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
|
/*
* TI/National Semiconductor LP3943 GPIO driver
*
* Copyright 2013 Texas Instruments
*
* Author: Milo Kim <milo.kim@ti.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; version 2.
*/
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/mfd/lp3943.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
enum lp3943_gpios {
LP3943_GPIO1,
LP3943_GPIO2,
LP3943_GPIO3,
LP3943_GPIO4,
LP3943_GPIO5,
LP3943_GPIO6,
LP3943_GPIO7,
LP3943_GPIO8,
LP3943_GPIO9,
LP3943_GPIO10,
LP3943_GPIO11,
LP3943_GPIO12,
LP3943_GPIO13,
LP3943_GPIO14,
LP3943_GPIO15,
LP3943_GPIO16,
LP3943_MAX_GPIO,
};
struct lp3943_gpio {
struct gpio_chip chip;
struct lp3943 *lp3943;
u16 input_mask; /* 1 = GPIO is input direction, 0 = output */
};
static int lp3943_gpio_request(struct gpio_chip *chip, unsigned offset)
{
struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
struct lp3943 *lp3943 = lp3943_gpio->lp3943;
/* Return an error if the pin is already assigned */
if (test_and_set_bit(offset, &lp3943->pin_used))
return -EBUSY;
return 0;
}
static void lp3943_gpio_free(struct gpio_chip *chip, unsigned offset)
{
struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
struct lp3943 *lp3943 = lp3943_gpio->lp3943;
clear_bit(offset, &lp3943->pin_used);
}
static int lp3943_gpio_set_mode(struct lp3943_gpio *lp3943_gpio, u8 offset,
u8 val)
{
struct lp3943 *lp3943 = lp3943_gpio->lp3943;
const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
return lp3943_update_bits(lp3943, mux[offset].reg, mux[offset].mask,
val << mux[offset].shift);
}
static int lp3943_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
lp3943_gpio->input_mask |= BIT(offset);
return lp3943_gpio_set_mode(lp3943_gpio, offset, LP3943_GPIO_IN);
}
static int lp3943_get_gpio_in_status(struct lp3943_gpio *lp3943_gpio,
struct gpio_chip *chip, unsigned offset)
{
u8 addr, read;
int err;
switch (offset) {
case LP3943_GPIO1 ... LP3943_GPIO8:
addr = LP3943_REG_GPIO_A;
break;
case LP3943_GPIO9 ... LP3943_GPIO16:
addr = LP3943_REG_GPIO_B;
offset = offset - 8;
break;
default:
return -EINVAL;
}
err = lp3943_read_byte(lp3943_gpio->lp3943, addr, &read);
if (err)
return err;
return !!(read & BIT(offset));
}
static int lp3943_get_gpio_out_status(struct lp3943_gpio *lp3943_gpio,
struct gpio_chip *chip, unsigned offset)
{
struct lp3943 *lp3943 = lp3943_gpio->lp3943;
const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
u8 read;
int err;
err = lp3943_read_byte(lp3943, mux[offset].reg, &read);
if (err)
return err;
read = (read & mux[offset].mask) >> mux[offset].shift;
if (read == LP3943_GPIO_OUT_HIGH)
return 1;
else if (read == LP3943_GPIO_OUT_LOW)
return 0;
else
return -EINVAL;
}
static int lp3943_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
/*
* Limitation:
* LP3943 doesn't have the GPIO direction register. It provides
* only input and output status registers.
* So, direction info is required to handle the 'get' operation.
* This variable is updated whenever the direction is changed and
* it is used here.
*/
if (lp3943_gpio->input_mask & BIT(offset))
return lp3943_get_gpio_in_status(lp3943_gpio, chip, offset);
else
return lp3943_get_gpio_out_status(lp3943_gpio, chip, offset);
}
static void lp3943_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
u8 data;
if (value)
data = LP3943_GPIO_OUT_HIGH;
else
data = LP3943_GPIO_OUT_LOW;
lp3943_gpio_set_mode(lp3943_gpio, offset, data);
}
static int lp3943_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
int value)
{
struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);
lp3943_gpio_set(chip, offset, value);
lp3943_gpio->input_mask &= ~BIT(offset);
return 0;
}
static const struct gpio_chip lp3943_gpio_chip = {
.label = "lp3943",
.owner = THIS_MODULE,
.request = lp3943_gpio_request,
.free = lp3943_gpio_free,
.direction_input = lp3943_gpio_direction_input,
.get = lp3943_gpio_get,
.direction_output = lp3943_gpio_direction_output,
.set = lp3943_gpio_set,
.base = -1,
.ngpio = LP3943_MAX_GPIO,
.can_sleep = 1,
};
static int lp3943_gpio_probe(struct platform_device *pdev)
{
struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
struct lp3943_gpio *lp3943_gpio;
lp3943_gpio = devm_kzalloc(&pdev->dev, sizeof(*lp3943_gpio),
GFP_KERNEL);
if (!lp3943_gpio)
return -ENOMEM;
lp3943_gpio->lp3943 = lp3943;
lp3943_gpio->chip = lp3943_gpio_chip;
lp3943_gpio->chip.parent = &pdev->dev;
platform_set_drvdata(pdev, lp3943_gpio);
return devm_gpiochip_add_data(&pdev->dev, &lp3943_gpio->chip,
lp3943_gpio);
}
static const struct of_device_id lp3943_gpio_of_match[] = {
{ .compatible = "ti,lp3943-gpio", },
{ }
};
MODULE_DEVICE_TABLE(of, lp3943_gpio_of_match);
static struct platform_driver lp3943_gpio_driver = {
.probe = lp3943_gpio_probe,
.driver = {
.name = "lp3943-gpio",
.of_match_table = lp3943_gpio_of_match,
},
};
module_platform_driver(lp3943_gpio_driver);
MODULE_DESCRIPTION("LP3943 GPIO driver");
MODULE_ALIAS("platform:lp3943-gpio");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");
|
