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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 <ostockemer@ereca.fr>
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Sonic Zhang 2010-10-16 18:22:34 -04:00 committed by Greg Kroah-Hartman
parent af7f374356
commit 0dd25df1a4
1 changed files with 6 additions and 1 deletions
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7
drivers/serial/bfin_sport_uart.c
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@ -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();