| From d7653964c590ba846aa11a8f6edf409773cbc492 Mon Sep 17 00:00:00 2001 |
| From: Wolfram Sang <wsa+renesas@sang-engineering.com> |
| Date: Mon, 5 May 2014 18:36:21 +0200 |
| Subject: i2c: rcar: bail out on zero length transfers |
| |
| From: Wolfram Sang <wsa+renesas@sang-engineering.com> |
| |
| 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> |
| |
| --- |
| drivers/i2c/busses/i2c-rcar.c | 9 ++++++++- |
| 1 file changed, 8 insertions(+), 1 deletion(-) |
| |
| --- 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 i |
| |
| 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 i |
| |
| 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 = { |
