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gerrit.devboardsforandroid.linaro.org / platform / external / u-boot / 429e048e4190b68b078c37c0012c59804e32818b / . / drivers / i2c / muxes / i2c-mux-gpio.c
blob: 28f640042f3fabd49a04e3e725288f79b0a9be5d [file] [log] [blame]
Tom Rini83d290c2018-05-06 17:58:06 -0400[diff] [blame]1// SPDX-License-Identifier: GPL-2.0+
Peng Fana4305562017-08-14 18:00:05 +0800[diff] [blame]2/*
3 * I2C multiplexer using GPIO API
4 *
5 * Copyright 2017 NXP
6 *
7 * Peng Fan <peng.fan@nxp.com>
Peng Fana4305562017-08-14 18:00:05 +0800[diff] [blame]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
19DECLARE_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 */
30struct 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
39static 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
54static 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
69static 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
120static const struct i2c_mux_ops i2c_mux_gpio_ops = {
121 .select = i2c_mux_gpio_select,
122 .deselect = i2c_mux_gpio_deselect,
123};
124
125static const struct udevice_id i2c_mux_gpio_ids[] = {
126 { .compatible = "i2c-mux-gpio", },
127 {}
128};
129
130U_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};