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| author | Peter Rosin <peda@axentia.se> | 2016-12-17 23:29:11 +0300 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2016-12-18 10:54:38 +0300 |
| commit | 649ac63a9ae5e08b7123f2fa98c2bf42f033bdb9 (patch) | |
| tree | 6e571792c6101cbe1d59f52db24e4f6562b21826 /drivers/i2c | |
| parent | 8e598769c55dd6c442a1c6cbd21e7abda2a52215 (diff) | |
| download | linux-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.c | 24 |
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; |