From: Lech Perczak <l.perczak@xxxxxxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Tomasz Moń <tomasz.mon@xxxxxxxxxxxxxxx>
---
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
