On Thu, Jan 04, 2018 at 10:29:21AM +0800, Ji-Ze Hong (Peter Hong) wrote: > The F81532/534 had 4 clocksource 1.846/18.46/14.77/24MHz and baud rates > can be up to 1.5Mbits with 24MHz. But on some baud rate (384~500kps), the > TX side will send the data frame too close to treat frame error on RX > side. This patch will force all TX data frame with delay 1bit gap. > > Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_ker...@gmail.com> > --- > V2: > 1: First introduced in this series patches. > > drivers/usb/serial/f81534.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c > index a4666171239a..513805eeae6a 100644 > --- a/drivers/usb/serial/f81534.c > +++ b/drivers/usb/serial/f81534.c > @@ -130,6 +130,7 @@ > #define F81534_CLK_18_46_MHZ (F81534_UART_EN | BIT(1)) > #define F81534_CLK_24_MHZ (F81534_UART_EN | BIT(2)) > #define F81534_CLK_14_77_MHZ (F81534_UART_EN | BIT(1) | BIT(2)) > +#define F81534_CLK_TX_DELAY_1BIT BIT(3) > > #define F81534_CLK_RS485_MODE BIT(4) > #define F81534_CLK_RS485_INVERT BIT(5) > @@ -1438,6 +1439,11 @@ static int f81534_port_probe(struct usb_serial_port > *port) > break; > } > > + /* > + * We'll make tx frame error when baud rate from 384~500kps. So we'll > + * delay all tx data frame with 1bit. > + */ > + port_priv->shadow_clk |= F81534_CLK_TX_DELAY_1BIT;
You don't wan't to enable this only for the affected rates? > return f81534_set_port_output_pin(port); > } Johan
