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gerrit.devboardsforandroid.linaro.org / platform / external / u-boot / 10c62f41e37b3c5dee36432f760851eb34ce8d6c / . / drivers / i2c / muxes / i2c-mux-gpio.c
blob: 0269b3a18eca24eaf56a65662e7d8960e5c1fe68 [file] [log] [blame]
Peng Fana4305562017-08-14 18:00:05 +0800[diff] [blame]1/*
2 * I2C multiplexer using GPIO API
3 *
4 * Copyright 2017 NXP
5 *
6 * Peng Fan <peng.fan@nxp.com>
7 *
8 * SPDX-License-Identifier: GPL-2.0+
9 */
10
11#include <asm/io.h>
12#include <asm-generic/gpio.h>
13#include <common.h>
14#include <dm.h>
15#include <dm/pinctrl.h>
16#include <fdtdec.h>
17#include <i2c.h>
18#include <linux/errno.h>
19
20DECLARE_GLOBAL_DATA_PTR;
21
22/**
23 * struct i2c_mux_gpio_priv - private data for i2c mux gpio
24 *
25 * @values: the reg value of each child node
26 * @n_values: num of regs
27 * @gpios: the mux-gpios array
28 * @n_gpios: num of gpios in mux-gpios
29 * @idle: the value of idle-state
30 */
31struct i2c_mux_gpio_priv {
32 u32 *values;
33 int n_values;
34 struct gpio_desc *gpios;
35 int n_gpios;
36 u32 idle;
37};
38
39
40static int i2c_mux_gpio_select(struct udevice *dev, struct udevice *bus,
41 uint channel)
42{
43 struct i2c_mux_gpio_priv *priv = dev_get_priv(dev);
44 int i, ret;
45
46 for (i = 0; i < priv->n_gpios; i++) {
47 ret = dm_gpio_set_value(&priv->gpios[i], (channel >> i) & 1);
48 if (ret)
49 return ret;
50 }
51
52 return 0;
53}
54
55static int i2c_mux_gpio_deselect(struct udevice *dev, struct udevice *bus,
56 uint channel)
57{
58 struct i2c_mux_gpio_priv *priv = dev_get_priv(dev);
59 int i, ret;
60
61 for (i = 0; i < priv->n_gpios; i++) {
62 ret = dm_gpio_set_value(&priv->gpios[i], (priv->idle >> i) & 1);
63 if (ret)
64 return ret;
65 }
66
67 return 0;
68}
69
70static int i2c_mux_gpio_probe(struct udevice *dev)
71{
72 const void *fdt = gd->fdt_blob;
73 int node = dev_of_offset(dev);
74 struct i2c_mux_gpio_priv *mux = dev_get_priv(dev);
75 struct gpio_desc *gpios;
76 u32 *values;
77 int i = 0, subnode, ret;
78
79 mux->n_values = fdtdec_get_child_count(fdt, node);
80 values = devm_kzalloc(dev, sizeof(*mux->values) * mux->n_values,
81 GFP_KERNEL);
82 if (!values) {
83 dev_err(dev, "Cannot alloc values array");
84 return -ENOMEM;
85 }
86
87 fdt_for_each_subnode(subnode, fdt, node) {
88 *(values + i) = fdtdec_get_uint(fdt, subnode, "reg", -1);
89 i++;
90 }
91
92 mux->values = values;
93
94 mux->idle = fdtdec_get_uint(fdt, node, "idle-state", -1);
95
96 mux->n_gpios = gpio_get_list_count(dev, "mux-gpios");
97 if (mux->n_gpios < 0) {
98 dev_err(dev, "Missing mux-gpios property\n");
99 return -EINVAL;
100 }
101
102 gpios = devm_kzalloc(dev, sizeof(struct gpio_desc) * mux->n_gpios,
103 GFP_KERNEL);
104 if (!gpios) {
105 dev_err(dev, "Cannot allocate gpios array\n");
106 return -ENOMEM;
107 }
108
109 ret = gpio_request_list_by_name(dev, "mux-gpios", gpios, mux->n_gpios,
110 GPIOD_IS_OUT_ACTIVE);
111 if (ret <= 0) {
112 dev_err(dev, "Failed to request mux-gpios\n");
113 return ret;
114 }
115
116 mux->gpios = gpios;
117
118 return 0;
119}
120
121static const struct i2c_mux_ops i2c_mux_gpio_ops = {
122 .select = i2c_mux_gpio_select,
123 .deselect = i2c_mux_gpio_deselect,
124};
125
126static const struct udevice_id i2c_mux_gpio_ids[] = {
127 { .compatible = "i2c-mux-gpio", },
128 {}
129};
130
131U_BOOT_DRIVER(i2c_mux_gpio) = {
132 .name = "i2c_mux_gpio",
133 .id = UCLASS_I2C_MUX,
134 .of_match = i2c_mux_gpio_ids,
135 .ops = &i2c_mux_gpio_ops,
136 .probe = i2c_mux_gpio_probe,
137 .priv_auto_alloc_size = sizeof(struct i2c_mux_gpio_priv),
138};