Commit ecd6b010 authored by Pali Rohár's avatar Pali Rohár Committed by Greg Kroah-Hartman
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serial: mvebu-uart: do not allow changing baudrate when uartclk is not available 



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: default avatarPali Rohár <pali@kernel.org>
Fixes: 68a0db1d ("serial: mvebu-uart: add function to change baudrate")
Link: https://lore.kernel.org/r/20210624224909.6350-3-pali@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9078204c

drivers/tty/serial/mvebu-uart.c

+2 −3
Original line number Diff line number Diff line
@@ -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: