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1ceacea2 WBG |
1 | /* |
2 | * GPIO driver for the ACCES 104-IDIO-16 family | |
3 | * Copyright (C) 2015 William Breathitt Gray | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License, version 2, as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, but | |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * General Public License for more details. | |
13 | */ | |
14 | #include <linux/device.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/gpio/driver.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/ioport.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/moduleparam.h> | |
22 | #include <linux/platform_device.h> | |
23 | #include <linux/spinlock.h> | |
24 | ||
25 | static unsigned idio_16_base; | |
26 | module_param(idio_16_base, uint, 0); | |
27 | MODULE_PARM_DESC(idio_16_base, "ACCES 104-IDIO-16 base address"); | |
28 | ||
29 | /** | |
30 | * struct idio_16_gpio - GPIO device private data structure | |
31 | * @chip: instance of the gpio_chip | |
32 | * @lock: synchronization lock to prevent gpio_set race conditions | |
33 | * @base: base port address of the GPIO device | |
34 | * @extent: extent of port address region of the GPIO device | |
35 | * @out_state: output bits state | |
36 | */ | |
37 | struct idio_16_gpio { | |
38 | struct gpio_chip chip; | |
39 | spinlock_t lock; | |
40 | unsigned base; | |
41 | unsigned extent; | |
42 | unsigned out_state; | |
43 | }; | |
44 | ||
45 | static int idio_16_gpio_get_direction(struct gpio_chip *chip, unsigned offset) | |
46 | { | |
47 | if (offset > 15) | |
48 | return 1; | |
49 | ||
50 | return 0; | |
51 | } | |
52 | ||
53 | static int idio_16_gpio_direction_input(struct gpio_chip *chip, unsigned offset) | |
54 | { | |
55 | return 0; | |
56 | } | |
57 | ||
58 | static int idio_16_gpio_direction_output(struct gpio_chip *chip, | |
59 | unsigned offset, int value) | |
60 | { | |
61 | chip->set(chip, offset, value); | |
62 | return 0; | |
63 | } | |
64 | ||
65 | static struct idio_16_gpio *to_idio16gpio(struct gpio_chip *gc) | |
66 | { | |
67 | return container_of(gc, struct idio_16_gpio, chip); | |
68 | } | |
69 | ||
70 | static int idio_16_gpio_get(struct gpio_chip *chip, unsigned offset) | |
71 | { | |
72 | struct idio_16_gpio *const idio16gpio = to_idio16gpio(chip); | |
73 | const unsigned BIT_MASK = 1U << (offset-16); | |
74 | ||
75 | if (offset < 16) | |
76 | return -EINVAL; | |
77 | ||
78 | if (offset < 24) | |
79 | return !!(inb(idio16gpio->base + 1) & BIT_MASK); | |
80 | ||
81 | return !!(inb(idio16gpio->base + 5) & (BIT_MASK>>8)); | |
82 | } | |
83 | ||
84 | static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value) | |
85 | { | |
86 | struct idio_16_gpio *const idio16gpio = to_idio16gpio(chip); | |
87 | const unsigned BIT_MASK = 1U << offset; | |
88 | unsigned long flags; | |
89 | ||
90 | if (offset > 15) | |
91 | return; | |
92 | ||
93 | spin_lock_irqsave(&idio16gpio->lock, flags); | |
94 | ||
95 | if (value) | |
96 | idio16gpio->out_state |= BIT_MASK; | |
97 | else | |
98 | idio16gpio->out_state &= ~BIT_MASK; | |
99 | ||
100 | if (offset > 7) | |
101 | outb(idio16gpio->out_state >> 8, idio16gpio->base + 4); | |
102 | else | |
103 | outb(idio16gpio->out_state, idio16gpio->base); | |
104 | ||
105 | spin_unlock_irqrestore(&idio16gpio->lock, flags); | |
106 | } | |
107 | ||
108 | static int __init idio_16_probe(struct platform_device *pdev) | |
109 | { | |
110 | struct device *dev = &pdev->dev; | |
111 | struct idio_16_gpio *idio16gpio; | |
112 | int err; | |
113 | ||
114 | const unsigned BASE = idio_16_base; | |
115 | const unsigned EXTENT = 8; | |
116 | const char *const NAME = dev_name(dev); | |
117 | ||
118 | idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL); | |
119 | if (!idio16gpio) | |
120 | return -ENOMEM; | |
121 | ||
122 | if (!request_region(BASE, EXTENT, NAME)) { | |
123 | dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n", | |
124 | NAME, BASE, BASE + EXTENT); | |
125 | err = -EBUSY; | |
126 | goto err_lock_io_port; | |
127 | } | |
128 | ||
129 | idio16gpio->chip.label = NAME; | |
130 | idio16gpio->chip.dev = dev; | |
131 | idio16gpio->chip.owner = THIS_MODULE; | |
132 | idio16gpio->chip.base = -1; | |
133 | idio16gpio->chip.ngpio = 32; | |
134 | idio16gpio->chip.get_direction = idio_16_gpio_get_direction; | |
135 | idio16gpio->chip.direction_input = idio_16_gpio_direction_input; | |
136 | idio16gpio->chip.direction_output = idio_16_gpio_direction_output; | |
137 | idio16gpio->chip.get = idio_16_gpio_get; | |
138 | idio16gpio->chip.set = idio_16_gpio_set; | |
139 | idio16gpio->base = BASE; | |
140 | idio16gpio->extent = EXTENT; | |
141 | idio16gpio->out_state = 0xFFFF; | |
142 | ||
143 | spin_lock_init(&idio16gpio->lock); | |
144 | ||
145 | dev_set_drvdata(dev, idio16gpio); | |
146 | ||
147 | err = gpiochip_add(&idio16gpio->chip); | |
148 | if (err) { | |
149 | dev_err(dev, "GPIO registering failed (%d)\n", err); | |
150 | goto err_gpio_register; | |
151 | } | |
152 | ||
153 | return 0; | |
154 | ||
155 | err_gpio_register: | |
156 | release_region(BASE, EXTENT); | |
157 | err_lock_io_port: | |
158 | return err; | |
159 | } | |
160 | ||
161 | static int idio_16_remove(struct platform_device *pdev) | |
162 | { | |
163 | struct idio_16_gpio *const idio16gpio = platform_get_drvdata(pdev); | |
164 | ||
165 | gpiochip_remove(&idio16gpio->chip); | |
166 | release_region(idio16gpio->base, idio16gpio->extent); | |
167 | ||
168 | return 0; | |
169 | } | |
170 | ||
171 | static struct platform_device *idio_16_device; | |
172 | ||
173 | static struct platform_driver idio_16_driver = { | |
174 | .driver = { | |
175 | .name = "104-idio-16" | |
176 | }, | |
177 | .remove = idio_16_remove | |
178 | }; | |
179 | ||
180 | static void __exit idio_16_exit(void) | |
181 | { | |
182 | platform_device_unregister(idio_16_device); | |
183 | platform_driver_unregister(&idio_16_driver); | |
184 | } | |
185 | ||
186 | static int __init idio_16_init(void) | |
187 | { | |
188 | int err; | |
189 | ||
190 | idio_16_device = platform_device_alloc(idio_16_driver.driver.name, -1); | |
191 | if (!idio_16_device) | |
192 | return -ENOMEM; | |
193 | ||
194 | err = platform_device_add(idio_16_device); | |
195 | if (err) | |
196 | goto err_platform_device; | |
197 | ||
198 | err = platform_driver_probe(&idio_16_driver, idio_16_probe); | |
199 | if (err) | |
200 | goto err_platform_driver; | |
201 | ||
202 | return 0; | |
203 | ||
204 | err_platform_driver: | |
205 | platform_device_del(idio_16_device); | |
206 | err_platform_device: | |
207 | platform_device_put(idio_16_device); | |
208 | return err; | |
209 | } | |
210 | ||
211 | module_init(idio_16_init); | |
212 | module_exit(idio_16_exit); | |
213 | ||
214 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); | |
215 | MODULE_DESCRIPTION("ACCES 104-IDIO-16 GPIO driver"); | |
216 | MODULE_LICENSE("GPL"); |