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83d290c5 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
a430556e PF |
2 | /* |
3 | * I2C multiplexer using GPIO API | |
4 | * | |
5 | * Copyright 2017 NXP | |
6 | * | |
7 | * Peng Fan <peng.fan@nxp.com> | |
a430556e PF |
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 | }; |