From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932162AbcKSPtN (ORCPT ); Sat, 19 Nov 2016 10:49:13 -0500 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:47503 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752985AbcKSPtI (ORCPT ); Sat, 19 Nov 2016 10:49:08 -0500 Subject: Re: [RFC PATCH v2 5/7] iio: multiplexer: new iio category and iio-mux driver To: Peter Rosin , linux-kernel@vger.kernel.org References: <1479419289-17553-1-git-send-email-peda@axentia.se> <1479419289-17553-6-git-send-email-peda@axentia.se> From: Jonathan Cameron Cc: Wolfram Sang , Rob Herring , Mark Rutland , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Arnd Bergmann , Greg Kroah-Hartman , linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-iio@vger.kernel.org Message-ID: Date: Sat, 19 Nov 2016 15:49:04 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1479419289-17553-6-git-send-email-peda@axentia.se> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/11/16 21:48, Peter Rosin wrote: > When a multiplexer changes how an iio device behaves (for example > by feeding different signals to an ADC), this driver can be used > create one virtual iio channel for each multiplexer state. > > Depends on the generic multiplexer driver. I'm not really following what all the ext info stuff in here is about. Could you add a little more description of that? Perhaps an example of how it is used and what the resulting interface looks like? Thanks, Jonathan > --- > drivers/iio/Kconfig | 1 + > drivers/iio/Makefile | 1 + > drivers/iio/multiplexer/Kconfig | 17 ++ > drivers/iio/multiplexer/Makefile | 6 + > drivers/iio/multiplexer/iio-mux.c | 444 ++++++++++++++++++++++++++++++++++++++ > 5 files changed, 469 insertions(+) > create mode 100644 drivers/iio/multiplexer/Kconfig > create mode 100644 drivers/iio/multiplexer/Makefile > create mode 100644 drivers/iio/multiplexer/iio-mux.c > > diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig > index 6743b18194fb..dcb541d0d70e 100644 > --- a/drivers/iio/Kconfig > +++ b/drivers/iio/Kconfig > @@ -82,6 +82,7 @@ source "drivers/iio/humidity/Kconfig" > source "drivers/iio/imu/Kconfig" > source "drivers/iio/light/Kconfig" > source "drivers/iio/magnetometer/Kconfig" > +source "drivers/iio/multiplexer/Kconfig" > source "drivers/iio/orientation/Kconfig" > if IIO_TRIGGER > source "drivers/iio/trigger/Kconfig" > diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile > index 87e4c4369e2f..f9879c29cf6f 100644 > --- a/drivers/iio/Makefile > +++ b/drivers/iio/Makefile > @@ -27,6 +27,7 @@ obj-y += humidity/ > obj-y += imu/ > obj-y += light/ > obj-y += magnetometer/ > +obj-y += multiplexer/ > obj-y += orientation/ > obj-y += potentiometer/ > obj-y += pressure/ > diff --git a/drivers/iio/multiplexer/Kconfig b/drivers/iio/multiplexer/Kconfig > new file mode 100644 > index 000000000000..31cbe4509366 > --- /dev/null > +++ b/drivers/iio/multiplexer/Kconfig > @@ -0,0 +1,17 @@ > +# > +# Multiplexer drivers > +# > +# When adding new entries keep the list in alphabetical order > + > +menu "Multiplexers" > + > +config IIO_MUX > + tristate "IIO multiplexer driver" > + depends on OF && MUX_GPIO > + 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 000000000000..68be3c4abd07 > --- /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 000000000000..2a8d00da990b > --- /dev/null > +++ b/drivers/iio/multiplexer/iio-mux.c > @@ -0,0 +1,444 @@ > +/* > + * IIO multiplexer driver > + * > + * Copyright (C) 2016 Axentia Technologies AB > + * > + * Author: Peter Rosin > + * > + * 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 > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct mux_ext_info_cache { > + char *data; > + size_t size; > +}; > + > +struct mux_child { > + u32 state; > + > + struct mux_ext_info_cache *ext_info_cache; > +}; > + > +struct mux { > + u32 cached_state; > + struct mux_control *control; > + struct iio_channel *parent; > + struct iio_dev *indio_dev; > + struct iio_chan_spec *c; > + 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]; > + int ret; > + int i; > + > + ret = mux_control_select(mux->control, child->state); > + if (ret < 0) { > + mux->cached_state = -1; > + return ret; > + } > + > + if (mux->cached_state == child->state) > + return 0; > + I don't follow what is going on here.. Perhaps you could explain futher? > + if (mux->c[idx].ext_info) { > + for (i = 0; mux->c[idx].ext_info[i].name; ++i) { > + const char *attr = mux->c[idx].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 = child->state; > + > + 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->c; > + 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->c; > + 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->c; > + 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->c; > + 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->c; > + char *new; > + ssize_t ret; > + > + 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, > + struct device_node *child_np, int idx) > +{ > + struct mux_child *child = &mux->child[idx]; > + struct iio_chan_spec *c = &mux->c[idx]; > + const struct iio_chan_spec *pc = mux->parent->channel; > + char *page; > + int num_ext_info; > + int i; > + int ret; > + > + c->indexed = 1; > + c->channel = idx; > + c->output = pc->output; > + c->datasheet_name = child_np->name; > + c->ext_info = mux->ext_info; > + > + ret = iio_get_channel_type(mux->parent, &c->type); > + if (ret < 0) { > + dev_err(dev, "failed to get parent channel type\n"); > + return ret; > + } > + > + if (iio_channel_has_info(pc, IIO_CHAN_INFO_RAW)) > + c->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW); > + if (iio_channel_has_info(pc, IIO_CHAN_INFO_SCALE)) > + c->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE); > + > + if (iio_channel_has_available(pc, IIO_CHAN_INFO_RAW)) > + c->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW); > + > + ret = of_property_read_u32(child_np, "reg", &child->state); > + if (ret < 0) { > + dev_err(dev, "no reg property for node '%s'\n", child_np->name); > + return ret; > + } > + > + for (i = 0; i < idx; ++i) { > + if (mux->child[i].state == child->state) { > + dev_err(dev, "double use of reg %d\n", child->state); > + return -EINVAL; > + } > + } > + > + 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 (!pc->ext_info[i].write) > + continue; > + if (!pc->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", > + pc->ext_info[i].name); > + return ret; > + } > + if (ret >= PAGE_SIZE) { > + dev_err(dev, "too large ext_info '%s'\n", > + pc->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 (num_ext_info) > + devm_kfree(dev, page); > + > + return 0; > +} > + > +static int mux_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct device_node *np = pdev->dev.of_node; > + struct device_node *child_np; > + struct iio_dev *indio_dev; > + struct iio_channel *parent; > + struct mux *mux; > + 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 = of_get_child_count(np); > + 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->c) * 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->c = (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->c; > + 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; > + } > + } > + > + i = 0; > + for_each_child_of_node(np, child_np) { > + ret = mux_configure_channel(dev, mux, child_np, i); > + if (ret < 0) > + return ret; > + i++; > + } > + > + mux->control = devm_mux_control_get(dev, "mux"); > + 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); > + } > + > + 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 = "iio-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 "); > +MODULE_LICENSE("GPL v2"); >