[PATCH] sc16is7xx: don't need "uart_handle_cts_change"

[PATCH] sc16is7xx: don't need "uart_handle_cts_change"

[Wills Wang]

SC16is7xx has feature for auto hardware flow control using RTS/CTS,
so we don't need "uart_handle_cts_change" to invoke "start_tx/stop_tx"
for flow control.

In addition, for software CTS, interrupt "SC16IS7XX_IIR_CTSRTS_SRC"
just report the nCTS change of state from active(low) to inactive(high),
driver don't know when the state of nCTS change from incactive to active,
so can't resume the transmission when a peer device is again ready and
re-assert nRTS signal.
---
 drivers/tty/serial/sc16is7xx.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 9d18c24..d19a7ba 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -653,7 +653,7 @@ static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
 	struct uart_port *port = &s->p[portno].port;
 
 	do {
-		unsigned int iir, msr, rxlen;
+		unsigned int iir, rxlen;
 
 		iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
 		if (iir & SC16IS7XX_IIR_NO_INT_BIT)
@@ -670,12 +670,6 @@ static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
 			if (rxlen)
 				sc16is7xx_handle_rx(port, rxlen, iir);
 			break;
-
-		case SC16IS7XX_IIR_CTSRTS_SRC:
-			msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
-			uart_handle_cts_change(port,
-					       !!(msr & SC16IS7XX_MSR_DCTS_BIT));
-			break;
 		case SC16IS7XX_IIR_THRI_SRC:
 			sc16is7xx_handle_tx(port);
 			break;
@@ -993,9 +987,8 @@ static int sc16is7xx_startup(struct uart_port *port)
 			      SC16IS7XX_EFCR_TXDISABLE_BIT,
 			      0);
 
-	/* Enable RX, TX, CTS change interrupts */
-	val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_THRI_BIT |
-	      SC16IS7XX_IER_CTSI_BIT;
+	/* Enable RX, TX interrupts */
+	val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_THRI_BIT;
 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
 
 	return 0;
-- 
1.9.1

Re: [PATCH] sc16is7xx: don't need "uart_handle_cts_change"

[Greg KH]

On Tue, Dec 22, 2015 at 05:19:56PM +0800, Wills Wang wrote:
> SC16is7xx has feature for auto hardware flow control using RTS/CTS,
> so we don't need "uart_handle_cts_change" to invoke "start_tx/stop_tx"
> for flow control.
> 
> In addition, for software CTS, interrupt "SC16IS7XX_IIR_CTSRTS_SRC"
> just report the nCTS change of state from active(low) to inactive(high),
> driver don't know when the state of nCTS change from incactive to active,
> so can't resume the transmission when a peer device is again ready and
> re-assert nRTS signal.
> ---
>  drivers/tty/serial/sc16is7xx.c | 13 +++----------
>  1 file changed, 3 insertions(+), 10 deletions(-)

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
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