diff options
Diffstat (limited to 'drivers/tty/serial/imx.c')
| -rw-r--r-- | drivers/tty/serial/imx.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 91f3a1a5cb7f..c2fc6bef7a6f 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -316,7 +316,7 @@ static u32 imx_uart_readl(struct imx_port *sport, u32 offset) * differ from the value that was last written. As it only * clears after being set, reread conditionally. */ - if (sport->ucr2 & UCR2_SRST) + if (!(sport->ucr2 & UCR2_SRST)) sport->ucr2 = readl(sport->port.membase + offset); return sport->ucr2; break; @@ -1833,6 +1833,11 @@ static int imx_uart_rs485_config(struct uart_port *port, rs485conf->flags &= ~SER_RS485_ENABLED; if (rs485conf->flags & SER_RS485_ENABLED) { + /* Enable receiver if low-active RTS signal is requested */ + if (sport->have_rtscts && !sport->have_rtsgpio && + !(rs485conf->flags & SER_RS485_RTS_ON_SEND)) + rs485conf->flags |= SER_RS485_RX_DURING_TX; + /* disable transmitter */ ucr2 = imx_uart_readl(sport, UCR2); if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND) @@ -2265,6 +2270,18 @@ static int imx_uart_probe(struct platform_device *pdev) (!sport->have_rtscts && !sport->have_rtsgpio)) dev_err(&pdev->dev, "no RTS control, disabling rs485\n"); + /* + * If using the i.MX UART RTS/CTS control then the RTS (CTS_B) + * signal cannot be set low during transmission in case the + * receiver is off (limitation of the i.MX UART IP). + */ + if (sport->port.rs485.flags & SER_RS485_ENABLED && + sport->have_rtscts && !sport->have_rtsgpio && + (!(sport->port.rs485.flags & SER_RS485_RTS_ON_SEND) && + !(sport->port.rs485.flags & SER_RS485_RX_DURING_TX))) + dev_err(&pdev->dev, + "low-active RTS not possible when receiver is off, enabling receiver\n"); + imx_uart_rs485_config(&sport->port, &sport->port.rs485); /* Disable interrupts before requesting them */ |