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    Subject[PATCH 4/5] IIO:hwmon interface client driver.
    Date
    From: Jonathan Cameron <jic23@cam.ac.uk>

    Should move to drivers/hwmon once people are happy with it.

    Minimal support of simple in, curr and temp attributes
    so far.

    Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
    ---
    drivers/iio/Kconfig | 8 ++
    drivers/iio/Makefile | 1 +
    drivers/iio/iio_hwmon.c | 227 +++++++++++++++++++++++++++++++++++++++++++++++
    3 files changed, 236 insertions(+), 0 deletions(-)

    diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
    index 308bc97..c2f0970 100644
    --- a/drivers/iio/Kconfig
    +++ b/drivers/iio/Kconfig
    @@ -11,6 +11,14 @@ menuconfig IIO

    if IIO

    +config IIO_HWMON
    + tristate "Hwmon driver that uses channels specified via iio maps"
    + depends on HWMON
    + help
    + This is a platform driver that in combination with a suitable
    + map allows IIO devices to provide basic hwmon functionality
    + for those channels specified in the map.
    +
    source "drivers/iio/adc/Kconfig"
    source "drivers/iio/imu/Kconfig"
    source "drivers/iio/light/Kconfig"
    diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
    index cfb588a..5f9c01a 100644
    --- a/drivers/iio/Makefile
    +++ b/drivers/iio/Makefile
    @@ -6,6 +6,7 @@ obj-y = inkern.o
    obj-$(CONFIG_IIO) += iio.o
    industrialio-y := core.o

    +obj-$(CONFIG_IIO_HWMON) += iio_hwmon.o
    obj-y += adc/
    obj-y += imu/
    obj-y += light/
    diff --git a/drivers/iio/iio_hwmon.c b/drivers/iio/iio_hwmon.c
    new file mode 100644
    index 0000000..4bd7651
    --- /dev/null
    +++ b/drivers/iio/iio_hwmon.c
    @@ -0,0 +1,227 @@
    +/* Hwmon client for industrial I/O devices
    + *
    + * Copyright (c) 2011 Jonathan Cameron
    + *
    + * 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.
    + *
    + * Limited functionality currently supported.
    + */
    +
    +#include <linux/kernel.h>
    +#include <linux/slab.h>
    +#include <linux/module.h>
    +#include <linux/err.h>
    +#include <linux/platform_device.h>
    +#include <linux/iio/inkern.h>
    +#include <linux/hwmon.h>
    +#include <linux/hwmon-sysfs.h>
    +
    +/**
    + * struct iio_hwmon_state - device instance state
    + * @channels: filled with null terminated array of channels from iio
    + * @num_channels: number of channels in channels (saves counting twice)
    + * @hwmon_dev: associated hwmon device
    + * @attr_group: the group of attributes
    + * @attrs: null terminated array of attribute pointers.
    + */
    +struct iio_hwmon_state {
    + struct iio_channel **channels;
    + int num_channels;
    + struct device *hwmon_dev;
    + struct attribute_group attr_group;
    + struct attribute **attrs;
    +};
    +
    +/*
    + * Assumes that IIO and hwmon operate in the same base units.
    + * This is supposed to be true, but needs verification for
    + * new channel types.
    + */
    +static ssize_t iio_hwmon_read_val(struct device *dev,
    + struct device_attribute *attr,
    + char *buf)
    +{
    + long result;
    + int val, ret, scaleint, scalepart;
    + struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
    + struct iio_hwmon_state *state = dev_get_drvdata(dev);
    +
    + /*
    + * No locking between this pair, so theoretically possible
    + * the scale has changed.
    + */
    + ret = iio_read_channel_raw(state->channels[sattr->index],
    + &val);
    + if (ret < 0)
    + return ret;
    +
    + ret = iio_read_channel_scale(state->channels[sattr->index],
    + &scaleint, &scalepart);
    + if (ret < 0)
    + return ret;
    + switch (ret) {
    + case IIO_VAL_INT:
    + result = val * scaleint;
    + break;
    + case IIO_VAL_INT_PLUS_MICRO:
    + result = (long)val * (long)scaleint +
    + div_s64((s64)val * (s64)scalepart, 1000000LL);
    + break;
    + case IIO_VAL_INT_PLUS_NANO:
    + result = (long)val * (long)scaleint +
    + div_s64((s64)val * (s64)scalepart, 1000000000LL);
    + break;
    + default:
    + return -EINVAL;
    + }
    + return sprintf(buf, "%ld\n", result);
    +}
    +
    +static void iio_hwmon_free_attrs(struct iio_hwmon_state *st)
    +{
    + int i;
    + struct sensor_device_attribute *a;
    + for (i = 0; i < st->num_channels; i++)
    + if (st->attrs[i]) {
    + a = to_sensor_dev_attr(
    + container_of(st->attrs[i],
    + struct device_attribute,
    + attr));
    + kfree(a);
    + }
    +}
    +
    +static int __devinit iio_hwmon_probe(struct platform_device *pdev)
    +{
    + struct iio_hwmon_state *st;
    + struct sensor_device_attribute *a;
    + int ret, i;
    + int in_i = 1, temp_i = 1, curr_i = 1;
    +
    + st = kzalloc(sizeof(*st), GFP_KERNEL);
    + if (st == NULL) {
    + ret = -ENOMEM;
    + goto error_ret;
    + }
    +
    + st->channels = iio_channel_get_all(&pdev->dev, NULL);
    + if (IS_ERR(st->channels)) {
    + ret = PTR_ERR(st->channels);
    + goto error_free_state;
    + }
    +
    + /* count how many attributes we have */
    + while (st->channels[st->num_channels])
    + st->num_channels++;
    +
    + st->attrs = kzalloc(sizeof(st->attrs) * (st->num_channels + 1),
    + GFP_KERNEL);
    + if (st->attrs == NULL) {
    + ret = -ENOMEM;
    + goto error_release_channels;
    + }
    + for (i = 0; i < st->num_channels; i++) {
    + a = kzalloc(sizeof(*a), GFP_KERNEL);
    + if (a == NULL) {
    + ret = -ENOMEM;
    + goto error_free_attrs;
    + }
    +
    + sysfs_attr_init(&a->dev_attr.attr);
    + switch (iio_get_channel_type(st->channels[i])) {
    + case IIO_VOLTAGE:
    + a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
    + "in%d_input",
    + in_i++);
    + break;
    + case IIO_TEMP:
    + a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
    + "temp%d_input",
    + temp_i++);
    + break;
    + case IIO_CURRENT:
    + a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
    + "curr%d_input",
    + curr_i++);
    + break;
    + default:
    + ret = -EINVAL;
    + kfree(a);
    + goto error_free_attrs;
    + }
    + if (a->dev_attr.attr.name == NULL) {
    + kfree(a);
    + ret = -ENOMEM;
    + goto error_free_attrs;
    + }
    + a->dev_attr.show = iio_hwmon_read_val;
    + a->dev_attr.attr.mode = S_IRUGO;
    + a->index = i;
    + st->attrs[i] = &a->dev_attr.attr;
    + }
    +
    + st->attr_group.attrs = st->attrs;
    + platform_set_drvdata(pdev, st);
    + ret = sysfs_create_group(&pdev->dev.kobj, &st->attr_group);
    + if (ret < 0)
    + goto error_free_attrs;
    +
    + st->hwmon_dev = hwmon_device_register(&pdev->dev);
    + if (IS_ERR(st->hwmon_dev)) {
    + ret = PTR_ERR(st->hwmon_dev);
    + goto error_remove_group;
    + }
    + return 0;
    +
    +error_remove_group:
    + sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
    +error_free_attrs:
    + iio_hwmon_free_attrs(st);
    + kfree(st->attrs);
    +error_release_channels:
    + iio_channel_release_all(st->channels);
    +error_free_state:
    + kfree(st);
    +error_ret:
    + return ret;
    +}
    +
    +static int __devexit iio_hwmon_remove(struct platform_device *pdev)
    +{
    + struct iio_hwmon_state *st = platform_get_drvdata(pdev);
    +
    + hwmon_device_unregister(st->hwmon_dev);
    + sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
    + iio_hwmon_free_attrs(st);
    + kfree(st->attrs);
    + iio_channel_release_all(st->channels);
    +
    + return 0;
    +}
    +
    +static struct platform_driver __refdata iio_hwmon_driver = {
    + .driver = {
    + .name = "iio_hwmon",
    + .owner = THIS_MODULE,
    + },
    + .probe = iio_hwmon_probe,
    + .remove = __devexit_p(iio_hwmon_remove),
    +};
    +
    +static int iio_inkern_init(void)
    +{
    + return platform_driver_register(&iio_hwmon_driver);
    +}
    +module_init(iio_inkern_init);
    +
    +static void iio_inkern_exit(void)
    +{
    + platform_driver_unregister(&iio_hwmon_driver);
    +}
    +module_exit(iio_inkern_exit);
    +
    +MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
    +MODULE_DESCRIPTION("IIO to hwmon driver");
    +MODULE_LICENSE("GPL v2");
    --
    1.7.7.2


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