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| author | Ji-Ze Hong (Peter Hong) <hpeter@gmail.com> | 2018-01-11 14:47:20 +0800 |
|---|---|---|
| committer | Johan Hovold <johan@kernel.org> | 2018-01-11 11:00:25 +0100 |
| commit | d1c48227d7c45fbb35c81f846a62ec92a74f4701 (patch) | |
| tree | c392eb4b308459b85833ec49b4b232468f66348c /drivers/usb | |
| parent | bb543ca287f5b14a61533f959e3f62ae58890311 (diff) | |
| download | linux-d1c48227d7c45fbb35c81f846a62ec92a74f4701.tar.gz linux-d1c48227d7c45fbb35c81f846a62ec92a74f4701.tar.bz2 linux-d1c48227d7c45fbb35c81f846a62ec92a74f4701.zip | |
USB: serial: f81534: fix tx error on some baud rate
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@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/serial/f81534.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c index 86edec3e8c05..4dfbff20bda4 100644 --- a/drivers/usb/serial/f81534.c +++ b/drivers/usb/serial/f81534.c @@ -131,6 +131,7 @@ #define F81534_CLK_24_MHZ BIT(2) #define F81534_CLK_14_77_MHZ (BIT(1) | BIT(2)) #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 +1387,11 @@ 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); |