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459 lines
9.9 KiB
459 lines
9.9 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* IIO multiplexer driver |
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* |
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* Copyright (C) 2017 Axentia Technologies AB |
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* |
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* Author: Peter Rosin <[email protected]> |
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*/ |
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#include <linux/err.h> |
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#include <linux/iio/consumer.h> |
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#include <linux/iio/iio.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/mux/consumer.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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struct mux_ext_info_cache { |
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char *data; |
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ssize_t size; |
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}; |
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struct mux_child { |
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struct mux_ext_info_cache *ext_info_cache; |
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}; |
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struct mux { |
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int cached_state; |
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struct mux_control *control; |
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struct iio_channel *parent; |
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struct iio_dev *indio_dev; |
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struct iio_chan_spec *chan; |
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struct iio_chan_spec_ext_info *ext_info; |
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struct mux_child *child; |
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}; |
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static int iio_mux_select(struct mux *mux, int idx) |
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{ |
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struct mux_child *child = &mux->child[idx]; |
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struct iio_chan_spec const *chan = &mux->chan[idx]; |
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int ret; |
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int i; |
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ret = mux_control_select(mux->control, chan->channel); |
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if (ret < 0) { |
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mux->cached_state = -1; |
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return ret; |
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} |
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if (mux->cached_state == chan->channel) |
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return 0; |
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if (chan->ext_info) { |
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for (i = 0; chan->ext_info[i].name; ++i) { |
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const char *attr = chan->ext_info[i].name; |
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struct mux_ext_info_cache *cache; |
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cache = &child->ext_info_cache[i]; |
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if (cache->size < 0) |
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continue; |
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ret = iio_write_channel_ext_info(mux->parent, attr, |
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cache->data, |
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cache->size); |
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if (ret < 0) { |
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mux_control_deselect(mux->control); |
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mux->cached_state = -1; |
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return ret; |
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} |
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} |
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} |
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mux->cached_state = chan->channel; |
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return 0; |
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} |
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static void iio_mux_deselect(struct mux *mux) |
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{ |
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mux_control_deselect(mux->control); |
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} |
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static int mux_read_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *chan, |
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int *val, int *val2, long mask) |
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{ |
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struct mux *mux = iio_priv(indio_dev); |
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int idx = chan - mux->chan; |
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int ret; |
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ret = iio_mux_select(mux, idx); |
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if (ret < 0) |
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return ret; |
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switch (mask) { |
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case IIO_CHAN_INFO_RAW: |
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ret = iio_read_channel_raw(mux->parent, val); |
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break; |
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case IIO_CHAN_INFO_SCALE: |
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ret = iio_read_channel_scale(mux->parent, val, val2); |
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break; |
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default: |
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ret = -EINVAL; |
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} |
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iio_mux_deselect(mux); |
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return ret; |
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} |
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static int mux_read_avail(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *chan, |
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const int **vals, int *type, int *length, |
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long mask) |
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{ |
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struct mux *mux = iio_priv(indio_dev); |
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int idx = chan - mux->chan; |
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int ret; |
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ret = iio_mux_select(mux, idx); |
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if (ret < 0) |
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return ret; |
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switch (mask) { |
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case IIO_CHAN_INFO_RAW: |
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*type = IIO_VAL_INT; |
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ret = iio_read_avail_channel_raw(mux->parent, vals, length); |
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break; |
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default: |
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ret = -EINVAL; |
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} |
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iio_mux_deselect(mux); |
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return ret; |
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} |
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static int mux_write_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *chan, |
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int val, int val2, long mask) |
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{ |
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struct mux *mux = iio_priv(indio_dev); |
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int idx = chan - mux->chan; |
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int ret; |
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ret = iio_mux_select(mux, idx); |
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if (ret < 0) |
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return ret; |
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switch (mask) { |
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case IIO_CHAN_INFO_RAW: |
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ret = iio_write_channel_raw(mux->parent, val); |
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break; |
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default: |
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ret = -EINVAL; |
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} |
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iio_mux_deselect(mux); |
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return ret; |
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} |
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static const struct iio_info mux_info = { |
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.read_raw = mux_read_raw, |
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.read_avail = mux_read_avail, |
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.write_raw = mux_write_raw, |
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}; |
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static ssize_t mux_read_ext_info(struct iio_dev *indio_dev, uintptr_t private, |
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struct iio_chan_spec const *chan, char *buf) |
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{ |
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struct mux *mux = iio_priv(indio_dev); |
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int idx = chan - mux->chan; |
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ssize_t ret; |
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ret = iio_mux_select(mux, idx); |
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if (ret < 0) |
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return ret; |
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ret = iio_read_channel_ext_info(mux->parent, |
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mux->ext_info[private].name, |
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buf); |
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iio_mux_deselect(mux); |
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return ret; |
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} |
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static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private, |
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struct iio_chan_spec const *chan, |
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const char *buf, size_t len) |
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{ |
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struct device *dev = indio_dev->dev.parent; |
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struct mux *mux = iio_priv(indio_dev); |
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int idx = chan - mux->chan; |
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char *new; |
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ssize_t ret; |
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if (len >= PAGE_SIZE) |
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return -EINVAL; |
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ret = iio_mux_select(mux, idx); |
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if (ret < 0) |
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return ret; |
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new = devm_kmemdup(dev, buf, len + 1, GFP_KERNEL); |
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if (!new) { |
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iio_mux_deselect(mux); |
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return -ENOMEM; |
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} |
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new[len] = 0; |
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ret = iio_write_channel_ext_info(mux->parent, |
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mux->ext_info[private].name, |
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buf, len); |
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if (ret < 0) { |
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iio_mux_deselect(mux); |
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devm_kfree(dev, new); |
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return ret; |
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} |
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devm_kfree(dev, mux->child[idx].ext_info_cache[private].data); |
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mux->child[idx].ext_info_cache[private].data = new; |
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mux->child[idx].ext_info_cache[private].size = len; |
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iio_mux_deselect(mux); |
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return ret; |
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} |
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static int mux_configure_channel(struct device *dev, struct mux *mux, |
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u32 state, const char *label, int idx) |
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{ |
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struct mux_child *child = &mux->child[idx]; |
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struct iio_chan_spec *chan = &mux->chan[idx]; |
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struct iio_chan_spec const *pchan = mux->parent->channel; |
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char *page = NULL; |
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int num_ext_info; |
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int i; |
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int ret; |
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chan->indexed = 1; |
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chan->output = pchan->output; |
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chan->datasheet_name = label; |
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chan->ext_info = mux->ext_info; |
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ret = iio_get_channel_type(mux->parent, &chan->type); |
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if (ret < 0) { |
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dev_err(dev, "failed to get parent channel type\n"); |
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return ret; |
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} |
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if (iio_channel_has_info(pchan, IIO_CHAN_INFO_RAW)) |
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chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW); |
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if (iio_channel_has_info(pchan, IIO_CHAN_INFO_SCALE)) |
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chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE); |
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if (iio_channel_has_available(pchan, IIO_CHAN_INFO_RAW)) |
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chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW); |
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if (state >= mux_control_states(mux->control)) { |
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dev_err(dev, "too many channels\n"); |
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return -EINVAL; |
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} |
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chan->channel = state; |
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num_ext_info = iio_get_channel_ext_info_count(mux->parent); |
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if (num_ext_info) { |
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page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL); |
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if (!page) |
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return -ENOMEM; |
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} |
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child->ext_info_cache = devm_kcalloc(dev, |
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num_ext_info, |
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sizeof(*child->ext_info_cache), |
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GFP_KERNEL); |
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if (!child->ext_info_cache) |
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return -ENOMEM; |
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for (i = 0; i < num_ext_info; ++i) { |
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child->ext_info_cache[i].size = -1; |
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if (!pchan->ext_info[i].write) |
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continue; |
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if (!pchan->ext_info[i].read) |
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continue; |
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ret = iio_read_channel_ext_info(mux->parent, |
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mux->ext_info[i].name, |
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page); |
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if (ret < 0) { |
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dev_err(dev, "failed to get ext_info '%s'\n", |
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pchan->ext_info[i].name); |
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return ret; |
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} |
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if (ret >= PAGE_SIZE) { |
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dev_err(dev, "too large ext_info '%s'\n", |
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pchan->ext_info[i].name); |
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return -EINVAL; |
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} |
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child->ext_info_cache[i].data = devm_kmemdup(dev, page, ret + 1, |
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GFP_KERNEL); |
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if (!child->ext_info_cache[i].data) |
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return -ENOMEM; |
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child->ext_info_cache[i].data[ret] = 0; |
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child->ext_info_cache[i].size = ret; |
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} |
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if (page) |
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devm_kfree(dev, page); |
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return 0; |
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} |
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/* |
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* Same as of_property_for_each_string(), but also keeps track of the |
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* index of each string. |
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*/ |
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#define of_property_for_each_string_index(np, propname, prop, s, i) \ |
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for (prop = of_find_property(np, propname, NULL), \ |
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s = of_prop_next_string(prop, NULL), \ |
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i = 0; \ |
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s; \ |
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s = of_prop_next_string(prop, s), \ |
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i++) |
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static int mux_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct device_node *np = pdev->dev.of_node; |
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struct iio_dev *indio_dev; |
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struct iio_channel *parent; |
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struct mux *mux; |
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struct property *prop; |
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const char *label; |
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u32 state; |
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int sizeof_ext_info; |
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int children; |
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int sizeof_priv; |
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int i; |
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int ret; |
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if (!np) |
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return -ENODEV; |
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parent = devm_iio_channel_get(dev, "parent"); |
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if (IS_ERR(parent)) |
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return dev_err_probe(dev, PTR_ERR(parent), |
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"failed to get parent channel\n"); |
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sizeof_ext_info = iio_get_channel_ext_info_count(parent); |
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if (sizeof_ext_info) { |
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sizeof_ext_info += 1; /* one extra entry for the sentinel */ |
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sizeof_ext_info *= sizeof(*mux->ext_info); |
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} |
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children = 0; |
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of_property_for_each_string(np, "channels", prop, label) { |
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if (*label) |
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children++; |
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} |
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if (children <= 0) { |
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dev_err(dev, "not even a single child\n"); |
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return -EINVAL; |
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} |
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sizeof_priv = sizeof(*mux); |
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sizeof_priv += sizeof(*mux->child) * children; |
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sizeof_priv += sizeof(*mux->chan) * children; |
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sizeof_priv += sizeof_ext_info; |
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indio_dev = devm_iio_device_alloc(dev, sizeof_priv); |
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if (!indio_dev) |
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return -ENOMEM; |
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mux = iio_priv(indio_dev); |
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mux->child = (struct mux_child *)(mux + 1); |
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mux->chan = (struct iio_chan_spec *)(mux->child + children); |
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platform_set_drvdata(pdev, indio_dev); |
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mux->parent = parent; |
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mux->cached_state = -1; |
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indio_dev->name = dev_name(dev); |
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indio_dev->info = &mux_info; |
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indio_dev->modes = INDIO_DIRECT_MODE; |
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indio_dev->channels = mux->chan; |
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indio_dev->num_channels = children; |
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if (sizeof_ext_info) { |
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mux->ext_info = devm_kmemdup(dev, |
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parent->channel->ext_info, |
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sizeof_ext_info, GFP_KERNEL); |
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if (!mux->ext_info) |
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return -ENOMEM; |
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for (i = 0; mux->ext_info[i].name; ++i) { |
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if (parent->channel->ext_info[i].read) |
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mux->ext_info[i].read = mux_read_ext_info; |
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if (parent->channel->ext_info[i].write) |
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mux->ext_info[i].write = mux_write_ext_info; |
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mux->ext_info[i].private = i; |
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} |
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} |
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mux->control = devm_mux_control_get(dev, NULL); |
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if (IS_ERR(mux->control)) { |
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if (PTR_ERR(mux->control) != -EPROBE_DEFER) |
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dev_err(dev, "failed to get control-mux\n"); |
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return PTR_ERR(mux->control); |
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} |
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i = 0; |
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of_property_for_each_string_index(np, "channels", prop, label, state) { |
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if (!*label) |
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continue; |
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ret = mux_configure_channel(dev, mux, state, label, i++); |
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if (ret < 0) |
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return ret; |
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} |
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ret = devm_iio_device_register(dev, indio_dev); |
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if (ret) { |
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dev_err(dev, "failed to register iio device\n"); |
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return ret; |
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} |
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return 0; |
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} |
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static const struct of_device_id mux_match[] = { |
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{ .compatible = "io-channel-mux" }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, mux_match); |
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static struct platform_driver mux_driver = { |
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.probe = mux_probe, |
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.driver = { |
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.name = "iio-mux", |
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.of_match_table = mux_match, |
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}, |
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}; |
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module_platform_driver(mux_driver); |
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MODULE_DESCRIPTION("IIO multiplexer driver"); |
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MODULE_AUTHOR("Peter Rosin <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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