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authorWolfram Sang <wsa+renesas@sang-engineering.com>2014-05-05 18:36:21 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-07 13:25:39 -0700
commit670a6ed522e0fa814d74547cb95fbc4854660474 (patch)
tree8c7fc82cf538e35ff5e21d5a804b35b2bb23f16d
parentfeed5a88f45f26e4fda34838b4929536d4a8e775 (diff)
downloadlinux-linaro-stable-670a6ed522e0fa814d74547cb95fbc4854660474.tar.gz
i2c: rcar: bail out on zero length transfers
commit d7653964c590ba846aa11a8f6edf409773cbc492 upstream. 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@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/i2c/busses/i2c-rcar.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 4ba4a95b6b26..8a806f5c40cf 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -541,6 +541,12 @@ 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);
@@ -605,7 +611,8 @@ 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 = {