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

/*
 * I2C multiplexer using a single register
 *
 * Copyright 2015 Freescale Semiconductor
 * York Sun  <yorksun@freescale.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 */

#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_find_property(np, "little-endian", NULL)) {
		mux->data.little_endian = true;
	} else if (of_find_property(np, "big-endian", NULL)) {
		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
	}
	if (of_find_property(np, "write-only", NULL))
		mux->data.write_only = true;
	else
		mux->data.write_only = false;

	values = devm_kzalloc(&pdev->dev,
			      sizeof(*mux->data.values) * mux->data.n_values,
			      GFP_KERNEL);
	if (!values) {
		dev_err(&pdev->dev, "Cannot allocate values array");
		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) {
			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
b3fdd327 YS	1	/*
	2	* I2C multiplexer using a single register
	3	*
	4	* Copyright 2015 Freescale Semiconductor
	5	* York Sun <yorksun@freescale.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms of the GNU General Public License as published by the
	9	* Free Software Foundation; either version 2 of the License, or (at your
	10	* option) any later version.
	11	*/
	12
	13	#include <linux/i2c.h>
	14	#include <linux/i2c-mux.h>
	15	#include <linux/init.h>
	16	#include <linux/io.h>
	17	#include <linux/module.h>
	18	#include <linux/of_address.h>
	19	#include <linux/platform_data/i2c-mux-reg.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/slab.h>
	22
	23	struct regmux {
b3fdd327 YS	24	struct i2c_mux_reg_platform_data data;
	25	};
	26
	27	static int i2c_mux_reg_set(const struct regmux *mux, unsigned int chan_id)
	28	{
	29	if (!mux->data.reg)
	30	return -EINVAL;
	31
5a73882f YS	32	/*
	33	* Write to the register, followed by a read to ensure the write is
	34	* completed on a "posted" bus, for example PCI or write buffers.
	35	* The endianness of reading doesn't matter and the return data
	36	* is not used.
	37	*/
b3fdd327 YS	38	switch (mux->data.reg_size) {
b3fdd327 YS	39	case 4:
5a73882f	40	if (mux->data.little_endian)
b3fdd327	41	iowrite32(chan_id, mux->data.reg);
5a73882f	42	else
b3fdd327	43	iowrite32be(chan_id, mux->data.reg);
5a73882f YS	44	if (!mux->data.write_only)
5a73882f YS	45	ioread32(mux->data.reg);
b3fdd327 YS	46	break;
b3fdd327 YS	47	case 2:
5a73882f	48	if (mux->data.little_endian)
b3fdd327	49	iowrite16(chan_id, mux->data.reg);
5a73882f	50	else
b3fdd327	51	iowrite16be(chan_id, mux->data.reg);
5a73882f YS	52	if (!mux->data.write_only)
5a73882f YS	53	ioread16(mux->data.reg);
b3fdd327 YS	54	break;
	55	case 1:
	56	iowrite8(chan_id, mux->data.reg);
	57	if (!mux->data.write_only)
	58	ioread8(mux->data.reg);
	59	break;
b3fdd327 YS	60	}
	61
	62	return 0;
	63	}
	64
193304ae	65	static int i2c_mux_reg_select(struct i2c_mux_core *muxc, u32 chan)
b3fdd327	66	{
193304ae	67	struct regmux *mux = i2c_mux_priv(muxc);
b3fdd327 YS	68
	69	return i2c_mux_reg_set(mux, chan);
	70	}
	71
193304ae	72	static int i2c_mux_reg_deselect(struct i2c_mux_core *muxc, u32 chan)
b3fdd327	73	{
193304ae	74	struct regmux *mux = i2c_mux_priv(muxc);
b3fdd327 YS	75
	76	if (mux->data.idle_in_use)
	77	return i2c_mux_reg_set(mux, mux->data.idle);
	78
	79	return 0;
	80	}
	81
	82	#ifdef CONFIG_OF
	83	static int i2c_mux_reg_probe_dt(struct regmux *mux,
193304ae	84	struct platform_device *pdev)
b3fdd327 YS	85	{
	86	struct device_node *np = pdev->dev.of_node;
	87	struct device_node adapter_np, child;
	88	struct i2c_adapter *adapter;
	89	struct resource res;
	90	unsigned *values;
	91	int i = 0;
	92
	93	if (!np)
	94	return -ENODEV;
	95
	96	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
	97	if (!adapter_np) {
	98	dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
	99	return -ENODEV;
	100	}
	101	adapter = of_find_i2c_adapter_by_node(adapter_np);
bdbf4a29	102	of_node_put(adapter_np);
b3fdd327 YS	103	if (!adapter)
	104	return -EPROBE_DEFER;
	105
b3fdd327 YS	106	mux->data.parent = i2c_adapter_id(adapter);
	107	put_device(&adapter->dev);
	108
	109	mux->data.n_values = of_get_child_count(np);
	110	if (of_find_property(np, "little-endian", NULL)) {
	111	mux->data.little_endian = true;
	112	} else if (of_find_property(np, "big-endian", NULL)) {
	113	mux->data.little_endian = false;
	114	} else {
	115	#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : \
	116	defined(__LITTLE_ENDIAN)
	117	mux->data.little_endian = true;
	118	#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : \
	119	defined(__BIG_ENDIAN)
	120	mux->data.little_endian = false;
	121	#else
	122	#error Endianness not defined?
	123	#endif
	124	}
	125	if (of_find_property(np, "write-only", NULL))
	126	mux->data.write_only = true;
	127	else
	128	mux->data.write_only = false;
	129
	130	values = devm_kzalloc(&pdev->dev,
	131	sizeof(mux->data.values) mux->data.n_values,
	132	GFP_KERNEL);
	133	if (!values) {
	134	dev_err(&pdev->dev, "Cannot allocate values array");
	135	return -ENOMEM;
	136	}
	137
	138	for_each_child_of_node(np, child) {
	139	of_property_read_u32(child, "reg", values + i);
	140	i++;
	141	}
	142	mux->data.values = values;
	143
	144	if (!of_property_read_u32(np, "idle-state", &mux->data.idle))
	145	mux->data.idle_in_use = true;
	146
	147	/* map address from "reg" if exists */
22ebf00e	148	if (of_address_to_resource(np, 0, &res) == 0) {
b3fdd327	149	mux->data.reg_size = resource_size(&res);
b3fdd327 YS	150	mux->data.reg = devm_ioremap_resource(&pdev->dev, &res);
	151	if (IS_ERR(mux->data.reg))
	152	return PTR_ERR(mux->data.reg);
	153	}
	154
	155	return 0;
	156	}
	157	#else
a05a34e7	158	static int i2c_mux_reg_probe_dt(struct regmux *mux,
193304ae	159	struct platform_device *pdev)
b3fdd327 YS	160	{
	161	return 0;
	162	}
	163	#endif
	164
	165	static int i2c_mux_reg_probe(struct platform_device *pdev)
	166	{
193304ae	167	struct i2c_mux_core *muxc;
b3fdd327 YS	168	struct regmux *mux;
	169	struct i2c_adapter *parent;
	170	struct resource *res;
b3fdd327 YS	171	unsigned int class;
	172	int i, ret, nr;
	173
	174	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
	175	if (!mux)
	176	return -ENOMEM;
	177
b3fdd327 YS	178	if (dev_get_platdata(&pdev->dev)) {
	179	memcpy(&mux->data, dev_get_platdata(&pdev->dev),
	180	sizeof(mux->data));
b3fdd327 YS	181	} else {
	182	ret = i2c_mux_reg_probe_dt(mux, pdev);
	183	if (ret < 0) {
	184	dev_err(&pdev->dev, "Error parsing device tree");
	185	return ret;
	186	}
	187	}
	188
193304ae PR	189	parent = i2c_get_adapter(mux->data.parent);
	190	if (!parent)
	191	return -EPROBE_DEFER;
	192
b3fdd327 YS	193	if (!mux->data.reg) {
	194	dev_info(&pdev->dev,
	195	"Register not set, using platform resource\n");
	196	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	197	mux->data.reg_size = resource_size(res);
b3fdd327	198	mux->data.reg = devm_ioremap_resource(&pdev->dev, res);
68118e0e PR	199	if (IS_ERR(mux->data.reg)) {
	200	ret = PTR_ERR(mux->data.reg);
	201	goto err_put_parent;
	202	}
b3fdd327 YS	203	}
b3fdd327 YS	204
fce388af WS	205	if (mux->data.reg_size != 4 && mux->data.reg_size != 2 &&
	206	mux->data.reg_size != 1) {
	207	dev_err(&pdev->dev, "Invalid register size\n");
68118e0e PR	208	ret = -EINVAL;
68118e0e PR	209	goto err_put_parent;
fce388af WS	210	}
fce388af WS	211
193304ae PR	212	muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, 0, 0,
193304ae PR	213	i2c_mux_reg_select, NULL);
68118e0e PR	214	if (!muxc) {
	215	ret = -ENOMEM;
	216	goto err_put_parent;
	217	}
193304ae PR	218	muxc->priv = mux;
	219
	220	platform_set_drvdata(pdev, muxc);
b3fdd327 YS	221
b3fdd327 YS	222	if (mux->data.idle_in_use)
193304ae	223	muxc->deselect = i2c_mux_reg_deselect;
b3fdd327 YS	224
	225	for (i = 0; i < mux->data.n_values; i++) {
	226	nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
	227	class = mux->data.classes ? mux->data.classes[i] : 0;
	228
193304ae	229	ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
f0892361	230	if (ret)
a36d4637	231	goto err_del_mux_adapters;
b3fdd327 YS	232	}
	233
	234	dev_dbg(&pdev->dev, "%d port mux on %s adapter\n",
193304ae	235	mux->data.n_values, muxc->parent->name);
b3fdd327 YS	236
	237	return 0;
	238
a36d4637	239	err_del_mux_adapters:
193304ae	240	i2c_mux_del_adapters(muxc);
68118e0e PR	241	err_put_parent:
68118e0e PR	242	i2c_put_adapter(parent);
b3fdd327 YS	243
	244	return ret;
	245	}
	246
	247	static int i2c_mux_reg_remove(struct platform_device *pdev)
	248	{
193304ae	249	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
b3fdd327	250
193304ae PR	251	i2c_mux_del_adapters(muxc);
193304ae PR	252	i2c_put_adapter(muxc->parent);
b3fdd327 YS	253
	254	return 0;
	255	}
	256
	257	static const struct of_device_id i2c_mux_reg_of_match[] = {
	258	{ .compatible = "i2c-mux-reg", },
	259	{},
	260	};
	261	MODULE_DEVICE_TABLE(of, i2c_mux_reg_of_match);
	262
	263	static struct platform_driver i2c_mux_reg_driver = {
	264	.probe = i2c_mux_reg_probe,
	265	.remove = i2c_mux_reg_remove,
	266	.driver = {
	267	.name = "i2c-mux-reg",
9f05e621	268	.of_match_table = of_match_ptr(i2c_mux_reg_of_match),
b3fdd327 YS	269	},
	270	};
	271
	272	module_platform_driver(i2c_mux_reg_driver);
	273
	274	MODULE_DESCRIPTION("Register-based I2C multiplexer driver");
	275	MODULE_AUTHOR("York Sun <yorksun@freescale.com>");
	276	MODULE_LICENSE("GPL");
	277	MODULE_ALIAS("platform:i2c-mux-reg");