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
|
// SPDX-License-Identifier: GPL-2.0
/*
* Touch Bus Negotiator for Google Pixel devices.
*
* Copyright (C) 2021 Google, Inc.
*/
#include <linux/module.h>
#include <linux/net.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/of_gpio.h>
#include <linux/delay.h>
#include "touch_bus_negotiator.h"
enum tbn_operation {
AP_RELEASE_BUS,
AP_REQUEST_BUS,
};
static irqreturn_t tbn_aoc2ap_irq_thread(int irq, void *ptr)
{
struct tbn_context *tbn = ptr;
if (completion_done(&tbn->bus_released) && completion_done(&tbn->bus_requested))
return IRQ_HANDLED;
/*
* For bus release, there two possibilities:
* 1. aoc2ap gpio value already changed to AOC
* 2. tbn_release_bus() with TBN_RELEASE_BUS_TIMEOUT_MS timeout
* for complete_all(&tbn->bus_released);
*/
while (!completion_done(&tbn->bus_released)) {
if (gpio_get_value(tbn->aoc2ap_gpio) == TBN_BUS_OWNER_AOC)
complete_all(&tbn->bus_released);
else
usleep_range(10000, 10000); /* wait 10 ms for gpio stablized */
}
/*
* For bus request, there two possibilities:
* 1. aoc2ap gpio value already changed to AP
* 2. tbn_request_bus() with TBN_REQUEST_BUS_TIMEOUT_MS timeout
* for complete_all(&tbn->bus_requested);
*/
while (!completion_done(&tbn->bus_requested)) {
if (gpio_get_value(tbn->aoc2ap_gpio) == TBN_BUS_OWNER_AP)
complete_all(&tbn->bus_requested);
else
usleep_range(10000, 10000); /* wait 10 ms for gpio stablized */
}
return IRQ_HANDLED;
}
int tbn_handshaking(struct tbn_context *tbn, enum tbn_operation operation)
{
struct completion *wait_for_completion;
enum tbn_bus_owner bus_owner;
unsigned int irq_type;
unsigned int timeout;
const char *msg;
if (!tbn || !tbn->connected)
return 0;
if (operation == AP_REQUEST_BUS) {
wait_for_completion = &tbn->bus_requested;
bus_owner = TBN_BUS_OWNER_AP;
irq_type = IRQF_TRIGGER_FALLING;
timeout = TBN_REQUEST_BUS_TIMEOUT_MS;
msg = "request";
} else {
wait_for_completion = &tbn->bus_released;
bus_owner = TBN_BUS_OWNER_AOC;
irq_type = IRQF_TRIGGER_RISING;
timeout = TBN_RELEASE_BUS_TIMEOUT_MS;
msg = "release";
}
reinit_completion(wait_for_completion);
if (tbn->mode == TBN_MODE_GPIO) {
irq_set_irq_type(tbn->aoc2ap_irq, irq_type);
enable_irq(tbn->aoc2ap_irq);
gpio_direction_output(tbn->ap2aoc_gpio, bus_owner);
if (wait_for_completion_timeout(wait_for_completion,
msecs_to_jiffies(timeout)) == 0) {
dev_err(tbn->dev, "AP %s bus ... timeout!\n", msg);
complete_all(wait_for_completion);
} else
dev_info(tbn->dev, "AP %s bus ... SUCCESS!\n", msg);
disable_irq_nosync(tbn->aoc2ap_irq);
}
return 0;
}
int tbn_request_bus(struct tbn_context *tbn)
{
return tbn_handshaking(tbn, AP_REQUEST_BUS);
}
EXPORT_SYMBOL_GPL(tbn_request_bus);
int tbn_release_bus(struct tbn_context *tbn)
{
return tbn_handshaking(tbn, AP_RELEASE_BUS);
}
EXPORT_SYMBOL_GPL(tbn_release_bus);
struct tbn_context *tbn_init(struct device *dev)
{
int err = 0;
struct tbn_context *tbn = NULL;
struct device_node *np = dev->of_node;
tbn = devm_kzalloc(dev, sizeof(struct tbn_context), GFP_KERNEL);
if (!tbn)
goto failed;
tbn->dev = dev;
if (of_property_read_bool(np, "tbn,ap2aoc_gpio") &&
of_property_read_bool(np, "tbn,aoc2ap_gpio")) {
tbn->mode = TBN_MODE_GPIO;
tbn->ap2aoc_gpio = of_get_named_gpio(np, "tbn,ap2aoc_gpio", 0);
if (gpio_is_valid(tbn->ap2aoc_gpio)) {
err = devm_gpio_request_one(tbn->dev, tbn->ap2aoc_gpio,
GPIOF_OUT_INIT_LOW, "tbn,ap2aoc_gpio");
if (err) {
dev_err(tbn->dev, "%s: Unable to request ap2aoc_gpio %d, err %d!\n",
__func__, tbn->ap2aoc_gpio, err);
goto failed;
}
}
tbn->aoc2ap_gpio = of_get_named_gpio(np, "tbn,aoc2ap_gpio", 0);
if (gpio_is_valid(tbn->aoc2ap_gpio)) {
err = devm_gpio_request_one(tbn->dev, tbn->aoc2ap_gpio,
GPIOF_DIR_IN, "tbn,aoc2ap_gpio");
if (err) {
dev_err(tbn->dev, "%s: Unable to request aoc2ap_gpio %d, err %d!\n",
__func__, tbn->aoc2ap_gpio, err);
goto failed;
}
tbn->aoc2ap_irq = gpio_to_irq(tbn->aoc2ap_gpio);
err = devm_request_threaded_irq(tbn->dev,
tbn->aoc2ap_irq, NULL,
tbn_aoc2ap_irq_thread,
IRQF_TRIGGER_RISING |
IRQF_ONESHOT, "tbn", tbn);
if (err) {
dev_err(tbn->dev,
"%s: Unable to request_threaded_irq, err %d!\n",
__func__, err);
goto failed;
}
disable_irq_nosync(tbn->aoc2ap_irq);
} else {
dev_err(tbn->dev, "%s: invalid aoc2ap_gpio %d!\n",
__func__, tbn->aoc2ap_gpio);
goto failed;
}
tbn->connected = true;
} else {
tbn->mode = TBN_MODE_DISABLED;
tbn->connected = false;
}
init_completion(&tbn->bus_requested);
init_completion(&tbn->bus_released);
complete_all(&tbn->bus_requested);
complete_all(&tbn->bus_released);
dev_info(tbn->dev,
"%s: gpios(aoc2ap: %d ap2aoc: %d), mode %d\n",
__func__, tbn->aoc2ap_gpio, tbn->ap2aoc_gpio, tbn->mode);
dev_dbg(tbn->dev, "bus negotiator initialized: %pK\n", tbn);
return tbn;
failed:
return NULL;
}
EXPORT_SYMBOL_GPL(tbn_init);
void tbn_cleanup(struct tbn_context *tbn)
{
if (!tbn)
return;
dev_dbg(tbn->dev, "destructing bus negotiator: %pK\n", tbn);
}
EXPORT_SYMBOL_GPL(tbn_cleanup);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Touch Bus Negotiator");
MODULE_AUTHOR("Google, Inc.");
|
