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serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control

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As documented in the data-sheet, the transmitter must be disabled before
activating AutoCTS or auto transmitter flow control. Accordingly, the
transmitter must be enabled after AutoCTS or auto transmitter flow
control gets deactivated.

Signed-off-by: Christoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
Link: https://lore.kernel.org/r/20190904121746.4641-1-c.vogtlaender@sigma-surface-science.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christoph Vogtländer 2019-09-04 14:17:46 +02:00 committed by Greg Kroah-Hartman
parent 5a8c296f53
commit 7d4f881ff1
1 changed files with 18 additions and 0 deletions
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18
drivers/tty/serial/max310x.c
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@ -956,6 +956,15 @@ static void max310x_set_termios(struct uart_port *port,
max310x_port_write(port, MAX310X_XON1_REG, termios->c_cc[VSTART]);
max310x_port_write(port, MAX310X_XOFF1_REG, termios->c_cc[VSTOP]);
/* Disable transmitter before enabling AutoCTS or auto transmitter
* flow control
*/
if (termios->c_cflag & CRTSCTS || termios->c_iflag & IXOFF) {
max310x_port_update(port, MAX310X_MODE1_REG,
MAX310X_MODE1_TXDIS_BIT,
MAX310X_MODE1_TXDIS_BIT);
}
port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
if (termios->c_cflag & CRTSCTS) {
@ -974,6 +983,15 @@ static void max310x_set_termios(struct uart_port *port,
}
max310x_port_write(port, MAX310X_FLOWCTRL_REG, flow);
/* Enable transmitter after disabling AutoCTS and auto transmitter
* flow control
*/
if (!(termios->c_cflag & CRTSCTS) && !(termios->c_iflag & IXOFF)) {
max310x_port_update(port, MAX310X_MODE1_REG,
MAX310X_MODE1_TXDIS_BIT,
0);
}
/* Get baud rate generator configuration */
baud = uart_get_baud_rate(port, termios, old,
port->uartclk / 16 / 0xffff,