From: Lino Sanfilippo Date: Wed, 3 Jan 2024 06:18:16 +0000 (+0100) Subject: serial: core, imx: do not set RS485 enabled if it is not supported X-Git-Tag: v6.6.14~208 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=67043c0a6ed51ab31b34e43cf406b1c9f9895108;p=platform%2Fkernel%2Flinux-starfive.git serial: core, imx: do not set RS485 enabled if it is not supported commit 74eab89b26ac433ad857292f4707b43c1a8f0209 upstream. If the imx driver cannot support RS485 it nullifies the ports rs485_supported structure. But it still calls uart_get_rs485_mode() which may set the RS485_ENABLED flag nevertheless. This may lead to an attempt to configure RS485 even if it is not supported when the flag is evaluated in uart_configure_port() at port startup. Avoid this by bailing out of uart_get_rs485_mode() if the RS485_ENABLED flag is not supported by the caller. With this fix a check for RTS availability is now obsolete in the imx driver, since it can not evaluate to true any more. So remove this check. Furthermore the explicit nullifcation of rs485_supported is not needed, since the memory has already been set to zeros at allocation. So remove this, too. Fixes: 00d7a00e2a6f ("serial: imx: Fill in rs485_supported") Cc: Shawn Guo Cc: Sascha Hauer Cc: Suggested-by: Uwe Kleine-König Signed-off-by: Lino Sanfilippo Reviewed-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20240103061818.564-6-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 13cb783..230660c 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -2214,7 +2214,6 @@ static enum hrtimer_restart imx_trigger_stop_tx(struct hrtimer *t) return HRTIMER_NORESTART; } -static const struct serial_rs485 imx_no_rs485 = {}; /* No RS485 if no RTS */ static const struct serial_rs485 imx_rs485_supported = { .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX, @@ -2298,8 +2297,6 @@ static int imx_uart_probe(struct platform_device *pdev) /* RTS is required to control the RS485 transmitter */ if (sport->have_rtscts || sport->have_rtsgpio) sport->port.rs485_supported = imx_rs485_supported; - else - sport->port.rs485_supported = imx_no_rs485; sport->port.flags = UPF_BOOT_AUTOCONF; timer_setup(&sport->timer, imx_uart_timeout, 0); @@ -2336,10 +2333,6 @@ static int imx_uart_probe(struct platform_device *pdev) return ret; } - if (sport->port.rs485.flags & SER_RS485_ENABLED && - (!sport->have_rtscts && !sport->have_rtsgpio)) - dev_err(&pdev->dev, "no RTS control, disabling rs485\n"); - /* * If using the i.MX UART RTS/CTS control then the RTS (CTS_B) * signal cannot be set low during transmission in case the diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 50e1b26..18b49b1 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -3576,6 +3576,9 @@ int uart_get_rs485_mode(struct uart_port *port) int ret; int rx_during_tx_gpio_flag; + if (!(port->rs485_supported.flags & SER_RS485_ENABLED)) + return 0; + ret = device_property_read_u32_array(dev, "rs485-rts-delay", rs485_delay, 2); if (!ret) {