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Commit 2de3ec4f authored by Jaedon Shin's avatar Jaedon Shin Committed by Wolfram Sang
Browse files

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: dd1aa252 ("i2c: brcmstb: Add Broadcom settop SoC i2c controller driver")
Signed-off-by: default avatarJaedon Shin <jaedon.shin@gmail.com>
Acked-by: default avatarKamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 02dbfa5e

drivers/i2c/busses/i2c-brcmstb.c

+21 −6
Original line number Diff line number Diff line
@@ -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;

		}

	}