| Message ID | yf9sjryq3gn.fsf@chiyo.mc.pp.se |
|---|---|
| State | New |
| Headers | show |
On Sat, May 28, 2011 at 3:55 PM, Marcus Comstedt <marcus@mc.pp.se> wrote: > 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> > --- > hw/bitbang_i2c.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) Seems like a simple change but I'm not familiar with the code or I2C details. Andrzej, care to take a look? > diff --git a/hw/bitbang_i2c.c b/hw/bitbang_i2c.c > index 4ee99a1..2937b5c 100644 > --- a/hw/bitbang_i2c.c > +++ b/hw/bitbang_i2c.c > @@ -38,7 +38,8 @@ typedef enum bitbang_i2c_state { > RECEIVING_BIT2, > RECEIVING_BIT1, > RECEIVING_BIT0, > - SENDING_ACK > + SENDING_ACK, > + SENT_NACK > } bitbang_i2c_state; > > struct bitbang_i2c_interface { > @@ -115,6 +116,7 @@ int bitbang_i2c_set(bitbang_i2c_interface *i2c, int line, int level) > } > switch (i2c->state) { > case STOPPED: > + case SENT_NACK: > return bitbang_i2c_ret(i2c, 1); > > 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; > if (data != 0) { > DPRINTF("NACKED\n"); > + i2c->state = SENT_NACK; > i2c_nack(i2c->bus); > } else { > DPRINTF("ACKED\n"); > -- > 1.7.4.1 > > >
Hi, On 28 May 2011 21:52, Stefan Hajnoczi <stefanha@gmail.com> wrote: > On Sat, May 28, 2011 at 3:55 PM, Marcus Comstedt <marcus@mc.pp.se> wrote: >> 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. Makes sense, I pushed this change to master. Cheers
diff --git a/hw/bitbang_i2c.c b/hw/bitbang_i2c.c index 4ee99a1..2937b5c 100644 --- a/hw/bitbang_i2c.c +++ b/hw/bitbang_i2c.c @@ -38,7 +38,8 @@ typedef enum bitbang_i2c_state { RECEIVING_BIT2, RECEIVING_BIT1, RECEIVING_BIT0, - SENDING_ACK + SENDING_ACK, + SENT_NACK } bitbang_i2c_state; struct bitbang_i2c_interface { @@ -115,6 +116,7 @@ int bitbang_i2c_set(bitbang_i2c_interface *i2c, int line, int level) } switch (i2c->state) { case STOPPED: + case SENT_NACK: return bitbang_i2c_ret(i2c, 1); 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; if (data != 0) { DPRINTF("NACKED\n"); + i2c->state = SENT_NACK; i2c_nack(i2c->bus); } else { DPRINTF("ACKED\n");
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> --- hw/bitbang_i2c.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-)