serial: st-asc: (De)Register GPIOD and swap Pinctrl profiles (d7356256) · Commits · 戴 / test

When hardware flow-control is disabled, manual toggling of the UART's reset line (RTS) using userland applications (e.g. stty) is not possible, since the ASC IP does not provide this functionality in the same was as some other IPs do. Thus, we have to do this manually. This patch ensures that when HW flow-control is disabled the RTS/CTS lines are free to be registered via the GPIO API. It also ensures any registered GPIO lines are unregistered when HW flow-control is requested, allowing the IP to control them automatically. Acked-by:

Peter Griffin <peter.griffin@linaro.org> Signed-off-by:

Lee Jones <lee.jones@linaro.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/st-asc.c

+26 −1

Original line number	Diff line number	Diff line
		@@ -513,6 +513,8 @@ static void asc_set_termios(struct uart_port port, struct ktermios termios,
		struct ktermios *old)
		{
		struct asc_port *ascport = to_asc_port(port);
		struct device_node *np = port->dev->of_node;
		struct gpio_desc *gpiod;
		unsigned int baud;
		u32 ctrl_val;
		tcflag_t cflag;
		@@ -556,9 +558,32 @@ static void asc_set_termios(struct uart_port port, struct ktermios termios,
		ctrl_val \|= ASC_CTL_PARITYODD;

		/* hardware flow control */
		if ((cflag & CRTSCTS))
		if ((cflag & CRTSCTS)) {
		ctrl_val \|= ASC_CTL_CTSENABLE;

		/* If flow-control selected, stop handling RTS manually */
		if (ascport->rts) {
		devm_gpiod_put(port->dev, ascport->rts);
		ascport->rts = NULL;

		pinctrl_select_state(ascport->pinctrl,
		ascport->states[DEFAULT]);
		}
		} else {
		/* If flow-control disabled, it's safe to handle RTS manually */
		if (!ascport->rts && ascport->states[NO_HW_FLOWCTRL]) {
		pinctrl_select_state(ascport->pinctrl,
		ascport->states[NO_HW_FLOWCTRL]);

		gpiod = devm_get_gpiod_from_child(port->dev, "rts",
		&np->fwnode);
		if (!IS_ERR(gpiod)) {
		gpiod_direction_output(gpiod, 0);
		ascport->rts = gpiod;
		}
		}
		}

		if ((baud < 19200) && !ascport->force_m1) {
		asc_out(port, ASC_BAUDRATE, (port->uartclk / (16 * baud)));
		} else {

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