This patch adds I2C_FUNC_NOSTART and I2C_M_REV_DIR_ADDR support for
MediaTek MT7621/7628/7688. This is useful for some I2C slave chips,
such as 'drivers/input/joystick/as5011.c'.

Signed-off-by: Jianhui Zhao <redacted>
---
  drivers/i2c/busses/i2c-mt7621.c | 9 ++++++++-
  1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-mt7621.c b/drivers/i2c/busses/i2c-mt7621.c
index 45fe4a7fe0c0..3d2763d9c090 100644
--- a/drivers/i2c/busses/i2c-mt7621.c
+++ b/drivers/i2c/busses/i2c-mt7621.c

@@ -150,6 +150,9 @@ static int mtk_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  	for (i = 0; i < num; i++) {
  		pmsg = &msgs[i];
  
+		if (pmsg->flags & I2C_M_NOSTART)
+			goto nostart;
+
  		/* wait hardware idle */
  		ret = mtk_i2c_wait_idle(i2c);
  		if (ret)

@@ -174,6 +177,8 @@ static int mtk_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  		} else {
  			/* 7 bits address */
  			addr = i2c_8bit_addr_from_msg(pmsg);
+			if (pmsg->flags & I2C_M_REV_DIR_ADDR)
+				addr ^= 1;
  			iowrite32(addr, i2c->base + REG_SM0D0_REG);
  			ret = mtk_i2c_master_cmd(i2c, SM0CTL1_WRITE, 1);
  			if (ret)

@@ -187,6 +192,7 @@ static int mtk_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  				goto err_ack;
  		}
  
+nostart:
  		/* transfer data */
  		for (len = pmsg->len, j = 0; len > 0; len -= 8, j += 8) {
  			page_len = (len >= 8) ? 8 : len;

@@ -242,7 +248,8 @@ static int mtk_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  
  static u32 mtk_i2c_func(struct i2c_adapter *a)
  {
-	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR
+		| I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART;