设备树配置：
pio:pinctrl@1c20800 {
compatible = "allwinner,suniv-pinctrl";
reg = <0x1c20800 0x400>;
interrupts = <0x26 0x27 0x28>;
clocks = <0x3 0x24 0x5 0xb>;
clock-names = "apb", "hosc", "losc";
gpio-controller;
interrupt-controller;
#interrupt-cells = <0x3>;
#gpio-cells = <0x3>;
phandle = <0xd>;
pwm1_pins: pwm1 {
pins = "PE6";
function = "pwm1";
};
};
pwm:pwm@1C21000 {
compatible = "allwinner,sun7i-a20-pwm";
reg = <0x1C21000 0x400>;
clocks = <0x5>;
#pwm-cells = <3>;
pinctrl-names = "default";
pinctrl-0 = <&pwm1_pins>;
status = "okay";
};内核配置：
--- Pulse-Width Modulation (PWM) Support │ │
│ │ < > Freescale FlexTimer Module (FTM) PWM support │ │
│ │ < > NXP PCA9685 PWM driver │ │
│ │ <*> Allwinner PWM support │ │
│ │
Symbol: PWM [=y] │
│ Type : boolean │
│ Prompt: Pulse-Width Modulation (PWM) Support │
│ Location: │
│ (1) -> Device Drivers │
│ Defined at drivers/pwm/Kconfig:1 │
│ Selected by: S3C24XX_PWM [=n] && PLAT_SAMSUNG [=n] && SAMSUNG_ATAGS [=n] || FB_SSD1307 [=y] && HAS_IOMEM [=y] && FB [=y │
│ │
│ │
│ Symbol: BACKLIGHT_PWM [=y] │
│ Type : tristate │
│ Prompt: Generic PWM based Backlight Driver │
│ Location: │
│ -> Device Drivers │
│ -> Graphics support │
│ -> Backlight & LCD device support (BACKLIGHT_LCD_SUPPORT [=y]) │
│ (2) -> Lowlevel Backlight controls (BACKLIGHT_CLASS_DEVICE [=y]) │
│ Defined at drivers/video/backlight/Kconfig:261 │
│ Depends on: HAS_IOMEM [=y] && BACKLIGHT_LCD_SUPPORT [=y] && BACKLIGHT_CLASS_DEVICE [=y] && PWM [=y]
Symbol: COMMON_CLK_PWM [=n] │
│ Type : tristate │
│ Prompt: Clock driver for PWMs used as clock outputs │
│ Location: │
│ -> Device Drivers │
│ (4) -> Common Clock Framework │
│ Defined at drivers/clk/Kconfig:197 │
│ Depends on: COMMON_CLK [=y] && PWM [=y]
驱动中已经打开了;
echo 1 > /sys/class/pwm/pwmchip0/export
echo 1000000 > /sys/class/pwm/pwmchip0/pwm1/period
echo 200000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
echo 1 > /sys/class/pwm/pwmchip0/pwm1/enable 由于默认设备树开启了led,我将下面的代码从设备树中移除了，并且去掉了默认的led驱动
leds {
compatible = "gpio-leds";
blue_led {
label = "licheepi:blue:usr";
gpios = <&pio 4 4 GPIO_ACTIVE_LOW>; /* PE4 */
};
green_led {
label = "licheepi:green:usr";
gpios = <&pio 4 5 GPIO_ACTIVE_LOW>; /* PE5 */
default-state = "on";
};
red_led {
label = "licheepi:red:usr";
gpios = <&pio 5 6 GPIO_ACTIVE_LOW>; /* PE6 */
};
};上面的命令都可以执行成功，但是PE6脚输出一直是高电平,没有PWM波形的输出，这个哪个问题导致的呀
最近编辑记录 vkaoke (2019-02-25 15:44:25)
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https://licheezero.readthedocs.io/zh/latest/%E9%A9%B1%E5%8A%A8/PWM.html
仔细核对了一下 荔枝派 V3s 的文档， 基本操作没有太大问题。
PWM_CTRL_REG 0x00 PWM Control Register
PWM_CH1_PERIOD 0x08 PWM Channel 1 Period Register
用 busybox 里面的 devmem 把这两个寄存器读出来看看:
devmem 0x01C21000
devmem 0x01C21008
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https://licheezero.readthedocs.io/zh/latest/%E9%A9%B1%E5%8A%A8/PWM.html
仔细核对了一下 荔枝派 V3s 的文档， 基本操作没有太大问题。
PWM_CTRL_REG 0x00 PWM Control Register
PWM_CH1_PERIOD 0x08 PWM Channel 1 Period Register用 busybox 里面的 devmem 把这两个寄存器读出来看看:
devmem 0x01C21000
devmem 0x01C21008
# devmem 0x01C21000
0x002F8000
# devmem 0x01C21008
0x5DBF12C0
pwm控制寄存器：
0000 0000 0010 1111 1000 0000 0000 0000
PWM_CH1_PRESCAL=1 PWM_CH1_EN=1 PWM_CH1_CLK_GATING=1（Gating the Special Clock for PWM1 (0: mask, 1: pass).）
设置的参数：
0101 1101 1011 1111 0001 0010 1100 0000
PWM_CH1_ACT_CYS=4800
PWM_CH1_ENTIRE_CYS=23999
我不知道，是不是pwm控制器里面有哪些位是不是还得设置一下。
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clk-24M {
#clock-cells = <0x0>;
compatible = "fixed-clock";
clock-frequency = <0x16e3600>;
clock-output-names = "osc24M";
phandle = <0x5>;
};
引用的应该是24M的时钟
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https://www.lotlab.org/2019/02/22/荔枝派nano的spi-flash系统编译创建全过程/
看屏幕背光亮度调整那一节 可能能帮到你
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试试这个帖子里面的驱动， https://whycan.cn/t_1457.html
是好的，我已经用过了。
离线
https://www.lotlab.org/2019/02/22/荔枝派nano的spi-flash系统编译创建全过程/
看屏幕背光亮度调整那一节 可能能帮到你
设备树中，去掉gpios的配置就正常啦，十分感谢大家
compatible = "qiaodian,qd43003c0-40", "simple-panel";
#address-cells = <1>;
#size-cells = <0>;
- enable-gpios = <&pio 4 6 GPIO_ACTIVE_HIGH>;离线
/dts-v1/;
#include <dt-bindings/input/input.h>
#include <dt-bindings/interrupt-controller/irq.h>
/ {
#address-cells = <0x1>;
#size-cells = <0x1>;
interrupt-parent = <0x1>;
model = "Lichee Pi Nano";
compatible = "licheepi,licheepi-nano", "allwinner,suniv-f1c100s", "allwinner,suniv";
clocks {
#address-cells = <0x1>;
#size-cells = <0x1>;
ranges;
clk-24M {
#clock-cells = <0x0>;
compatible = "fixed-clock";
clock-frequency = <0x16e3600>;
clock-output-names = "osc24M";
phandle = <0x5>;
};
clk-32k {
#clock-cells = <0x0>;
compatible = "fixed-clock";
clock-frequency = <0x8000>;
clock-output-names = "osc32k";
phandle = <0xb>;
};
clk-100M {
#clock-cells = <0x0>;
compatible = "fixed-clock";
clock-frequency = <0x5f5e100>;
clock-output-names = "fake-100M";
};
};
cpus {
#address-cells = <0x0>;
#size-cells = <0x0>;
cpu {
compatible = "arm,arm926ej-s";
device_type = "cpu";
};
};
display-engine {
compatible = "allwinner,suniv-display-engine";
allwinner,pipelines = <0x2>;
status = "okay";
};
soc {
compatible = "simple-bus";
#address-cells = <0x1>;
#size-cells = <0x1>;
ranges;
sram-controller@1c00000 {
compatible = "allwinner,sun4i-a10-sram-controller";
reg = <0x1c00000 0x30>;
#address-cells = <0x1>;
#size-cells = <0x1>;
ranges;
sram@10000 {
compatible = "mmio-sram";
reg = <0x10000 0x1000>;
#address-cells = <0x1>;
#size-cells = <0x1>;
ranges = <0x0 0x10000 0x1000>;
sram-section@0 {
compatible = "allwinner,sun4i-a10-sram-d";
reg = <0x0 0x1000>;
status = "okay";
phandle = <0x11>;
};
};
};
spi@1c05000 {
compatible = "allwinner,suniv-spi", "allwinner,sun8i-h3-spi";
reg = <0x1c05000 0x1000>;
interrupts = <0xa>;
clocks = <0x3 0x11 0x3 0x11>;
clock-names = "ahb", "mod";
resets = <0x3 0x4>;
status = "okay";
#address-cells = <0x1>;
#size-cells = <0x0>;
pinctrl-names = "default";
pinctrl-0 = <0x4>;
flash@0 {
#address-cells = <0x1>;
#size-cells = <0x1>;
compatible = "winbond,w25q128", "jedec,spi-nor";
reg = <0x0>;
spi-max-frequency = <0x2625a00>;
};
};
spi@1c06000 {
compatible = "allwinner,suniv-spi", "allwinner,sun8i-h3-spi";
reg = <0x1c06000 0x1000>;
interrupts = <0xb>;
clocks = <0x3 0x12 0x3 0x12>;
clock-names = "ahb", "mod";
resets = <0x3 0x5>;
status = "disabled";
#address-cells = <0x1>;
#size-cells = <0x0>;
};
lcd-controller@1c0c000 {
compatible = "allwinner,suniv-tcon";
reg = <0x1c0c000 0x1000>;
interrupts = <0x1d>;
clocks = <0x3 0x15 0x3 0x39 0x5>;
clock-names = "ahb", "tcon-ch0", "tcon-ch1";
clock-output-names = "tcon-pixel-clock";
resets = <0x3 0x8>;
reset-names = "lcd";
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <0x6>;
ports {
#address-cells = <0x1>;
#size-cells = <0x0>;
port@0 {
#address-cells = <0x1>;
#size-cells = <0x0>;
reg = <0x0>;
endpoint@0 {
reg = <0x0>;
remote-endpoint = <0x7>;
phandle = <0x14>;
};
};
port@1 {
#address-cells = <0x1>;
#size-cells = <0x0>;
reg = <0x1>;
endpoint@0 {
reg = <0x0>;
remote-endpoint = <0x8>;
phandle = <0x15>;
};
};
};
};
mmc@1c0f000 {
compatible = "allwinner,suniv-mmc", "allwinner,sun7i-a20-mmc";
reg = <0x1c0f000 0x1000>;
clocks = <0x3 0xe 0x3 0x28 0x3 0x2a 0x3 0x29>;
clock-names = "ahb", "mmc", "output", "sample";
resets = <0x3 0x1>;
reset-names = "ahb";
interrupts = <0x17>;
pinctrl-names = "default";
pinctrl-0 = <0x9>;
status = "okay";
#address-cells = <0x1>;
#size-cells = <0x0>;
vmmc-supply = <0xa>;
bus-width = <0x4>;
broken-cd;
};
mmc@1c10000 {
compatible = "allwinner,suniv-mmc", "allwinner,sun7i-a20-mmc";
reg = <0x1c10000 0x1000>;
clocks = <0x3 0xf 0x3 0x2b 0x3 0x2d 0x3 0x2c>;
clock-names = "ahb", "mmc", "output", "sample";
resets = <0x3 0x2>;
reset-names = "ahb";
interrupts = <0x18>;
status = "disabled";
#address-cells = <0x1>;
#size-cells = <0x0>;
};
clock@1c20000 {
compatible = "allwinner,suniv-ccu";
reg = <0x1c20000 0x400>;
clocks = <0x5 0xb>;
clock-names = "hosc", "losc";
#clock-cells = <0x1>;
#reset-cells = <0x1>;
phandle = <0x3>;
};
interrupt-controller@1c20400 {
compatible = "allwinner,suniv-ic";
reg = <0x1c20400 0x400>;
interrupt-controller;
#interrupt-cells = <0x1>;
phandle = <0x1>;
};
pio:pinctrl@1c20800 {
compatible = "allwinner,suniv-pinctrl";
reg = <0x1c20800 0x400>;
interrupts = <0x26 0x27 0x28>;
clocks = <0x3 0x24 0x5 0xb>;
clock-names = "apb", "hosc", "losc";
gpio-controller;
interrupt-controller;
#interrupt-cells = <0x3>;
#gpio-cells = <0x3>;
phandle = <0xd>;
spi0-pins-pc {
pins = "PC0", "PC1", "PC2", "PC3";
function = "spi0";
phandle = <0x4>;
};
i2c0 {
pins = "PE11", "PE12";
function = "i2c0";
phandle = <0xc>;
};
lcd-rgb666-pins {
pins = "PD0", "PD1", "PD2", "PD3", "PD4", "PD5", "PD6", "PD7", "PD8", "PD9", "PD10", "PD11", "PD12", "PD13", "PD14", "PD15", "PD16", "PD17", "PD18", "PD19", "PD20", "PD21";
function = "lcd";
phandle = <0x6>;
};
uart-pins-pe {
pins = "PE0", "PE1";
function = "uart0";
phandle = <0xf>;
};
uart-pins-pina{
pins = "PA2", "PA3";
function = "uart1";
phandle = <0x1a>;
};
uart-pins-pinb{
pins = "PE7", "PE8";
function = "uart2";
phandle = <0xe>;
};
mmc0-pins {
pins = "PF0", "PF1", "PF2", "PF3", "PF4", "PF5";
function = "mmc0";
phandle = <0x9>;
};
pwm1_pins: pwm1 {
pins = "PE6";
function = "pwm1";
};
};
timer@1c20c00 {
compatible = "allwinner,suniv-timer";
reg = <0x1c20c00 0x90>;
interrupts = <0xd>;
clocks = <0x5>;
};
watchdog@1c20ca0 {
compatible = "allwinner,sun6i-a31-wdt";
reg = <0x1c20ca0 0x20>;
};
pwm:pwm@1C21000 {
compatible = "allwinner,sun7i-a20-pwm";
reg = <0x1C21000 0xC>;
clocks = <0x5>;
#pwm-cells = <3>;
pinctrl-names = "default";
pinctrl-0 = <&pwm1_pins>;
status = "okay";
};
i2c@1C27000 {
compatible = "allwinner,sun6i-a31-i2c";
reg = <0x1c27000 0x400>;
interrupts = <0x7>;
clocks = <0x3 0x21>;
resets = <0x3 0x14>;
pinctrl-names = "default";
pinctrl-0 = <0xc>;
status = "okay";
#address-cells = <0x1>;
#size-cells = <0x0>;
lcos@0x48 {
compatible = "lcos,lcos_hx7097";
reg = <0x48>;
};
axp209:pmic@0x34 {
compatible = "x-powers,axp209";
reg = <0x34>;
interrupt-parent = <&pio>;
interrupts = <4 2 IRQ_TYPE_LEVEL_LOW>; /* (PE2) */
/* interrupts = <0 IRQ_TYPE_LEVEL_LOW>;*/
interrupt-controller;
#interrupt-cells = <1>;
battery_power_supply: battery-power-supply{
compatible = "x-powers,axp209-battery-power-supply";
};
ac_power_supply:ac-power-supply{
compatible = "x-powers,axp202-ac-power-supply";
};
axp_gpio:gpio{
compatible = "x-powers,axp209-gpio";
gpio-controller;
#gpio-cells = <2>;
};
};
};
serial@1c25000 {
compatible = "snps,dw-apb-uart";
reg = <0x1c25000 0x400>;
interrupts = <0x1>;
reg-shift = <0x2>;
reg-io-width = <0x4>;
clocks = <0x3 0x25>;
resets = <0x3 0x17>;
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <0xf>;
};
serial@1c25400 {
compatible = "snps,dw-apb-uart";
reg = <0x1c25400 0x400>;
interrupts = <0x2>;
reg-shift = <0x2>;
reg-io-width = <0x4>;
clocks = <0x3 0x26>;
resets = <0x3 0x18>;
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <0x1a>;
};
serial@1c25800 {
compatible = "snps,dw-apb-uart";
reg = <0x1c25800 0x400>;
interrupts = <0x3>;
reg-shift = <0x2>;
reg-io-width = <0x4>;
clocks = <0x3 0x27>;
resets = <0x3 0x19>;
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <0xe>;
};
usb@1c13000 {
compatible = "allwinner,suniv-musb";
reg = <0x1c13000 0x400>;
clocks = <0x3 0x13>;
resets = <0x3 0x6>;
interrupts = <0x1a>;
interrupt-names = "mc";
phys = <0x10 0x0>;
phy-names = "usb";
extcon = <0x10 0x0>;
allwinner,sram = <0x11 0x1>;
status = "okay";
dr_mode = "otg";
};
phy@1c13400 {
compatible = "allwinner,suniv-usb-phy";
reg = <0x1c13400 0x10>;
reg-names = "phy_ctrl";
clocks = <0x3 0x30>;
clock-names = "usb0_phy";
resets = <0x3 0x0>;
reset-names = "usb0_reset";
#phy-cells = <0x1>;
status = "okay";
usb0_id_det-gpio = <0xd 0x4 0x2 0x0>;
phandle = <0x10>;
};
display-frontend@1e00000 {
compatible = "allwinner,suniv-display-frontend";
reg = <0x1e00000 0x20000>;
interrupts = <0x1e>;
clocks = <0x3 0x1b 0x3 0x38 0x3 0x35>;
clock-names = "ahb", "mod", "ram";
resets = <0x3 0xe>;
status = "disabled";
phandle = <0x2>;
ports {
#address-cells = <0x1>;
#size-cells = <0x0>;
port@1 {
#address-cells = <0x1>;
#size-cells = <0x0>;
reg = <0x1>;
endpoint@0 {
reg = <0x0>;
remote-endpoint = <0x12>;
phandle = <0x13>;
};
};
};
};
display-backend@1e60000 {
compatible = "allwinner,suniv-display-backend";
reg = <0x1e60000 0x10000>;
reg-names = "be";
interrupts = <0x1f>;
clocks = <0x3 0x1a 0x3 0x37 0x3 0x36>;
clock-names = "ahb", "mod", "ram";
resets = <0x3 0xd>;
reset-names = "be";
assigned-clocks = <0x3 0x37>;
assigned-clock-rates = <0x11e1a300>;
ports {
#address-cells = <0x1>;
#size-cells = <0x0>;
port@0 {
#address-cells = <0x1>;
#size-cells = <0x0>;
reg = <0x0>;
endpoint@0 {
reg = <0x0>;
remote-endpoint = <0x13>;
phandle = <0x12>;
};
};
port@1 {
#address-cells = <0x1>;
#size-cells = <0x0>;
reg = <0x1>;
endpoint@0 {
reg = <0x0>;
remote-endpoint = <0x14>;
phandle = <0x7>;
};
};
};
};
};
aliases {
serial0 = "/soc/serial@1c25000";
spi0 = "/soc/spi@1c05000";
i2c0 = "/soc/i2c@1C27000";
};
chosen {
stdout-path = "serial0:115200n8";
};
panel {
compatible = "lg,lb070wv8", "simple-panel";
#address-cells = <0x1>;
#size-cells = <0x0>;
port@0 {
reg = <0x0>;
#address-cells = <0x1>;
#size-cells = <0x0>;
endpoint@0 {
reg = <0x0>;
remote-endpoint = <0x15>;
phandle = <0x8>;
};
};
};
vcc3v3 {
compatible = "regulator-fixed";
regulator-name = "vcc3v3";
regulator-min-microvolt = <0x325aa0>;
regulator-max-microvolt = <0x325aa0>;
phandle = <0xa>;
};
backlight
{
compatible = "pwm-backlight";
pwms = <&pwm 1 500000 0>;
brightness-levels = <0 4 8 16 32 64 128 255>;
default-brightness-level = <6>;
};
};离线
jiangming1399 说：https://www.lotlab.org/2019/02/22/荔枝派nano的spi-flash系统编译创建全过程/
看屏幕背光亮度调整那一节 可能能帮到你
设备树中，去掉gpios的配置就正常啦，十分感谢大家
compatible = "qiaodian,qd43003c0-40", "simple-panel";
#address-cells = <1>;
#size-cells = <0>;
- enable-gpios = <&pio 4 6 GPIO_ACTIVE_HIGH>;
感谢分享经验，应该是这里把IO的复用状态切换到GPIO了，而不是PWM。
离线
先 mark, 晚点我也要调试 c100 linux 4.15 的背光调节.
离线
jiangming1399 说：https://www.lotlab.org/2019/02/22/荔枝派nano的spi-flash系统编译创建全过程/
看屏幕背光亮度调整那一节 可能能帮到你
设备树中，去掉gpios的配置就正常啦，十分感谢大家
compatible = "qiaodian,qd43003c0-40", "simple-panel"; #address-cells = <1>; #size-cells = <0>; - enable-gpios = <&pio 4 6 GPIO_ACTIVE_HIGH>;
进了同一个坑， 开始怎么调都出不来，总是保持高电平，后来输出 PE6 复用寄存器状态才恍然大悟。
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https://www.kernel.org/doc/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt
https://superuser.com/questions/1091697/setting-pwm-backlight-brightness-on-boot
https://developer.toradex.com/knowledge-base/backlight-(linux)
echo 7 > /sys/class/backlight/backlight/brightness
这种驱动方式玩 LCD 背光， 有没有哪位试过？
离线
楼主，你好：
正好要做leds驱动，请教一个问题，没有看到有leds目录，是少了那个配置文件呢？
板子log:
# ls /sys/bus/platform/devices
10000.sram 1c20ca0.watchdog regulatory.0
1c00000.sram-controller 1c25000.serial serial8250
1c05000.spi 1e60000.display-backend snd-soc-dummy
1c0c000.lcd-controller alarmtimer snd_aloop.0
1c0f000.mmc display-engine soc
1c13000.usb musb-hdrc.1.auto usb_phy_generic.0.auto
1c13400.phy my-leds2 vcc3v3
1c20800.pinctrl panel
1c20c00.timer reg-dummy
# ls /sys/bus/platform/devices/my-leds2
driver_override of_node subsystem
modalias power uevent
# 设备树：
my-leds2 {
compatible = "gpio-leds"; /* 才能被识别为Led */
pinctrl-names = "default";
pinctrl-0 = <&leds_pins>;
blue_led {
label = "licheepi:blue:usr";
gpios = <&pio 4 4 GPIO_ACTIVE_LOW>; /* PE4 */
};
green_led {
label = "licheepi:green:usr";
gpios = <&pio 4 5 GPIO_ACTIVE_LOW>; /* PE5 */
default-state = "on";
};
red_led {
label = "licheepi:red:usr";
gpios = <&pio 5 6 GPIO_ACTIVE_LOW>; /* PE6 */
};
};
pio: pinctrl@1c20800 {
compatible = "allwinner,suniv-pinctrl";
reg = <0x01c20800 0x400>;
interrupts = <38>, <39>, <40>;
clocks = <&ccu CLK_BUS_PIO>, <&osc24M>, <&osc32k>;
clock-names = "apb", "hosc", "losc";
gpio-controller;
interrupt-controller;
#interrupt-cells = <3>;
#gpio-cells = <3>;
leds_pins: leds-pins {
pins = "PE4","PE5","PE6";
function = "gpio_out";
};
}；离线
设备树中，去掉gpios的配置就正常啦，十分感谢大家
compatible = "qiaodian,qd43003c0-40", "simple-panel"; #address-cells = <1>; #size-cells = <0>; - enable-gpios = <&pio 4 6 GPIO_ACTIVE_HIGH>;
原来如此, 调了大半天死活不起作用，正在准备放弃治疗了。
离线
https://www.kernel.org/doc/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt
https://superuser.com/questions/1091697/setting-pwm-backlight-brightness-on-boot
https://developer.toradex.com/knowledge-base/backlight-(linux)echo 7 > /sys/class/backlight/backlight/brightness
这种驱动方式玩 LCD 背光， 有没有哪位试过？
这个好用， 我以前在别的平台就是这样调液晶背光的。
离线