From 40c63177d4c0f4755a148503c3b8bb2192ce8c0e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= 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 Reviewed-by: Eric Anholt --- 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)