diff mbox series

[v2,4/9] serial: 8250: add support for rs485 RTS delays in microseconds

Message ID 20190221171758.10322-4-martin.kepplinger@ginzinger.com (mailing list archive)
State New, archived
Headers show
Series [v2,1/9] serial: uapi: add SER_RS485_DELAY_IN_USEC flag to struct serial_rs485 | expand

Commit Message

Martin Kepplinger Feb. 21, 2019, 5:17 p.m. UTC
Read struct serial_rs485's flag SER_RS485_DELAY_IN_USEC and apply the delay
accordingly.

Signed-off-by: Martin Kepplinger <martin.kepplinger@ginzinger.com>
---
 drivers/tty/serial/8250/8250_omap.c | 13 +++++++++++--
 drivers/tty/serial/8250/8250_port.c | 25 +++++++++++++++++++++----
 2 files changed, 32 insertions(+), 6 deletions(-)

Comments

Ahmad Fatoum March 29, 2019, 2:36 p.m. UTC | #1
On 21/2/19 18:17, Martin Kepplinger wrote:
> Read struct serial_rs485's flag SER_RS485_DELAY_IN_USEC and apply the delay
> accordingly.
> 
> Signed-off-by: Martin Kepplinger <martin.kepplinger@ginzinger.com>
> ---
>  drivers/tty/serial/8250/8250_omap.c | 13 +++++++++++--
>  drivers/tty/serial/8250/8250_port.c | 25 +++++++++++++++++++++----
>  2 files changed, 32 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
> index 0a8316632d75..cbce43ac60b1 100644
> --- a/drivers/tty/serial/8250/8250_omap.c
> +++ b/drivers/tty/serial/8250/8250_omap.c
> @@ -720,8 +720,17 @@ static int omap_8250_rs485_config(struct uart_port *port,
>  	struct uart_8250_port *up = up_to_u8250p(port);
>  
>  	/* Clamp the delays to [0, 100ms] */
> -	rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
> -	rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);
> +	if (rs485->flags & SER_RS485_DELAY_IN_USEC) {
> +		rs485->delay_rts_before_send = min(rs485->delay_rts_before_send,
> +						   100000U);
> +		rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send,
> +						   100000U);
> +	} else {
> +		rs485->delay_rts_before_send = min(rs485->delay_rts_before_send,
> +						   100U);
> +		rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send,
> +						   100U);
> +	}
>  
>  	port->rs485 = *rs485;
>  
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index d2f3310abe54..0cee4aa8323d 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -1483,6 +1483,15 @@ static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
>  	hrtimer_start(hrt, t, HRTIMER_MODE_REL);
>  }
>  
> +static void start_hrtimer_us(struct hrtimer *hrt, unsigned long usec)
> +{
> +	long sec = usec / 1000000;
> +	long nsec = (usec % 1000000) * 1000000000;

This 1e9 should be 1000 ("NSEC_PER_USEC").
While at it you might want to use USEC_PER_SEC (and MSEC_PER_SEC
above) to make the code more readable.

Cheers
Ahmad
diff mbox series

Patch

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 0a8316632d75..cbce43ac60b1 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -720,8 +720,17 @@  static int omap_8250_rs485_config(struct uart_port *port,
 	struct uart_8250_port *up = up_to_u8250p(port);
 
 	/* Clamp the delays to [0, 100ms] */
-	rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
-	rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send, 100U);
+	if (rs485->flags & SER_RS485_DELAY_IN_USEC) {
+		rs485->delay_rts_before_send = min(rs485->delay_rts_before_send,
+						   100000U);
+		rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send,
+						   100000U);
+	} else {
+		rs485->delay_rts_before_send = min(rs485->delay_rts_before_send,
+						   100U);
+		rs485->delay_rts_after_send  = min(rs485->delay_rts_after_send,
+						   100U);
+	}
 
 	port->rs485 = *rs485;
 
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index d2f3310abe54..0cee4aa8323d 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1483,6 +1483,15 @@  static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
 	hrtimer_start(hrt, t, HRTIMER_MODE_REL);
 }
 
+static void start_hrtimer_us(struct hrtimer *hrt, unsigned long usec)
+{
+	long sec = usec / 1000000;
+	long nsec = (usec % 1000000) * 1000000000;
+	ktime_t t = ktime_set(sec, nsec);
+
+	hrtimer_start(hrt, t, HRTIMER_MODE_REL);
+}
+
 static void __stop_tx_rs485(struct uart_8250_port *p)
 {
 	struct uart_8250_em485 *em485 = p->em485;
@@ -1493,8 +1502,12 @@  static void __stop_tx_rs485(struct uart_8250_port *p)
 	 */
 	if (p->port.rs485.delay_rts_after_send > 0) {
 		em485->active_timer = &em485->stop_tx_timer;
-		start_hrtimer_ms(&em485->stop_tx_timer,
-				   p->port.rs485.delay_rts_after_send);
+		if (p->port.rs485.flags & SER_RS485_DELAY_IN_USEC)
+			start_hrtimer_us(&em485->stop_tx_timer,
+					 p->port.rs485.delay_rts_after_send);
+		else
+			start_hrtimer_ms(&em485->stop_tx_timer,
+					 p->port.rs485.delay_rts_after_send);
 	} else {
 		__do_stop_tx_rs485(p);
 	}
@@ -1600,8 +1613,12 @@  static inline void start_tx_rs485(struct uart_port *port)
 
 		if (up->port.rs485.delay_rts_before_send > 0) {
 			em485->active_timer = &em485->start_tx_timer;
-			start_hrtimer_ms(&em485->start_tx_timer,
-					 up->port.rs485.delay_rts_before_send);
+			if (up->port.rs485.flags & SER_RS485_DELAY_IN_USEC)
+				start_hrtimer_us(&em485->start_tx_timer,
+					up->port.rs485.delay_rts_before_send);
+			else
+				start_hrtimer_ms(&em485->start_tx_timer,
+					up->port.rs485.delay_rts_before_send);
 			return;
 		}
 	}