From 0dd25df1a4e63c078f357aaffb09789c9438378f Mon Sep 17 00:00:00 2001 From: Sonic Zhang Date: Sat, 16 Oct 2010 18:22:34 -0400 Subject: [PATCH] serial: bfin_sport_uart: speed up sport RX sample rate to be 3% faster The actual uart baud rate of devices vary between +/-2% of what is asked. The SPORT RX sample rate should be faster than double of the worst case. Otherwise, wrong data may be received. So set SPORT RX clock to be 3% faster in general. Reported-by: Olivier STOCK Signed-off-by: Sonic Zhang Signed-off-by: Mike Frysinger Signed-off-by: Greg Kroah-Hartman --- drivers/serial/bfin_sport_uart.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/serial/bfin_sport_uart.c b/drivers/serial/bfin_sport_uart.c index 5318dd3774ae..6f1b51e231e4 100644 --- a/drivers/serial/bfin_sport_uart.c +++ b/drivers/serial/bfin_sport_uart.c @@ -131,7 +131,12 @@ static int sport_uart_setup(struct sport_uart_port *up, int size, int baud_rate) pr_debug("%s RCR1:%x, RCR2:%x\n", __func__, SPORT_GET_RCR1(up), SPORT_GET_RCR2(up)); tclkdiv = sclk / (2 * baud_rate) - 1; - rclkdiv = sclk / (2 * baud_rate * 2) - 1; + /* The actual uart baud rate of devices vary between +/-2%. The sport + * RX sample rate should be faster than the double of the worst case, + * otherwise, wrong data are received. So, set sport RX clock to be + * 3% faster. + */ + rclkdiv = sclk / (2 * baud_rate * 2 * 97 / 100) - 1; SPORT_PUT_TCLKDIV(up, tclkdiv); SPORT_PUT_RCLKDIV(up, rclkdiv); SSYNC();