i2c: mux: mlxcpld: fix i2c mux selection caching (649ac63a) · Commits · 戴 / test

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 ("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>

drivers/i2c/muxes/i2c-mux-mlxcpld.c

+13 −11

Original line number	Diff line number	Diff line
		@@ -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,
		ret = adap->algo->smbus_xfer(adap, client->addr,
		client->flags, I2C_SMBUS_WRITE,
		pdata->sel_reg_addr,
		I2C_SMBUS_BYTE_DATA, &data);
		} else
		return -ENODEV;
		}

		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;

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