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serial: 8250_bcm7271: Save/restore RTS in suspend/resume

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[ Upstream commit 3182efd036c1b955403d131258234896cbd9fbeb ]

Commit 9cabe26e65a8 ("serial: 8250_bcm7271: UART errors after resuming
from S2") prevented an early enabling of RTS during resume, but it did
not actively restore the RTS state after resume.

Fixes: 9cabe26e65a8 ("serial: 8250_bcm7271: UART errors after resuming from S2")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220714031316.404918-1-f.fainelli@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Doug Berger 2022-07-13 20:13:15 -07:00 committed by Greg Kroah-Hartman
parent 3d69d86b3e
commit 9a06340c9d
1 changed files with 18 additions and 6 deletions

24
drivers/tty/serial/8250/8250_bcm7271.c

@ -1141,16 +1141,19 @@ static int __maybe_unused brcmuart_suspend(struct device *dev)
struct brcmuart_priv *priv = dev_get_drvdata(dev);
struct uart_8250_port *up = serial8250_get_port(priv->line);
struct uart_port *port = &up->port;
serial8250_suspend_port(priv->line);
clk_disable_unprepare(priv->baud_mux_clk);
unsigned long flags;
/*
* This will prevent resume from enabling RTS before the
* baud rate has been resored.
* baud rate has been restored.
*/
spin_lock_irqsave(&port->lock, flags);
priv->saved_mctrl = port->mctrl;
port->mctrl = 0;
port->mctrl &= ~TIOCM_RTS;
spin_unlock_irqrestore(&port->lock, flags);
serial8250_suspend_port(priv->line);
clk_disable_unprepare(priv->baud_mux_clk);
return 0;
}
@ -1160,6 +1163,7 @@ static int __maybe_unused brcmuart_resume(struct device *dev)
struct brcmuart_priv *priv = dev_get_drvdata(dev);
struct uart_8250_port *up = serial8250_get_port(priv->line);
struct uart_port *port = &up->port;
unsigned long flags;
int ret;
ret = clk_prepare_enable(priv->baud_mux_clk);
@ -1182,7 +1186,15 @@ static int __maybe_unused brcmuart_resume(struct device *dev)
start_rx_dma(serial8250_get_port(priv->line));
}
serial8250_resume_port(priv->line);
port->mctrl = priv->saved_mctrl;
if (priv->saved_mctrl & TIOCM_RTS) {
/* Restore RTS */
spin_lock_irqsave(&port->lock, flags);
port->mctrl |= TIOCM_RTS;
port->ops->set_mctrl(port, port->mctrl);
spin_unlock_irqrestore(&port->lock, flags);
}
return 0;
}