APPLIED: [PATCH v2 1/1][SRU][Bionic][OEM-B]UBUNTU: SAUCE: platform/x86: dell-uart-backlight: new backlight driver for DELL AIO
Kleber Souza
kleber.souza at canonical.com
Tue Jul 31 14:44:41 UTC 2018
On 07/17/18 09:13, AceLan Kao wrote:
> BugLink: https://bugs.launchpad.net/bugs/1727235
>
> The Dell AIO machines released after 2017 come with a UART interface
> to communicate with the backlight scalar board. This driver creates
> a standard backlight interface and talks to the scalar board through
> UART.
>
> In DSDT this uart port will be defined as
> Name (_HID, "DELL0501")
> Name (_CID, EisaId ("PNP0501")
> The 8250 PNP driver will be loaded by default, and this driver uses
> "DELL0501" to confirm the uart port is a backlight interface and
> leverage the port created by 8250 PNP driver to communicate with
> the scalar board.
>
> v2:
> 1. move struct uart_cmd to .c file
> 2. make dell_uart_get_bl_power() inline
> 3. add space to ternary operator "bl_cmd->cmd[2] = power ? 0 : 1;"
> 4. check return value of kzalloc()
> 5. add kzfree()
> 6. check return value of backlight_device_register()
> 7. check return value of filp_open() at init
>
> Signed-off-by: AceLan Kao <acelan.kao at canonical.com>
> ---
> drivers/platform/x86/Kconfig | 14 +
> drivers/platform/x86/Makefile | 1 +
> drivers/platform/x86/dell-uart-backlight.c | 463 +++++++++++++++++++++
> drivers/platform/x86/dell-uart-backlight.h | 35 ++
> 4 files changed, 513 insertions(+)
> create mode 100644 drivers/platform/x86/dell-uart-backlight.c
> create mode 100644 drivers/platform/x86/dell-uart-backlight.h
>
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 683a875f3b6c..6edfa935a434 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -199,6 +199,20 @@ config DELL_RBTN
> To compile this driver as a module, choose M here: the module will
> be called dell-rbtn.
>
> +config DELL_UART_BACKLIGHT
> + tristate "Dell AIO UART Backlight driver"
> + depends on SERIAL_8250
> + depends on ACPI
> + ---help---
> + Say Y here if you want to support Dell AIO UART backlight interface.
> + The Dell AIO machines released after 2017 come with a UART interface
> + to communicate with the backlight scalar board. This driver creates
> + a standard backlight interface and talks to the scalar board through
> + UART to adjust the AIO screen brightness.
> +
> + To compile this driver as a module, choose M here: the module will
> + be called dell_uart_backlight.
> +
>
> config FUJITSU_LAPTOP
> tristate "Fujitsu Laptop Extras"
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index c32b34a72467..85329fd26afd 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_DELL_WMI_AIO) += dell-wmi-aio.o
> obj-$(CONFIG_DELL_WMI_LED) += dell-wmi-led.o
> obj-$(CONFIG_DELL_SMO8800) += dell-smo8800.o
> obj-$(CONFIG_DELL_RBTN) += dell-rbtn.o
> +obj-$(CONFIG_DELL_UART_BACKLIGHT) += dell-uart-backlight.o
> obj-$(CONFIG_ACER_WMI) += acer-wmi.o
> obj-$(CONFIG_ACERHDF) += acerhdf.o
> obj-$(CONFIG_HP_ACCEL) += hp_accel.o
> diff --git a/drivers/platform/x86/dell-uart-backlight.c b/drivers/platform/x86/dell-uart-backlight.c
> new file mode 100644
> index 000000000000..7508ceca34a5
> --- /dev/null
> +++ b/drivers/platform/x86/dell-uart-backlight.c
> @@ -0,0 +1,463 @@
> +/*
> + * Dell AIO Serial Backlight Driver
> + *
> + * Copyright (C) 2017 AceLan Kao <acelan.kao at canonical.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/acpi.h>
> +#include <linux/serial_8250.h>
> +#include <linux/delay.h>
> +#include <linux/backlight.h>
> +#include <acpi/video.h>
> +
> +#include "dell-uart-backlight.h"
> +
> +struct dell_uart_backlight {
> + struct device *dev;
> + struct backlight_device *dell_uart_bd;
> + struct mutex brightness_mutex;
> + int line;
> + int bl_power;
> +};
> +struct uart_8250_port *serial8250_get_port(int line);
> +struct tty_struct *tty;
> +struct file *ftty;
> +
> +unsigned int (*io_serial_in)(struct uart_port *p, int offset);
> +int (*uart_write)(struct tty_struct *tty, const unsigned char *buf, int count);
> +int (*uart_chars_in_buffer)(struct tty_struct *tty);
> +
> +static const struct dell_uart_bl_cmd uart_cmd[] = {
> + /*
> + * Get Firmware Version: Tool uses this command to get firmware version.
> + * Command: 0x6A 0x06 0x8F (Length:3 Type: 0x0A, Cmd:6 Checksum:0x8F)
> + * Return data: 0x0D 0x06 Data checksum (Length:13,Cmd:0x06,
> + * Data :F/W version(APRILIA=APR27-VXXX,PHINE=PHI23-VXXX),
> + * checksum:SUM(Length and Cmd and Data)xor 0xFF .
> + */
> + [DELL_UART_GET_FIRMWARE_VER] = {
> + .cmd = {0x6A, 0x06, 0x8F},
> + .tx_len = 3,
> + },
> + /*
> + * Get Brightness level: Application uses this command for scaler to get brightness.
> + * Command: 0x6A 0x0C 0x89 (Length:3 Type: 0x0A, Cmd:0x0C, Checksum:0x89)
> + * Return data: 0x04 0x0C Data checksum
> + * (Length:4 Cmd: 0x0C Data: brightness level checksum: SUM(Length and Cmd and Data)xor 0xFF)
> + * brightness level which ranges from 0~100.
> + */
> + [DELL_UART_GET_BRIGHTNESS] = {
> + .cmd = {0x6A, 0x0C, 0x89},
> + .ret = {0x04, 0x0C, 0x00, 0x00},
> + .tx_len = 3,
> + .rx_len = 4,
> + },
> + /* Set Brightness level: Application uses this command for scaler to set brightness.
> + * Command: 0x8A 0x0B Byte2 Checksum (Length:4 Type: 0x0A, Cmd:0x0B)
> + * where Byte2 is the brightness level which ranges from 0~100.
> + * Return data: 0x03 0x0B 0xF1(Length:3,Cmd:B,checksum:0xF1)
> + * Scaler must send the 3bytes ack within 1 second when success, other value if error
> + */
> + [DELL_UART_SET_BRIGHTNESS] = {
> + .cmd = {0x8A, 0x0B, 0x0, 0x0},
> + .ret = {0x03, 0x0B, 0xF1},
> + .tx_len = 4,
> + .rx_len = 3,
> + },
> + /*
> + * Screen ON/OFF Control: Application uses this command to control screen ON or OFF.
> + * Command: 0x8A 0x0E Byte2 Checksum (Length:4 Type: 0x0A, Cmd:0x0E) where
> + * Byte2=0 to turn OFF the screen.
> + * Byte2=1 to turn ON the screen
> + * Other value of Byte2 is reserved and invalid.
> + * Return data: 0x03 0x0E 0xEE(Length:3,Cmd:E,checksum:0xEE)
> + */
> + [DELL_UART_SET_BACKLIGHT_POWER] = {
> + .cmd = {0x8A, 0x0E, 0x00, 0x0},
> + .ret = {0x03, 0x0E, 0xEE},
> + .tx_len = 4,
> + .rx_len = 3,
> + },
> +};
> +
> +static int dell_uart_write(struct uart_8250_port *up, __u8 *buf, int len)
> +{
> + int actual = 0;
> + struct uart_port *port = &up->port;
> +
> + tty_port_tty_wakeup(&port->state->port);
> + tty = tty_port_tty_get(&port->state->port);
> + actual = uart_write(tty, buf, len);
> + while (uart_chars_in_buffer(tty)) {
> + udelay(10);
> + }
> +
> + return actual;
> +}
> +
> +static int dell_uart_read(struct uart_8250_port *up, __u8 *buf, int len)
> +{
> + int i, retry;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&up->port.lock, flags);
> + for (i = 0; i < len; i++) {
> + retry = 10;
> + while (!(io_serial_in(&up->port, UART_LSR) & UART_LSR_DR)) {
> + if (--retry == 0)
> + break;
> + mdelay(20);
> + }
> +
> + if (retry == 0)
> + break;
> + buf[i] = io_serial_in(&up->port, UART_RX);
> + }
> + spin_unlock_irqrestore(&up->port.lock, flags);
> +
> + return i;
> +}
> +
> +static void dell_uart_dump_cmd(const char *func, const char *prefix,
> + const char *cmd, int len)
> +{
> + char buf[80];
> +
> + snprintf(buf, 80, "dell_uart_backlight:%s:%s", func, prefix);
> + if (len != 0)
> + print_hex_dump_debug(buf, DUMP_PREFIX_NONE,
> + 16, 1, cmd, len, false);
> + else
> + pr_debug("dell_uart_backlight:%s:%sNULL\n", func, prefix);
> +
> +}
> +
> +/*
> + * checksum: SUM(Length and Cmd and Data)xor 0xFF)
> + */
> +static unsigned char dell_uart_checksum(unsigned char *buf, int len)
> +{
> + unsigned char val = 0;
> +
> + while (len-- > 0)
> + val += buf[len];
> +
> + return val ^ 0xff;
> +}
> +
> +/*
> + * There is no command to get backlight power status,
> + * so we set the backlight power to "on" while initializing,
> + * and then track and report its status by bl_power variable
> + */
> +static inline int dell_uart_get_bl_power(struct dell_uart_backlight *dell_pdata)
> +{
> + return dell_pdata->bl_power;
> +}
> +
> +static int dell_uart_set_bl_power(struct backlight_device *bd, int power)
> +{
> + struct dell_uart_bl_cmd *bl_cmd =
> + &uart_cmd[DELL_UART_SET_BACKLIGHT_POWER];
> + struct dell_uart_backlight *dell_pdata = bl_get_data(bd);
> + struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line);
> + int rx_len;
> +
> + if (power != FB_BLANK_POWERDOWN)
> + power = FB_BLANK_UNBLANK;
> +
> + bl_cmd->cmd[2] = power ? 0 : 1;
> + bl_cmd->cmd[3] = dell_uart_checksum(bl_cmd->cmd, bl_cmd->tx_len - 1);
> +
> + dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len);
> +
> + if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) {
> + pr_debug("Failed to get mutex_lock");
> + return 0;
> + }
> +
> + dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len);
> + rx_len = dell_uart_read(uart, bl_cmd->ret, bl_cmd->rx_len);
> +
> + mutex_unlock(&dell_pdata->brightness_mutex);
> +
> + dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len);
> +
> + bd->props.power = power;
> + dell_pdata->bl_power = power;
> +
> + return 0;
> +}
> +
> +static int dell_uart_get_brightness(struct backlight_device *bd)
> +{
> + struct dell_uart_bl_cmd *bl_cmd = &uart_cmd[DELL_UART_GET_BRIGHTNESS];
> + struct dell_uart_backlight *dell_pdata = bl_get_data(bd);
> + struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line);
> + int rx_len, brightness = 0;
> +
> + dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len);
> +
> + if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) {
> + pr_debug("Failed to get mutex_lock");
> + return 0;
> + }
> +
> + dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len);
> + rx_len = dell_uart_read(uart, bl_cmd->ret, bl_cmd->rx_len);
> +
> + mutex_unlock(&dell_pdata->brightness_mutex);
> +
> + dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len);
> +
> + brightness = (unsigned int)bl_cmd->ret[2];
> +
> + return brightness;
> +}
> +
> +static int dell_uart_update_status(struct backlight_device *bd)
> +{
> + struct dell_uart_bl_cmd *bl_cmd = &uart_cmd[DELL_UART_SET_BRIGHTNESS];
> + struct dell_uart_backlight *dell_pdata = bl_get_data(bd);
> + struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line);
> + int rx_len;
> +
> + bl_cmd->cmd[2] = bd->props.brightness;
> + bl_cmd->cmd[3] = dell_uart_checksum(bl_cmd->cmd, bl_cmd->tx_len - 1);
> +
> + dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len);
> +
> + if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) {
> + pr_debug("Failed to get mutex_lock");
> + return 0;
> + }
> +
> + dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len);
> + rx_len = dell_uart_read(uart, bl_cmd->ret, bl_cmd->rx_len);
> +
> + mutex_unlock(&dell_pdata->brightness_mutex);
> +
> + dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len);
> +
> + if (bd->props.power != dell_uart_get_bl_power(dell_pdata))
> + dell_uart_set_bl_power(bd, bd->props.power);
> +
> + return 0;
> +}
> +
> +static int dell_uart_get_scalar_status(struct dell_uart_backlight *dell_pdata)
> +{
> + struct dell_uart_bl_cmd *bl_cmd = &uart_cmd[DELL_UART_GET_SCALAR];
> + struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line);
> + int rx_len, status = 1; /* assume the scalar IC controls backlight if the command failed */
> +
> + dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len);
> +
> + if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) {
> + pr_debug("Failed to get mutex_lock");
> + return 0;
> + }
> +
> + dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len);
> + rx_len = dell_uart_read(uart, bl_cmd->ret, bl_cmd->rx_len);
> +
> + mutex_unlock(&dell_pdata->brightness_mutex);
> +
> + dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len);
> +
> + if (rx_len == 4)
> + status = (unsigned int)bl_cmd->ret[2];
> +
> + return status;
> +}
> +
> +static int dell_uart_show_firmware_ver(struct dell_uart_backlight *dell_pdata)
> +{
> + struct dell_uart_bl_cmd *bl_cmd = &uart_cmd[DELL_UART_GET_FIRMWARE_VER];
> + struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line);
> + int rx_len = 0, retry = 10;
> +
> + dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len);
> +
> + if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) {
> + pr_debug("Failed to get mutex_lock");
> + return -1;
> + }
> +
> + dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len);
> + while (retry-- > 0) {
> + /* first byte is data length */
> + dell_uart_read(uart, bl_cmd->ret, 1);
> + rx_len = (int)bl_cmd->ret[0];
> + if (bl_cmd->ret[0] > 80 || bl_cmd->ret[0] <= 0) {
> + pr_debug("Failed to get firmware version\n");
> + if (retry == 0) {
> + mutex_unlock(&dell_pdata->brightness_mutex);
> + return -1;
> + }
> + msleep(100);
> + continue;
> + }
> +
> + dell_uart_read(uart, bl_cmd->ret+1, rx_len-1);
> + break;
> + }
> + mutex_unlock(&dell_pdata->brightness_mutex);
> +
> + dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len);
> +
> + pr_debug("Firmare str(%d)= %s\n", (int)bl_cmd->ret[0], bl_cmd->ret+2);
> + return rx_len;
> +}
> +
> +static const struct backlight_ops dell_uart_backlight_ops = {
> + .get_brightness = dell_uart_get_brightness,
> + .update_status = dell_uart_update_status,
> +};
> +
> +static int dell_uart_startup(struct dell_uart_backlight *dell_pdata)
> +{
> + struct uart_8250_port *uartp;
> + struct uart_port *port;
> +
> + dell_pdata->line = 0;
> + uartp = serial8250_get_port(dell_pdata->line);
> + port = &uartp->port;
> + tty = port->state->port.tty;
> + io_serial_in = port->serial_in;
> + uart_write = tty->driver->ops->write;
> + uart_chars_in_buffer = tty->driver->ops->chars_in_buffer;
> +
> + return 0;
> +}
> +
> +static int dell_uart_bl_add(struct acpi_device *dev)
> +{
> + struct dell_uart_backlight *dell_pdata;
> + struct backlight_properties props;
> + struct backlight_device *dell_uart_bd;
> +
> + dell_pdata = kzalloc(sizeof(struct dell_uart_backlight), GFP_KERNEL);
> + if (!dell_pdata) {
> + pr_debug("Failed to allocate memory for dell_uart_backlight\n");
> + return -1;
> + }
> + dell_pdata->dev = &dev->dev;
> + dell_uart_startup(dell_pdata);
> + dev->driver_data = dell_pdata;
> +
> + mutex_init(&dell_pdata->brightness_mutex);
> +
> + if (!dell_uart_get_scalar_status(dell_pdata)) {
> + udelay(50);
> + /* try another command to make sure there is no scalar IC */
> + if (!dell_uart_show_firmware_ver(dell_pdata) <= 0) {
> + pr_debug("Scalar doesn't in charge of brightness adjustment.\n");
> + kzfree(dell_pdata);
> + return -1;
> + }
> + }
> +
> + memset(&props, 0, sizeof(struct backlight_properties));
> + props.type = BACKLIGHT_PLATFORM;
> + props.max_brightness = 100;
> +
> + dell_uart_bd = backlight_device_register("dell_uart_backlight",
> + &dev->dev,
> + dell_pdata,
> + &dell_uart_backlight_ops,
> + &props);
> + if (IS_ERR(dell_uart_bd)) {
> + kzfree(dell_pdata);
> + pr_debug("Backlight registration failed\n");
> + return -1;
> + }
> +
> + dell_pdata->dell_uart_bd = dell_uart_bd;
> +
> + dell_uart_set_bl_power(dell_uart_bd, FB_BLANK_UNBLANK);
> + dell_uart_bd->props.brightness = 100;
> + backlight_update_status(dell_uart_bd);
> +
> + /* unregister acpi backlight interface */
> + acpi_video_set_dmi_backlight_type(acpi_backlight_vendor);
> +
> + return 0;
> +}
> +
> +static int dell_uart_bl_remove(struct acpi_device *dev)
> +{
> + struct dell_uart_backlight *dell_pdata = dev->driver_data;
> +
> + backlight_device_unregister(dell_pdata->dell_uart_bd);
> + kzfree(dell_pdata);
> +
> + return 0;
> +}
> +
> +static int dell_uart_bl_suspend(struct device *dev)
> +{
> + filp_close(ftty, NULL);
> + return 0;
> +}
> +
> +static int dell_uart_bl_resume(struct device *dev)
> +{
> + ftty = filp_open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY, 0);
> + return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(dell_uart_bl_pm, dell_uart_bl_suspend, dell_uart_bl_resume);
> +
> +static const struct acpi_device_id dell_uart_bl_ids[] = {
> + {"DELL0501", 0},
> + {"", 0},
> +};
> +
> +static struct acpi_driver dell_uart_backlight_driver = {
> + .name = "Dell AIO serial backlight",
> + .ids = dell_uart_bl_ids,
> + .ops = {
> + .add = dell_uart_bl_add,
> + .remove = dell_uart_bl_remove,
> + },
> + .drv.pm = &dell_uart_bl_pm,
> +};
> +
> +static int __init dell_uart_bl_init(void)
> +{
> + ftty = filp_open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY, 0);
> + if (IS_ERR(ftty)) {
> + pr_debug("cannot open /dev/ttyS0\n");
> + return -EINVAL;
> + }
> +
> + return acpi_bus_register_driver(&dell_uart_backlight_driver);
> +}
> +
> +static void __exit dell_uart_bl_exit(void)
> +{
> + filp_close(ftty, NULL);
> +
> + acpi_bus_unregister_driver(&dell_uart_backlight_driver);
> +}
> +
> +module_init(dell_uart_bl_init);
> +module_exit(dell_uart_bl_exit);
> +MODULE_DEVICE_TABLE(acpi, dell_uart_bl_ids);
> +MODULE_DESCRIPTION("Dell AIO Serial Backlight module");
> +MODULE_AUTHOR("AceLan Kao <acelan.kao at canonical.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/platform/x86/dell-uart-backlight.h b/drivers/platform/x86/dell-uart-backlight.h
> new file mode 100644
> index 000000000000..4e32b5df76dc
> --- /dev/null
> +++ b/drivers/platform/x86/dell-uart-backlight.h
> @@ -0,0 +1,35 @@
> +/*
> + * Dell AIO Serial Backlight Driver
> + *
> + * Copyright (C) 2017 AceLan Kao <acelan.kao at canonical.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef _DELL_UART_BACKLIGHT_H_
> +#define _DELL_UART_BACKLIGHT_H_
> +
> +enum {
> + DELL_UART_GET_FIRMWARE_VER,
> + DELL_UART_GET_BRIGHTNESS,
> + DELL_UART_SET_BRIGHTNESS,
> + DELL_UART_SET_BACKLIGHT_POWER,
> +};
> +
> +struct dell_uart_bl_cmd {
> + unsigned char cmd[10];
> + unsigned char ret[80];
> + unsigned short tx_len;
> + unsigned short rx_len;
> +};
> +
> +#endif /* _DELL_UART_BACKLIGHT_H_ */
>
Hi AceLan,
Applied to bionic/master-next branch.
If Khaled's comments are relevant, please consider sending a follow-up
fix for the driver (with a different LP bug number).
Thanks,
Kleber
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