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_kernel@xxxxxxxxx> --- V3: 1: had not noticeable changes. V2: 1: First introduced in this series patches. drivers/usb/serial/f81534.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c index 08ef72ea2eec..92c9d8f18a5a 100644 --- a/drivers/usb/serial/f81534.c +++ b/drivers/usb/serial/f81534.c @@ -131,6 +131,8 @@ #define F81534_CLK_24_MHZ BIT(2) #define F81534_CLK_14_77_MHZ GENMASK(2, 1) #define F81534_CLK_MASK GENMASK(2, 1) +#define F81534_CLK_TX_DELAY_1BIT BIT(3) + #define F81534_CLK_RS485_MODE BIT(4) #define F81534_CLK_RS485_INVERT BIT(5) @@ -1386,7 +1388,11 @@ static int f81534_port_probe(struct usb_serial_port *port) if (!port_priv) return -ENOMEM; - port_priv->shadow_clk = F81534_UART_EN; + /* + * 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_UART_EN | F81534_CLK_TX_DELAY_1BIT; spin_lock_init(&port_priv->msr_lock); mutex_init(&port_priv->mcr_mutex); mutex_init(&port_priv->lcr_mutex); -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
