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SubjectRe: [PATCH v5 05/26] leds: core: Add support for composing LED class device names
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Gentle reminder.

Pavel, Dan - any conclusions?

This patch is the main part of the proposed changes,
so it would be good to spot any remaining issues.

What needs a consensus is also a new
Documentation/leds/led-functions.txt file I introduce
in the patch 26/26.

Best regards,
Jacek Anaszewski

On 6/9/19 9:07 PM, Jacek Anaszewski wrote:
> Add generic support for composing LED class device name. The newly
> introduced led_compose_name() function composes device name according
> to either <color:function> or <devicename:color:function> pattern,
> depending on the configuration of initialization data.
>
> Backward compatibility with in-driver hard-coded LED class device
> names is assured thanks to the default_label and devicename properties
> of newly introduced struct led_init_data.
>
> In case none of the aforementioned properties was found, then, for OF
> nodes, the node name is adopted for LED class device name.
>
> At the occassion of amending the Documentation/leds/leds-class.txt
> unify spelling: colour -> color.
>
> 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 using vendor or product name for devicename part
> of LED name doesn't convey any added value since that information had been
> already available in sysfs. The script performs also basic validation
> of a LED class device name.
>
> Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
> Cc: Baolin Wang <baolin.wang@linaro.org>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: Dan Murphy <dmurphy@ti.com>
> Cc: Daniel Mack <daniel@zonque.org>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Oleh Kravchenko <oleg@kaa.org.ua>
> Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
> Cc: Simon Shields <simon@lineageos.org>
> ---
> Documentation/leds/leds-class.txt | 67 ++++++++++++-
> drivers/leds/led-class.c | 20 +++-
> drivers/leds/led-core.c | 127 ++++++++++++++++++++++++
> drivers/leds/leds.h | 1 +
> include/linux/leds.h | 45 +++++++++
> tools/leds/get_led_device_info.sh | 201 ++++++++++++++++++++++++++++++++++++++
> 6 files changed, 455 insertions(+), 6 deletions(-)
> 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..e7316e37b57d 100644
> --- a/Documentation/leds/leds-class.txt
> +++ b/Documentation/leds/leds-class.txt
> @@ -43,9 +43,70 @@ LED Device Naming
>
> Is currently of the form:
>
> -"devicename:colour:function"
> -
> -There have been calls for LED properties such as colour to be exported as
> +"devicename:color:function"
> +
> +devicename: It should refer to a unique identifier created by the kernel,
> + like e.g. phyN for network devices or inputN for input devices,
> + rather than to the hardware. The information related to the product
> + and the bus to which given device is hooked is available in the
> + sysfs and can be retrieved using get_led_device_info.sh script
> + from tools/leds. Generally this section is expected mostly for
> + LEDs that are somehow associated with other devices.
> +
> +color: one of the color strings from led_colors array defined
> + in drivers/leds/led-core.c.
> +
> +function: one of the LED_FUNCTION* definitions from the header
> + include/dt-bindings/leds/common.h.
> +
> +If required color or function is missing, please submit a patch
> +to linux-leds@vger.kernel.org, adding required entries.
> +
> +It is possible that more than one LED with the same color and function will
> +be required for given platform, differing only with an ordinal number.
> +In this case it is preferable to just concatenate the predefined LED_FUNCTION*
> +name with required "-N" suffix in the driver. fwnode based drivers can use
> +function-enumerator property for that and then the concatenation will be handled
> +automatically by the LED core upon LED class device registration.
> +
> +LED subsystem has also a protection against name clash, that may occur
> +when LED class device is created by a driver of hot-pluggable device and
> +it doesn't provide unique devicename section. In this case numerical
> +suffix (e.g. "_1", "_2", "_3" etc.) is added to the requested LED class
> +device name.
> +
> +There might be still LED class drivers around using vendor or product name
> +for devicename, but this approach is now deprecated as it doesn't convey
> +any added value. Product information can be found in other places in sysfs
> +(see tools/leds/get_led_device_info.sh).
> +
> +Examples of proper LED names:
> +
> +"red:disk"
> +"white:flash"
> +"red:indicator"
> +"phy1:green:wlan"
> +"phy3::wlan"
> +":kbd_backlight"
> +"input5::kbd_backlight"
> +"input3::numlock"
> +"input3::scrolllock"
> +"input3::capslock"
> +"mmc1::status"
> +"white:status"
> +
> +get_led_device_info.sh script can be used for verifying if the LED name
> +meets the requirements pointed out here. It performs validation of the LED class
> +devicename sections and gives hints on expected value for a section in case
> +the validation fails for it. So far the script supports validation
> +of associations between LEDs and following types of devices:
> +
> +- input devices
> +- ieee80211 compliant USB devices
> +
> +The script is open to extensions.
> +
> +There have been calls for LED properties such as color to be exported as
> individual led class attributes. As a solution which doesn't incur as much
> 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
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index a564948e5f53..e3af0b71c9a9 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -257,17 +257,31 @@ int led_classdev_register_ext(struct device *parent,
> struct led_classdev *led_cdev,
> struct led_init_data *init_data)
> {
> - char name[LED_MAX_NAME_SIZE];
> + char composed_name[LED_MAX_NAME_SIZE];
> + char final_name[LED_MAX_NAME_SIZE];
> + const char *proposed_name = composed_name;
> int ret;
>
> - ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
> + if (init_data) {
> + if (init_data->devname_mandatory && !init_data->devicename) {
> + dev_err(parent, "Mandatory device name is missing");
> + return -EINVAL;
> + }
> + ret = led_compose_name(parent, init_data, composed_name);
> + if (ret < 0)
> + return ret;
> + } else {
> + proposed_name = led_cdev->name;
> + }
> +
> + ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
> if (ret < 0)
> return ret;
>
> mutex_init(&led_cdev->led_access);
> mutex_lock(&led_cdev->led_access);
> led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
> - led_cdev, led_cdev->groups, "%s", name);
> + led_cdev, led_cdev->groups, "%s", final_name);
> if (IS_ERR(led_cdev->dev)) {
> mutex_unlock(&led_cdev->led_access);
> return PTR_ERR(led_cdev->dev);
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index e3da7c03da1b..dcd14ea40687 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -17,8 +17,10 @@
> #include <linux/module.h>
> #include <linux/mutex.h>
> #include <linux/of.h>
> +#include <linux/property.h>
> #include <linux/rwsem.h>
> #include <linux/slab.h>
> +#include <uapi/linux/uleds.h>
> #include "leds.h"
>
> DECLARE_RWSEM(leds_list_lock);
> @@ -27,6 +29,18 @@ EXPORT_SYMBOL_GPL(leds_list_lock);
> LIST_HEAD(leds_list);
> EXPORT_SYMBOL_GPL(leds_list);
>
> +const char *led_colors[LED_COLOR_ID_MAX] = {
> + [LED_COLOR_ID_WHITE] = "white",
> + [LED_COLOR_ID_RED] = "red",
> + [LED_COLOR_ID_GREEN] = "green",
> + [LED_COLOR_ID_BLUE] = "blue",
> + [LED_COLOR_ID_AMBER] = "amber",
> + [LED_COLOR_ID_VIOLET] = "violet",
> + [LED_COLOR_ID_YELLOW] = "yellow",
> + [LED_COLOR_ID_IR] = "ir",
> +};
> +EXPORT_SYMBOL_GPL(led_colors);
> +
> static int __led_set_brightness(struct led_classdev *led_cdev,
> enum led_brightness value)
> {
> @@ -357,3 +371,116 @@ 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_fwnode_props(struct device *dev,
> + 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)
> + dev_err(dev, "Error parsing \'label\' property (%d)\n", ret);
> + return;
> + }
> +
> + if (fwnode_property_present(fwnode, "color")) {
> + ret = fwnode_property_read_u32(fwnode, "color", &props->color);
> + if (ret)
> + dev_err(dev, "Error parsing \'color\' property (%d)\n", ret);
> + else if (props->color >= LED_COLOR_ID_MAX)
> + dev_err(dev, "LED color identifier out of range\n");
> + else
> + props->color_present = true;
> + }
> +
> +
> + if (fwnode_property_present(fwnode, "function")) {
> + ret = fwnode_property_read_string(fwnode, "function", &props->function);
> + if (ret) {
> + dev_err(dev,
> + "Error parsing \'function\' property (%d)\n",
> + ret);
> + }
> + } else {
> + return;
> + }
> +
> + if (fwnode_property_present(fwnode, "function-enumerator")) {
> + ret = fwnode_property_read_u32(fwnode, "function-enumerator",
> + &props->func_enum);
> + if (ret) {
> + dev_err(dev,
> + "Error parsing \'function-enumerator\' property (%d)\n",
> + ret);
> + } else {
> + props->func_enum_present = true;
> + }
> + }
> +}
> +
> +int led_compose_name(struct device *dev, struct led_init_data *init_data,
> + char *led_classdev_name)
> +{
> + struct led_properties props = {};
> + struct fwnode_handle *fwnode = init_data->fwnode;
> + const char *devicename = init_data->devicename;
> +
> + if (!led_classdev_name)
> + return -EINVAL;
> +
> + led_parse_fwnode_props(dev, fwnode, &props);
> +
> + if (props.label) {
> + /*
> + * If init_data.devicename is NULL, then it indicates that
> + * DT label should be used as-is for LED class device name.
> + * Otherwise the label is prepended with devicename to compose
> + * the final LED class device name.
> + */
> + if (!devicename) {
> + strncpy(led_classdev_name, props.label,
> + LED_MAX_NAME_SIZE);
> + } else {
> + snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
> + devicename, props.label);
> + }
> + } else if (props.function || props.color_present) {
> + char tmp_buf[LED_MAX_NAME_SIZE];
> +
> + if (props.func_enum_present) {
> + snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d",
> + props.color_present ? led_colors[props.color] : "",
> + props.function ?: "", props.func_enum);
> + } else {
> + snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s",
> + props.color_present ? led_colors[props.color] : "",
> + props.function ?: "");
> + }
> + if (init_data->devname_mandatory) {
> + snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
> + devicename, tmp_buf);
> + } else {
> + strncpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE);
> +
> + }
> + } else if (init_data->default_label) {
> + if (!devicename) {
> + dev_err(dev, "Legacy LED naming requires devicename segment");
> + return -EINVAL;
> + }
> + snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s",
> + devicename, init_data->default_label);
> + } 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);
> diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
> index 7d38e6b9a740..0d223c1f93b2 100644
> --- a/drivers/leds/leds.h
> +++ b/drivers/leds/leds.h
> @@ -31,5 +31,6 @@ void led_set_brightness_nosleep(struct led_classdev *led_cdev,
> extern struct rw_semaphore leds_list_lock;
> extern struct list_head leds_list;
> extern struct list_head trigger_list;
> +extern const char *led_colors[LED_COLOR_ID_MAX];
>
> #endif /* __LEDS_H_INCLUDED */
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index fab83a2d7bff..03e9795fa23b 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -12,6 +12,7 @@
> #ifndef __LINUX_LEDS_H_INCLUDED
> #define __LINUX_LEDS_H_INCLUDED
>
> +#include <dt-bindings/leds/common.h>
> #include <linux/device.h>
> #include <linux/kernfs.h>
> #include <linux/list.h>
> @@ -37,6 +38,25 @@ enum led_brightness {
> struct led_init_data {
> /* device fwnode handle */
> struct fwnode_handle *fwnode;
> + /*
> + * default <color:function> tuple, for backward compatibility
> + * with in-driver hard-coded LED names used as a fallback when
> + * DT "label" property is absent; it should be set to NULL
> + * in new LED class drivers.
> + */
> + const char *default_label;
> + /*
> + * string to be used for devicename section of LED class device
> + * either for label based LED name composition path or for fwnode
> + * based when devname_mandatory is true
> + */
> + const char *devicename;
> + /*
> + * indicates if LED name should always comprise devicename section;
> + * only LEDs exposed by drivers of hot-pluggable devices should
> + * set it to true
> + */
> + bool devname_mandatory;
> };
>
> struct led_classdev {
> @@ -262,6 +282,22 @@ 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
> + * @dev: LED controller device object
> + * @child: child fwnode_handle describing a LED or a group of synchronized LEDs;
> + * it must be provided only for fwnode based LEDs
> + * @led_classdev_name: composed LED class device name
> + *
> + * Create LED class device name basing on the provided init_data argument.
> + * The name can have <devicename:color:function> or <color:function>.
> + * form, depending on the init_data configuration.
> + *
> + * Returns: 0 on success or negative error value on failure
> + */
> +extern int led_compose_name(struct device *dev, struct led_init_data *init_data,
> + char *led_classdev_name);
> +
> +/**
> * led_sysfs_is_disabled - check if LED sysfs interface is disabled
> * @led_cdev: the LED to query
> *
> @@ -438,6 +474,15 @@ struct led_platform_data {
> struct led_info *leds;
> };
>
> +struct led_properties {
> + u32 color;
> + bool color_present;
> + const char *function;
> + u32 func_enum;
> + bool func_enum_present;
> + 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..ccfa442db5fe
> --- /dev/null
> +++ b/tools/leds/get_led_device_info.sh
> @@ -0,0 +1,201 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +
> +led_common_defs_path="include/dt-bindings/leds/common.h"
> +
> +num_args=$#
> +if [ $num_args -eq 1 ]; then
> + linux_top=$(dirname `realpath $0` | awk -F/ \
> + '{ \
> + i=1; \
> + while (i <= NF - 2) { \
> + printf $i"/"; \
> + i++; \
> + }; \
> + }')
> + led_defs_path=$linux_top/$led_common_defs_path
> +elif [ $num_args -eq 2 ]; then
> + led_defs_path=`realpath $2`
> +else
> + echo "Usage: get_led_device_info.sh LED_CDEV_PATH [LED_COMMON_DEFS_PATH]"
> + exit 1
> +fi
> +
> +if [ ! -f $led_defs_path ]; then
> + echo "$led_defs_path doesn't exist"
> + 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\/ -f3`
> + cd $led_cdev_path/../$usb_subdev
> + driver=`readlink $usb_interface/driver | sed s'/.*\///'`
> + if [ -d "$usb_interface/ieee80211" ]; then
> + wifi_phy=`ls -l $usb_interface/ieee80211 | grep phy | awk '{print $9}'`
> + fi
> + idVendor=`cat idVendor`
> + idProduct=`cat idProduct`
> + manufacturer=`cat manufacturer`
> + product=`cat product`
> +elif [ "$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 | awk -F, '{print $1}'`
> + product=`echo $compatible | awk -F, '{print $2}'`
> + fi
> +else
> + echo "Unknown device type."
> + exit 1
> +fi
> +
> +printf "\n#####################################\n"
> +printf "# LED class device hardware details #\n"
> +printf "#####################################\n\n"
> +
> +printf "bus:\t\t\t$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
> +
> +printf "\n####################################\n"
> +printf "# LED class device name validation #\n"
> +printf "####################################\n\n"
> +
> +led_name=`echo $led_cdev_path | sed s'/.*\///'`
> +
> +num_sections=`echo $led_name | awk -F: '{print NF}'`
> +
> +if [ $num_sections -eq 1 ]; then
> + printf "\":\" delimiter not detected.\t[ FAILED ]\n"
> + exit 1
> +elif [ $num_sections -eq 2 ]; then
> + color=`echo $led_name | cut -d: -f1`
> + function=`echo $led_name | cut -d: -f2`
> +elif [ $num_sections -eq 3 ]; then
> + devicename=`echo $led_name | cut -d: -f1`
> + color=`echo $led_name | cut -d: -f2`
> + function=`echo $led_name | cut -d: -f3`
> +else
> + printf "Detected %d sections in the LED class device name - should the script be updated?\n" $num_sections
> + exit 1
> +fi
> +
> +S_DEV="devicename"
> +S_CLR="color "
> +S_FUN="function "
> +status_tab=20
> +
> +print_msg_ok()
> +{
> + local section_name="$1"
> + local section_val="$2"
> + local msg="$3"
> + printf "$section_name :\t%-${status_tab}.${status_tab}s %s %s\n" "$section_val" "[ OK ] " "$msg"
> +}
> +
> +print_msg_failed()
> +{
> + local section_name="$1"
> + local section_val="$2"
> + local msg="$3"
> + printf "$section_name :\t%-${status_tab}.${status_tab}s %s %s\n" "$section_val" "[ FAILED ]" "$msg"
> +}
> +
> +if [ ! -z "$input_node" ]; then
> + expected_devname=$input_node
> +elif [ ! -z "$wifi_phy" ]; then
> + expected_devname=$wifi_phy
> +fi
> +
> +if [ ! -z "$devicename" ]; then
> + if [ ! -z "$expected_devname" ]; then
> + if [ "$devicename" = "$expected_devname" ]; then
> + print_msg_ok "$S_DEV" "$devicename"
> + else
> + print_msg_failed "$S_DEV" "$devicename" "Expected: $expected_devname"
> + fi
> + else
> + if [ "$devicename" = "$manufacturer" ]; then
> + print_msg_failed "$S_DEV" "$devicename" "Redundant: use of vendor name is discouraged"
> + elif [ "$devicename" = "$product" ]; then
> + print_msg_failed "$S_DEV" "$devicename" "Redundant: use of product name is discouraged"
> + else
> + print_msg_failed "$S_DEV" "$devicename" "Unknown devicename - should the script be updated?"
> + fi
> + fi
> +elif [ ! -z "$expected_devname" ]; then
> + print_msg_failed "$S_DEV" "blank" "Expected: $expected_devname"
> +fi
> +
> +if [ ! -z "$color" ]; then
> + color_upper=`echo $color | tr [:lower:] [:upper:]`
> + color_id_definition=$(cat $led_defs_path | grep "_$color_upper\s" | awk '{print $2}')
> + if [ ! -z "$color_id_definition" ]; then
> + print_msg_ok "$S_CLR" "$color" "Matching definition: $color_id_definition"
> + else
> + print_msg_failed "$S_CLR" "$color" "Definition not found in $led_defs_path"
> + fi
> +
> +fi
> +
> +if [ ! -z "$function" ]; then
> + # strip optional enumerator
> + function=`echo $function | sed s'/\(.*\)-[0-9]*$/\1/'`
> + fun_definition=$(cat $led_defs_path | grep "\"$function\"" | awk '{print $2}')
> + if [ ! -z "$fun_definition" ]; then
> + print_msg_ok "$S_FUN" "$function" "Matching definition: $fun_definition"
> + else
> + print_msg_failed "$S_FUN" "$function" "Definition not found in $led_defs_path"
> + fi
> +
> +fi
>

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