lkml.org 
[lkml]   [2011]   [Oct]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 5/6] IIO:hwmon interface client driver.
On Wed, Oct 19, 2011 at 10:47:07AM -0400, Jonathan Cameron wrote:
> 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>

Couple of comments below.

> ---
> drivers/iio/Kconfig | 8 ++
> drivers/iio/Makefile | 1 +
> drivers/iio/iio_hwmon.c | 214 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 223 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
> index 308bc97..fb6d0a1 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"
> + 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.
> +
Should probably also depend on HWMON

> +
> 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..6eeceeb
> --- /dev/null
> +++ b/drivers/iio/iio_hwmon.c
> @@ -0,0 +1,214 @@
> +/* 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);

Does this need more than one line ?

> + 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 = val * (scaleint * 1000000 + scalepart)/1000000;
> + break;
> + case IIO_VAL_INT_PLUS_NANO:
> + result = val * (scaleint * 1000000000 + scalepart)/1000000000;

I think you might want to use long or even long long for all variables here,
or at least typecast to long or long long. Concern is that for example
"scaleint * 1000000000" may be calculated as int and would easily overflow;
even as long it would easily overflow.
There should be blanks around '/' (why doesn't checkpatch complain about this anymore ?).

> + 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 = 0;
> + 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)*(i+1), GFP_KERNEL);

Blanks around '*' and '+'.
i == 0 here, so what is the point, and what are you trying to do ?
Should it be st->num_channels instead of i + 1 ?

> + if (st->attrs == NULL) {
> + ret = -ENOMEM;
> + goto error_release_channels;
> + }
> + for (i = 0; i < st->num_channels; i++) {
> + a = kzalloc(sizeof(*a), GFP_KERNEL);

What if this fails ?

> + 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;
> + goto error_free_attrs;
> + }
> + if (a->dev_attr.attr.name == NULL) {
> + ret = -ENOMEM;
> + goto error_free_attrs;
> + }
I think this and the above EINVAL will result in leaking "a" since you did not store it
in st->attrs[i] yet.

> + 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;
> + st->hwmon_dev = hwmon_device_register(&pdev->dev);
> +
Would be better to do this after successfully creating the sysfs attributes.

> + ret = sysfs_create_group(&pdev->dev.kobj, &st->attr_group);
> + if (ret < 0)
> + goto error_free_attrs;
> +
> + platform_set_drvdata(pdev, st);
> +
You need to do this prior to creating the sysfs entries, since the read functions
expect it to be there.

> + return 0;
> +
> +error_free_attrs:

This doesn't unregister the hwmon device.

> + 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);
> +
> + sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
> + iio_hwmon_free_attrs(st);
> + kfree(st->attrs);
> + hwmon_device_unregister(st->hwmon_dev);
> + 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
>

--
Guenter Roeck
Distinguished Engineer
PDU IP Systems


\
 
 \ /
  Last update: 2011-10-19 18:43    [from the cache]
©2003-2011 Jasper Spaans