1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
3  * Mellanox i2c mux driver
5  * Copyright (C) 2016-2020 Mellanox Technologies
10 #include <linux/i2c-mux.h>
11 #include <linux/io.h>
18 /* mlxcpld_mux - mux control structure:
19  * @last_val - last selected register value or -1 if mux deselected
20  * @client - I2C device client
29 /* MUX logic description.
30  * Driver can support different mux control logic, according to CPLD
35  * i2c-mlxcpld                                 Digital               Analog
37  * *--------*                                 * -> mux1 (virt bus2) -> mux -> |
38  * | I2CLPC | i2c physical                    * -> mux2 (virt bus3) -> mux -> |
39  * | bridge | bus 1                 *---------*                               |
40  * | logic  |---------------------> * mux reg *                               |
41  * | in CPLD|                       *---------*                               |
42  * *--------*   i2c-mux-mlxpcld          ^    * -> muxn (virt busn) -> mux -> |
44  *     |        *---------------*        |                              Devices
46  *     |        * registers for *--------*
47  *     |        * mux selection * deselect
48  *     |        *---------------*
50  * <-------->     <----------->
52  * reg space      space (mux select,
53  *                IO, LED, WD, info)
57 /* Write to mux register. Don't use i2c_transfer() and i2c_smbus_xfer()
61 				 struct mlxcpld_mux *mux, u32 val)  in mlxcpld_mux_reg_write()  argument
63 	struct i2c_client *client = mux->client;  in mlxcpld_mux_reg_write()
68 	switch (mux->pdata.reg_size) {  in mlxcpld_mux_reg_write()
71 		return __i2c_smbus_xfer(adap, client->addr, client->flags,  in mlxcpld_mux_reg_write()
72 					I2C_SMBUS_WRITE, mux->pdata.sel_reg_addr,  in mlxcpld_mux_reg_write()
75 		buf[0] = mux->pdata.sel_reg_addr >> 8;  in mlxcpld_mux_reg_write()
76 		buf[1] = mux->pdata.sel_reg_addr;  in mlxcpld_mux_reg_write()
78 		msg.addr = client->addr;  in mlxcpld_mux_reg_write()
80 		msg.len = mux->pdata.reg_size + 1;  in mlxcpld_mux_reg_write()
84 		return -EINVAL;  in mlxcpld_mux_reg_write()
90 	struct mlxcpld_mux *mux = i2c_mux_priv(muxc);  in mlxcpld_mux_select_chan()  local
94 	if (mux->pdata.reg_size == 1)  in mlxcpld_mux_select_chan()
97 	/* Only select the channel if its different from the last channel */  in mlxcpld_mux_select_chan()
98 	if (mux->last_val != regval) {  in mlxcpld_mux_select_chan()
99 		err = mlxcpld_mux_reg_write(muxc->parent, mux, regval);  in mlxcpld_mux_select_chan()
100 		mux->last_val = err < 0 ? -1 : regval;  in mlxcpld_mux_select_chan()
108 	struct mlxcpld_mux *mux = i2c_mux_priv(muxc);  in mlxcpld_mux_deselect()  local
110 	/* Deselect active channel */  in mlxcpld_mux_deselect()
111 	mux->last_val = -1;  in mlxcpld_mux_deselect()
113 	return mlxcpld_mux_reg_write(muxc->parent, mux, 0);  in mlxcpld_mux_deselect()
119 	struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&pdev->dev);  in mlxcpld_mux_probe()
120 	struct i2c_client *client = to_i2c_client(pdev->dev.parent);  in mlxcpld_mux_probe()
127 		return -EINVAL;  in mlxcpld_mux_probe()
129 	switch (pdata->reg_size) {  in mlxcpld_mux_probe()
137 		return -EINVAL;  in mlxcpld_mux_probe()
140 	if (!i2c_check_functionality(client->adapter, func))  in mlxcpld_mux_probe()
141 		return -ENODEV;  in mlxcpld_mux_probe()
143 	muxc = i2c_mux_alloc(client->adapter, &pdev->dev, pdata->num_adaps,  in mlxcpld_mux_probe()
147 		return -ENOMEM;  in mlxcpld_mux_probe()
151 	data->client = client;  in mlxcpld_mux_probe()
152 	memcpy(&data->pdata, pdata, sizeof(*pdata));  in mlxcpld_mux_probe()
153 	data->last_val = -1; /* force the first selection */  in mlxcpld_mux_probe()
155 	/* Create an adapter for each channel. */  in mlxcpld_mux_probe()
156 	for (num = 0; num < pdata->num_adaps; num++) {  in mlxcpld_mux_probe()
157 		err = i2c_mux_add_adapter(muxc, 0, pdata->chan_ids[num], 0);  in mlxcpld_mux_probe()
163 	if (pdata->completion_notify)  in mlxcpld_mux_probe()
164 		pdata->completion_notify(pdata->handle, muxc->parent, muxc->adapter);  in mlxcpld_mux_probe()
182 		.name = "i2c-mux-mlxcpld",
191 MODULE_DESCRIPTION("Mellanox I2C-CPLD-MUX driver");
193 MODULE_ALIAS("platform:i2c-mux-mlxcpld");