1/*
2 * GPIO driver for the ACCES 104-IDI-48 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 * This driver supports the following ACCES devices: 104-IDI-48A,
15 * 104-IDI-48AC, 104-IDI-48B, and 104-IDI-48BC.
16 */
17#include <linux/bitmap.h>
18#include <linux/bitops.h>
19#include <linux/device.h>
20#include <linux/errno.h>
21#include <linux/gpio/driver.h>
22#include <linux/io.h>
23#include <linux/ioport.h>
24#include <linux/interrupt.h>
25#include <linux/irqdesc.h>
26#include <linux/isa.h>
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/moduleparam.h>
30#include <linux/spinlock.h>
31
32#define IDI_48_EXTENT 8
33#define MAX_NUM_IDI_48 max_num_isa_dev(IDI_48_EXTENT)
34
35static unsigned int base[MAX_NUM_IDI_48];
36static unsigned int num_idi_48;
37module_param_hw_array(base, uint, ioport, &num_idi_48, 0);
38MODULE_PARM_DESC(base, "ACCES 104-IDI-48 base addresses");
39
40static unsigned int irq[MAX_NUM_IDI_48];
41module_param_hw_array(irq, uint, irq, NULL, 0);
42MODULE_PARM_DESC(irq, "ACCES 104-IDI-48 interrupt line numbers");
43
44/**
45 * struct idi_48_gpio - GPIO device private data structure
46 * @chip: instance of the gpio_chip
47 * @lock: synchronization lock to prevent I/O race conditions
48 * @ack_lock: synchronization lock to prevent IRQ handler race conditions
49 * @irq_mask: input bits affected by interrupts
50 * @base: base port address of the GPIO device
51 * @cos_enb: Change-Of-State IRQ enable boundaries mask
52 */
53struct idi_48_gpio {
54 struct gpio_chip chip;
55 raw_spinlock_t lock;
56 spinlock_t ack_lock;
57 unsigned char irq_mask[6];
58 unsigned base;
59 unsigned char cos_enb;
60};
61
62static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
63{
64 return 1;
65}
66
67static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
68{
69 return 0;
70}
71
72static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
73{
74 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
75 unsigned i;
76 const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
77 unsigned base_offset;
78 unsigned mask;
79
80 for (i = 0; i < 48; i += 8)
81 if (offset < i + 8) {
82 base_offset = register_offset[i / 8];
83 mask = BIT(offset - i);
84
85 return !!(inb(idi48gpio->base + base_offset) & mask);
86 }
87
88 /* The following line should never execute since offset < 48 */
89 return 0;
90}
91
92static int idi_48_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
93 unsigned long *bits)
94{
95 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
96 size_t i;
97 static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
98 const unsigned int gpio_reg_size = 8;
99 unsigned int bits_offset;
100 size_t word_index;
101 unsigned int word_offset;
102 unsigned long word_mask;
103 const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
104 unsigned long port_state;
105
106 /* clear bits array to a clean slate */
107 bitmap_zero(bits, chip->ngpio);
108
109 /* get bits are evaluated a gpio port register at a time */
110 for (i = 0; i < ARRAY_SIZE(ports); i++) {
111 /* gpio offset in bits array */
112 bits_offset = i * gpio_reg_size;
113
114 /* word index for bits array */
115 word_index = BIT_WORD(bits_offset);
116
117 /* gpio offset within current word of bits array */
118 word_offset = bits_offset % BITS_PER_LONG;
119
120 /* mask of get bits for current gpio within current word */
121 word_mask = mask[word_index] & (port_mask << word_offset);
122 if (!word_mask) {
123 /* no get bits in this port so skip to next one */
124 continue;
125 }
126
127 /* read bits from current gpio port */
128 port_state = inb(idi48gpio->base + ports[i]);
129
130 /* store acquired bits at respective bits array offset */
131 bits[word_index] |= (port_state << word_offset) & word_mask;
132 }
133
134 return 0;
135}
136
137static void idi_48_irq_ack(struct irq_data *data)
138{
139}
140
141static void idi_48_irq_mask(struct irq_data *data)
142{
143 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
144 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
145 const unsigned offset = irqd_to_hwirq(data);
146 unsigned i;
147 unsigned mask;
148 unsigned boundary;
149 unsigned long flags;
150
151 for (i = 0; i < 48; i += 8)
152 if (offset < i + 8) {
153 mask = BIT(offset - i);
154 boundary = i / 8;
155
156 idi48gpio->irq_mask[boundary] &= ~mask;
157
158 if (!idi48gpio->irq_mask[boundary]) {
159 idi48gpio->cos_enb &= ~BIT(boundary);
160
161 raw_spin_lock_irqsave(&idi48gpio->lock, flags);
162
163 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
164
165 raw_spin_unlock_irqrestore(&idi48gpio->lock,
166 flags);
167 }
168
169 return;
170 }
171}
172
173static void idi_48_irq_unmask(struct irq_data *data)
174{
175 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
176 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
177 const unsigned offset = irqd_to_hwirq(data);
178 unsigned i;
179 unsigned mask;
180 unsigned boundary;
181 unsigned prev_irq_mask;
182 unsigned long flags;
183
184 for (i = 0; i < 48; i += 8)
185 if (offset < i + 8) {
186 mask = BIT(offset - i);
187 boundary = i / 8;
188 prev_irq_mask = idi48gpio->irq_mask[boundary];
189
190 idi48gpio->irq_mask[boundary] |= mask;
191
192 if (!prev_irq_mask) {
193 idi48gpio->cos_enb |= BIT(boundary);
194
195 raw_spin_lock_irqsave(&idi48gpio->lock, flags);
196
197 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
198
199 raw_spin_unlock_irqrestore(&idi48gpio->lock,
200 flags);
201 }
202
203 return;
204 }
205}
206
207static int idi_48_irq_set_type(struct irq_data *data, unsigned flow_type)
208{
209 /* The only valid irq types are none and both-edges */
210 if (flow_type != IRQ_TYPE_NONE &&
211 (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
212 return -EINVAL;
213
214 return 0;
215}
216
217static struct irq_chip idi_48_irqchip = {
218 .name = "104-idi-48",
219 .irq_ack = idi_48_irq_ack,
220 .irq_mask = idi_48_irq_mask,
221 .irq_unmask = idi_48_irq_unmask,
222 .irq_set_type = idi_48_irq_set_type
223};
224
225static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
226{
227 struct idi_48_gpio *const idi48gpio = dev_id;
228 unsigned long cos_status;
229 unsigned long boundary;
230 unsigned long irq_mask;
231 unsigned long bit_num;
232 unsigned long gpio;
233 struct gpio_chip *const chip = &idi48gpio->chip;
234
235 spin_lock(&idi48gpio->ack_lock);
236
237 raw_spin_lock(&idi48gpio->lock);
238
239 cos_status = inb(idi48gpio->base + 7);
240
241 raw_spin_unlock(&idi48gpio->lock);
242
243 /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
244 if (cos_status & BIT(6)) {
245 spin_unlock(&idi48gpio->ack_lock);
246 return IRQ_NONE;
247 }
248
249 /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
250 cos_status &= 0x3F;
251
252 for_each_set_bit(boundary, &cos_status, 6) {
253 irq_mask = idi48gpio->irq_mask[boundary];
254
255 for_each_set_bit(bit_num, &irq_mask, 8) {
256 gpio = bit_num + boundary * 8;
257
258 generic_handle_irq(irq_find_mapping(chip->irq.domain,
259 gpio));
260 }
261 }
262
263 spin_unlock(&idi48gpio->ack_lock);
264
265 return IRQ_HANDLED;
266}
267
268#define IDI48_NGPIO 48
269static const char *idi48_names[IDI48_NGPIO] = {
270 "Bit 0 A", "Bit 1 A", "Bit 2 A", "Bit 3 A", "Bit 4 A", "Bit 5 A",
271 "Bit 6 A", "Bit 7 A", "Bit 8 A", "Bit 9 A", "Bit 10 A", "Bit 11 A",
272 "Bit 12 A", "Bit 13 A", "Bit 14 A", "Bit 15 A", "Bit 16 A", "Bit 17 A",
273 "Bit 18 A", "Bit 19 A", "Bit 20 A", "Bit 21 A", "Bit 22 A", "Bit 23 A",
274 "Bit 0 B", "Bit 1 B", "Bit 2 B", "Bit 3 B", "Bit 4 B", "Bit 5 B",
275 "Bit 6 B", "Bit 7 B", "Bit 8 B", "Bit 9 B", "Bit 10 B", "Bit 11 B",
276 "Bit 12 B", "Bit 13 B", "Bit 14 B", "Bit 15 B", "Bit 16 B", "Bit 17 B",
277 "Bit 18 B", "Bit 19 B", "Bit 20 B", "Bit 21 B", "Bit 22 B", "Bit 23 B"
278};
279
280static int idi_48_probe(struct device *dev, unsigned int id)
281{
282 struct idi_48_gpio *idi48gpio;
283 const char *const name = dev_name(dev);
284 int err;
285
286 idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
287 if (!idi48gpio)
288 return -ENOMEM;
289
290 if (!devm_request_region(dev, base[id], IDI_48_EXTENT, name)) {
291 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
292 base[id], base[id] + IDI_48_EXTENT);
293 return -EBUSY;
294 }
295
296 idi48gpio->chip.label = name;
297 idi48gpio->chip.parent = dev;
298 idi48gpio->chip.owner = THIS_MODULE;
299 idi48gpio->chip.base = -1;
300 idi48gpio->chip.ngpio = IDI48_NGPIO;
301 idi48gpio->chip.names = idi48_names;
302 idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
303 idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
304 idi48gpio->chip.get = idi_48_gpio_get;
305 idi48gpio->chip.get_multiple = idi_48_gpio_get_multiple;
306 idi48gpio->base = base[id];
307
308 raw_spin_lock_init(&idi48gpio->lock);
309 spin_lock_init(&idi48gpio->ack_lock);
310
311 err = devm_gpiochip_add_data(dev, &idi48gpio->chip, idi48gpio);
312 if (err) {
313 dev_err(dev, "GPIO registering failed (%d)\n", err);
314 return err;
315 }
316
317 /* Disable IRQ by default */
318 outb(0, base[id] + 7);
319 inb(base[id] + 7);
320
321 err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0,
322 handle_edge_irq, IRQ_TYPE_NONE);
323 if (err) {
324 dev_err(dev, "Could not add irqchip (%d)\n", err);
325 return err;
326 }
327
328 err = devm_request_irq(dev, irq[id], idi_48_irq_handler, IRQF_SHARED,
329 name, idi48gpio);
330 if (err) {
331 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
332 return err;
333 }
334
335 return 0;
336}
337
338static struct isa_driver idi_48_driver = {
339 .probe = idi_48_probe,
340 .driver = {
341 .name = "104-idi-48"
342 },
343};
344module_isa_driver(idi_48_driver, num_idi_48);
345
346MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
347MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
348MODULE_LICENSE("GPL v2");
349