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/*
* drivers/i2c/muxes/i2c-mux-mlxcpld.c
* Copyright (c) 2016 Mellanox Technologies. All rights reserved.
* Copyright (c) 2016 Michael Shych <michaels@mellanox.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/i2c/mlxcpld.h>
#define CPLD_MUX_MAX_NCHANS 8
/* mlxcpld_mux - mux control structure:
* @last_chan - last register value
* @client - I2C device client
*/
struct mlxcpld_mux {
u8 last_chan;
struct i2c_client *client;
};
/* MUX logic description.
* Driver can support different mux control logic, according to CPLD
* implementation.
*
* Connectivity schema.
*
* i2c-mlxcpld Digital Analog
* driver
* *--------* * -> mux1 (virt bus2) -> mux -> |
* | I2CLPC | i2c physical * -> mux2 (virt bus3) -> mux -> |
* | bridge | bus 1 *---------* |
* | logic |---------------------> * mux reg * |
* | in CPLD| *---------* |
* *--------* i2c-mux-mlxpcld ^ * -> muxn (virt busn) -> mux -> |
* | driver | |
* | *---------------* | Devices
* | * CPLD (i2c bus)* select |
* | * registers for *--------*
* | * mux selection * deselect
* | *---------------*
* | |
* <--------> <----------->
* i2c cntrl Board cntrl reg
* reg space space (mux select,
* IO, LED, WD, info)
*
*/
static const struct i2c_device_id mlxcpld_mux_id[] = {
{ "mlxcpld_mux_module", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mlxcpld_mux_id);
/* Write to mux register. Don't use i2c_transfer() and i2c_smbus_xfer()
* for this as they will try to lock adapter a second time.
*/
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;
u8 msgbuf[] = {pdata->sel_reg_addr, val};
msg.addr = client->addr;
msg.flags = 0;
msg.len = 2;
msg.buf = msgbuf;
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;
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)
{
struct mlxcpld_mux *data = i2c_mux_priv(muxc);
struct i2c_client *client = data->client;
u8 regval = chan + 1;
int err = 0;
/* 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);
data->last_chan = err < 0 ? 0 : regval;
}
return err;
}
static int mlxcpld_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
{
struct mlxcpld_mux *data = i2c_mux_priv(muxc);
struct i2c_client *client = data->client;
/* Deselect active channel */
data->last_chan = 0;
return mlxcpld_mux_reg_write(muxc->parent, client, data->last_chan);
}
/* Probe/reomove functions */
static int mlxcpld_mux_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&client->dev);
struct i2c_mux_core *muxc;
int num, force;
struct mlxcpld_mux *data;
int err;
if (!pdata)
return -EINVAL;
if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
return -ENODEV;
muxc = i2c_mux_alloc(adap, &client->dev, CPLD_MUX_MAX_NCHANS,
sizeof(*data), 0, mlxcpld_mux_select_chan,
mlxcpld_mux_deselect);
if (!muxc)
return -ENOMEM;
data = i2c_mux_priv(muxc);
i2c_set_clientdata(client, muxc);
data->client = client;
data->last_chan = 0; /* force the first selection */
/* Create an adapter for each channel. */
for (num = 0; num < CPLD_MUX_MAX_NCHANS; num++) {
if (num >= pdata->num_adaps)
/* discard unconfigured channels */
break;
force = pdata->adap_ids[num];
err = i2c_mux_add_adapter(muxc, force, num, 0);
if (err)
goto virt_reg_failed;
}
return 0;
virt_reg_failed:
i2c_mux_del_adapters(muxc);
return err;
}
static int mlxcpld_mux_remove(struct i2c_client *client)
{
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
i2c_mux_del_adapters(muxc);
return 0;
}
static struct i2c_driver mlxcpld_mux_driver = {
.driver = {
.name = "mlxcpld-mux",
},
.probe = mlxcpld_mux_probe,
.remove = mlxcpld_mux_remove,
.id_table = mlxcpld_mux_id,
};
module_i2c_driver(mlxcpld_mux_driver);
MODULE_AUTHOR("Michael Shych (michaels@mellanox.com)");
MODULE_DESCRIPTION("Mellanox I2C-CPLD-MUX driver");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_ALIAS("platform:i2c-mux-mlxcpld");
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