[components][serial] fix serial v2 rx indicate setup

[Old-Ding]

Summary

• Move the POSIX serial v2 rx indication callback setup until after the close/open sequence in serial_fops_open().
• Keep rt_serial_close() cleanup behavior unchanged.
• Avoid leaving serial_fops_rx_ind cleared by the internal rt_device_close() call, so poll/select waiters can be woken after opening the serial device through DFS.

Closes #11538

Validation

• git diff --check
• Rechecked open PRs for duplicate serial_fops_open / rx_indicate fixes.
• Reviewed the call chain: serial_fops_open() -> rt_device_close() -> rt_serial_close() clears rx_indicate, then rt_device_open() returns.

Build not run locally: this Windows environment does not have scons or gcc in PATH.

[github-actions]

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[github-actions]

📌 Code Review Assignment

🏷️ Tag: components

Reviewers: @Maihuanyi

Changed Files (Click to expand)

• components/drivers/serial/dev_serial_v2.c

🏷️ Tag: components_driver_serial_v2

Reviewers: @Ryan-CW-Code

Changed Files (Click to expand)

• components/drivers/serial/dev_serial_v2.c

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📊 Current Review Status (Last Updated: 2026-07-01 09:34 CST)

• ⌛ @Maihuanyi Pending Review
• ⌛ @Ryan-CW-Code Pending Review

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[github-actions]

MemBrowse Memory Report

No memory changes detected for:

• at32f415-start
• esp32-c3
• gd32105r-start
• hc32f334
• hpmicro-hpm5301evklite
• infineon-psoc6
• k230
• loongson-ls1cdev
• nordic-nrf51822
• nuvoton-m487
• nxp-lpc1114
• qemu-virt64-aarch64
• raspberry-pico-rp2040
• renesas-ra2l1
• simulator
• stm32f407-rt-spark
• stm32l475-atk-pandora-llvm
• wch-ch32v208w-r0
• x86
• xuantie-e901plus

[Ryan-CW-Code]

对posix这方面了解甚少，大佬可以增加 components/drivers/serial/utest 跑一遍试试吗？

[Old-Ding]

我看了 components/drivers/serial/utest/v2 这组用例：它是 RT-Thread 目标侧测试，需要在 BSP 中启用 RT_UTEST_SERIAL_V2，按 README 在 MSH 里运行对应 utest_run ...；多数普通串口用例还要求测试串口 TX/RX 做回环，POSIX 用例需要启用 RT_UTEST_SERIAL_POSIX。

这个 PR 的改动只在 serial_fops_open() 中把 rt_device_set_rx_indicate() 移到 rt_device_open() 成功之后，避免 open 失败时提前设置 rx callback。

我当前本地 Windows 环境没有可运行这组目标侧 utest 的工具链/运行环境：缺 scons、qemu-system-*、arm-none-eabi-gcc/aarch64-none-elf-gcc/riscv64-unknown-elf-gcc，也没有可做 TX/RX 回环的串口硬件。所以这边没法给出真实的 serial utest 运行日志。

已核对当前 PR CI：format/license、static analysis、BSP static build、MemBrowse、现有 utest_auto_run 矩阵均没有失败；不过上游 .github/utest/configs 里目前没有 serial v2 专项配置，现有 utest 矩阵没有覆盖这组 serial 用例。

如果你们有推荐的 BSP/config 用来跑 serial v2 POSIX 用例，我可以按那个配置继续补验证。