96aa0c6b0b
Patches from Raspberry Pi repo: https://github.com/raspberrypi/linux/commits/rpi-4.9.y Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
44 lines
1.5 KiB
Diff
44 lines
1.5 KiB
Diff
From 9d8c576116c4818dd745ff112504f0fdf78c9e1e 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
|
|
@@ -212,10 +212,6 @@ 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)
|