1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * I2C multiplexer using GPIO API
4 *
5 * Copyright 2017 NXP
6 *
7 * Peng Fan <peng.fan@nxp.com>
8 */
9
10#include <asm/global_data.h>
11#include <asm/io.h>
12#include <asm-generic/gpio.h>
13#include <common.h>
14#include <dm.h>
15#include <dm/device_compat.h>
16#include <dm/devres.h>
17#include <dm/pinctrl.h>
18#include <fdtdec.h>
19#include <i2c.h>
20#include <linux/errno.h>
21#include <linux/libfdt.h>
22
23DECLARE_GLOBAL_DATA_PTR;
24
25/**
26 * struct i2c_mux_gpio_priv - private data for i2c mux gpio
27 *
28 * @values: the reg value of each child node
29 * @n_values: num of regs
30 * @gpios: the mux-gpios array
31 * @n_gpios: num of gpios in mux-gpios
32 * @idle: the value of idle-state
33 */
34struct i2c_mux_gpio_priv {
35	u32 *values;
36	int n_values;
37	struct gpio_desc *gpios;
38	int n_gpios;
39	u32 idle;
40};
41
42
43static int i2c_mux_gpio_select(struct udevice *dev, struct udevice *bus,
44			       uint channel)
45{
46	struct i2c_mux_gpio_priv *priv = dev_get_priv(dev);
47	int i, ret;
48
49	for (i = 0; i < priv->n_gpios; i++) {
50		ret = dm_gpio_set_value(&priv->gpios[i], (channel >> i) & 1);
51		if (ret)
52			return ret;
53	}
54
55	return 0;
56}
57
58static int i2c_mux_gpio_deselect(struct udevice *dev, struct udevice *bus,
59				 uint channel)
60{
61	struct i2c_mux_gpio_priv *priv = dev_get_priv(dev);
62	int i, ret;
63
64	for (i = 0; i < priv->n_gpios; i++) {
65		ret = dm_gpio_set_value(&priv->gpios[i], (priv->idle >> i) & 1);
66		if (ret)
67			return ret;
68	}
69
70	return 0;
71}
72
73static int i2c_mux_gpio_probe(struct udevice *dev)
74{
75	const void *fdt = gd->fdt_blob;
76	int node = dev_of_offset(dev);
77	struct i2c_mux_gpio_priv *mux = dev_get_priv(dev);
78	struct gpio_desc *gpios;
79	u32 *values;
80	int i = 0, subnode, ret;
81
82	mux->n_values = fdtdec_get_child_count(fdt, node);
83	values = devm_kzalloc(dev, sizeof(*mux->values) * mux->n_values,
84			      GFP_KERNEL);
85	if (!values) {
86		dev_err(dev, "Cannot alloc values array");
87		return -ENOMEM;
88	}
89
90	fdt_for_each_subnode(subnode, fdt, node) {
91		*(values + i) = fdtdec_get_uint(fdt, subnode, "reg", -1);
92		i++;
93	}
94
95	mux->values = values;
96
97	mux->idle = fdtdec_get_uint(fdt, node, "idle-state", -1);
98
99	mux->n_gpios = gpio_get_list_count(dev, "mux-gpios");
100	if (mux->n_gpios < 0) {
101		dev_err(dev, "Missing mux-gpios property\n");
102		return -EINVAL;
103	}
104
105	gpios = devm_kzalloc(dev, sizeof(struct gpio_desc) * mux->n_gpios,
106			     GFP_KERNEL);
107	if (!gpios) {
108		dev_err(dev, "Cannot allocate gpios array\n");
109		return -ENOMEM;
110	}
111
112	ret = gpio_request_list_by_name(dev, "mux-gpios", gpios, mux->n_gpios,
113					GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
114	if (ret <= 0) {
115		dev_err(dev, "Failed to request mux-gpios\n");
116		return ret;
117	}
118
119	mux->gpios = gpios;
120
121	return 0;
122}
123
124static const struct i2c_mux_ops i2c_mux_gpio_ops = {
125	.select = i2c_mux_gpio_select,
126	.deselect = i2c_mux_gpio_deselect,
127};
128
129static const struct udevice_id i2c_mux_gpio_ids[] = {
130	{ .compatible = "i2c-mux-gpio", },
131	{}
132};
133
134U_BOOT_DRIVER(i2c_mux_gpio) = {
135	.name = "i2c_mux_gpio",
136	.id = UCLASS_I2C_MUX,
137	.of_match = i2c_mux_gpio_ids,
138	.ops = &i2c_mux_gpio_ops,
139	.probe = i2c_mux_gpio_probe,
140	.priv_auto	= sizeof(struct i2c_mux_gpio_priv),
141};
142