Commit 6cca8f15 authored by Lech Perczak's avatar Lech Perczak Committed by Greg Kroah-Hartman
Browse files

sc16is7xx: Update status lines in single call 



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: default avatarLech Perczak <l.perczak@camlintechnologies.com>
Signed-off-by: default avatarTomasz Moń <tomasz.mon@camlingroup.com>
Link: https://lore.kernel.org/r/20220221105618.3503470-3-tomasz.mon@camlingroup.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c112653b

drivers/tty/serial/sc16is7xx.c

+15 −10
Original line number Diff line number Diff line
@@ -784,19 +784,24 @@ 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);