From: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
This hardware does not support zero length transfers. Instead, the
driver does one (random) byte transfers currently with undefined results
for the slaves. We now bail out.
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-rcar.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 72a400a73cce..66c952e62f0a 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -552,6 +552,13 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
ret = -EINVAL;
for (i = 0; i < num; i++) {
+
+ /* This HW can't send STOP after address phase */
+ if (msgs[i].len == 0) {
+ ret = -EOPNOTSUPP;
+ break;
+ }
+
/*-------------- spin lock -----------------*/
spin_lock_irqsave(&priv->lock, flags);
@@ -616,7 +623,8 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
static u32 rcar_i2c_func(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+ /* This HW can't do SMBUS_QUICK and NOSTART */
+ return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}
static const struct i2c_algorithm rcar_i2c_algo = {
--
1.9.2
--
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