};
+
+static ssize_t mux_read_ext_info(struct iio_dev *indio_dev, uintptr_t private,
+				 struct iio_chan_spec const *chan, char *buf)
+{
+	struct mux *mux = iio_priv(indio_dev);
+	int idx = chan - mux->chan;
+	ssize_t ret;
+
+	ret = iio_mux_select(mux, idx);
+	if (ret < 0)
+		return ret;
+
+	ret = iio_read_channel_ext_info(mux->parent,
+					mux->ext_info[private].name,
+					buf);
+
+	iio_mux_deselect(mux);
+
+	return ret;
+}
+
+static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private,
+				  struct iio_chan_spec const *chan,
+				  const char *buf, size_t len)
+{
+	struct device *dev = indio_dev->dev.parent;
+	struct mux *mux = iio_priv(indio_dev);
+	int idx = chan - mux->chan;
+	char *new;
+	ssize_t ret;
+
+	if (len >= PAGE_SIZE)
+		return -EINVAL;
+
+	ret = iio_mux_select(mux, idx);
+	if (ret < 0)
+		return ret;
+
+	new = devm_kmemdup(dev, buf, len + 1, GFP_KERNEL);
+	if (!new) {
+		iio_mux_deselect(mux);
+		return -ENOMEM;
+	}
+
+	new[len] = 0;
+
+	ret = iio_write_channel_ext_info(mux->parent,
+					 mux->ext_info[private].name,
+					 buf, len);
+	if (ret < 0) {
+		iio_mux_deselect(mux);
+		devm_kfree(dev, new);
+		return ret;
+	}
+
+	devm_kfree(dev, mux->child[idx].ext_info_cache[private].data);
+	mux->child[idx].ext_info_cache[private].data = new;
+	mux->child[idx].ext_info_cache[private].size = len;
+
+	iio_mux_deselect(mux);
+
+	return ret;
+}
+
+static int mux_configure_channel(struct device *dev, struct mux *mux,
+				 u32 state, const char *label, int idx)
+{
+	struct mux_child *child = &mux->child[idx];
+	struct iio_chan_spec *chan = &mux->chan[idx];
+	struct iio_chan_spec const *pchan = mux->parent->channel;
+	char *page = NULL;
+	int num_ext_info;
+	int i;
+	int ret;
+
+	chan->indexed = 1;
+	chan->output = pchan->output;
+	chan->datasheet_name = label;
+	chan->ext_info = mux->ext_info;
+
+	ret = iio_get_channel_type(mux->parent, &chan->type);
+	if (ret < 0) {
+		dev_err(dev, "failed to get parent channel type\n");
+		return ret;
+	}
+
+	if (iio_channel_has_info(pchan, IIO_CHAN_INFO_RAW))
+		chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW);
+	if (iio_channel_has_info(pchan, IIO_CHAN_INFO_SCALE))
+		chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE);
+
+	if (iio_channel_has_available(pchan, IIO_CHAN_INFO_RAW))
+		chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW);
+
+	if (state >= mux_control_states(mux->control)) {
+		dev_err(dev, "too many channels\n");
+		return -EINVAL;
+	}
+
+	chan->channel = state;
+
+	num_ext_info = iio_get_channel_ext_info_count(mux->parent);
+	if (num_ext_info) {
+		page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
+		if (!page)
+			return -ENOMEM;
+	}
+	child->ext_info_cache = devm_kcalloc(dev,
+					     num_ext_info,
+					     sizeof(*child->ext_info_cache),
+					     GFP_KERNEL);
+	if (!child->ext_info_cache)
+		return -ENOMEM;
+
+	for (i = 0; i < num_ext_info; ++i) {
+		child->ext_info_cache[i].size = -1;
+
+		if (!pchan->ext_info[i].write)
+			continue;
+		if (!pchan->ext_info[i].read)
+			continue;
+
+		ret = iio_read_channel_ext_info(mux->parent,
+						mux->ext_info[i].name,
+						page);
+		if (ret < 0) {
+			dev_err(dev, "failed to get ext_info '%s'\n",
+				pchan->ext_info[i].name);
+			return ret;
+		}
+		if (ret >= PAGE_SIZE) {
+			dev_err(dev, "too large ext_info '%s'\n",
+				pchan->ext_info[i].name);
+			return -EINVAL;
+		}
+
+		child->ext_info_cache[i].data = devm_kmemdup(dev, page, ret + 1,
+							     GFP_KERNEL);
+		if (!child->ext_info_cache[i].data)
+			return -ENOMEM;
+
+		child->ext_info_cache[i].data[ret] = 0;
+		child->ext_info_cache[i].size = ret;
+	}
+
+	if (page)
+		devm_kfree(dev, page);
+
+	return 0;
+}
+
+/*
+ * Same as of_property_for_each_string(), but also keeps track of the
+ * index of each string.
+ */
+#define of_property_for_each_string_index(np, propname, prop, s, i)	\
+	for (prop = of_find_property(np, propname, NULL),		\
+	     s = of_prop_next_string(prop, NULL),			\
+	     i = 0;							\
+	     s;								\
+	     s = of_prop_next_string(prop, s),				\
+	     i++)
+
+static int mux_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node;
+	struct iio_dev *indio_dev;
+	struct iio_channel *parent;
+	struct mux *mux;
+	struct property *prop;
+	const char *label;
+	u32 state;
+	int sizeof_ext_info;
+	int children;
+	int sizeof_priv;
+	int i;
+	int ret;
+
+	if (!np)
+		return -ENODEV;
+
+	parent = devm_iio_channel_get(dev, "parent");
+	if (IS_ERR(parent)) {
+		if (PTR_ERR(parent) != -EPROBE_DEFER)
+			dev_err(dev, "failed to get parent channel\n");
+		return PTR_ERR(parent);
+	}
+
+	sizeof_ext_info = iio_get_channel_ext_info_count(parent);
+	if (sizeof_ext_info) {
+		sizeof_ext_info += 1; /* one extra entry for the sentinel */
+		sizeof_ext_info *= sizeof(*mux->ext_info);
+	}
+
+	children = 0;
+	of_property_for_each_string(np, "channels", prop, label) {
+		if (*label)
+			children++;
+	}
+	if (children <= 0) {
+		dev_err(dev, "not even a single child\n");
+		return -EINVAL;
+	}
+
+	sizeof_priv = sizeof(*mux);
+	sizeof_priv += sizeof(*mux->child) * children;
+	sizeof_priv += sizeof(*mux->chan) * children;
+	sizeof_priv += sizeof_ext_info;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof_priv);
+	if (!indio_dev)
+		return -ENOMEM;
+
+	mux = iio_priv(indio_dev);
+	mux->child = (struct mux_child *)(mux + 1);
+	mux->chan = (struct iio_chan_spec *)(mux->child + children);
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	mux->parent = parent;
+	mux->cached_state = -1;
+
+	indio_dev->name = dev_name(dev);
+	indio_dev->dev.parent = dev;
+	indio_dev->info = &mux_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = mux->chan;
+	indio_dev->num_channels = children;
+	if (sizeof_ext_info) {
+		mux->ext_info = devm_kmemdup(dev,
+					     parent->channel->ext_info,
+					     sizeof_ext_info, GFP_KERNEL);
+		if (!mux->ext_info)
+			return -ENOMEM;
+
+		for (i = 0; mux->ext_info[i].name; ++i) {
+			if (parent->channel->ext_info[i].read)
+				mux->ext_info[i].read = mux_read_ext_info;
+			if (parent->channel->ext_info[i].write)
+				mux->ext_info[i].write = mux_write_ext_info;
+			mux->ext_info[i].private = i;
+		}
+	}
+
+	mux->control = devm_mux_control_get(dev, NULL);
+	if (IS_ERR(mux->control)) {
+		if (PTR_ERR(mux->control) != -EPROBE_DEFER)
+			dev_err(dev, "failed to get control-mux\n");
+		return PTR_ERR(mux->control);
+	}
+
+	i = 0;
+	of_property_for_each_string_index(np, "channels", prop, label, state) {
+		if (!*label)
+			continue;
+
+		ret = mux_configure_channel(dev, mux, state, label, i++);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret) {
+		dev_err(dev, "failed to register iio device\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id mux_match[] = {
+	{ .compatible = "io-channel-mux" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mux_match);
+
+static struct platform_driver mux_driver = {
+	.probe = mux_probe,
+	.driver = {
+		.name = "iio-mux",
+		.of_match_table = mux_match,
+	},
+};
+module_platform_driver(mux_driver);
+
+MODULE_DESCRIPTION("IIO multiplexer driver");
+MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
+MODULE_LICENSE("GPL v2");