From: Nandor Han <nandor.han@xxxxxx> The CTSC and CTS bits affect operation of the CTS/RTS hardware flow control signal (depending on whether the device is in DCE or DTE mode) and are not related to DMA. When in RS-232 mode, the driver is using the automatic CTSC control based on a rxFIFO fill level unless the state of the CTS signal is explictly set via an ioctl call. Previous improvements to the imx serial driver have resulted on imx_disable_dma() only being called on shutdown, by which point the serial core has already correctly deasserted CTS. Testing shows that without this handling in imx_disable_dma() the CTS signal state is set correctly when the device is open and TIOCM_RTS is set/cleared via the TIOCMGET ioctl. The CTS signal is also correctly deasserted when the device file is closed. When in RS-485 mode, the driver uses the CTS signal very differently and appears to control it via calls to imx_port_rts_active() and imx_port_rts_inactive(). This configuration of the CTSC and CTS bits are therefore not needed. Signed-off-by: Nandor Han <nandor.han@xxxxxx> Signed-off-by: Romain Perier <romain.perier@xxxxxxxxxxxxx> Signed-off-by: Martyn Welch <martyn.welch@xxxxxxxxxxxxxxx> --- drivers/tty/serial/imx.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index fe368a4..d90dae3 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1225,11 +1225,6 @@ static void imx_disable_dma(struct imx_port *sport) temp &= ~(UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN); writel(temp, sport->port.membase + UCR1); - /* clear UCR2 */ - temp = readl(sport->port.membase + UCR2); - temp &= ~(UCR2_CTSC | UCR2_CTS | UCR2_ATEN); - writel(temp, sport->port.membase + UCR2); - imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); sport->dma_is_enabled = 0; -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
