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bitbang_i2c: Fix spurious slave read after NACK

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After NACKing a read operation, a raising SCL should not trigger a new
read from the slave.  Introduce a new state which just waits for a stop
or start condition after NACK.

Signed-off-by: Marcus Comstedt <marcus@mc.pp.se>
Signed-off-by: Andrzej Zaborowski <andrew.zaborowski@intel.com>
This commit is contained in:
Marcus Comstedt 2011-05-28 16:55:52 +02:00 committed by Andrzej Zaborowski
parent 42a623c7db
commit 2eb9f24182
1 changed files with 4 additions and 1 deletions
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5
hw/bitbang_i2c.c
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@ -38,7 +38,8 @@ typedef enum bitbang_i2c_state {
RECEIVING_BIT2, RECEIVING_BIT2,
RECEIVING_BIT1, RECEIVING_BIT1,
RECEIVING_BIT0, RECEIVING_BIT0,
SENDING_ACK SENDING_ACK,
SENT_NACK
} bitbang_i2c_state; } bitbang_i2c_state;
struct bitbang_i2c_interface { struct bitbang_i2c_interface {
@ -115,6 +116,7 @@ int bitbang_i2c_set(bitbang_i2c_interface *i2c, int line, int level)
} }
switch (i2c->state) { switch (i2c->state) {
case STOPPED: case STOPPED:
case SENT_NACK:
return bitbang_i2c_ret(i2c, 1); return bitbang_i2c_ret(i2c, 1);
case SENDING_BIT7 ... SENDING_BIT0: case SENDING_BIT7 ... SENDING_BIT0:
@ -155,6 +157,7 @@ int bitbang_i2c_set(bitbang_i2c_interface *i2c, int line, int level)
i2c->state = RECEIVING_BIT7; i2c->state = RECEIVING_BIT7;
if (data != 0) { if (data != 0) {
DPRINTF("NACKED\n"); DPRINTF("NACKED\n");
i2c->state = SENT_NACK;
i2c_nack(i2c->bus); i2c_nack(i2c->bus);
} else { } else {
DPRINTF("ACKED\n"); DPRINTF("ACKED\n");