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1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.02/*3 * Mellanox i2c mux driver4 *5 * Copyright (C) 2016-2020 Mellanox Technologies6 */7 8#include <linux/device.h>9#include <linux/i2c.h>10#include <linux/i2c-mux.h>11#include <linux/io.h>12#include <linux/init.h>13#include <linux/module.h>14#include <linux/platform_data/mlxcpld.h>15#include <linux/platform_device.h>16#include <linux/slab.h>17 18/* mlxcpld_mux - mux control structure:19 * @last_val - last selected register value or -1 if mux deselected20 * @client - I2C device client21 * @pdata: platform data22 */23struct mlxcpld_mux {24 int last_val;25 struct i2c_client *client;26 struct mlxcpld_mux_plat_data pdata;27};28 29/* MUX logic description.30 * Driver can support different mux control logic, according to CPLD31 * implementation.32 *33 * Connectivity schema.34 *35 * i2c-mlxcpld Digital Analog36 * driver37 * *--------* * -> 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 -> |43 * | driver | |44 * | *---------------* | Devices45 * | * CPLD (i2c bus)* select |46 * | * registers for *--------*47 * | * mux selection * deselect48 * | *---------------*49 * | |50 * <--------> <----------->51 * i2c cntrl Board cntrl reg52 * reg space space (mux select,53 * IO, LED, WD, info)54 *55 */56 57/* Write to mux register. Don't use i2c_transfer() and i2c_smbus_xfer()58 * for this as they will try to lock adapter a second time.59 */60static int mlxcpld_mux_reg_write(struct i2c_adapter *adap,61 struct mlxcpld_mux *mux, u32 val)62{63 struct i2c_client *client = mux->client;64 union i2c_smbus_data data;65 struct i2c_msg msg;66 u8 buf[3];67 68 switch (mux->pdata.reg_size) {69 case 1:70 data.byte = val;71 return __i2c_smbus_xfer(adap, client->addr, client->flags,72 I2C_SMBUS_WRITE, mux->pdata.sel_reg_addr,73 I2C_SMBUS_BYTE_DATA, &data);74 case 2:75 buf[0] = mux->pdata.sel_reg_addr >> 8;76 buf[1] = mux->pdata.sel_reg_addr;77 buf[2] = val;78 msg.addr = client->addr;79 msg.buf = buf;80 msg.len = mux->pdata.reg_size + 1;81 msg.flags = 0;82 return __i2c_transfer(adap, &msg, 1);83 default:84 return -EINVAL;85 }86}87 88static int mlxcpld_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)89{90 struct mlxcpld_mux *mux = i2c_mux_priv(muxc);91 u32 regval = chan;92 int err = 0;93 94 if (mux->pdata.reg_size == 1)95 regval += 1;96 97 /* Only select the channel if its different from the last channel */98 if (mux->last_val != regval) {99 err = mlxcpld_mux_reg_write(muxc->parent, mux, regval);100 mux->last_val = err < 0 ? -1 : regval;101 }102 103 return err;104}105 106static int mlxcpld_mux_deselect(struct i2c_mux_core *muxc, u32 chan)107{108 struct mlxcpld_mux *mux = i2c_mux_priv(muxc);109 110 /* Deselect active channel */111 mux->last_val = -1;112 113 return mlxcpld_mux_reg_write(muxc->parent, mux, 0);114}115 116/* Probe/reomove functions */117static int mlxcpld_mux_probe(struct platform_device *pdev)118{119 struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&pdev->dev);120 struct i2c_client *client = to_i2c_client(pdev->dev.parent);121 struct i2c_mux_core *muxc;122 struct mlxcpld_mux *data;123 int num, err;124 u32 func;125 126 if (!pdata)127 return -EINVAL;128 129 switch (pdata->reg_size) {130 case 1:131 func = I2C_FUNC_SMBUS_WRITE_BYTE_DATA;132 break;133 case 2:134 func = I2C_FUNC_I2C;135 break;136 default:137 return -EINVAL;138 }139 140 if (!i2c_check_functionality(client->adapter, func))141 return -ENODEV;142 143 muxc = i2c_mux_alloc(client->adapter, &pdev->dev, pdata->num_adaps,144 sizeof(*data), 0, mlxcpld_mux_select_chan,145 mlxcpld_mux_deselect);146 if (!muxc)147 return -ENOMEM;148 149 platform_set_drvdata(pdev, muxc);150 data = i2c_mux_priv(muxc);151 data->client = client;152 memcpy(&data->pdata, pdata, sizeof(*pdata));153 data->last_val = -1; /* force the first selection */154 155 /* Create an adapter for each channel. */156 for (num = 0; num < pdata->num_adaps; num++) {157 err = i2c_mux_add_adapter(muxc, 0, pdata->chan_ids[num]);158 if (err)159 goto virt_reg_failed;160 }161 162 /* Notify caller when all channels' adapters are created. */163 if (pdata->completion_notify)164 pdata->completion_notify(pdata->handle, muxc->parent, muxc->adapter);165 166 return 0;167 168virt_reg_failed:169 i2c_mux_del_adapters(muxc);170 return err;171}172 173static void mlxcpld_mux_remove(struct platform_device *pdev)174{175 struct i2c_mux_core *muxc = platform_get_drvdata(pdev);176 177 i2c_mux_del_adapters(muxc);178}179 180static struct platform_driver mlxcpld_mux_driver = {181 .driver = {182 .name = "i2c-mux-mlxcpld",183 },184 .probe = mlxcpld_mux_probe,185 .remove_new = mlxcpld_mux_remove,186};187 188module_platform_driver(mlxcpld_mux_driver);189 190MODULE_AUTHOR("Michael Shych <michaels@mellanox.com>");191MODULE_DESCRIPTION("Mellanox I2C-CPLD-MUX driver");192MODULE_LICENSE("Dual BSD/GPL");193MODULE_ALIAS("platform:i2c-mux-mlxcpld");194