From 2de3ec4f1d4ba6ee380478055104eb918bd50cce Mon Sep 17 00:00:00 2001 From: Jaedon Shin Date: Fri, 3 Mar 2017 10:55:03 +0900 Subject: [PATCH] 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: dd1aa2524bc5 ("i2c: brcmstb: Add Broadcom settop SoC i2c controller driver") Signed-off-by: Jaedon Shin Acked-by: Kamal Dasu Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-brcmstb.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-brcmstb.c b/drivers/i2c/busses/i2c-brcmstb.c index 0652281662a8..78792b4d6437 100644 --- 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_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; } } -- 2.20.1