On Wed, Feb 12, 2020 at 10:35:38AM -0600, George Hilliard wrote:
> The peripheral has support for inverting its input and/or output
> signals. This is useful if the hardware flips polarity of the
> peripheral's signal, such as swapped +/- pins on an RS-422 transceiver,
> or an inverting level shifter. Add support for these control registers
> via the device tree binding.
>
> Signed-off-by: George Hilliard <ghilliard@xxxxxxxxxxxxxxx>
> ---
> v1..v2: Remove confidentiality spam
> v2..v3: Set *and* clear register, and do it before TX enable
>
> drivers/tty/serial/imx.c | 28 +++++++++++++++++++++++-----
> 1 file changed, 23 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 0c6c63166250..205627bcad66 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -195,6 +195,8 @@ struct imx_port {
> unsigned int have_rtscts:1;
> unsigned int have_rtsgpio:1;
> unsigned int dte_mode:1;
> + unsigned int inverted_tx:1;
> + unsigned int inverted_rx:1;
> struct clk *clk_ipg;
> struct clk *clk_per;
> const struct imx_uart_data *devdata;
> @@ -1335,7 +1337,7 @@ static int imx_uart_startup(struct uart_port *port)
> int retval, i;
> unsigned long flags;
> int dma_is_inited = 0;
> - u32 ucr1, ucr2, ucr4;
> + u32 ucr1, ucr2, ucr3, ucr4;
>
> retval = clk_prepare_enable(sport->clk_per);
> if (retval)
> @@ -1390,8 +1392,22 @@ static int imx_uart_startup(struct uart_port *port)
> ucr4 = imx_uart_readl(sport, UCR4) & ~UCR4_OREN;
> if (!sport->dma_is_enabled)
> ucr4 |= UCR4_OREN;
> + if (sport->inverted_rx)
> + ucr4 |= UCR4_INVR;
> + else
> + ucr4 &= ~UCR4_INVR;
Maybe clear UCR4_INVR in the same way as UCR4_OREN is cleared just
above?
> imx_uart_writel(sport, ucr4, UCR4);
>
> + /*
> + * configure tx polarity before enabling tx
> + */
> + ucr3 = imx_uart_readl(sport, UCR3);
> + if (sport->inverted_tx)
> + ucr3 |= UCR3_INVT;
> + else
> + ucr3 &= ~UCR3_INVT;
> + imx_uart_writel(sport, ucr3, UCR3);
> +
> ucr2 = imx_uart_readl(sport, UCR2) & ~UCR2_ATEN;
> ucr2 |= (UCR2_RXEN | UCR2_TXEN);
> if (!sport->have_rtscts)
> @@ -1405,10 +1421,6 @@ static int imx_uart_startup(struct uart_port *port)
> imx_uart_writel(sport, ucr2, UCR2);
>
> if (!imx_uart_is_imx1(sport)) {
If this complete if block would be moved up, you only need to write this
register once.
> - u32 ucr3;
> -
> - ucr3 = imx_uart_readl(sport, UCR3);
> -
> ucr3 |= UCR3_DTRDEN | UCR3_RI | UCR3_DCD;
>
> if (sport->dte_mode)
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
