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ftdi: Optimize GPIO toggling 

Only send the new I/O state for the bytes that changed.

Change-Id: I930edc9518e6019331e68e4756acc5e92dda25a4
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/1999
Tested-by: jenkins
Reviewed-by: Jens Bauer <jens@gpio.dk>
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>
This commit is contained in:
Andreas Fritiofson 2014-02-27 22:23:58 +01:00
parent 2eb8a31a6b
commit 4a4f716163
1 changed files with 7 additions and 2 deletions
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9
src/jtag/drivers/ftdi.c
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@ -174,14 +174,19 @@ static int ftdi_set_signal(const struct signal *s, char value)
return ERROR_FAIL; return ERROR_FAIL;
} }
uint16_t old_output = output;
uint16_t old_direction = direction;
output = data ? output | s->data_mask : output & ~s->data_mask; output = data ? output | s->data_mask : output & ~s->data_mask;
if (s->oe_mask == s->data_mask) if (s->oe_mask == s->data_mask)
direction = oe ? direction | s->oe_mask : direction & ~s->oe_mask; direction = oe ? direction | s->oe_mask : direction & ~s->oe_mask;
else else
output = oe ? output | s->oe_mask : output & ~s->oe_mask; output = oe ? output | s->oe_mask : output & ~s->oe_mask;
mpsse_set_data_bits_low_byte(mpsse_ctx, output & 0xff, direction & 0xff); if ((output & 0xff) != (old_output & 0xff) || (direction & 0xff) != (old_direction & 0xff))
mpsse_set_data_bits_high_byte(mpsse_ctx, output >> 8, direction >> 8); mpsse_set_data_bits_low_byte(mpsse_ctx, output & 0xff, direction & 0xff);
if ((output >> 8 != old_output >> 8) || (direction >> 8 != old_direction >> 8))
mpsse_set_data_bits_high_byte(mpsse_ctx, output >> 8, direction >> 8);
return ERROR_OK; return ERROR_OK;
} }