diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.9/0110-i2c-bcm2835-Can-t-support-I2C_M_IGNORE_NAK.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.9/0110-i2c-bcm2835-Can-t-support-I2C_M_IGNORE_NAK.patch | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.9/0110-i2c-bcm2835-Can-t-support-I2C_M_IGNORE_NAK.patch b/target/linux/brcm2708/patches-4.9/0110-i2c-bcm2835-Can-t-support-I2C_M_IGNORE_NAK.patch new file mode 100644 index 0000000000..946c316bc1 --- /dev/null +++ b/target/linux/brcm2708/patches-4.9/0110-i2c-bcm2835-Can-t-support-I2C_M_IGNORE_NAK.patch @@ -0,0 +1,44 @@ +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) |