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i2c: brcmstb: Fix START and STOP conditions 

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: dd1aa2524b ("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>
zero-colors
Jaedon Shin 2017-03-03 10:55:03 +09:00 committed by Wolfram Sang
parent 02dbfa5e55
commit 2de3ec4f1d
1 changed files with 21 additions and 6 deletions
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27
drivers/i2c/busses/i2c-brcmstb.c
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@ -465,6 +465,7 @@ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
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_adapter *adapter,
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_adapter *adapter,
}
}
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_adapter *adapter,
len -= bytes_to_xfer;
tmp_buf += bytes_to_xfer;
cond_per_msg = COND_NOSTART | COND_NOSTOP;
}
}