2 * GPIO driver for the ACCES 104-IDI-48 family
3 * Copyright (C) 2015 William Breathitt Gray
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.
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.
14 #include <linux/bitops.h>
15 #include <linux/device.h>
16 #include <linux/errno.h>
17 #include <linux/gpio/driver.h>
19 #include <linux/ioport.h>
20 #include <linux/interrupt.h>
21 #include <linux/irqdesc.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/platform_device.h>
26 #include <linux/spinlock.h>
28 static unsigned idi_48_base;
29 module_param(idi_48_base, uint, 0);
30 MODULE_PARM_DESC(idi_48_base, "ACCES 104-IDI-48 base address");
31 static unsigned idi_48_irq;
32 module_param(idi_48_irq, uint, 0);
33 MODULE_PARM_DESC(idi_48_irq, "ACCES 104-IDI-48 interrupt line number");
36 * struct idi_48_gpio - GPIO device private data structure
37 * @chip: instance of the gpio_chip
38 * @lock: synchronization lock to prevent I/O race conditions
39 * @irq_mask: input bits affected by interrupts
40 * @base: base port address of the GPIO device
41 * @extent: extent of port address region of the GPIO device
42 * @irq: Interrupt line number
43 * @cos_enb: Change-Of-State IRQ enable boundaries mask
46 struct gpio_chip chip;
48 unsigned char irq_mask[6];
52 unsigned char cos_enb;
55 static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
60 static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
65 static struct idi_48_gpio *to_idi48gpio(struct gpio_chip *gc)
67 return container_of(gc, struct idi_48_gpio, chip);
70 static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
72 struct idi_48_gpio *const idi48gpio = to_idi48gpio(chip);
74 const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
78 for (i = 0; i < 48; i += 8)
80 base_offset = register_offset[i / 8];
81 mask = BIT(offset - i);
83 return !!(inb(idi48gpio->base + base_offset) & mask);
86 /* The following line should never execute since offset < 48 */
90 static void idi_48_irq_ack(struct irq_data *data)
92 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
93 struct idi_48_gpio *const idi48gpio = to_idi48gpio(chip);
96 spin_lock_irqsave(&idi48gpio->lock, flags);
98 inb(idi48gpio->base + 7);
100 spin_unlock_irqrestore(&idi48gpio->lock, flags);
103 static void idi_48_irq_mask(struct irq_data *data)
105 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
106 struct idi_48_gpio *const idi48gpio = to_idi48gpio(chip);
107 const unsigned offset = irqd_to_hwirq(data);
113 for (i = 0; i < 48; i += 8)
114 if (offset < i + 8) {
115 mask = BIT(offset - i);
118 idi48gpio->irq_mask[boundary] &= ~mask;
120 if (!idi48gpio->irq_mask[boundary]) {
121 idi48gpio->cos_enb &= ~BIT(boundary);
123 spin_lock_irqsave(&idi48gpio->lock, flags);
125 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
127 spin_unlock_irqrestore(&idi48gpio->lock, flags);
134 static void idi_48_irq_unmask(struct irq_data *data)
136 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
137 struct idi_48_gpio *const idi48gpio = to_idi48gpio(chip);
138 const unsigned offset = irqd_to_hwirq(data);
142 unsigned prev_irq_mask;
145 for (i = 0; i < 48; i += 8)
146 if (offset < i + 8) {
147 mask = BIT(offset - i);
149 prev_irq_mask = idi48gpio->irq_mask[boundary];
151 idi48gpio->irq_mask[boundary] |= mask;
153 if (!prev_irq_mask) {
154 idi48gpio->cos_enb |= BIT(boundary);
156 spin_lock_irqsave(&idi48gpio->lock, flags);
158 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
160 spin_unlock_irqrestore(&idi48gpio->lock, flags);
167 static int idi_48_irq_set_type(struct irq_data *data, unsigned flow_type)
169 /* The only valid irq types are none and both-edges */
170 if (flow_type != IRQ_TYPE_NONE &&
171 (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
177 static struct irq_chip idi_48_irqchip = {
178 .name = "104-idi-48",
179 .irq_ack = idi_48_irq_ack,
180 .irq_mask = idi_48_irq_mask,
181 .irq_unmask = idi_48_irq_unmask,
182 .irq_set_type = idi_48_irq_set_type
185 static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
187 struct idi_48_gpio *const idi48gpio = dev_id;
188 unsigned long cos_status;
189 unsigned long boundary;
190 unsigned long irq_mask;
191 unsigned long bit_num;
193 struct gpio_chip *const chip = &idi48gpio->chip;
195 spin_lock(&idi48gpio->lock);
197 cos_status = inb(idi48gpio->base + 7);
199 spin_unlock(&idi48gpio->lock);
201 /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
202 if (cos_status & BIT(6))
205 /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
208 for_each_set_bit(boundary, &cos_status, 6) {
209 irq_mask = idi48gpio->irq_mask[boundary];
211 for_each_set_bit(bit_num, &irq_mask, 8) {
212 gpio = bit_num + boundary * 8;
214 generic_handle_irq(irq_find_mapping(chip->irqdomain,
222 static int __init idi_48_probe(struct platform_device *pdev)
224 struct device *dev = &pdev->dev;
225 struct idi_48_gpio *idi48gpio;
226 const unsigned base = idi_48_base;
227 const unsigned extent = 8;
228 const char *const name = dev_name(dev);
230 const unsigned irq = idi_48_irq;
232 idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
236 if (!request_region(base, extent, name)) {
237 dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n",
238 name, base, base + extent);
240 goto err_lock_io_port;
243 idi48gpio->chip.label = name;
244 idi48gpio->chip.parent = dev;
245 idi48gpio->chip.owner = THIS_MODULE;
246 idi48gpio->chip.base = -1;
247 idi48gpio->chip.ngpio = 48;
248 idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
249 idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
250 idi48gpio->chip.get = idi_48_gpio_get;
251 idi48gpio->base = base;
252 idi48gpio->extent = extent;
253 idi48gpio->irq = irq;
255 spin_lock_init(&idi48gpio->lock);
257 dev_set_drvdata(dev, idi48gpio);
259 err = gpiochip_add(&idi48gpio->chip);
261 dev_err(dev, "GPIO registering failed (%d)\n", err);
262 goto err_gpio_register;
265 /* Disable IRQ by default */
269 err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0,
270 handle_edge_irq, IRQ_TYPE_NONE);
272 dev_err(dev, "Could not add irqchip (%d)\n", err);
273 goto err_gpiochip_irqchip_add;
276 err = request_irq(irq, idi_48_irq_handler, 0, name, idi48gpio);
278 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
279 goto err_request_irq;
285 err_gpiochip_irqchip_add:
286 gpiochip_remove(&idi48gpio->chip);
288 release_region(base, extent);
293 static int idi_48_remove(struct platform_device *pdev)
295 struct idi_48_gpio *const idi48gpio = platform_get_drvdata(pdev);
297 free_irq(idi48gpio->irq, idi48gpio);
298 gpiochip_remove(&idi48gpio->chip);
299 release_region(idi48gpio->base, idi48gpio->extent);
304 static struct platform_device *idi_48_device;
306 static struct platform_driver idi_48_driver = {
310 .remove = idi_48_remove
313 static void __exit idi_48_exit(void)
315 platform_device_unregister(idi_48_device);
316 platform_driver_unregister(&idi_48_driver);
319 static int __init idi_48_init(void)
323 idi_48_device = platform_device_alloc(idi_48_driver.driver.name, -1);
327 err = platform_device_add(idi_48_device);
329 goto err_platform_device;
331 err = platform_driver_probe(&idi_48_driver, idi_48_probe);
333 goto err_platform_driver;
338 platform_device_del(idi_48_device);
340 platform_device_put(idi_48_device);
344 module_init(idi_48_init);
345 module_exit(idi_48_exit);
347 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
348 MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
349 MODULE_LICENSE("GPL");