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authorPeter Rosin <peda@axentia.se>2016-12-17 23:29:11 +0300
committerWolfram Sang <wsa@the-dreams.de>2016-12-18 10:54:38 +0300
commit649ac63a9ae5e08b7123f2fa98c2bf42f033bdb9 (patch)
tree6e571792c6101cbe1d59f52db24e4f6562b21826 /drivers/i2c
parent8e598769c55dd6c442a1c6cbd21e7abda2a52215 (diff)
downloadlinux-649ac63a9ae5e08b7123f2fa98c2bf42f033bdb9.tar.xz
i2c: mux: mlxcpld: fix i2c mux selection caching
smbus functions return -ve on error, 0 on success. However, __i2c_transfer() have a different return signature - -ve on error, or number of buffers transferred (which may be zero or greater). The upshot of this is that the sense of the test is reversed when using the mux on a bus supporting the master_xfer method: we cache the value and never retry if we fail to transfer any buffers, but if we succeed, we clear the cached value. Fix this by making mlxcpld_mux_reg_write() return a -ve error code for all failure cases, just as was done in commit 7f638c1cb0a1 ("i2c: mux: pca954x: fix i2c mux selection caching"). This also aligns the implementations of these two muxes in this area. Signed-off-by: Peter Rosin <peda@axentia.se> Acked-by: Vadim Pasternak <vadimp@mellanox.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/muxes/i2c-mux-mlxcpld.c24
1 files changed, 13 insertions, 11 deletions
diff --git a/drivers/i2c/muxes/i2c-mux-mlxcpld.c b/drivers/i2c/muxes/i2c-mux-mlxcpld.c
index 3ab654bbfab5..b7ca249ec9c3 100644
--- a/drivers/i2c/muxes/i2c-mux-mlxcpld.c
+++ b/drivers/i2c/muxes/i2c-mux-mlxcpld.c
@@ -95,6 +95,7 @@ static int mlxcpld_mux_reg_write(struct i2c_adapter *adap,
struct i2c_client *client, u8 val)
{
struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&client->dev);
+ int ret = -ENODEV;
if (adap->algo->master_xfer) {
struct i2c_msg msg;
@@ -104,17 +105,21 @@ static int mlxcpld_mux_reg_write(struct i2c_adapter *adap,
msg.flags = 0;
msg.len = 2;
msg.buf = msgbuf;
- return __i2c_transfer(adap, &msg, 1);
+ ret = __i2c_transfer(adap, &msg, 1);
+
+ if (ret >= 0 && ret != 1)
+ ret = -EREMOTEIO;
} else if (adap->algo->smbus_xfer) {
union i2c_smbus_data data;
data.byte = val;
- return adap->algo->smbus_xfer(adap, client->addr,
- client->flags, I2C_SMBUS_WRITE,
- pdata->sel_reg_addr,
- I2C_SMBUS_BYTE_DATA, &data);
- } else
- return -ENODEV;
+ ret = adap->algo->smbus_xfer(adap, client->addr,
+ client->flags, I2C_SMBUS_WRITE,
+ pdata->sel_reg_addr,
+ I2C_SMBUS_BYTE_DATA, &data);
+ }
+
+ return ret;
}
static int mlxcpld_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)
@@ -127,10 +132,7 @@ static int mlxcpld_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)
/* Only select the channel if its different from the last channel */
if (data->last_chan != regval) {
err = mlxcpld_mux_reg_write(muxc->parent, client, regval);
- if (err)
- data->last_chan = 0;
- else
- data->last_chan = regval;
+ data->last_chan = err < 0 ? 0 : regval;
}
return err;