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From:   =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
To:     Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Gregory Clement <gregory.clement@bootlin.com>,
        Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
        Vladimir Vid <vladimir.vid@sartura.hr>,
        =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>,
        linux-clk@vger.kernel.org, linux-serial@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH 02/10] serial: mvebu-uart: do not allow changing baudrate when uartclk is not available
Date:   Fri, 25 Jun 2021 00:49:01 +0200
Message-Id: <20210624224909.6350-3-pali@kernel.org>
In-Reply-To: <20210624224909.6350-1-pali@kernel.org>
References: <20210624224909.6350-1-pali@kernel.org>
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Precedence: bulk

Testing mvuart->clk for non-error is not enough as mvuart->clk may contain
valid clk pointer but when clk_prepare_enable(mvuart->clk) failed then
port->uartclk is zero.

When mvuart->clk is not available then port->uartclk is zero too.

Parent clock rate port->uartclk is needed to calculate UART clock divisor
and without it is not possible to change baudrate.

So fix test condition when it is possible to change baudrate.

Signed-off-by: Pali Rohár <pali@kernel.org>
Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate")
---
 drivers/tty/serial/mvebu-uart.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index f81bfdaa608c..dc0c26824ddb 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -445,12 +445,11 @@ static void mvebu_uart_shutdown(struct uart_port *port)
 
 static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
 {
-	struct mvebu_uart *mvuart = to_mvuart(port);
 	unsigned int d_divisor, m_divisor;
 	u32 brdv, osamp;
 
-	if (IS_ERR(mvuart->clk))
-		return -PTR_ERR(mvuart->clk);
+	if (!port->uartclk)
+		return -EOPNOTSUPP;
 
 	/*
 	 * The baudrate is derived from the UART clock thanks to two divisors:
-- 
2.20.1