From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([85.220.165.71]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8f23-0004PH-Tt for barebox@lists.infradead.org; Thu, 20 Aug 2020 07:30:44 +0000 From: Oleksij Rempel Date: Thu, 20 Aug 2020 09:30:39 +0200 Message-Id: <20200820073039.3042-1-o.rempel@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH v2] serial: imx: set CTS if DT property "linux, rs485-enabled-at-boot-time" is present To: barebox@lists.infradead.org, david@protonic.nl Cc: Oleksij Rempel If we have a "linux,rs485-enabled-at-boot-time" DT property, we should set CTS flag as soon as possible to the active state. This will set an RS485 transmitter to receive-enable mode. Otherwise the RS485 bus will be blocked for entire system boot time and other bus participants will not be able to communicate. Signed-off-by: Oleksij Rempel --- drivers/serial/serial_imx.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/serial/serial_imx.c b/drivers/serial/serial_imx.c index c0265fc2d7..056fa14c2a 100644 --- a/drivers/serial/serial_imx.c +++ b/drivers/serial/serial_imx.c @@ -60,6 +60,7 @@ struct imx_serial_priv { void __iomem *regs; struct clk *clk; struct imx_serial_devtype_data *devtype; + bool rs485_mode; }; static int imx_serial_reffreq(struct imx_serial_priv *priv) @@ -107,6 +108,9 @@ static int imx_serial_init_port(struct console_device *cdev) /* Enable FIFOs */ val = readl(regs + UCR2); + /* set CTS to not block RS485 bus */ + if (priv->rs485_mode) + val |= UCR2_CTS; val |= UCR2_SRST | UCR2_RXEN | UCR2_TXEN; writel(val, regs + UCR2); @@ -252,6 +256,10 @@ static int imx_serial_probe(struct device_d *dev) if (of_property_read_bool(dev->device_node, "fsl,dte-mode")) priv->dte_mode = 1; + if (of_property_read_bool(dev->device_node, "linux,rs485-enabled-at-boot-time") && + !of_property_read_bool(dev->device_node, "rs485-rts-active-low")) + priv->rs485_mode = 1; + imx_serial_init_port(cdev); /* Enable UART */ -- 2.28.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox