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tty: serial: meson: Use DIV_ROUND_CLOSEST to calculate baud rates

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Due to chip process differences, chip designers recommend using baud
rates as close to and larger as possible in order to reduce clock
errors.

Signed-off-by: Yu Tu <yu.tu@amlogic.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20220407081355.13602-2-yu.tu@amlogic.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yu Tu 2022-04-07 16:13:53 +08:00 committed by Greg Kroah-Hartman
parent 19401e9755
commit 368ab68b18
1 changed files with 2 additions and 2 deletions
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4
drivers/tty/serial/meson_uart.c
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@ -299,10 +299,10 @@ static void meson_uart_change_speed(struct uart_port *port, unsigned long baud)
cpu_relax();
if (port->uartclk == 24000000) {
val = ((port->uartclk / 3) / baud) - 1;
val = DIV_ROUND_CLOSEST(port->uartclk / 3, baud) - 1;
val |= AML_UART_BAUD_XTAL;
} else {
val = ((port->uartclk * 10 / (baud * 4) + 5) / 10) - 1;
val = DIV_ROUND_CLOSEST(port->uartclk / 4, baud) - 1;
}
val |= AML_UART_BAUD_USE;
writel(val, port->membase + AML_UART_REG5);