linux-kernel - [PATCH v4 5/8] serial: core: sanitize RS485 delays read from device tree

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Date:   Sun, 10 Jul 2022 18:44:39 +0200
From:   Lino Sanfilippo <LinoSanfilippo@....de>
To:     gregkh@...uxfoundation.org, jirislaby@...nel.org
Cc:     ilpo.jarvinen@...ux.intel.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org,
        andriy.shevchenko@...ux.intel.com, vz@...ia.com,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        lukas@...ner.de, p.rosenberger@...bus.com,
        Lino Sanfilippo <l.sanfilippo@...bus.com>
Subject: [PATCH v4 5/8] serial: core: sanitize RS485 delays read from device tree

From: Lino Sanfilippo <l.sanfilippo@...bus.com>

Currently the RTS delays set via device tree are not clamped to a maximum
value although the device tree bindings documentation for RS485 claims that
only a maximum of 1000 msecs is allowed.

So clamp the values to avoid arbitrary high delay settings. However clamp
the values to 100 instead of 1000 msecs to be consistent which the maximum
that is allowed when setting the delays from userspace via the UART ioctl
TIOCSRS485.

Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
---
 drivers/tty/serial/serial_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 3158f05a328c..ac198d0d4c80 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3395,6 +3395,8 @@ int uart_get_rs485_mode(struct uart_port *port)
 		rs485conf->delay_rts_after_send = 0;
 	}
 
+	uart_sanitize_serial_rs485_delays(port, rs485conf);
+
 	/*
 	 * Clear full-duplex and enabled flags, set RTS polarity to active high
 	 * to get to a defined state with the following properties:
-- 
2.25.1