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
|
/*
* Kontron PLD GPIO driver
*
* Copyright (c) 2010-2013 Kontron Europe GmbH
* Author: Michael Brunner <michael.brunner@kontron.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/mfd/kempld.h>
#define KEMPLD_GPIO_MAX_NUM 16
#define KEMPLD_GPIO_MASK(x) (BIT((x) % 8))
#define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8)
#define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8)
#define KEMPLD_GPIO_EVT_LVL_EDGE 0x46
#define KEMPLD_GPIO_IEN 0x4A
struct kempld_gpio_data {
struct gpio_chip chip;
struct kempld_device_data *pld;
};
/*
* Set or clear GPIO bit
* kempld_get_mutex must be called prior to calling this function.
*/
static void kempld_gpio_bitop(struct kempld_device_data *pld,
u8 reg, u8 bit, u8 val)
{
u8 status;
status = kempld_read8(pld, reg);
if (val)
status |= KEMPLD_GPIO_MASK(bit);
else
status &= ~KEMPLD_GPIO_MASK(bit);
kempld_write8(pld, reg, status);
}
static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)
{
u8 status;
kempld_get_mutex(pld);
status = kempld_read8(pld, reg);
kempld_release_mutex(pld);
return !!(status & KEMPLD_GPIO_MASK(bit));
}
static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct kempld_gpio_data *gpio
= container_of(chip, struct kempld_gpio_data, chip);
struct kempld_device_data *pld = gpio->pld;
return kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset), offset);
}
static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct kempld_gpio_data *gpio
= container_of(chip, struct kempld_gpio_data, chip);
struct kempld_device_data *pld = gpio->pld;
kempld_get_mutex(pld);
kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
kempld_release_mutex(pld);
}
static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct kempld_gpio_data *gpio
= container_of(chip, struct kempld_gpio_data, chip);
struct kempld_device_data *pld = gpio->pld;
kempld_get_mutex(pld);
kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 0);
kempld_release_mutex(pld);
return 0;
}
static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
int value)
{
struct kempld_gpio_data *gpio
= container_of(chip, struct kempld_gpio_data, chip);
struct kempld_device_data *pld = gpio->pld;
kempld_get_mutex(pld);
kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 1);
kempld_release_mutex(pld);
return 0;
}
static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
struct kempld_gpio_data *gpio
= container_of(chip, struct kempld_gpio_data, chip);
struct kempld_device_data *pld = gpio->pld;
return !kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset), offset);
}
static int kempld_gpio_pincount(struct kempld_device_data *pld)
{
u16 evt, evt_back;
kempld_get_mutex(pld);
/* Backup event register as it might be already initialized */
evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
/* Clear event register */
kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);
/* Read back event register */
evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
/* Restore event register */
kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);
kempld_release_mutex(pld);
return evt ? __ffs(evt) : 16;
}
static int kempld_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct kempld_device_data *pld = dev_get_drvdata(dev->parent);
struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
struct kempld_gpio_data *gpio;
struct gpio_chip *chip;
int ret;
if (pld->info.spec_major < 2) {
dev_err(dev,
"Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
return -ENODEV;
}
gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
return -ENOMEM;
gpio->pld = pld;
platform_set_drvdata(pdev, gpio);
chip = &gpio->chip;
chip->label = "gpio-kempld";
chip->owner = THIS_MODULE;
chip->dev = dev;
chip->can_sleep = true;
if (pdata && pdata->gpio_base)
chip->base = pdata->gpio_base;
else
chip->base = -1;
chip->direction_input = kempld_gpio_direction_input;
chip->direction_output = kempld_gpio_direction_output;
chip->get_direction = kempld_gpio_get_direction;
chip->get = kempld_gpio_get;
chip->set = kempld_gpio_set;
chip->ngpio = kempld_gpio_pincount(pld);
if (chip->ngpio == 0) {
dev_err(dev, "No GPIO pins detected\n");
return -ENODEV;
}
ret = gpiochip_add(chip);
if (ret) {
dev_err(dev, "Could not register GPIO chip\n");
return ret;
}
dev_info(dev, "GPIO functionality initialized with %d pins\n",
chip->ngpio);
return 0;
}
static int kempld_gpio_remove(struct platform_device *pdev)
{
struct kempld_gpio_data *gpio = platform_get_drvdata(pdev);
gpiochip_remove(&gpio->chip);
return 0;
}
static struct platform_driver kempld_gpio_driver = {
.driver = {
.name = "kempld-gpio",
},
.probe = kempld_gpio_probe,
.remove = kempld_gpio_remove,
};
module_platform_driver(kempld_gpio_driver);
MODULE_DESCRIPTION("KEM PLD GPIO Driver");
MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:kempld-gpio");
|
