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
23 DECLARE_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 */
34 struct 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
i2c_mux_gpio_select(struct udevice * dev,struct udevice * bus,uint channel)43 static 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
i2c_mux_gpio_deselect(struct udevice * dev,struct udevice * bus,uint channel)58 static 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
i2c_mux_gpio_probe(struct udevice * dev)73 static 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
124 static const struct i2c_mux_ops i2c_mux_gpio_ops = {
125 .select = i2c_mux_gpio_select,
126 .deselect = i2c_mux_gpio_deselect,
127 };
128
129 static const struct udevice_id i2c_mux_gpio_ids[] = {
130 { .compatible = "i2c-mux-gpio", },
131 {}
132 };
133
134 U_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