| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Tue, 12 Mar 2019 19:19:33 +0100
From: Jacek Anaszewski <jacek.anaszewski@...il.com>
To: Dan Murphy <dmurphy@...com>, linux-leds@...r.kernel.org
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
pavel@....cz, robh@...nel.org,
Baolin Wang <baolin.wang@...aro.org>,
Daniel Mack <daniel@...que.org>,
Linus Walleij <linus.walleij@...aro.org>,
Oleh Kravchenko <oleg@....org.ua>,
Sakari Ailus <sakari.ailus@...ux.intel.com>
Subject: Re: [PATCH 02/25] leds: core: Add support for composing LED class
device names
On 3/12/19 6:46 PM, Dan Murphy wrote:
> On 3/12/19 12:28 PM, Jacek Anaszewski wrote:
>> Hi Dan,
>>
>> On 3/12/19 6:15 PM, Dan Murphy wrote:
>>> On 3/10/19 1:28 PM, Jacek Anaszewski wrote:
>>>> Add public led_compose_name() API for composing LED class device
>>>> name basing on fwnode_handle data. The function composes device name
>>>> according to either a new <color:function> pattern or the legacy
>>>> <devicename:color:function> pattern. The decision on using the
>>>> particular pattern is made basing on whether fwnode contains new
>>>> "function" and "color" properties, or the legacy "label" proeprty.
>>>>
>>>> Backwards compatibility with in-driver hard-coded LED class device
>>>> names is assured thanks to the default_desc argument.
>>>>
>>>> In case none of the aforementioned properties was found, then, for OF
>>>> nodes, the node name is adopted for LED class device name.
>>>>
>>>> Alongside these changes added is a new tool - tools/leds/get_led_device_info.sh.
>>>> The tool allows retrieving details of a LED class device's parent device,
>>>> which proves that getting rid of a devicename section from LED name pattern
>>>> is justified since this information is already available in sysfs.
>>>>
>>>> Signed-off-by: Jacek Anaszewski <jacek.anaszewski@...il.com>
>>>> Cc: Baolin Wang <baolin.wang@...aro.org>
>>>> Cc: Daniel Mack <daniel@...que.org>
>>>> Cc: Dan Murphy <dmurphy@...com>
>>>> Cc: Linus Walleij <linus.walleij@...aro.org>
>>>> Cc: Oleh Kravchenko <oleg@....org.ua>
>>>> Cc: Sakari Ailus <sakari.ailus@...ux.intel.com>
>>>> ---
>>>> Documentation/leds/leds-class.txt | 20 +++++++++-
>>>> drivers/leds/led-core.c | 82 +++++++++++++++++++++++++++++++++++++++
>>>> include/linux/leds.h | 31 +++++++++++++++
>>>> tools/leds/get_led_device_info.sh | 81 ++++++++++++++++++++++++++++++++++++++
>>>> 4 files changed, 213 insertions(+), 1 deletion(-)
>>>> create mode 100755 tools/leds/get_led_device_info.sh
>>>>
>>>> diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt
>>>> index 8b39cc6b03ee..866fe87063d4 100644
>>>> --- a/Documentation/leds/leds-class.txt
>>>> +++ b/Documentation/leds/leds-class.txt
>>>> @@ -43,7 +43,22 @@ LED Device Naming
>>>> Is currently of the form:
>>>> -"devicename:colour:function"
>>>> +"colour:function"
>>>> +
>>>> +There might be still LED class drivers around using "devicename:colour:function"
>>>> +naming pattern, but the "devicename" section is now deprecated since it used
>>>> +to convey information that was already available in the sysfs, like product
>>>> +name. There is a tool (tools/leds/get_led_device_info.sh) available for
>>>> +retrieving that information per a LED class device.
>>>> +
>>>> +Associations with other devices, like network ones, should be defined
>>>> +via LED triggr mechanism. This approach is applied by some of wireless
>>>> +network drivers that create triggers dynamically and incorporate phy
>>>> +name into its name. On the other hand input subsystem offers LED - input
>>>> +bridge (drivers/input/input-leds.c) for exposing keyboard LEDs as LED class
>>>> +devices. The get_led_device_info.sh script has support for retrieving related
>>>> +input device node name. Should it support discovery of associations between
>>>> +LEDs and other subsystems, please don't hesitate to submit a relevant patch.
>>>> There have been calls for LED properties such as colour to be exported as
>>>> individual led class attributes. As a solution which doesn't incur as much
>>>> @@ -51,6 +66,9 @@ overhead, I suggest these become part of the device name. The naming scheme
>>>> above leaves scope for further attributes should they be needed. If sections
>>>> of the name don't apply, just leave that section blank.
>>>> +Please also keep in mind that LED subsystem has a protection against LED name
>>>> +conflict. It adds numerical suffix (e.g. "_1", "_2", "_3" etc.) to the requested
>>>> +LED class device name in case it is already in use.
>>>> Brightness setting API
>>>> ======================
>>>> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
>>>> index ede4fa0ac2cc..bad92250d1d5 100644
>>>> --- a/drivers/leds/led-core.c
>>>> +++ b/drivers/leds/led-core.c
>>>> @@ -16,6 +16,8 @@
>>>> #include <linux/list.h>
>>>> #include <linux/module.h>
>>>> #include <linux/mutex.h>
>>>> +#include <linux/of.h>
>>>> +#include <linux/property.h>
>>>> #include <linux/rwsem.h>
>>>> #include "leds.h"
>>>> @@ -327,3 +329,83 @@ void led_sysfs_enable(struct led_classdev *led_cdev)
>>>> led_cdev->flags &= ~LED_SYSFS_DISABLE;
>>>> }
>>>> EXPORT_SYMBOL_GPL(led_sysfs_enable);
>>>> +
>>>> +static void led_parse_properties(struct fwnode_handle *fwnode,
>>>> + struct led_properties *props)
>>>> +{
>>>> + int ret;
>>>> +
>>>> + if (!fwnode)
>>>> + return;
>>>> +
>>>> + if (fwnode_property_present(fwnode, "label")) {
>>>> + ret = fwnode_property_read_string(fwnode, "label", &props->label);
>>>> + if (ret)
>>>> + pr_err("Error parsing \'label\' property (%d)\n", ret);
>>>> + return;
>>>> + }
>>>> +
>>>> + if (fwnode_property_present(fwnode, "function")) {
>>>> + ret = fwnode_property_read_string(fwnode, "function", &props->function);
>>>> + if (ret)
>>>> + pr_err("Error parsing \'function\' property (%d)\n", ret);
>>>> + } else {
>>>> + pr_info("\'function\' property not found\n");
>>>> + }
>>>> +
>>>> + if (fwnode_property_present(fwnode, "color")) {
>>>> + ret = fwnode_property_read_string(fwnode, "color", &props->color);
>>>> + if (ret)
>>>> + pr_info("Error parsing \'color\' property (%d)\n", ret);
>>>> + } else {
>>>> + pr_info("\'color\' property not found\n");
>>>> + }
>>>> +}
>>>> +
>>>> +int led_compose_name(struct fwnode_handle *fwnode, const char *led_hw_name,
>>>> + const char *default_desc, char *led_classdev_name)
>>>> +{
>>>> + struct led_properties props = {};
>>>> +
>>>> + if (!led_classdev_name)
>>>> + return -EINVAL;
>>>> +
>>>> + led_parse_properties(fwnode, &props);
>>>> +
>>>> + if (props.label) {
>>>> + /*
>>>> + * Presence of 'label' DT property implies legacy LED name,
>>>> + * formatted as <devicename:color:function>, with possible
>>>> + * section omission if doesn't apply to given device.
>>>> + *
>>>> + * If no led_hw_name has been passed, then it indicates that
>>>> + * DT label should be used as-is for LED class device name.
>>>> + * Otherwise the label is prepended with led_hw_name to compose
>>>> + * the final LED class device name.
>>>> + */
>>>> + if (!led_hw_name) {
>>>> + strncpy(led_classdev_name, props.label,
>>>> + LED_MAX_NAME_SIZE);
>>>> + } else {
>>>> + snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
>>>> + led_hw_name, props.label);
>>>> + }
>>>> + } else if (props.function || props.color) {
>>>> + snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
>>>> + props.color ?: "", props.function ?: "");
>>>> + } else if (default_desc) {
>>>> + if (!led_hw_name) {
>>>> + pr_err("Legacy LED naming requires devicename segment");
>>>> + return -EINVAL;
>>>> + }
>>>> + snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
>>>> + led_hw_name, default_desc);
>>>> + } else if (is_of_node(fwnode)) {
>>>> + strncpy(led_classdev_name, to_of_node(fwnode)->name,
>>>> + LED_MAX_NAME_SIZE);
>>>> + } else
>>>> + return -EINVAL;
>>>> +
>>>> + return 0;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(led_compose_name);
>
> I was thinking a bit more about this.
> Why do we want to export this function to have the drivers call it?
> Can't we just set the required parameters in the led_class struct?
>
> struct led_properties can be extended to set the needed strings in the LED driver.
> The pointer to this struct can be set in the LED driver for the class
>
> Then we can just call compose_name during class registration.
Adding to the struct led_classdev anything needed only in
led_classdev_register() would be waste of memory, but we can
add required properties to the new struct led_init_data and
then call led_compose_name() inside led_classdev_register().
I will change it in the v3.
> If we add the fwnode to the struct this may help in the multi-color registration as we could pick off
> the parent node and look for the specific labels/handles.
struct led_init_data already has fwnode property in this set.
>
>>>> diff --git a/include/linux/leds.h b/include/linux/leds.h
>>>> index bffb4315fd66..c2936fc989d4 100644
>>>> --- a/include/linux/leds.h
>>>> +++ b/include/linux/leds.h
>>>> @@ -252,6 +252,31 @@ extern void led_sysfs_disable(struct led_classdev *led_cdev);
>>>> extern void led_sysfs_enable(struct led_classdev *led_cdev);
>>>> /**
>>>> + * led_compose_name - compose LED class device name
>>>> + * @child: child fwnode_handle describing a LED,
>>>> + * or a group of synchronized LEDs.
>>>> + * @led_hw_name: name of the LED controller, used when falling back to legacy
>>>> + * LED naming; it should be set to NULL in new LED class drivers
>>>> + * @default_desc: default <color:function> tuple, for backwards compatibility
>>>> + * with in-driver hard-coded LED names used as a fallback when
>>>> + * "label" DT property is absent; it should be set to NULL
>>>> + * in new LED class drivers
>>>> + * @led_classdev_name: composed LED class device name
>>>> + *
>>>> + * Create LED class device name basing on the configuration provided by the
>>>> + * board firmware. The name can have a legacy form <devicename:color:function>,
>>>> + * or a new form <color:function>. The latter is chosen if "label" property is
>>>> + * absent and at least one of "color" or "function" is present in the fwnode,
>>>> + * leaving the section blank if the related property is absent. In case none
>>>> + * of the aforementioned properties is found, then, for OF nodes, the node name
>>>> + * is adopted for LED class device name.
>>>> + *
>>>> + * Returns: 0 on success or negative error value on failure
>>>> + */
>>>> +extern int led_compose_name(struct fwnode_handle *child, const char *led_hw_name,
>>>> + const char *default_desc, char *led_classdev_name);
>>>> +
>>>> +/**
>>>> * led_sysfs_is_disabled - check if LED sysfs interface is disabled
>>>> * @led_cdev: the LED to query
>>>> *
>>>> @@ -428,6 +453,12 @@ struct led_platform_data {
>>>> struct led_info *leds;
>>>> };
>>>> +struct led_properties {
>>>> + const char *color;
>>>> + const char *function;
>>>> + const char *label;
>>>> +};
>>>> +
>>>> struct gpio_desc;
>>>> typedef int (*gpio_blink_set_t)(struct gpio_desc *desc, int state,
>>>> unsigned long *delay_on,
>>>> diff --git a/tools/leds/get_led_device_info.sh b/tools/leds/get_led_device_info.sh
>>>> new file mode 100755
>>>> index 000000000000..4671aa690e4a
>>>> --- /dev/null
>>>> +++ b/tools/leds/get_led_device_info.sh
>>>> @@ -0,0 +1,81 @@
>>>> +#!/bin/sh
>>>> +# SPDX-License-Identifier: GPL-2.0
>>>> +
>>>
>>> Is there a way to give usage or help here? It's not entirely clear what the argument to pass in is.
>>
>> It is in the first statement of this script - see below.
>> It is customary to print help when unexpected arguments or a number
>> thereof is given.
>>
>> I can print help also when "--help" is passed.
>>
>
> OK. Maybe doing --help or --? would be to much. Maybe a bit better help message I could not tell that
> was an error message.
>
> maybe
>
> echo "usage: get_led_device_info.sh LED_CDEV_PATH"
Ack.
>>> maybe if $1 = "?" then print usage
>>>
>>> Dan
>>>
>>>
>>>> +if [ $# -ne 1 ]; then
>>>> + echo "get_led_devicename.sh LED_CDEV_PATH"
>>
>> s/get_led_devicename/get_led_device_info/
>>
>> It is a leftover from earlier stage of development.
>>
>>>> + exit 1
>>>> +fi
>>>> +
>>>> +led_cdev_path=`echo $1 | sed s'/\/$//'`
>>>> +
>>>> +ls "$led_cdev_path/brightness" > /dev/null 2>&1
>>>> +if [ $? -ne 0 ]; then
>>>> + echo "Device \"$led_cdev_path\" does not exist."
>>>> + exit 1
>>>> +fi
>>>> +
>>>> +bus=`readlink $led_cdev_path/device/subsystem | sed s'/.*\///'`
>>>> +usb_subdev=`readlink $led_cdev_path | grep usb | sed s'/\(.*usb[0-9]*\/[0-9]*-[0-9]*\)\/.*/\1/'`
>>>> +ls "$led_cdev_path/device/of_node/compatible" > /dev/null 2>&1
>>>> +of_node_missing=$?
>>>> +
>>>> +if [ "$bus" = "input" ]; then
>>>> + input_node=`readlink $led_cdev_path/device | sed s'/.*\///'`
>>>> + if [ ! -z $usb_subdev ]; then
>>>> + bus="usb"
>>>> + fi
>>>> +fi
>>>> +
>>>> +if [ "$bus" = "usb" ]; then
>>>> + usb_interface=`readlink $led_cdev_path | sed s'/.*\(usb[0-9]*\)/\1/' | cut -d \/ -f 3`
>>>> + driver=`readlink $usb_interface/driver | sed s'/.*\///'`
>>>> + cd $led_cdev_path/../$usb_subdev
>>>> + idVendor=`cat idVendor`
>>>> + idProduct=`cat idProduct`
>>>> + manufacturer=`cat manufacturer`
>>>> + product=`cat product`
>>>> +elif [ "$bus" = "input" ]; then
>>>> + cd $led_cdev_path
>>>> + product=`cat device/name`
>>>> + driver=`cat device/device/driver/description`
>>>> +elif [ $of_node_missing -eq 0 ]; then
>>>> + cd $led_cdev_path
>>>> + compatible=`cat device/of_node/compatible`
>>>> + if [ "$compatible" = "gpio-leds" ]; then
>>>> + driver="leds-gpio"
>>>> + elif [ "$compatible" = "pwm-leds" ]; then
>>>> + driver="leds-pwm"
>>>> + else
>>>> + manufacturer=`echo $compatible | cut -d, -f1`
>>>> + product=`echo $compatible | cut -d, -f2`
>>>> + fi
>>>> +else
>>>> + echo "Unknown device type."
>>>> + exit 1
>>>> +fi
>>>> +
>>>> +printf "bus:\t\t\t$bus\n"
>>>> +
>>>> +if [ ! -z "$idVendor" ]; then
>>>> + printf "idVendor:\t\t$idVendor\n"
>>>> +fi
>>>> +
>>>> +if [ ! -z "$idProduct" ]; then
>>>> + printf "idProduct:\t\t$idProduct\n"
>>>> +fi
>>>> +
>>>> +if [ ! -z "$manufacturer" ]; then
>>>> + printf "manufacturer:\t\t$manufacturer\n"
>>>> +fi
>>>> +
>>>> +if [ ! -z "$product" ]; then
>>>> + printf "product:\t\t$product\n"
>>>> +fi
>>>> +
>>>> +if [ ! -z "$driver" ]; then
>>>> + printf "driver:\t\t\t$driver\n"
>>>> +fi
>>>> +
>>>> +if [ ! -z "$input_node" ]; then
>>>> + printf "associated input node:\t$input_node\n"
>>>> +fi
>>>>
>>>
>>>
>>
>
>
--
Best regards,
Jacek Anaszewski
Powered by blists - more mailing lists