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From: "Tomasz Moń" <tomasz.mon@camlingroup.com>
To: linux-serial@vger.kernel.org
Cc: "Phil Elwell" <phil@raspberrypi.com>,
	"Daniel Mack" <daniel@zonque.org>,
	"Jiri Slaby" <jirislaby@kernel.org>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Krzysztof Drobiński" <k.drobinski@camlintechnologies.com>,
	"Lech Perczak" <l.perczak@camlintechnologies.com>,
	"Tomasz Moń" <tomasz.mon@camlingroup.com>
Subject: [PATCH 2/6] sc16is7xx: Update status lines in single call
Date: Mon, 21 Feb 2022 11:56:14 +0100	[thread overview]
Message-ID: <20220221105618.3503470-3-tomasz.mon@camlingroup.com> (raw)
In-Reply-To: <20220221105618.3503470-1-tomasz.mon@camlingroup.com>

From: Lech Perczak <l.perczak@camlintechnologies.com>

RTS, DTR and LOOP bits can be updated in a single MCR register update.
This reduces the number of (slow) SPI/I2C bus transactions.

Signed-off-by: Lech Perczak <l.perczak@camlintechnologies.com>
Signed-off-by: Tomasz Moń <tomasz.mon@camlingroup.com>
---
 drivers/tty/serial/sc16is7xx.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 3800733452fe..c62531b2efe2 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -787,19 +787,24 @@ static void sc16is7xx_reg_proc(struct kthread_work *ws)
 	spin_unlock_irqrestore(&one->port.lock, irqflags);
 
 	if (config.flags & SC16IS7XX_RECONF_MD) {
+		u8 mcr = 0;
+
+		/* Device ignores RTS setting when hardware flow is enabled */
+		if (one->port.mctrl & TIOCM_RTS)
+			mcr |= SC16IS7XX_MCR_RTS_BIT;
+
+		if (one->port.mctrl & TIOCM_DTR)
+			mcr |= SC16IS7XX_MCR_DTR_BIT;
+
+		if (one->port.mctrl & TIOCM_LOOP)
+			mcr |= SC16IS7XX_MCR_LOOP_BIT;
 		sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
+				      SC16IS7XX_MCR_RTS_BIT |
+				      SC16IS7XX_MCR_DTR_BIT |
 				      SC16IS7XX_MCR_LOOP_BIT,
-				      (one->port.mctrl & TIOCM_LOOP) ?
-				      SC16IS7XX_MCR_LOOP_BIT : 0);
-		sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
-				      SC16IS7XX_MCR_RTS_BIT,
-				      (one->port.mctrl & TIOCM_RTS) ?
-				      SC16IS7XX_MCR_RTS_BIT : 0);
-		sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
-				      SC16IS7XX_MCR_DTR_BIT,
-				      (one->port.mctrl & TIOCM_DTR) ?
-				      SC16IS7XX_MCR_DTR_BIT : 0);
+				      mcr);
 	}
+
 	if (config.flags & SC16IS7XX_RECONF_IER)
 		sc16is7xx_port_update(&one->port, SC16IS7XX_IER_REG,
 				      config.ier_clear, 0);
-- 
2.25.1


  parent reply	other threads:[~2022-02-21 11:16 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-21 10:56 [PATCH 0/6] sc16is7xx: Hardware flow control fixes Tomasz Moń
2022-02-21 10:56 ` [PATCH 1/6] sc16is7xx: Preserve EFR bits on update Tomasz Moń
2022-02-21 10:56 ` Tomasz Moń [this message]
2022-02-21 10:56 ` [PATCH 3/6] sc16is7xx: Separate GPIOs from modem control lines Tomasz Moń
2022-02-21 10:56 ` [PATCH 4/6] sc16is7xx: Properly resume TX after stop Tomasz Moń
2022-02-21 10:56 ` [PATCH 5/6] sc16is7xx: Handle modem status lines Tomasz Moń
2022-02-21 10:56 ` [PATCH 6/6] sc16is7xx: Set AUTOCTS and AUTORTS bits Tomasz Moń
2022-02-25  9:25 ` [PATCH 0/6] sc16is7xx: Hardware flow control fixes Greg Kroah-Hartman
2022-02-25  9:37   ` Tomasz Moń
2022-02-25 10:47     ` Greg Kroah-Hartman
2022-02-25 11:26       ` Greg Kroah-Hartman

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