From: "Noralf Trønnes" <noralf@tronnes.org>
To: wsa@the-dreams.de, swarren@wwwdotorg.org, eric@anholt.net
Cc: linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-rpi-kernel@lists.infradead.org,
"Noralf Trønnes" <noralf@tronnes.org>
Subject: [PATCH v4 4/7] i2c: bcm2835: Can't support I2C_M_IGNORE_NAK
Date: Mon, 3 Oct 2016 22:06:11 +0200 [thread overview]
Message-ID: <1475525174-28604-5-git-send-email-noralf@tronnes.org> (raw)
In-Reply-To: <1475525174-28604-1-git-send-email-noralf@tronnes.org>
The controller can't support this flag, so remove it.
Documentation/i2c/i2c-protocol states that all of the message is sent:
I2C_M_IGNORE_NAK:
Normally message is interrupted immediately if there is [NA] from the
client. Setting this flag treats any [NA] as [A], and all of
message is sent.
>From the BCM2835 ARM Peripherals datasheet:
The ERR field is set when the slave fails to acknowledge either
its address or a data byte written to it.
So when the controller doesn't receive an ack, it sets ERR and raises
an interrupt. In other words, the whole message is not sent.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
---
drivers/i2c/busses/i2c-bcm2835.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index 54d510a..565ef69 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -212,10 +212,6 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
if (likely(!i2c_dev->msg_err))
return 0;
- if ((i2c_dev->msg_err & BCM2835_I2C_S_ERR) &&
- (msg->flags & I2C_M_IGNORE_NAK))
- return 0;
-
dev_dbg(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)
--
2.8.2
next prev parent reply other threads:[~2016-10-03 20:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-03 20:06 [PATCH v4 0/7] i2c: bcm2835: Bring in changes from downstream Noralf Trønnes
2016-10-03 20:06 ` [PATCH v4 1/7] i2c: bcm2835: Fix hang for writing messages larger than 16 bytes Noralf Trønnes
2016-10-03 20:06 ` [PATCH v4 2/7] i2c: bcm2835: Protect against unexpected TXW/RXR interrupts Noralf Trønnes
2016-10-03 20:06 ` [PATCH v4 3/7] i2c: bcm2835: Use dev_dbg logging on transfer errors Noralf Trønnes
2016-10-03 20:06 ` Noralf Trønnes [this message]
2016-10-03 20:06 ` [PATCH v4 5/7] i2c: bcm2835: Add support for Repeated Start Condition Noralf Trønnes
2016-10-03 20:06 ` [PATCH v4 6/7] i2c: bcm2835: Support i2c-dev ioctl I2C_TIMEOUT Noralf Trønnes
2016-10-03 20:06 ` [PATCH v4 7/7] i2c: bcm2835: Add support for dynamic clock Noralf Trønnes
2016-11-07 0:36 ` [PATCH v4 0/7] i2c: bcm2835: Bring in changes from downstream Wolfram Sang
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