The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 9078204ca5c33ba20443a8623a41a68a9995a70d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pali=20Roh=C3=A1r?= pali@kernel.org Date: Fri, 25 Jun 2021 00:49:00 +0200 Subject: [PATCH] serial: mvebu-uart: fix calculation of clock divisor MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
The clock divisor should be rounded to the closest value.
Signed-off-by: Pali Rohár pali@kernel.org Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate") Cc: stable@vger.kernel.org # 0e4cf69ede87 ("serial: mvebu-uart: clarify the baud rate derivation") Link: https://lore.kernel.org/r/20210624224909.6350-2-pali@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index 04c41689d81c..f3ecbcf495ee 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -463,7 +463,7 @@ static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud) * makes use of D to configure the desired baudrate. */ m_divisor = OSAMP_DEFAULT_DIVISOR; - d_divisor = DIV_ROUND_UP(port->uartclk, baud * m_divisor); + d_divisor = DIV_ROUND_CLOSEST(port->uartclk, baud * m_divisor);
brdv = readl(port->membase + UART_BRDV); brdv &= ~BRDV_BAUD_MASK;