diff options
Diffstat (limited to 'drivers/iio/multiplexer/iio-mux.c')
| -rw-r--r-- | drivers/iio/multiplexer/iio-mux.c | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/iio-mux.c new file mode 100644 index 000000000000..37ba007f8dca --- /dev/null +++ b/drivers/iio/multiplexer/iio-mux.c @@ -0,0 +1,459 @@ +/* + * 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, + .driver_module = THIS_MODULE, +}; + +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_kzalloc(dev, + sizeof(*child->ext_info_cache) * + num_ext_info, GFP_KERNEL); + 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); + 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"); |