linux-imx

// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * I2C multiplexer using a single register

 *

 * Copyright 2015 Freescale Semiconductor

 * York Sun  <yorksun@freescale.com>

 */

​

#include <linux/i2c.h>

#include <linux/i2c-mux.h>

#include <linux/init.h>

#include <linux/io.h>

#include <linux/module.h>

#include <linux/of_address.h>

#include <linux/platform_data/i2c-mux-reg.h>

#include <linux/platform_device.h>

#include <linux/slab.h>

​

struct regmux {

    struct i2c_mux_reg_platform_data data;

};

​

static int i2c_mux_reg_set(const struct regmux *mux, unsigned int chan_id)

{

    if (!mux->data.reg)

        return -EINVAL;

​

    /*

     * Write to the register, followed by a read to ensure the write is

     * completed on a "posted" bus, for example PCI or write buffers.

     * The endianness of reading doesn't matter and the return data

     * is not used.

     */

    switch (mux->data.reg_size) {

    case 4:

        if (mux->data.little_endian)

            iowrite32(chan_id, mux->data.reg);

        else

            iowrite32be(chan_id, mux->data.reg);

        if (!mux->data.write_only)

            ioread32(mux->data.reg);

        break;

    case 2:

        if (mux->data.little_endian)

            iowrite16(chan_id, mux->data.reg);

        else

            iowrite16be(chan_id, mux->data.reg);

        if (!mux->data.write_only)

            ioread16(mux->data.reg);

        break;

    case 1:

        iowrite8(chan_id, mux->data.reg);

        if (!mux->data.write_only)

            ioread8(mux->data.reg);

        break;

    }

​

    return 0;

}

​

static int i2c_mux_reg_select(struct i2c_mux_core *muxc, u32 chan)

{

    struct regmux *mux = i2c_mux_priv(muxc);

​

    return i2c_mux_reg_set(mux, chan);

}

​

static int i2c_mux_reg_deselect(struct i2c_mux_core *muxc, u32 chan)

{

    struct regmux *mux = i2c_mux_priv(muxc);

​

    if (mux->data.idle_in_use)

        return i2c_mux_reg_set(mux, mux->data.idle);

​

    return 0;

}

​

#ifdef CONFIG_OF

static int i2c_mux_reg_probe_dt(struct regmux *mux,

                struct platform_device *pdev)

{

    struct device_node *np = pdev->dev.of_node;

    struct device_node *adapter_np, *child;

    struct i2c_adapter *adapter;

    struct resource res;

    unsigned *values;

    int i = 0;

​

    if (!np)

        return -ENODEV;

​

    adapter_np = of_parse_phandle(np, "i2c-parent", 0);