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45 lines
1.5 KiB
45 lines
1.5 KiB
8 years ago
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From 40c63177d4c0f4755a148503c3b8bb2192ce8c0e Mon Sep 17 00:00:00 2001
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8 years ago
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From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
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Date: Thu, 22 Sep 2016 22:05:50 +0200
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Subject: [PATCH] i2c: bcm2835: Can't support I2C_M_IGNORE_NAK
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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The controller can't support this flag, so remove it.
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Documentation/i2c/i2c-protocol states that all of the message is sent:
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I2C_M_IGNORE_NAK:
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Normally message is interrupted immediately if there is [NA] from the
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client. Setting this flag treats any [NA] as [A], and all of
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message is sent.
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From the BCM2835 ARM Peripherals datasheet:
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The ERR field is set when the slave fails to acknowledge either
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its address or a data byte written to it.
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So when the controller doesn't receive an ack, it sets ERR and raises
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an interrupt. In other words, the whole message is not sent.
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Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
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Reviewed-by: Eric Anholt <eric@anholt.net>
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---
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drivers/i2c/busses/i2c-bcm2835.c | 4 ----
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1 file changed, 4 deletions(-)
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--- a/drivers/i2c/busses/i2c-bcm2835.c
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+++ b/drivers/i2c/busses/i2c-bcm2835.c
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@@ -212,10 +212,6 @@ static int bcm2835_i2c_xfer_msg(struct b
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if (likely(!i2c_dev->msg_err))
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return 0;
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- if ((i2c_dev->msg_err & BCM2835_I2C_S_ERR) &&
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- (msg->flags & I2C_M_IGNORE_NAK))
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- return 0;
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-
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dev_dbg(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
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if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)
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