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@xxxxxxxxxxxxxxx> know about it.
>From 2de3ec4f1d4ba6ee380478055104eb918bd50cce Mon Sep 17 00:00:00 2001
From: Jaedon Shin <jaedon.shin@xxxxxxxxx>
Date: Fri, 3 Mar 2017 10:55:03 +0900
Subject: i2c: brcmstb: Fix START and STOP conditions
From: Jaedon Shin <jaedon.shin@xxxxxxxxx>
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@xxxxxxxxx>
Acked-by: Kamal Dasu <kdasu.kdev@xxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxx are
queue-4.9/i2c-brcmstb-fix-start-and-stop-conditions.patch