Commit 8d2cc5cc authored Oct 03, 2016 by Noralf Trønnes Committed by Wolfram Sang Nov 07, 2016

i2c: bcm2835: Can't support I2C_M_IGNORE_NAK



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>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

parent 23c9540b

drivers/i2c/busses/i2c-bcm2835.c

+0 −4

Original line number	Original line	Diff line number	Diff line
	@@ -212,10 +212,6 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
	if (likely(!i2c_dev->msg_err))		if (likely(!i2c_dev->msg_err))
	return 0;		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);		dev_dbg(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);

	if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)		if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)

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