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
247
248
249
250
251
252
253
254
255
256
|
// SPDX-License-Identifier: GPL-2.0+
/*
* Raspberry Pi 3 expander GPIO driver
*
* Uses the firmware mailbox service to communicate with the
* GPIO expander on the VPU.
*
* Copyright (C) 2017 Raspberry Pi Trading Ltd.
*/
#include <linux/err.h>
#include <linux/gpio/driver.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <soc/bcm2835/raspberrypi-firmware.h>
#define MODULE_NAME "raspberrypi-exp-gpio"
#define NUM_GPIO 8
#define RPI_EXP_GPIO_BASE 128
#define RPI_EXP_GPIO_DIR_IN 0
#define RPI_EXP_GPIO_DIR_OUT 1
struct rpi_exp_gpio {
struct gpio_chip gc;
struct rpi_firmware *fw;
};
/* VC4 firmware mailbox interface data structures */
struct gpio_set_config {
u32 gpio;
u32 direction;
u32 polarity;
u32 term_en;
u32 term_pull_up;
u32 state;
};
struct gpio_get_config {
u32 gpio;
u32 direction;
u32 polarity;
u32 term_en;
u32 term_pull_up;
};
struct gpio_get_set_state {
u32 gpio;
u32 state;
};
static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off)
{
struct rpi_exp_gpio *gpio;
struct gpio_get_config get;
int ret;
gpio = gpiochip_get_data(gc);
get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
&get, sizeof(get));
if (ret || get.gpio != 0) {
dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n",
off, ret, get.gpio);
return ret ? ret : -EIO;
}
return get.polarity;
}
static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off)
{
struct rpi_exp_gpio *gpio;
struct gpio_set_config set_in;
int ret;
gpio = gpiochip_get_data(gc);
set_in.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
set_in.direction = RPI_EXP_GPIO_DIR_IN;
set_in.term_en = 0; /* termination disabled */
set_in.term_pull_up = 0; /* n/a as termination disabled */
set_in.state = 0; /* n/a as configured as an input */
ret = rpi_exp_gpio_get_polarity(gc, off);
if (ret < 0)
return ret;
set_in.polarity = ret; /* Retain existing setting */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,
&set_in, sizeof(set_in));
if (ret || set_in.gpio != 0) {
dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n",
off, ret, set_in.gpio);
return ret ? ret : -EIO;
}
return 0;
}
static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val)
{
struct rpi_exp_gpio *gpio;
struct gpio_set_config set_out;
int ret;
gpio = gpiochip_get_data(gc);
set_out.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
set_out.direction = RPI_EXP_GPIO_DIR_OUT;
set_out.term_en = 0; /* n/a as an output */
set_out.term_pull_up = 0; /* n/a as termination disabled */
set_out.state = val; /* Output state */
ret = rpi_exp_gpio_get_polarity(gc, off);
if (ret < 0)
return ret;
set_out.polarity = ret; /* Retain existing setting */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,
&set_out, sizeof(set_out));
if (ret || set_out.gpio != 0) {
dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n",
off, ret, set_out.gpio);
return ret ? ret : -EIO;
}
return 0;
}
static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
{
struct rpi_exp_gpio *gpio;
struct gpio_get_config get;
int ret;
gpio = gpiochip_get_data(gc);
get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
&get, sizeof(get));
if (ret || get.gpio != 0) {
dev_err(gc->parent,
"Failed to get GPIO %u config (%d %x)\n", off, ret,
get.gpio);
return ret ? ret : -EIO;
}
if (get.direction)
return GPIO_LINE_DIRECTION_OUT;
return GPIO_LINE_DIRECTION_IN;
}
static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off)
{
struct rpi_exp_gpio *gpio;
struct gpio_get_set_state get;
int ret;
gpio = gpiochip_get_data(gc);
get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
get.state = 0; /* storage for returned value */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE,
&get, sizeof(get));
if (ret || get.gpio != 0) {
dev_err(gc->parent,
"Failed to get GPIO %u state (%d %x)\n", off, ret,
get.gpio);
return ret ? ret : -EIO;
}
return !!get.state;
}
static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
{
struct rpi_exp_gpio *gpio;
struct gpio_get_set_state set;
int ret;
gpio = gpiochip_get_data(gc);
set.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
set.state = val; /* Output state */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE,
&set, sizeof(set));
if (ret || set.gpio != 0)
dev_err(gc->parent,
"Failed to set GPIO %u state (%d %x)\n", off, ret,
set.gpio);
}
static int rpi_exp_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct device_node *fw_node;
struct rpi_firmware *fw;
struct rpi_exp_gpio *rpi_gpio;
fw_node = of_get_parent(np);
if (!fw_node) {
dev_err(dev, "Missing firmware node\n");
return -ENOENT;
}
fw = devm_rpi_firmware_get(&pdev->dev, fw_node);
of_node_put(fw_node);
if (!fw)
return -EPROBE_DEFER;
rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL);
if (!rpi_gpio)
return -ENOMEM;
rpi_gpio->fw = fw;
rpi_gpio->gc.parent = dev;
rpi_gpio->gc.label = MODULE_NAME;
rpi_gpio->gc.owner = THIS_MODULE;
rpi_gpio->gc.of_node = np;
rpi_gpio->gc.base = -1;
rpi_gpio->gc.ngpio = NUM_GPIO;
rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in;
rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out;
rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction;
rpi_gpio->gc.get = rpi_exp_gpio_get;
rpi_gpio->gc.set = rpi_exp_gpio_set;
rpi_gpio->gc.can_sleep = true;
return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio);
}
static const struct of_device_id rpi_exp_gpio_ids[] = {
{ .compatible = "raspberrypi,firmware-gpio" },
{ }
};
MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids);
static struct platform_driver rpi_exp_gpio_driver = {
.driver = {
.name = MODULE_NAME,
.of_match_table = of_match_ptr(rpi_exp_gpio_ids),
},
.probe = rpi_exp_gpio_probe,
};
module_platform_driver(rpi_exp_gpio_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>");
MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver");
MODULE_ALIAS("platform:rpi-exp-gpio");
|
