diff options
Diffstat (limited to 'drivers/tty/serial/imx.c')
| -rw-r--r-- | drivers/tty/serial/imx.c | 64 |
1 files changed, 58 insertions, 6 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index a7548d0a1aee..11ac805663ae 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -489,7 +489,7 @@ static void imx_uart_stop_tx(struct uart_port *port) static void imx_uart_stop_rx(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; - u32 ucr1, ucr2, ucr4; + u32 ucr1, ucr2, ucr4, uts; ucr1 = imx_uart_readl(sport, UCR1); ucr2 = imx_uart_readl(sport, UCR2); @@ -505,7 +505,18 @@ static void imx_uart_stop_rx(struct uart_port *port) imx_uart_writel(sport, ucr1, UCR1); imx_uart_writel(sport, ucr4, UCR4); - ucr2 &= ~UCR2_RXEN; + /* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */ + if (port->rs485.flags & SER_RS485_ENABLED && + port->rs485.flags & SER_RS485_RTS_ON_SEND && + sport->have_rtscts && !sport->have_rtsgpio) { + uts = imx_uart_readl(sport, imx_uart_uts_reg(sport)); + uts |= UTS_LOOP; + imx_uart_writel(sport, uts, imx_uart_uts_reg(sport)); + ucr2 |= UCR2_RXEN; + } else { + ucr2 &= ~UCR2_RXEN; + } + imx_uart_writel(sport, ucr2, UCR2); } @@ -1390,7 +1401,7 @@ static int imx_uart_startup(struct uart_port *port) int retval, i; unsigned long flags; int dma_is_inited = 0; - u32 ucr1, ucr2, ucr3, ucr4; + u32 ucr1, ucr2, ucr3, ucr4, uts; retval = clk_prepare_enable(sport->clk_per); if (retval) @@ -1495,6 +1506,11 @@ static int imx_uart_startup(struct uart_port *port) imx_uart_writel(sport, ucr2, UCR2); } + /* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */ + uts = imx_uart_readl(sport, imx_uart_uts_reg(sport)); + uts &= ~UTS_LOOP; + imx_uart_writel(sport, uts, imx_uart_uts_reg(sport)); + spin_unlock_irqrestore(&sport->port.lock, flags); return 0; @@ -1504,7 +1520,7 @@ static void imx_uart_shutdown(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; unsigned long flags; - u32 ucr1, ucr2, ucr4; + u32 ucr1, ucr2, ucr4, uts; if (sport->dma_is_enabled) { dmaengine_terminate_sync(sport->dma_chan_tx); @@ -1548,7 +1564,18 @@ static void imx_uart_shutdown(struct uart_port *port) spin_lock_irqsave(&sport->port.lock, flags); ucr1 = imx_uart_readl(sport, UCR1); - ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN | UCR1_RXDMAEN | UCR1_ATDMAEN); + ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_RXDMAEN | UCR1_ATDMAEN); + /* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */ + if (port->rs485.flags & SER_RS485_ENABLED && + port->rs485.flags & SER_RS485_RTS_ON_SEND && + sport->have_rtscts && !sport->have_rtsgpio) { + uts = imx_uart_readl(sport, imx_uart_uts_reg(sport)); + uts |= UTS_LOOP; + imx_uart_writel(sport, uts, imx_uart_uts_reg(sport)); + ucr1 |= UCR1_UARTEN; + } else { + ucr1 &= ~UCR1_UARTEN; + } imx_uart_writel(sport, ucr1, UCR1); ucr4 = imx_uart_readl(sport, UCR4); @@ -2210,7 +2237,7 @@ static int imx_uart_probe(struct platform_device *pdev) void __iomem *base; u32 dma_buf_conf[2]; int ret = 0; - u32 ucr1; + u32 ucr1, ucr2, uts; struct resource *res; int txirq, rxirq, rtsirq; @@ -2347,6 +2374,31 @@ static int imx_uart_probe(struct platform_device *pdev) ucr1 &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN | UCR1_RTSDEN); imx_uart_writel(sport, ucr1, UCR1); + /* + * In case RS485 is enabled without GPIO RTS control, the UART IP + * is used to control CTS signal. Keep both the UART and Receiver + * enabled, otherwise the UART IP pulls CTS signal always HIGH no + * matter how the UCR2 CTSC and CTS bits are set. To prevent any + * data from being fed into the RX FIFO, enable loopback mode in + * UTS register, which disconnects the RX path from external RXD + * pin and connects it to the Transceiver, which is disabled, so + * no data can be fed to the RX FIFO that way. + */ + if (sport->port.rs485.flags & SER_RS485_ENABLED && + sport->have_rtscts && !sport->have_rtsgpio) { + uts = imx_uart_readl(sport, imx_uart_uts_reg(sport)); + uts |= UTS_LOOP; + imx_uart_writel(sport, uts, imx_uart_uts_reg(sport)); + + ucr1 = imx_uart_readl(sport, UCR1); + ucr1 |= UCR1_UARTEN; + imx_uart_writel(sport, ucr1, UCR1); + + ucr2 = imx_uart_readl(sport, UCR2); + ucr2 |= UCR2_RXEN; + imx_uart_writel(sport, ucr2, UCR2); + } + if (!imx_uart_is_imx1(sport) && sport->dte_mode) { /* * The DCEDTE bit changes the direction of DSR, DCD, DTR and RI |