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-only
/*
* GPIO driver for Exar XR17V35X chip
*
* Copyright (C) 2015 Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
*/
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#define EXAR_OFFSET_MPIOLVL_LO 0x90
#define EXAR_OFFSET_MPIOSEL_LO 0x93
#define EXAR_OFFSET_MPIOLVL_HI 0x96
#define EXAR_OFFSET_MPIOSEL_HI 0x99
#define DRIVER_NAME "gpio_exar"
static DEFINE_IDA(ida_index);
struct exar_gpio_chip {
struct gpio_chip gpio_chip;
struct mutex lock;
int index;
void __iomem *regs;
char name[20];
unsigned int first_pin;
};
static void exar_update(struct gpio_chip *chip, unsigned int reg, int val,
unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
int temp;
mutex_lock(&exar_gpio->lock);
temp = readb(exar_gpio->regs + reg);
temp &= ~BIT(offset);
if (val)
temp |= BIT(offset);
writeb(temp, exar_gpio->regs + reg);
mutex_unlock(&exar_gpio->lock);
}
static int exar_set_direction(struct gpio_chip *chip, int direction,
unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
unsigned int bit = (offset + exar_gpio->first_pin) % 8;
exar_update(chip, addr, direction, bit);
return 0;
}
static int exar_get(struct gpio_chip *chip, unsigned int reg)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
int value;
mutex_lock(&exar_gpio->lock);
value = readb(exar_gpio->regs + reg);
mutex_unlock(&exar_gpio->lock);
return value;
}
static int exar_get_direction(struct gpio_chip *chip, unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
unsigned int bit = (offset + exar_gpio->first_pin) % 8;
if (exar_get(chip, addr) & BIT(bit))
return GPIO_LINE_DIRECTION_IN;
return GPIO_LINE_DIRECTION_OUT;
}
static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
unsigned int bit = (offset + exar_gpio->first_pin) % 8;
return !!(exar_get(chip, addr) & BIT(bit));
}
static void exar_set_value(struct gpio_chip *chip, unsigned int offset,
int value)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
unsigned int bit = (offset + exar_gpio->first_pin) % 8;
exar_update(chip, addr, value, bit);
}
static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
int value)
{
exar_set_value(chip, offset, value);
return exar_set_direction(chip, 0, offset);
}
static int exar_direction_input(struct gpio_chip *chip, unsigned int offset)
{
return exar_set_direction(chip, 1, offset);
}
static int gpio_exar_probe(struct platform_device *pdev)
{
struct pci_dev *pcidev = to_pci_dev(pdev->dev.parent);
struct exar_gpio_chip *exar_gpio;
u32 first_pin, ngpios;
void __iomem *p;
int index, ret;
/*
* The UART driver must have mapped region 0 prior to registering this
* device - use it.
*/
p = pcim_iomap_table(pcidev)[0];
if (!p)
return -ENOMEM;
ret = device_property_read_u32(&pdev->dev, "exar,first-pin",
&first_pin);
if (ret)
return ret;
ret = device_property_read_u32(&pdev->dev, "ngpios", &ngpios);
if (ret)
return ret;
exar_gpio = devm_kzalloc(&pdev->dev, sizeof(*exar_gpio), GFP_KERNEL);
if (!exar_gpio)
return -ENOMEM;
mutex_init(&exar_gpio->lock);
index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
if (index < 0)
goto err_destroy;
sprintf(exar_gpio->name, "exar_gpio%d", index);
exar_gpio->gpio_chip.label = exar_gpio->name;
exar_gpio->gpio_chip.parent = &pdev->dev;
exar_gpio->gpio_chip.direction_output = exar_direction_output;
exar_gpio->gpio_chip.direction_input = exar_direction_input;
exar_gpio->gpio_chip.get_direction = exar_get_direction;
exar_gpio->gpio_chip.get = exar_get_value;
exar_gpio->gpio_chip.set = exar_set_value;
exar_gpio->gpio_chip.base = -1;
exar_gpio->gpio_chip.ngpio = ngpios;
exar_gpio->regs = p;
exar_gpio->index = index;
exar_gpio->first_pin = first_pin;
ret = devm_gpiochip_add_data(&pdev->dev,
&exar_gpio->gpio_chip, exar_gpio);
if (ret)
goto err_destroy;
platform_set_drvdata(pdev, exar_gpio);
return 0;
err_destroy:
ida_simple_remove(&ida_index, index);
mutex_destroy(&exar_gpio->lock);
return ret;
}
static int gpio_exar_remove(struct platform_device *pdev)
{
struct exar_gpio_chip *exar_gpio = platform_get_drvdata(pdev);
ida_simple_remove(&ida_index, exar_gpio->index);
mutex_destroy(&exar_gpio->lock);
return 0;
}
static struct platform_driver gpio_exar_driver = {
.probe = gpio_exar_probe,
.remove = gpio_exar_remove,
.driver = {
.name = DRIVER_NAME,
},
};
module_platform_driver(gpio_exar_driver);
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_DESCRIPTION("Exar GPIO driver");
MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>");
MODULE_LICENSE("GPL");
|
