| // 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"); |
| mux->data.reg = devm_platform_get_and_ioremap_resource(pdev, 0, &res); |
| if (IS_ERR(mux->data.reg)) { |
| ret = PTR_ERR(mux->data.reg); |
| goto err_put_parent; |
| } |
| mux->data.reg_size = resource_size(res); |
| } |
| |
| 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"); |