From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: [PATCH v2 04/10] serial: st-asc: (De)Register GPIOD and swap Pinctrl profiles Date: Fri, 27 Jan 2017 17:27:58 +0000 Message-ID: <20170127172804.23881-5-lee.jones@linaro.org> References: <20170127172804.23881-1-lee.jones@linaro.org> Return-path: In-Reply-To: <20170127172804.23881-1-lee.jones@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: gregkh@linuxfoundation.org, jslaby@suse.com, linux-serial@vger.kernel.org, dt@kernel.org, devicetree@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel@stlinux.com, patrice.chotard@st.com, Lee Jones List-Id: devicetree@vger.kernel.org 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 Signed-off-by: Lee Jones --- drivers/tty/serial/st-asc.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c index 82f5714..713d7bb 100644 --- a/drivers/tty/serial/st-asc.c +++ b/drivers/tty/serial/st-asc.c @@ -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[MANUAL_RTS]) { + pinctrl_select_state(ascport->pinctrl, + ascport->states[MANUAL_RTS]); + + 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 { -- 2.9.3