tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Turris Mox Moxtet GPIO expander
4 *
5 * Copyright (C) 2018 Marek Behún <kabel@kernel.org>
6 */
7
8#include <linux/bitops.h>
9#include <linux/gpio/driver.h>
10#include <linux/moxtet.h>
11#include <linux/module.h>
12
13#define MOXTET_GPIO_NGPIOS 12
14#define MOXTET_GPIO_INPUTS 4
15
16struct moxtet_gpio_desc {
17 u16 in_mask;
18 u16 out_mask;
19};
20
21static const struct moxtet_gpio_desc descs[] = {
22 [TURRIS_MOX_MODULE_SFP] = {
23 .in_mask = GENMASK(2, 0),
24 .out_mask = GENMASK(5, 4),
25 },
26};
27
28struct moxtet_gpio_chip {
29 struct device *dev;
30 struct gpio_chip gpio_chip;
31 const struct moxtet_gpio_desc *desc;
32};
33
34static int moxtet_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
35{
36 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
37 int ret;
38
39 if (chip->desc->in_mask & BIT(offset)) {
40 ret = moxtet_device_read(chip->dev);
41 } else if (chip->desc->out_mask & BIT(offset)) {
42 ret = moxtet_device_written(chip->dev);
43 if (ret >= 0)
44 ret <<= MOXTET_GPIO_INPUTS;
45 } else {
46 return -EINVAL;
47 }
48
49 if (ret < 0)
50 return ret;
51
52 return !!(ret & BIT(offset));
53}
54
55static int moxtet_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
56 int val)
57{
58 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
59 int state;
60
61 state = moxtet_device_written(chip->dev);
62 if (state < 0)
63 return state;
64
65 offset -= MOXTET_GPIO_INPUTS;
66
67 if (val)
68 state |= BIT(offset);
69 else
70 state &= ~BIT(offset);
71
72 return moxtet_device_write(chip->dev, state);
73}
74
75static int moxtet_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
76{
77 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
78
79 /* All lines are hard wired to be either input or output, not both. */
80 if (chip->desc->in_mask & BIT(offset))
81 return GPIO_LINE_DIRECTION_IN;
82 else if (chip->desc->out_mask & BIT(offset))
83 return GPIO_LINE_DIRECTION_OUT;
84 else
85 return -EINVAL;
86}
87
88static int moxtet_gpio_direction_input(struct gpio_chip *gc,
89 unsigned int offset)
90{
91 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
92
93 if (chip->desc->in_mask & BIT(offset))
94 return 0;
95 else if (chip->desc->out_mask & BIT(offset))
96 return -ENOTSUPP;
97 else
98 return -EINVAL;
99}
100
101static int moxtet_gpio_direction_output(struct gpio_chip *gc,
102 unsigned int offset, int val)
103{
104 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
105
106 if (chip->desc->out_mask & BIT(offset))
107 return moxtet_gpio_set_value(gc, offset, val);
108 else if (chip->desc->in_mask & BIT(offset))
109 return -ENOTSUPP;
110
111 return -EINVAL;
112}
113
114static int moxtet_gpio_probe(struct device *dev)
115{
116 struct moxtet_gpio_chip *chip;
117 struct device_node *nc = dev->of_node;
118 int id;
119
120 id = to_moxtet_device(dev)->id;
121
122 if (id >= ARRAY_SIZE(descs)) {
123 dev_err(dev, "%pOF Moxtet device id 0x%x is not supported by gpio-moxtet driver\n",
124 nc, id);
125 return -ENOTSUPP;
126 }
127
128 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
129 if (!chip)
130 return -ENOMEM;
131
132 chip->dev = dev;
133 chip->gpio_chip.parent = dev;
134 chip->desc = &descs[id];
135
136 dev_set_drvdata(dev, chip);
137
138 chip->gpio_chip.label = dev_name(dev);
139 chip->gpio_chip.get_direction = moxtet_gpio_get_direction;
140 chip->gpio_chip.direction_input = moxtet_gpio_direction_input;
141 chip->gpio_chip.direction_output = moxtet_gpio_direction_output;
142 chip->gpio_chip.get = moxtet_gpio_get_value;
143 chip->gpio_chip.set = moxtet_gpio_set_value;
144 chip->gpio_chip.base = -1;
145
146 chip->gpio_chip.ngpio = MOXTET_GPIO_NGPIOS;
147
148 chip->gpio_chip.can_sleep = true;
149 chip->gpio_chip.owner = THIS_MODULE;
150
151 return devm_gpiochip_add_data(dev, &chip->gpio_chip, chip);
152}
153
154static const struct of_device_id moxtet_gpio_dt_ids[] = {
155 { .compatible = "cznic,moxtet-gpio", },
156 {},
157};
158MODULE_DEVICE_TABLE(of, moxtet_gpio_dt_ids);
159
160static const enum turris_mox_module_id moxtet_gpio_module_table[] = {
161 TURRIS_MOX_MODULE_SFP,
162 0,
163};
164
165static struct moxtet_driver moxtet_gpio_driver = {
166 .driver = {
167 .name = "moxtet-gpio",
168 .of_match_table = moxtet_gpio_dt_ids,
169 .probe = moxtet_gpio_probe,
170 },
171 .id_table = moxtet_gpio_module_table,
172};
173module_moxtet_driver(moxtet_gpio_driver);
174
175MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
176MODULE_DESCRIPTION("Turris Mox Moxtet GPIO expander");
177MODULE_LICENSE("GPL v2");