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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/i2c/muxes/i2c-mux-reg.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | drivers/i2c/muxes/i2c-mux-reg.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/drivers/i2c/muxes/i2c-mux-reg.c b/drivers/i2c/muxes/i2c-mux-reg.c new file mode 100644 index 0000000000..9efc1ed015 --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-reg.c @@ -0,0 +1,264 @@ +// 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 void 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); +} + +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_new = 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"); |