[mirror_ubuntu-hirsute-kernel.git] / drivers / i2c / muxes / i2c-mux-reg.c

// 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 == -EPROBE_DEFER)
			return ret;

		if (ret < 0) {
			dev_err(&pdev->dev, "Error parsing device tree");
			return ret;
		}
	}

	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");
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
b3fdd327 YS	2	/*
	3	* I2C multiplexer using a single register
	4	*
	5	* Copyright 2015 Freescale Semiconductor
	6	* York Sun <yorksun@freescale.com>
b3fdd327 YS	7	*/
	8
	9	#include <linux/i2c.h>
	10	#include <linux/i2c-mux.h>
	11	#include <linux/init.h>
	12	#include <linux/io.h>
	13	#include <linux/module.h>
	14	#include <linux/of_address.h>
	15	#include <linux/platform_data/i2c-mux-reg.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/slab.h>
	18
	19	struct regmux {
b3fdd327 YS	20	struct i2c_mux_reg_platform_data data;
	21	};
	22
	23	static int i2c_mux_reg_set(const struct regmux *mux, unsigned int chan_id)
	24	{
	25	if (!mux->data.reg)
	26	return -EINVAL;
	27
5a73882f YS	28	/*
	29	* Write to the register, followed by a read to ensure the write is
	30	* completed on a "posted" bus, for example PCI or write buffers.
	31	* The endianness of reading doesn't matter and the return data
	32	* is not used.
	33	*/
b3fdd327 YS	34	switch (mux->data.reg_size) {
b3fdd327 YS	35	case 4:
5a73882f	36	if (mux->data.little_endian)
b3fdd327	37	iowrite32(chan_id, mux->data.reg);
5a73882f	38	else
b3fdd327	39	iowrite32be(chan_id, mux->data.reg);
5a73882f YS	40	if (!mux->data.write_only)
5a73882f YS	41	ioread32(mux->data.reg);
b3fdd327 YS	42	break;
b3fdd327 YS	43	case 2:
5a73882f	44	if (mux->data.little_endian)
b3fdd327	45	iowrite16(chan_id, mux->data.reg);
5a73882f	46	else
b3fdd327	47	iowrite16be(chan_id, mux->data.reg);
5a73882f YS	48	if (!mux->data.write_only)
5a73882f YS	49	ioread16(mux->data.reg);
b3fdd327 YS	50	break;
	51	case 1:
	52	iowrite8(chan_id, mux->data.reg);
	53	if (!mux->data.write_only)
	54	ioread8(mux->data.reg);
	55	break;
b3fdd327 YS	56	}
	57
	58	return 0;
	59	}
	60
193304ae	61	static int i2c_mux_reg_select(struct i2c_mux_core *muxc, u32 chan)
b3fdd327	62	{
193304ae	63	struct regmux *mux = i2c_mux_priv(muxc);
b3fdd327 YS	64
	65	return i2c_mux_reg_set(mux, chan);
	66	}
	67
193304ae	68	static int i2c_mux_reg_deselect(struct i2c_mux_core *muxc, u32 chan)
b3fdd327	69	{
193304ae	70	struct regmux *mux = i2c_mux_priv(muxc);
b3fdd327 YS	71
	72	if (mux->data.idle_in_use)
	73	return i2c_mux_reg_set(mux, mux->data.idle);
	74
	75	return 0;
	76	}
	77
	78	#ifdef CONFIG_OF
	79	static int i2c_mux_reg_probe_dt(struct regmux *mux,
193304ae	80	struct platform_device *pdev)
b3fdd327 YS	81	{
	82	struct device_node *np = pdev->dev.of_node;
	83	struct device_node adapter_np, child;
	84	struct i2c_adapter *adapter;
	85	struct resource res;
	86	unsigned *values;
	87	int i = 0;
	88
	89	if (!np)
	90	return -ENODEV;
	91
	92	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
	93	if (!adapter_np) {
	94	dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
	95	return -ENODEV;
	96	}
	97	adapter = of_find_i2c_adapter_by_node(adapter_np);
bdbf4a29	98	of_node_put(adapter_np);
b3fdd327 YS	99	if (!adapter)
	100	return -EPROBE_DEFER;
	101
b3fdd327 YS	102	mux->data.parent = i2c_adapter_id(adapter);
	103	put_device(&adapter->dev);
	104
	105	mux->data.n_values = of_get_child_count(np);
3997fb74	106	if (of_property_read_bool(np, "little-endian")) {
b3fdd327	107	mux->data.little_endian = true;
3997fb74	108	} else if (of_property_read_bool(np, "big-endian")) {
b3fdd327 YS	109	mux->data.little_endian = false;
	110	} else {
	111	#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : \
	112	defined(__LITTLE_ENDIAN)
	113	mux->data.little_endian = true;
	114	#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : \
	115	defined(__BIG_ENDIAN)
	116	mux->data.little_endian = false;
	117	#else
	118	#error Endianness not defined?
	119	#endif
	120	}
3997fb74	121	mux->data.write_only = of_property_read_bool(np, "write-only");
b3fdd327	122
a86854d0 KC	123	values = devm_kcalloc(&pdev->dev,
a86854d0 KC	124	mux->data.n_values, sizeof(*mux->data.values),
b3fdd327	125	GFP_KERNEL);
b30c08a2	126	if (!values)
b3fdd327	127	return -ENOMEM;
b3fdd327 YS	128
	129	for_each_child_of_node(np, child) {
	130	of_property_read_u32(child, "reg", values + i);
	131	i++;
	132	}
	133	mux->data.values = values;
	134
	135	if (!of_property_read_u32(np, "idle-state", &mux->data.idle))
	136	mux->data.idle_in_use = true;
	137
	138	/* map address from "reg" if exists */
22ebf00e	139	if (of_address_to_resource(np, 0, &res) == 0) {
b3fdd327	140	mux->data.reg_size = resource_size(&res);
b3fdd327 YS	141	mux->data.reg = devm_ioremap_resource(&pdev->dev, &res);
	142	if (IS_ERR(mux->data.reg))
	143	return PTR_ERR(mux->data.reg);
	144	}
	145
	146	return 0;
	147	}
	148	#else
a05a34e7	149	static int i2c_mux_reg_probe_dt(struct regmux *mux,
193304ae	150	struct platform_device *pdev)
b3fdd327 YS	151	{
	152	return 0;
	153	}
	154	#endif
	155
	156	static int i2c_mux_reg_probe(struct platform_device *pdev)
	157	{
193304ae	158	struct i2c_mux_core *muxc;
b3fdd327 YS	159	struct regmux *mux;
	160	struct i2c_adapter *parent;
	161	struct resource *res;
b3fdd327 YS	162	unsigned int class;
	163	int i, ret, nr;
	164
	165	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
	166	if (!mux)
	167	return -ENOMEM;
	168
b3fdd327 YS	169	if (dev_get_platdata(&pdev->dev)) {
	170	memcpy(&mux->data, dev_get_platdata(&pdev->dev),
	171	sizeof(mux->data));
b3fdd327 YS	172	} else {
b3fdd327 YS	173	ret = i2c_mux_reg_probe_dt(mux, pdev);
ac5b85de TB	174	if (ret == -EPROBE_DEFER)
	175	return ret;
	176
b3fdd327 YS	177	if (ret < 0) {
	178	dev_err(&pdev->dev, "Error parsing device tree");
	179	return ret;
	180	}
	181	}
	182
193304ae PR	183	parent = i2c_get_adapter(mux->data.parent);
	184	if (!parent)
	185	return -EPROBE_DEFER;
	186
b3fdd327 YS	187	if (!mux->data.reg) {
	188	dev_info(&pdev->dev,
	189	"Register not set, using platform resource\n");
	190	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	191	mux->data.reg_size = resource_size(res);
b3fdd327	192	mux->data.reg = devm_ioremap_resource(&pdev->dev, res);
68118e0e PR	193	if (IS_ERR(mux->data.reg)) {
	194	ret = PTR_ERR(mux->data.reg);
	195	goto err_put_parent;
	196	}
b3fdd327 YS	197	}
b3fdd327 YS	198
fce388af WS	199	if (mux->data.reg_size != 4 && mux->data.reg_size != 2 &&
	200	mux->data.reg_size != 1) {
	201	dev_err(&pdev->dev, "Invalid register size\n");
68118e0e PR	202	ret = -EINVAL;
68118e0e PR	203	goto err_put_parent;
fce388af WS	204	}
fce388af WS	205
193304ae PR	206	muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, 0, 0,
193304ae PR	207	i2c_mux_reg_select, NULL);
68118e0e PR	208	if (!muxc) {
	209	ret = -ENOMEM;
	210	goto err_put_parent;
	211	}
193304ae PR	212	muxc->priv = mux;
	213
	214	platform_set_drvdata(pdev, muxc);
b3fdd327 YS	215
b3fdd327 YS	216	if (mux->data.idle_in_use)
193304ae	217	muxc->deselect = i2c_mux_reg_deselect;
b3fdd327 YS	218
	219	for (i = 0; i < mux->data.n_values; i++) {
	220	nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
	221	class = mux->data.classes ? mux->data.classes[i] : 0;
	222
193304ae	223	ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
f0892361	224	if (ret)
a36d4637	225	goto err_del_mux_adapters;
b3fdd327 YS	226	}
	227
	228	dev_dbg(&pdev->dev, "%d port mux on %s adapter\n",
193304ae	229	mux->data.n_values, muxc->parent->name);
b3fdd327 YS	230
	231	return 0;
	232
a36d4637	233	err_del_mux_adapters:
193304ae	234	i2c_mux_del_adapters(muxc);
68118e0e PR	235	err_put_parent:
68118e0e PR	236	i2c_put_adapter(parent);
b3fdd327 YS	237
	238	return ret;
	239	}
	240
	241	static int i2c_mux_reg_remove(struct platform_device *pdev)
	242	{
193304ae	243	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
b3fdd327	244
193304ae PR	245	i2c_mux_del_adapters(muxc);
193304ae PR	246	i2c_put_adapter(muxc->parent);
b3fdd327 YS	247
	248	return 0;
	249	}
	250
	251	static const struct of_device_id i2c_mux_reg_of_match[] = {
	252	{ .compatible = "i2c-mux-reg", },
	253	{},
	254	};
	255	MODULE_DEVICE_TABLE(of, i2c_mux_reg_of_match);
	256
	257	static struct platform_driver i2c_mux_reg_driver = {
	258	.probe = i2c_mux_reg_probe,
	259	.remove = i2c_mux_reg_remove,
	260	.driver = {
	261	.name = "i2c-mux-reg",
9f05e621	262	.of_match_table = of_match_ptr(i2c_mux_reg_of_match),
b3fdd327 YS	263	},
	264	};
	265
	266	module_platform_driver(i2c_mux_reg_driver);
	267
	268	MODULE_DESCRIPTION("Register-based I2C multiplexer driver");
	269	MODULE_AUTHOR("York Sun <yorksun@freescale.com>");
	270	MODULE_LICENSE("GPL");
	271	MODULE_ALIAS("platform:i2c-mux-reg");