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| author | Oleksij Rempel <o.rempel@pengutronix.de> | 2020-08-20 09:30:39 +0200 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2020-09-23 11:20:41 +0200 |
| commit | 9537d843650aebdb4ed5d088f1e4bb8ec8089151 (patch) | |
| tree | 312304e42d6ad61643e81350c83da46dfa41bd5d /drivers/serial | |
| parent | 4d720d3552059fd279224898860d3b58465fcadc (diff) | |
| download | barebox-9537d843650aebdb4ed5d088f1e4bb8ec8089151.tar.gz barebox-9537d843650aebdb4ed5d088f1e4bb8ec8089151.tar.xz | |
serial: imx: set CTS if DT property "linux, rs485-enabled-at-boot-time" is present
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 <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/serial')
| -rw-r--r-- | drivers/serial/serial_imx.c | 8 |
1 files changed, 8 insertions, 0 deletions
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 */ |