Patch "i2c: brcmstb: Fix START and STOP conditions" has been added to the 4.9-stable tree

Patch "i2c: brcmstb: Fix START and STOP conditions" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    i2c: brcmstb: Fix START and STOP conditions

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i2c-brcmstb-fix-start-and-stop-conditions.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 2de3ec4f1d4ba6ee380478055104eb918bd50cce Mon Sep 17 00:00:00 2001
From: Jaedon Shin <jaedon.shin@gmail.com>
Date: Fri, 3 Mar 2017 10:55:03 +0900
Subject: i2c: brcmstb: Fix START and STOP conditions

From: Jaedon Shin <jaedon.shin@gmail.com>

commit 2de3ec4f1d4ba6ee380478055104eb918bd50cce upstream.

The BSC data buffers to send and receive data are each of size 32 bytes
or 8 bytes 'xfersz' depending on SoC. The problem observed for all the
combined message transfer was if length of data transfer was a multiple
of 'xfersz' a repeated START was being transmitted by BSC driver. Fixed
this by appropriately setting START/STOP conditions for such transfers.

Fixes: dd1aa2524bc5 ("i2c: brcmstb: Add Broadcom settop SoC i2c controller driver")
Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
Acked-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/i2c/busses/i2c-brcmstb.c |   27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

--- a/drivers/i2c/busses/i2c-brcmstb.c
+++ b/drivers/i2c/busses/i2c-brcmstb.c
@@ -465,6 +465,7 @@ static int brcmstb_i2c_xfer(struct i2c_a
 	u8 *tmp_buf;
 	int len = 0;
 	int xfersz = brcmstb_i2c_get_xfersz(dev);
+	u32 cond, cond_per_msg;
 
 	if (dev->is_suspended)
 		return -EBUSY;
@@ -481,10 +482,11 @@ static int brcmstb_i2c_xfer(struct i2c_a
 			pmsg->buf ? pmsg->buf[0] : '0', pmsg->len);
 
 		if (i < (num - 1) && (msgs[i + 1].flags & I2C_M_NOSTART))
-			brcmstb_set_i2c_start_stop(dev, ~(COND_START_STOP));
+			cond = ~COND_START_STOP;
 		else
-			brcmstb_set_i2c_start_stop(dev,
-						   COND_RESTART | COND_NOSTOP);
+			cond = COND_RESTART | COND_NOSTOP;
+
+		brcmstb_set_i2c_start_stop(dev, cond);
 
 		/* Send slave address */
 		if (!(pmsg->flags & I2C_M_NOSTART)) {
@@ -497,13 +499,24 @@ static int brcmstb_i2c_xfer(struct i2c_a
 			}
 		}
 
+		cond_per_msg = cond;
+
 		/* Perform data transfer */
 		while (len) {
 			bytes_to_xfer = min(len, xfersz);
 
-			if (len <= xfersz && i == (num - 1))
-				brcmstb_set_i2c_start_stop(dev,
-							   ~(COND_START_STOP));
+			if (len <= xfersz) {
+				if (i == (num - 1))
+					cond_per_msg = cond_per_msg &
+						~(COND_RESTART | COND_NOSTOP);
+				else
+					cond_per_msg = cond;
+			} else {
+				cond_per_msg = (cond_per_msg & ~COND_RESTART) |
+					COND_NOSTOP;
+			}
+
+			brcmstb_set_i2c_start_stop(dev, cond_per_msg);
 
 			rc = brcmstb_i2c_xfer_bsc_data(dev, tmp_buf,
 						       bytes_to_xfer, pmsg);
@@ -512,6 +525,8 @@ static int brcmstb_i2c_xfer(struct i2c_a
 
 			len -=  bytes_to_xfer;
 			tmp_buf += bytes_to_xfer;
+
+			cond_per_msg = COND_NOSTART | COND_NOSTOP;
 		}
 	}
 


Patches currently in stable-queue which might be from jaedon.shin@gmail.com are

queue-4.9/i2c-brcmstb-fix-start-and-stop-conditions.patch