1 files changed, 132 insertions, 49 deletions

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 0973b03eeeaa..dfdbcf092fac 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -35,6 +35,75 @@
 #include "serial_mctrl_gpio.h"
 #include "stm32-usart.h"
 
+
+/* Register offsets */
+static struct stm32_usart_info __maybe_unused stm32f4_info = {
+	.ofs = {
+		.isr	= 0x00,
+		.rdr	= 0x04,
+		.tdr	= 0x04,
+		.brr	= 0x08,
+		.cr1	= 0x0c,
+		.cr2	= 0x10,
+		.cr3	= 0x14,
+		.gtpr	= 0x18,
+		.rtor	= UNDEF_REG,
+		.rqr	= UNDEF_REG,
+		.icr	= UNDEF_REG,
+	},
+	.cfg = {
+		.uart_enable_bit = 13,
+		.has_7bits_data = false,
+		.fifosize = 1,
+	}
+};
+
+static struct stm32_usart_info __maybe_unused stm32f7_info = {
+	.ofs = {
+		.cr1	= 0x00,
+		.cr2	= 0x04,
+		.cr3	= 0x08,
+		.brr	= 0x0c,
+		.gtpr	= 0x10,
+		.rtor	= 0x14,
+		.rqr	= 0x18,
+		.isr	= 0x1c,
+		.icr	= 0x20,
+		.rdr	= 0x24,
+		.tdr	= 0x28,
+	},
+	.cfg = {
+		.uart_enable_bit = 0,
+		.has_7bits_data = true,
+		.has_swap = true,
+		.fifosize = 1,
+	}
+};
+
+static struct stm32_usart_info __maybe_unused stm32h7_info = {
+	.ofs = {
+		.cr1	= 0x00,
+		.cr2	= 0x04,
+		.cr3	= 0x08,
+		.brr	= 0x0c,
+		.gtpr	= 0x10,
+		.rtor	= 0x14,
+		.rqr	= 0x18,
+		.isr	= 0x1c,
+		.icr	= 0x20,
+		.rdr	= 0x24,
+		.tdr	= 0x28,
+	},
+	.cfg = {
+		.uart_enable_bit = 0,
+		.has_7bits_data = true,
+		.has_swap = true,
+		.has_wakeup = true,
+		.has_fifo = true,
+		.fifosize = 16,
+	}
+};
+
 static void stm32_usart_stop_tx(struct uart_port *port);
 static void stm32_usart_transmit_chars(struct uart_port *port);
 static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch);
@@ -62,6 +131,53 @@ static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits)
 	writel_relaxed(val, port->membase + reg);
 }
 
+static unsigned int stm32_usart_tx_empty(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
+		return TIOCSER_TEMT;
+
+	return 0;
+}
+
+static void stm32_usart_rs485_rts_enable(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	struct serial_rs485 *rs485conf = &port->rs485;
+
+	if (stm32_port->hw_flow_control ||
+	    !(rs485conf->flags & SER_RS485_ENABLED))
+		return;
+
+	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);
+	}
+}
+
+static void stm32_usart_rs485_rts_disable(struct uart_port *port)
+{
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	struct serial_rs485 *rs485conf = &port->rs485;
+
+	if (stm32_port->hw_flow_control ||
+	    !(rs485conf->flags & SER_RS485_ENABLED))
+		return;
+
+	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);
+	}
+}
+
 static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
 					 u32 delay_DDE, u32 baud)
 {
@@ -99,7 +215,7 @@ static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
 	*cr1 |= rs485_deat_dedt;
 }
 
-static int stm32_usart_config_rs485(struct uart_port *port,
+static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *termios,
 				    struct serial_rs485 *rs485conf)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
@@ -145,6 +261,12 @@ static int stm32_usart_config_rs485(struct uart_port *port,
 
 	stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 
+	/* Adjust RTS polarity in case it's driven in software */
+	if (stm32_usart_tx_empty(port))
+		stm32_usart_rs485_rts_disable(port);
+	else
+		stm32_usart_rs485_rts_enable(port);
+
 	return 0;
 }
 
@@ -460,42 +582,6 @@ static void stm32_usart_tc_interrupt_disable(struct uart_port *port)
 	stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TCIE);
 }
 
-static void stm32_usart_rs485_rts_enable(struct uart_port *port)
-{
-	struct stm32_port *stm32_port = to_stm32_port(port);
-	struct serial_rs485 *rs485conf = &port->rs485;
-
-	if (stm32_port->hw_flow_control ||
-	    !(rs485conf->flags & SER_RS485_ENABLED))
-		return;
-
-	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);
-	}
-}
-
-static void stm32_usart_rs485_rts_disable(struct uart_port *port)
-{
-	struct stm32_port *stm32_port = to_stm32_port(port);
-	struct serial_rs485 *rs485conf = &port->rs485;
-
-	if (stm32_port->hw_flow_control ||
-	    !(rs485conf->flags & SER_RS485_ENABLED))
-		return;
-
-	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);
-	}
-}
-
 static void stm32_usart_transmit_chars_pio(struct uart_port *port)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
@@ -738,17 +824,6 @@ static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr)
 	return IRQ_HANDLED;
 }
 
-static unsigned int stm32_usart_tx_empty(struct uart_port *port)
-{
-	struct stm32_port *stm32_port = to_stm32_port(port);
-	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
-
-	if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
-		return TIOCSER_TEMT;
-
-	return 0;
-}
-
 static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
@@ -1020,7 +1095,7 @@ static void stm32_usart_shutdown(struct uart_port *port)
 
 static void stm32_usart_set_termios(struct uart_port *port,
 				    struct ktermios *termios,
-				    struct ktermios *old)
+				    const struct ktermios *old)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
@@ -1377,6 +1452,13 @@ static void stm32_usart_deinit_port(struct stm32_port *stm32port)
 	clk_disable_unprepare(stm32port->clk);
 }
 
+static const struct serial_rs485 stm32_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
+		 SER_RS485_RX_DURING_TX,
+	.delay_rts_before_send = 1,
+	.delay_rts_after_send = 1,
+};
+
 static int stm32_usart_init_port(struct stm32_port *stm32port,
 				 struct platform_device *pdev)
 {
@@ -1396,6 +1478,7 @@ static int stm32_usart_init_port(struct stm32_port *stm32port,
 	port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE);
 	port->irq = irq;
 	port->rs485_config = stm32_usart_config_rs485;
+	port->rs485_supported = stm32_rs485_supported;
 
 	ret = stm32_usart_init_rs485(port, pdev);
 	if (ret)