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authorMarek Vasut <marex@denx.de>2020-07-25 16:49:47 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-07-30 08:46:22 +0200
commit7df5081cbf5e1c342acd30850a483ef504519937 (patch)
tree656f57830f9eeee82fcc2007adf36430fc1b8946 /drivers/tty
parentcc816969d7b5973d2720d9afd381f06f0eac6885 (diff)
serial: stm32: Add RS485 RTS GPIO control
While the STM32 does support RS485 drive-enable control within the UART IP itself, some systems have the drive-enable line connected to a pin which cannot be pinmuxed as RTS. Add support for toggling the RTS GPIO line using the modem control GPIOs to provide at least some sort of emulation. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Alexandre Torgue <alexandre.torgue@st.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Manivannan Sadhasivam <mani@kernel.org> Cc: Fabrice Gasnier <fabrice.gasnier@st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-stm32@st-md-mailman.stormreply.com Link: https://lore.kernel.org/r/20200725144947.537007-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/stm32-usart.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index d1c5e536a167..143300a80090 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -129,9 +129,13 @@ static int stm32_config_rs485(struct uart_port *port,
if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
cr3 &= ~USART_CR3_DEP;
rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
+ mctrl_gpio_set(stm32_port->gpios,
+ stm32_port->port.mctrl & ~TIOCM_RTS);
} else {
cr3 |= USART_CR3_DEP;
rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
+ mctrl_gpio_set(stm32_port->gpios,
+ stm32_port->port.mctrl | TIOCM_RTS);
}
writel_relaxed(cr3, port->membase + ofs->cr3);
@@ -847,9 +851,13 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
cr3 &= ~USART_CR3_DEP;
rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
+ mctrl_gpio_set(stm32_port->gpios,
+ stm32_port->port.mctrl & ~TIOCM_RTS);
} else {
cr3 |= USART_CR3_DEP;
rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
+ mctrl_gpio_set(stm32_port->gpios,
+ stm32_port->port.mctrl | TIOCM_RTS);
}
} else {