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 * @ack_lock: synchronization lock to prevent IRQ handler race conditions
40 * @irq_mask: input bits affected by interrupts
41 * @base: base port address of the GPIO device
42 * @extent: extent of port address region of the GPIO device
43 * @irq: Interrupt line number
44 * @cos_enb: Change-Of-State IRQ enable boundaries mask
47 struct gpio_chip chip;
50 unsigned char irq_mask[6];
54 unsigned char cos_enb;
57 static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
62 static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
67 static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
69 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
71 const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
75 for (i = 0; i < 48; i += 8)
77 base_offset = register_offset[i / 8];
78 mask = BIT(offset - i);
80 return !!(inb(idi48gpio->base + base_offset) & mask);
83 /* The following line should never execute since offset < 48 */
87 static void idi_48_irq_ack(struct irq_data *data)
91 static void idi_48_irq_mask(struct irq_data *data)
93 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
94 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
95 const unsigned offset = irqd_to_hwirq(data);
101 for (i = 0; i < 48; i += 8)
102 if (offset < i + 8) {
103 mask = BIT(offset - i);
106 idi48gpio->irq_mask[boundary] &= ~mask;
108 if (!idi48gpio->irq_mask[boundary]) {
109 idi48gpio->cos_enb &= ~BIT(boundary);
111 spin_lock_irqsave(&idi48gpio->lock, flags);
113 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
115 spin_unlock_irqrestore(&idi48gpio->lock, flags);
122 static void idi_48_irq_unmask(struct irq_data *data)
124 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
125 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
126 const unsigned offset = irqd_to_hwirq(data);
130 unsigned prev_irq_mask;
133 for (i = 0; i < 48; i += 8)
134 if (offset < i + 8) {
135 mask = BIT(offset - i);
137 prev_irq_mask = idi48gpio->irq_mask[boundary];
139 idi48gpio->irq_mask[boundary] |= mask;
141 if (!prev_irq_mask) {
142 idi48gpio->cos_enb |= BIT(boundary);
144 spin_lock_irqsave(&idi48gpio->lock, flags);
146 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
148 spin_unlock_irqrestore(&idi48gpio->lock, flags);
155 static int idi_48_irq_set_type(struct irq_data *data, unsigned flow_type)
157 /* The only valid irq types are none and both-edges */
158 if (flow_type != IRQ_TYPE_NONE &&
159 (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
165 static struct irq_chip idi_48_irqchip = {
166 .name = "104-idi-48",
167 .irq_ack = idi_48_irq_ack,
168 .irq_mask = idi_48_irq_mask,
169 .irq_unmask = idi_48_irq_unmask,
170 .irq_set_type = idi_48_irq_set_type
173 static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
175 struct idi_48_gpio *const idi48gpio = dev_id;
176 unsigned long cos_status;
177 unsigned long boundary;
178 unsigned long irq_mask;
179 unsigned long bit_num;
181 struct gpio_chip *const chip = &idi48gpio->chip;
183 spin_lock(&idi48gpio->ack_lock);
185 spin_lock(&idi48gpio->lock);
187 cos_status = inb(idi48gpio->base + 7);
189 spin_unlock(&idi48gpio->lock);
191 /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
192 if (cos_status & BIT(6)) {
193 spin_unlock(&idi48gpio->ack_lock);
197 /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
200 for_each_set_bit(boundary, &cos_status, 6) {
201 irq_mask = idi48gpio->irq_mask[boundary];
203 for_each_set_bit(bit_num, &irq_mask, 8) {
204 gpio = bit_num + boundary * 8;
206 generic_handle_irq(irq_find_mapping(chip->irqdomain,
211 spin_unlock(&idi48gpio->ack_lock);
216 static int __init idi_48_probe(struct platform_device *pdev)
218 struct device *dev = &pdev->dev;
219 struct idi_48_gpio *idi48gpio;
220 const unsigned base = idi_48_base;
221 const unsigned extent = 8;
222 const char *const name = dev_name(dev);
224 const unsigned irq = idi_48_irq;
226 idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
230 if (!request_region(base, extent, name)) {
231 dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n",
232 name, base, base + extent);
234 goto err_lock_io_port;
237 idi48gpio->chip.label = name;
238 idi48gpio->chip.parent = dev;
239 idi48gpio->chip.owner = THIS_MODULE;
240 idi48gpio->chip.base = -1;
241 idi48gpio->chip.ngpio = 48;
242 idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
243 idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
244 idi48gpio->chip.get = idi_48_gpio_get;
245 idi48gpio->base = base;
246 idi48gpio->extent = extent;
247 idi48gpio->irq = irq;
249 spin_lock_init(&idi48gpio->lock);
251 dev_set_drvdata(dev, idi48gpio);
253 err = gpiochip_add_data(&idi48gpio->chip, idi48gpio);
255 dev_err(dev, "GPIO registering failed (%d)\n", err);
256 goto err_gpio_register;
259 /* Disable IRQ by default */
263 err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0,
264 handle_edge_irq, IRQ_TYPE_NONE);
266 dev_err(dev, "Could not add irqchip (%d)\n", err);
267 goto err_gpiochip_irqchip_add;
270 err = request_irq(irq, idi_48_irq_handler, 0, name, idi48gpio);
272 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
273 goto err_request_irq;
279 err_gpiochip_irqchip_add:
280 gpiochip_remove(&idi48gpio->chip);
282 release_region(base, extent);
287 static int idi_48_remove(struct platform_device *pdev)
289 struct idi_48_gpio *const idi48gpio = platform_get_drvdata(pdev);
291 free_irq(idi48gpio->irq, idi48gpio);
292 gpiochip_remove(&idi48gpio->chip);
293 release_region(idi48gpio->base, idi48gpio->extent);
298 static struct platform_device *idi_48_device;
300 static struct platform_driver idi_48_driver = {
304 .remove = idi_48_remove
307 static void __exit idi_48_exit(void)
309 platform_device_unregister(idi_48_device);
310 platform_driver_unregister(&idi_48_driver);
313 static int __init idi_48_init(void)
317 idi_48_device = platform_device_alloc(idi_48_driver.driver.name, -1);
321 err = platform_device_add(idi_48_device);
323 goto err_platform_device;
325 err = platform_driver_probe(&idi_48_driver, idi_48_probe);
327 goto err_platform_driver;
332 platform_device_del(idi_48_device);
334 platform_device_put(idi_48_device);
338 module_init(idi_48_init);
339 module_exit(idi_48_exit);
341 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
342 MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
343 MODULE_LICENSE("GPL");