/* * drivers/i2c/muxes/i2c-mux-mlxcpld.c * Copyright (c) 2016 Mellanox Technologies. All rights reserved. * Copyright (c) 2016 Michael Shych * * 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 #include #include #include #include #include #include #include #include #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); union i2c_smbus_data data = { .byte = val }; return __i2c_smbus_xfer(adap, client->addr, client->flags, I2C_SMBUS_WRITE, pdata->sel_reg_addr, I2C_SMBUS_BYTE_DATA, &data); } 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 = client->adapter; 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");