From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:42241) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QQLXE-0008Ar-Ec for qemu-devel@nongnu.org; Sat, 28 May 2011 11:34:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QQLXD-0003JB-C2 for qemu-devel@nongnu.org; Sat, 28 May 2011 11:34:40 -0400 From: Marcus Comstedt Date: Sat, 28 May 2011 16:55:52 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: [Qemu-devel] [PATCH] bitbang_i2c: Fix spurious slave read after NACK List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-trivial@nongnu.org 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 --- hw/bitbang_i2c.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) 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