1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
|
/*
* OF helpers for the GPIO API
*
* Copyright (c) 2007-2008 MontaVista Software, Inc.
*
* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <linux/slab.h>
/**
* of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
* @np: device node to get GPIO from
* @propname: property name containing gpio specifier(s)
* @index: index of the GPIO
* @flags: a flags pointer to fill in
*
* Returns GPIO number to use with Linux generic GPIO API, or one of the errno
* value on the error condition. If @flags is not NULL the function also fills
* in flags for the GPIO.
*/
int of_get_named_gpio_flags(struct device_node *np, const char *propname,
int index, enum of_gpio_flags *flags)
{
int ret;
struct device_node *gpio_np;
struct gpio_chip *gc;
int size;
const void *gpio_spec;
const __be32 *gpio_cells;
ret = of_parse_phandles_with_args(np, propname, "#gpio-cells", index,
&gpio_np, &gpio_spec);
if (ret) {
pr_debug("%s: can't parse gpios property\n", __func__);
goto err0;
}
gc = of_node_to_gpiochip(gpio_np);
if (!gc) {
pr_debug("%s: gpio controller %s isn't registered\n",
np->full_name, gpio_np->full_name);
ret = -ENODEV;
goto err1;
}
gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size);
if (!gpio_cells || size != sizeof(*gpio_cells) ||
be32_to_cpup(gpio_cells) != gc->of_gpio_n_cells) {
pr_debug("%s: wrong #gpio-cells for %s\n",
np->full_name, gpio_np->full_name);
ret = -EINVAL;
goto err1;
}
/* .xlate might decide to not fill in the flags, so clear it. */
if (flags)
*flags = 0;
ret = gc->of_xlate(gc, np, gpio_spec, flags);
if (ret < 0)
goto err1;
ret += gc->base;
err1:
of_node_put(gpio_np);
err0:
pr_debug("%s exited with status %d\n", __func__, ret);
return ret;
}
EXPORT_SYMBOL(of_get_named_gpio_flags);
/**
* of_gpio_count - Count GPIOs for a device
* @np: device node to count GPIOs for
*
* The function returns the count of GPIOs specified for a node.
*
* Note that the empty GPIO specifiers counts too. For example,
*
* gpios = <0
* &pio1 1 2
* 0
* &pio2 3 4>;
*
* defines four GPIOs (so this function will return 4), two of which
* are not specified.
*/
unsigned int of_gpio_count(struct device_node *np)
{
unsigned int cnt = 0;
do {
int ret;
ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells",
cnt, NULL, NULL);
/* A hole in the gpios = <> counts anyway. */
if (ret < 0 && ret != -EEXIST)
break;
} while (++cnt);
return cnt;
}
EXPORT_SYMBOL(of_gpio_count);
/**
* of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
* @gc: pointer to the gpio_chip structure
* @np: device node of the GPIO chip
* @gpio_spec: gpio specifier as found in the device tree
* @flags: a flags pointer to fill in
*
* This is simple translation function, suitable for the most 1:1 mapped
* gpio chips. This function performs only one sanity check: whether gpio
* is less than ngpios (that is specified in the gpio_chip).
*/
int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
const void *gpio_spec, u32 *flags)
{
const __be32 *gpio = gpio_spec;
const u32 n = be32_to_cpup(gpio);
/*
* We're discouraging gpio_cells < 2, since that way you'll have to
* write your own xlate function (that will have to retrive the GPIO
* number and the flags from a single gpio cell -- this is possible,
* but not recommended).
*/
if (gc->of_gpio_n_cells < 2) {
WARN_ON(1);
return -EINVAL;
}
if (n > gc->ngpio)
return -EINVAL;
if (flags)
*flags = be32_to_cpu(gpio[1]);
return n;
}
EXPORT_SYMBOL(of_gpio_simple_xlate);
/**
* of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
* @np: device node of the GPIO chip
* @mm_gc: pointer to the of_mm_gpio_chip allocated structure
*
* To use this function you should allocate and fill mm_gc with:
*
* 1) In the gpio_chip structure:
* - all the callbacks
* - of_gpio_n_cells
* - of_xlate callback (optional)
*
* 3) In the of_mm_gpio_chip structure:
* - save_regs callback (optional)
*
* If succeeded, this function will map bank's memory and will
* do all necessary work for you. Then you'll able to use .regs
* to manage GPIOs from the callbacks.
*/
int of_mm_gpiochip_add(struct device_node *np,
struct of_mm_gpio_chip *mm_gc)
{
int ret = -ENOMEM;
struct gpio_chip *gc = &mm_gc->gc;
gc->label = kstrdup(np->full_name, GFP_KERNEL);
if (!gc->label)
goto err0;
mm_gc->regs = of_iomap(np, 0);
if (!mm_gc->regs)
goto err1;
gc->base = -1;
if (mm_gc->save_regs)
mm_gc->save_regs(mm_gc);
mm_gc->gc.of_node = np;
ret = gpiochip_add(gc);
if (ret)
goto err2;
pr_debug("%s: registered as generic GPIO chip, base is %d\n",
np->full_name, gc->base);
return 0;
err2:
iounmap(mm_gc->regs);
err1:
kfree(gc->label);
err0:
pr_err("%s: GPIO chip registration failed with status %d\n",
np->full_name, ret);
return ret;
}
EXPORT_SYMBOL(of_mm_gpiochip_add);
void of_gpiochip_add(struct gpio_chip *chip)
{
if ((!chip->of_node) && (chip->dev))
chip->of_node = chip->dev->of_node;
if (!chip->of_node)
return;
if (!chip->of_xlate) {
chip->of_gpio_n_cells = 2;
chip->of_xlate = of_gpio_simple_xlate;
}
of_node_get(chip->of_node);
}
void of_gpiochip_remove(struct gpio_chip *chip)
{
if (chip->of_node)
of_node_put(chip->of_node);
}
/* Private function for resolving node pointer to gpio_chip */
static int of_gpiochip_is_match(struct gpio_chip *chip, void *data)
{
return chip->of_node == data;
}
struct gpio_chip *of_node_to_gpiochip(struct device_node *np)
{
return gpiochip_find(np, of_gpiochip_is_match);
}
|
