diff options
| author | Marek Vasut <marex@denx.de> | 2020-08-31 19:10:45 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-04 17:16:40 +0200 |
| commit | ad0c2748059fff13e8295ae91f51073d6c0311b7 (patch) | |
| tree | 1b5dd714fdb75f83caa150753f4976fb85d12312 /drivers/tty | |
| parent | 0fb9342d06b0f667b915ba58bfefc030e534a218 (diff) | |
serial: stm32: Add RS485 RTS GPIO control again
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.
Fixes: 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control")
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: linux-stm32@st-md-mailman.stormreply.com
Link: https://lore.kernel.org/r/20200831171045.205691-1-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.c | 33 |
1 files changed, 25 insertions, 8 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index ba503dd04ce2..ee6c7762d355 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -129,13 +129,9 @@ 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); @@ -541,17 +537,42 @@ static void stm32_disable_ms(struct uart_port *port) /* Transmit stop */ static void stm32_stop_tx(struct uart_port *port) { + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; + stm32_tx_interrupt_disable(port); + + if (rs485conf->flags & SER_RS485_ENABLED) { + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl & ~TIOCM_RTS); + } else { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl | TIOCM_RTS); + } + } } /* There are probably characters waiting to be transmitted. */ static void stm32_start_tx(struct uart_port *port) { + struct stm32_port *stm32_port = to_stm32_port(port); + struct serial_rs485 *rs485conf = &port->rs485; struct circ_buf *xmit = &port->state->xmit; if (uart_circ_empty(xmit)) return; + if (rs485conf->flags & SER_RS485_ENABLED) { + if (rs485conf->flags & SER_RS485_RTS_ON_SEND) { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl | TIOCM_RTS); + } else { + mctrl_gpio_set(stm32_port->gpios, + stm32_port->port.mctrl & ~TIOCM_RTS); + } + } + stm32_transmit_chars(port); } @@ -851,13 +872,9 @@ 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 { |