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serial: sh-sci: Simplify baud rate calculation algorithms 

Rewrite the baud rate register value calculations in easier to read
forms. The computed value isn't modified.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
This commit is contained in:
Laurent Pinchart 2013-12-06 10:59:12 +01:00 committed by Simon Horman
parent 6db201da25
commit 6557b1f69e
2 changed files with 8 additions and 8 deletions
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8
drivers/tty/serial/sh-sci.c
View File

@ -1818,13 +1818,13 @@ static unsigned int sci_scbrr_calc(unsigned int algo_id, unsigned int bps,
{
switch (algo_id) {
case SCBRR_ALGO_1:
return ((freq + 16 * bps) / (16 * bps) - 1);
return freq / (16 * bps);
case SCBRR_ALGO_2:
return ((freq + 16 * bps) / (32 * bps) - 1);
return DIV_ROUND_CLOSEST(freq, 32 * bps) - 1;
case SCBRR_ALGO_3:
return (((freq * 2) + 16 * bps) / (16 * bps) - 1);
return freq / (8 * bps);
case SCBRR_ALGO_4:
return (((freq * 2) + 16 * bps) / (32 * bps) - 1);
return DIV_ROUND_CLOSEST(freq, 16 * bps) - 1;
}
/* Warn, but use a safe default */

8
include/linux/serial_sci.h
View File

@ -11,10 +11,10 @@
#define SCIx_NOT_SUPPORTED (-1)
enum {
SCBRR_ALGO_1, /* ((clk + 16 * bps) / (16 * bps) - 1) */
SCBRR_ALGO_2, /* ((clk + 16 * bps) / (32 * bps) - 1) */
SCBRR_ALGO_3, /* (((clk * 2) + 16 * bps) / (16 * bps) - 1) */
SCBRR_ALGO_4, /* (((clk * 2) + 16 * bps) / (32 * bps) - 1) */
SCBRR_ALGO_1, /* clk / (16 * bps) */
SCBRR_ALGO_2, /* DIV_ROUND_CLOSEST(clk, 32 * bps) - 1 */
SCBRR_ALGO_3, /* clk / (8 * bps) */
SCBRR_ALGO_4, /* DIV_ROUND_CLOSEST(clk, 16 * bps) - 1 */
SCBRR_ALGO_6, /* HSCIF variable sample rate algorithm */
};