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From 40c63177d4c0f4755a148503c3b8bb2192ce8c0e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Thu, 22 Sep 2016 22:05:50 +0200
Subject: [PATCH] i2c: bcm2835: Can't support I2C_M_IGNORE_NAK
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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(-)
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -214,10 +214,6 @@ static int bcm2835_i2c_xfer_msg(struct b
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)
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