Re: [PATCH v3 08/16] HID: ft260: uart: add modem pins control via ioctl

[sashiko-bot@kernel.org]

> Add TIOCMGET/TIOCMSET (and thus TIOCMBIS/TIOCMBIC) support so userspace
> can drive DTR/RTS when the modem pins are in GPIO mode. This enables
> programming an ESP32 over the FT260 with esptool, which resets the chip
> via those lines.
> 
> Set up the gpiochip and the sysfs attributes on the UART interface when
> the chip mode has UART, and on the I2C interface only in the I2C-only
> mode. Before, the choice depended on USB interface number 0, which is
> the I2C interface in mode 3, but TIOCMGET and TIOCMSET run on the UART
> interface and need the GPIO state there. Add DCD and RI (GPIO4 and
> GPIO5) to the GPIO set of UART modes 3 and 4, so the mask that TIOCMGET
> and TIOCMSET check covers the two lines that TIOCMGET reports.
> 
> The RTS, CTS, DTR and DSR pins are active-low, so TIOCMGET inverts the
> sense of those four lines and TIOCMSET drives 0 to assert them. DCD and
> [ ... ]
> instead of using hdev after hid_hw_stop().
> 
> Co-developed-by: Rio Liu <rio@r26.me>
> Signed-off-by: Rio Liu <rio@r26.me>
> Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261114230800.1344401-1-michael.zaidman@gmail.com?part=8