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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-11-23 01:35:55 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-11-23 01:35:55 -0300
commitd26f4ddb48463e2ff798859505af1cc520e75685 (patch)
treea1268534c14d9a7db61b4758ac72c33a3c7712bb /drivers/tty/serial
parent3326a1803802aa4730d32304b003f50720996b31 (diff)
Linux-libre 4.8.10-gnupck-4.8.10-gnu
Diffstat (limited to 'drivers/tty/serial')
-rw-r--r--drivers/tty/serial/atmel_serial.c27
1 files changed, 23 insertions, 4 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 8bbde52db..21aeac59d 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2026,6 +2026,7 @@ static void atmel_serial_pm(struct uart_port *port, unsigned int state,
static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned long flags;
unsigned int old_mode, mode, imr, quot, baud;
@@ -2129,11 +2130,29 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
mode |= ATMEL_US_USMODE_RS485;
} else if (termios->c_cflag & CRTSCTS) {
/* RS232 with hardware handshake (RTS/CTS) */
- if (atmel_use_dma_rx(port) && !atmel_use_fifo(port)) {
- dev_info(port->dev, "not enabling hardware flow control because DMA is used");
- termios->c_cflag &= ~CRTSCTS;
- } else {
+ if (atmel_use_fifo(port) &&
+ !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) {
+ /*
+ * with ATMEL_US_USMODE_HWHS set, the controller will
+ * be able to drive the RTS pin high/low when the RX
+ * FIFO is above RXFTHRES/below RXFTHRES2.
+ * It will also disable the transmitter when the CTS
+ * pin is high.
+ * This mode is not activated if CTS pin is a GPIO
+ * because in this case, the transmitter is always
+ * disabled (there must be an internal pull-up
+ * responsible for this behaviour).
+ * If the RTS pin is a GPIO, the controller won't be
+ * able to drive it according to the FIFO thresholds,
+ * but it will be handled by the driver.
+ */
mode |= ATMEL_US_USMODE_HWHS;
+ } else {
+ /*
+ * For platforms without FIFO, the flow control is
+ * handled by the driver.
+ */
+ mode |= ATMEL_US_USMODE_NORMAL;
}
} else {
/* RS232 without hadware handshake */