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Message-ID: <CAEnQRZCa-h9o--2aRXiXHwy9e2xbKENfKk-Xqy9GF5qExud+cg@mail.gmail.com>
Date: Sun, 26 Apr 2015 22:36:11 +0300
From: Daniel Baluta <daniel.baluta@...el.com>
To: Jonathan Cameron <jic23@...nel.org>
Cc: Daniel Baluta <daniel.baluta@...el.com>,
Joel Becker <jlbec@...lplan.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Hartmut Knaack <knaack.h@....de>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
"octavian.purdila@...el.com" <octavian.purdila@...el.com>,
Paul Bolle <pebolle@...cali.nl>, patrick.porlan@...el.com,
adriana.reus@...el.com, constantin.musca@...el.com,
marten@...uitiveaerial.com
Subject: Re: [PATCH v4 2/4] iio: core: Introduce IIO configfs support
On Sun, Apr 26, 2015 at 10:26 PM, Jonathan Cameron <jic23@...nel.org> wrote:
> On 20/04/15 15:02, Daniel Baluta wrote:
>> This creates an IIO configfs subystem named "iio", with a default "triggers"
>> group.
>>
>> Triggers group is used for handling software triggers. To create a new software
>> trigger one must create a directory inside the trigger directory.
>>
>> Software trigger name MUST follow the following convention:
>> * <trigger-type>-<trigger-name>
>> Where:
>> * <trigger_type>, specifies the interrupt source (e.g: hrtimer)
>> * <trigger-name>, specifies the IIO device trigger name
>>
>> Failing to follow this convention will result in an directory creation error.
>>
>> E.g, assuming that hrtimer trigger type is registered with IIO software
>> trigger core:
>>
>> $ mkdir /config/iio/triggers/hrtimer-instance1
>>
>> Signed-off-by: Daniel Baluta <daniel.baluta@...el.com>
> Looks good. Couple of little comments inline.
>
> Jonathan
>> ---
>> drivers/iio/Kconfig | 8 +++
>> drivers/iio/Makefile | 1 +
>> drivers/iio/industrialio-configfs.c | 117 ++++++++++++++++++++++++++++++++++++
>> 3 files changed, 126 insertions(+)
>> create mode 100644 drivers/iio/industrialio-configfs.c
>>
>> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
>> index de7f1d9..c310156 100644
>> --- a/drivers/iio/Kconfig
>> +++ b/drivers/iio/Kconfig
>> @@ -18,6 +18,14 @@ config IIO_BUFFER
>> Provide core support for various buffer based data
>> acquisition methods.
>>
>> +config IIO_CONFIGFS
>> + tristate "Enable IIO configuration via configfs"
>> + select CONFIGFS_FS
>> + help
>> + This allows configuring various IIO bits through configfs
>> + (e.g. software triggers). For more info see
>> + Documentation/iio/iio_configfs.txt.
>> +
>> if IIO_BUFFER
>>
>> config IIO_BUFFER_CB
>> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
>> index df87975..31aead3 100644
>> --- a/drivers/iio/Makefile
>> +++ b/drivers/iio/Makefile
>> @@ -10,6 +10,7 @@ industrialio-$(CONFIG_IIO_SW_TRIGGER) += industrialio-sw-trigger.o
>> industrialio-$(CONFIG_IIO_BUFFER_CB) += buffer_cb.o
>>
>> obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
>> +obj-$(CONFIG_IIO_CONFIGFS) += industrialio-configfs.o
>> obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
>>
>> obj-y += accel/
>> diff --git a/drivers/iio/industrialio-configfs.c b/drivers/iio/industrialio-configfs.c
>> new file mode 100644
>> index 0000000..0361434
>> --- /dev/null
>> +++ b/drivers/iio/industrialio-configfs.c
>> @@ -0,0 +1,117 @@
>> +/*
>> + * Industrial I/O configfs bits
>> + *
>> + * Copyright (c) 2015 Intel Corporation
>> + *
>> + * 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/configfs.h>
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/kmod.h>
>> +#include <linux/slab.h>
>> +
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/sw_trigger.h>
>> +
>> +#define MAX_NAME_LEN 32
> Strikes me as perhaps a little short given we want to allow 'almost' arbitary names for the triggers.
We are anyhow, limited by the configfs name len here.
http://lxr.linux.no/linux+v3.19.1/include/linux/configfs.h#L47
>> +
>> +static struct config_group *trigger_make_group(struct config_group *group,
>> + const char *name)
>> +{
>> + char *type_name;
>> + char *trigger_name;
>> + char buf[MAX_NAME_LEN];
>> + struct iio_sw_trigger *t;
>> +
>> + snprintf(buf, MAX_NAME_LEN, "%s", name);
>> +
>> + /* group name should have the form <trigger-type>-<trigger-name> */
>> + type_name = buf;
>> + trigger_name = strchr(buf, '-');
>> + if (!trigger_name) {
>> + pr_err("Unable to locate '-' in %s. Use <type>-<name>.\n", buf);
>> + return ERR_PTR(-EINVAL);
>> + }
>> +
>> + /* replace - with \0, this nicely separates the two strings */
>> + *trigger_name = '\0';
> Dirty trick, but I like it.
Me too, I borrowed it from the usb gadget code. :)
>> + trigger_name++;
>> +
>> + t = iio_sw_trigger_create(type_name, trigger_name);
>> + if (IS_ERR(t))
>> + return ERR_CAST(t);
>> +
>> + config_item_set_name(&t->group.cg_item, name);
>> +
>> + return &t->group;
>> +}
>> +
>> +static void trigger_drop_group(struct config_group *group,
>> + struct config_item *item)
>> +{
>> + struct iio_sw_trigger *t = to_iio_sw_trigger(item);
>> +
>> + if (t)
>> + iio_sw_trigger_destroy(t);
>> + config_item_put(item);
>> +}
>> +
>> +static struct configfs_group_operations triggers_ops = {
>> + .make_group = &trigger_make_group,
>> + .drop_item = &trigger_drop_group,
>> +};
>> +
>> +static struct config_item_type iio_triggers_group_type = {
>> + .ct_group_ops = &triggers_ops,
>> + .ct_owner = THIS_MODULE,
>> +};
>> +
>> +static struct config_group iio_triggers_group = {
>> + .cg_item = {
>> + .ci_namebuf = "triggers",
>> + .ci_type = &iio_triggers_group_type,
>> + },
>> +};
>> +
>> +static struct config_group *iio_root_default_groups[] = {
>> + &iio_triggers_group,
>> + NULL
>> +};
>> +
>> +static struct config_item_type iio_root_group_type = {
>> + .ct_owner = THIS_MODULE,
>> +};
>> +
>> +static struct configfs_subsystem iio_configfs_subsys = {
>> + .su_group = {
>> + .cg_item = {
>> + .ci_namebuf = "iio",
>> + .ci_type = &iio_root_group_type,
>> + },
>> + .default_groups = iio_root_default_groups,
>> + },
>> + .su_mutex = __MUTEX_INITIALIZER(iio_configfs_subsys.su_mutex),
>> +};
>> +
>> +static int __init iio_configfs_init(void)
>> +{
>> + config_group_init(&iio_triggers_group);
>> + config_group_init(&iio_configfs_subsys.su_group);
>> +
>> + return configfs_register_subsystem(&iio_configfs_subsys);
>> +}
>> +module_init(iio_configfs_init);
>> +
>> +static void __exit iio_configfs_exit(void)
>> +{
>> + configfs_unregister_subsystem(&iio_configfs_subsys);
>> +}
>> +module_exit(iio_configfs_exit);
>> +
>> +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@...el.com>");
>> +MODULE_DESCRIPTION("Industrial I/O configfs support");
>> +MODULE_LICENSE("GPL v2");
thanks,
Daniel.
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