Orange Pi5 kernel

// 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);
<------>if (!adapter_np) {
<------><------>dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
<------><------>return -ENODEV;
<------>}
<------>adapter = of_find_i2c_adapter_by_node(adapter_np);
<------>of_node_put(adapter_np);
<------>if (!adapter)
<------><------>return -EPROBE_DEFER;
 
<------>mux->data.parent = i2c_adapter_id(adapter);
<------>put_device(&adapter->dev);
 
<------>mux->data.n_values = of_get_child_count(np);
<------>if (of_property_read_bool(np, "little-endian")) {
<------><------>mux->data.little_endian = true;
<------>} else if (of_property_read_bool(np, "big-endian")) {
<------><------>mux->data.little_endian = false;
<------>} else {
#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : \
<------>defined(__LITTLE_ENDIAN)
<------><------>mux->data.little_endian = true;
#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : \
<------>defined(__BIG_ENDIAN)
<------><------>mux->data.little_endian = false;
#else
#error Endianness not defined?
#endif
<------>}
<------>mux->data.write_only = of_property_read_bool(np, "write-only");
 
<------>values = devm_kcalloc(&pdev->dev,
<------><------><------>      mux->data.n_values, sizeof(*mux->data.values),
<------><------><------>      GFP_KERNEL);
<------>if (!values)
<------><------>return -ENOMEM;
 
<------>for_each_child_of_node(np, child) {
<------><------>of_property_read_u32(child, "reg", values + i);
<------><------>i++;
<------>}
<------>mux->data.values = values;
 
<------>if (!of_property_read_u32(np, "idle-state", &mux->data.idle))
<------><------>mux->data.idle_in_use = true;
 
<------>/* map address from "reg" if exists */
<------>if (of_address_to_resource(np, 0, &res) == 0) {
<------><------>mux->data.reg_size = resource_size(&res);
<------><------>mux->data.reg = devm_ioremap_resource(&pdev->dev, &res);
<------><------>if (IS_ERR(mux->data.reg))
<------><------><------>return PTR_ERR(mux->data.reg);
<------>}
 
<------>return 0;
}
#else
static int i2c_mux_reg_probe_dt(struct regmux *mux,
<------><------><------><------>struct platform_device *pdev)
{
<------>return 0;
}
#endif
 
static int i2c_mux_reg_probe(struct platform_device *pdev)
{
<------>struct i2c_mux_core *muxc;
<------>struct regmux *mux;
<------>struct i2c_adapter *parent;
<------>struct resource *res;
<------>unsigned int class;
<------>int i, ret, nr;
 
<------>mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
<------>if (!mux)
<------><------>return -ENOMEM;
 
<------>if (dev_get_platdata(&pdev->dev)) {
<------><------>memcpy(&mux->data, dev_get_platdata(&pdev->dev),
<------><------><------>sizeof(mux->data));
<------>} else {
<------><------>ret = i2c_mux_reg_probe_dt(mux, pdev);
<------><------>if (ret < 0)
<------><------><------>return dev_err_probe(&pdev->dev, ret,
<------><------><------><------><------>     "Error parsing device tree");
<------>}
 
<------>parent = i2c_get_adapter(mux->data.parent);
<------>if (!parent)
<------><------>return -EPROBE_DEFER;
 
<------>if (!mux->data.reg) {
<------><------>dev_info(&pdev->dev,
<------><------><------>"Register not set, using platform resource\n");
<------><------>res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
<------><------>mux->data.reg_size = resource_size(res);
<------><------>mux->data.reg = devm_ioremap_resource(&pdev->dev, res);
<------><------>if (IS_ERR(mux->data.reg)) {
<------><------><------>ret = PTR_ERR(mux->data.reg);
<------><------><------>goto err_put_parent;
<------><------>}
<------>}
 
<------>if (mux->data.reg_size != 4 && mux->data.reg_size != 2 &&
<------>    mux->data.reg_size != 1) {
<------><------>dev_err(&pdev->dev, "Invalid register size\n");
<------><------>ret = -EINVAL;
<------><------>goto err_put_parent;
<------>}
 
<------>muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, 0, 0,
<------><------><------>     i2c_mux_reg_select, NULL);
<------>if (!muxc) {
<------><------>ret = -ENOMEM;
<------><------>goto err_put_parent;
<------>}
<------>muxc->priv = mux;
 
<------>platform_set_drvdata(pdev, muxc);
 
<------>if (mux->data.idle_in_use)
<------><------>muxc->deselect = i2c_mux_reg_deselect;
 
<------>for (i = 0; i < mux->data.n_values; i++) {
<------><------>nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
<------><------>class = mux->data.classes ? mux->data.classes[i] : 0;
 
<------><------>ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
<------><------>if (ret)
<------><------><------>goto err_del_mux_adapters;
<------>}
 
<------>dev_dbg(&pdev->dev, "%d port mux on %s adapter\n",
<------><------> mux->data.n_values, muxc->parent->name);
 
<------>return 0;
 
err_del_mux_adapters:
<------>i2c_mux_del_adapters(muxc);
err_put_parent:
<------>i2c_put_adapter(parent);
 
<------>return ret;
}
 
static int i2c_mux_reg_remove(struct platform_device *pdev)
{
<------>struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
 
<------>i2c_mux_del_adapters(muxc);
<------>i2c_put_adapter(muxc->parent);
 
<------>return 0;
}
 
static const struct of_device_id i2c_mux_reg_of_match[] = {
<------>{ .compatible = "i2c-mux-reg", },
<------>{},
};
MODULE_DEVICE_TABLE(of, i2c_mux_reg_of_match);
 
static struct platform_driver i2c_mux_reg_driver = {
<------>.probe	= i2c_mux_reg_probe,
<------>.remove	= i2c_mux_reg_remove,
<------>.driver	= {
<------><------>.name	= "i2c-mux-reg",
<------><------>.of_match_table = of_match_ptr(i2c_mux_reg_of_match),
<------>},
};
 
module_platform_driver(i2c_mux_reg_driver);
 
MODULE_DESCRIPTION("Register-based I2C multiplexer driver");
MODULE_AUTHOR("York Sun <yorksun@freescale.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:i2c-mux-reg");