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