[PATCH] i2c: algo-bit: add support for I2C_M_STOP

[Wolfram Sang]

Support for enforced STOPs will allow us to use SCCB compatible devices.

Signed-off-by: Wolfram Sang <wsa+rene...@sang-engineering.com>
---

Notes: I don't actually have any SCCB compatible sensor but verified with a
logic analyzer that repeated starts got replaced with a stop + start sequence.
However, we have members in our team who might need this feature soon. I'll
likely wait for their Tested-by unless something unforseen happens.

 drivers/i2c/algos/i2c-algo-bit.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index a8e89df665b904..4758058352959d 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -549,12 +549,17 @@ static int bit_xfer(struct i2c_adapter *i2c_adap,
        bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
        i2c_start(adap);
        for (i = 0; i < num; i++) {
+               bool did_stop = false;
+
                pmsg = &msgs[i];
                nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
                if (!(pmsg->flags & I2C_M_NOSTART)) {
-                       if (i) {
-                               bit_dbg(3, &i2c_adap->dev, "emitting "
-                                       "repeated start condition\n");
+                       if (did_stop) {
+                               bit_dbg(3, &i2c_adap->dev, "emitting start 
condition\n");
+                               i2c_start(adap);
+                               did_stop = false;
+                       } else if (i) {
+                               bit_dbg(3, &i2c_adap->dev, "emitting repeated 
start condition\n");
                                i2c_repstart(adap);
                        }
                        ret = bit_doAddress(i2c_adap, pmsg);
@@ -588,6 +593,12 @@ static int bit_xfer(struct i2c_adapter *i2c_adap,
                                goto bailout;
                        }
                }
+
+               if (pmsg->flags & I2C_M_STOP && i != num - 1) {
+                       bit_dbg(3, &i2c_adap->dev, "emitting enforced stop 
condition\n");
+                       i2c_stop(adap);
+                       did_stop = true;
+               }
        }
        ret = i;
 
-- 
2.11.0