1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * GPIO driver for the ACCES PCI-IDIO-16
4 * Copyright (C) 2017 William Breathitt Gray
5 */
6 #include <linux/bitmap.h>
7 #include <linux/bitops.h>
8 #include <linux/device.h>
9 #include <linux/errno.h>
10 #include <linux/gpio/driver.h>
11 #include <linux/interrupt.h>
12 #include <linux/irqdesc.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/pci.h>
16 #include <linux/spinlock.h>
17 #include <linux/types.h>
18
19 /**
20 * struct idio_16_gpio_reg - GPIO device registers structure
21 * @out0_7: Read: FET Drive Outputs 0-7
22 * Write: FET Drive Outputs 0-7
23 * @in0_7: Read: Isolated Inputs 0-7
24 * Write: Clear Interrupt
25 * @irq_ctl: Read: Enable IRQ
26 * Write: Disable IRQ
27 * @filter_ctl: Read: Activate Input Filters 0-15
28 * Write: Deactivate Input Filters 0-15
29 * @out8_15: Read: FET Drive Outputs 8-15
30 * Write: FET Drive Outputs 8-15
31 * @in8_15: Read: Isolated Inputs 8-15
32 * Write: Unused
33 * @irq_status: Read: Interrupt status
34 * Write: Unused
35 */
36 struct idio_16_gpio_reg {
37 u8 out0_7;
38 u8 in0_7;
39 u8 irq_ctl;
40 u8 filter_ctl;
41 u8 out8_15;
42 u8 in8_15;
43 u8 irq_status;
44 };
45
46 /**
47 * struct idio_16_gpio - GPIO device private data structure
48 * @chip: instance of the gpio_chip
49 * @lock: synchronization lock to prevent I/O race conditions
50 * @reg: I/O address offset for the GPIO device registers
51 * @irq_mask: I/O bits affected by interrupts
52 */
53 struct idio_16_gpio {
54 struct gpio_chip chip;
55 raw_spinlock_t lock;
56 struct idio_16_gpio_reg __iomem *reg;
57 unsigned long irq_mask;
58 };
59
idio_16_gpio_get_direction(struct gpio_chip * chip,unsigned int offset)60 static int idio_16_gpio_get_direction(struct gpio_chip *chip,
61 unsigned int offset)
62 {
63 if (offset > 15)
64 return 1;
65
66 return 0;
67 }
68
idio_16_gpio_direction_input(struct gpio_chip * chip,unsigned int offset)69 static int idio_16_gpio_direction_input(struct gpio_chip *chip,
70 unsigned int offset)
71 {
72 return 0;
73 }
74
idio_16_gpio_direction_output(struct gpio_chip * chip,unsigned int offset,int value)75 static int idio_16_gpio_direction_output(struct gpio_chip *chip,
76 unsigned int offset, int value)
77 {
78 chip->set(chip, offset, value);
79 return 0;
80 }
81
idio_16_gpio_get(struct gpio_chip * chip,unsigned int offset)82 static int idio_16_gpio_get(struct gpio_chip *chip, unsigned int offset)
83 {
84 struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
85 unsigned long mask = BIT(offset);
86
87 if (offset < 8)
88 return !!(ioread8(&idio16gpio->reg->out0_7) & mask);
89
90 if (offset < 16)
91 return !!(ioread8(&idio16gpio->reg->out8_15) & (mask >> 8));
92
93 if (offset < 24)
94 return !!(ioread8(&idio16gpio->reg->in0_7) & (mask >> 16));
95
96 return !!(ioread8(&idio16gpio->reg->in8_15) & (mask >> 24));
97 }
98
idio_16_gpio_get_multiple(struct gpio_chip * chip,unsigned long * mask,unsigned long * bits)99 static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
100 unsigned long *mask, unsigned long *bits)
101 {
102 struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
103 size_t i;
104 const unsigned int gpio_reg_size = 8;
105 unsigned int bits_offset;
106 size_t word_index;
107 unsigned int word_offset;
108 unsigned long word_mask;
109 const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
110 unsigned long port_state;
111 void __iomem *ports[] = {
112 &idio16gpio->reg->out0_7, &idio16gpio->reg->out8_15,
113 &idio16gpio->reg->in0_7, &idio16gpio->reg->in8_15,
114 };
115
116 /* clear bits array to a clean slate */
117 bitmap_zero(bits, chip->ngpio);
118
119 /* get bits are evaluated a gpio port register at a time */
120 for (i = 0; i < ARRAY_SIZE(ports); i++) {
121 /* gpio offset in bits array */
122 bits_offset = i * gpio_reg_size;
123
124 /* word index for bits array */
125 word_index = BIT_WORD(bits_offset);
126
127 /* gpio offset within current word of bits array */
128 word_offset = bits_offset % BITS_PER_LONG;
129
130 /* mask of get bits for current gpio within current word */
131 word_mask = mask[word_index] & (port_mask << word_offset);
132 if (!word_mask) {
133 /* no get bits in this port so skip to next one */
134 continue;
135 }
136
137 /* read bits from current gpio port */
138 port_state = ioread8(ports[i]);
139
140 /* store acquired bits at respective bits array offset */
141 bits[word_index] |= (port_state << word_offset) & word_mask;
142 }
143
144 return 0;
145 }
146
idio_16_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)147 static void idio_16_gpio_set(struct gpio_chip *chip, unsigned int offset,
148 int value)
149 {
150 struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
151 unsigned int mask = BIT(offset);
152 void __iomem *base;
153 unsigned long flags;
154 unsigned int out_state;
155
156 if (offset > 15)
157 return;
158
159 if (offset > 7) {
160 mask >>= 8;
161 base = &idio16gpio->reg->out8_15;
162 } else
163 base = &idio16gpio->reg->out0_7;
164
165 raw_spin_lock_irqsave(&idio16gpio->lock, flags);
166
167 if (value)
168 out_state = ioread8(base) | mask;
169 else
170 out_state = ioread8(base) & ~mask;
171
172 iowrite8(out_state, base);
173
174 raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
175 }
176
idio_16_gpio_set_multiple(struct gpio_chip * chip,unsigned long * mask,unsigned long * bits)177 static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
178 unsigned long *mask, unsigned long *bits)
179 {
180 struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
181 unsigned long flags;
182 unsigned int out_state;
183
184 raw_spin_lock_irqsave(&idio16gpio->lock, flags);
185
186 /* process output lines 0-7 */
187 if (*mask & 0xFF) {
188 out_state = ioread8(&idio16gpio->reg->out0_7) & ~*mask;
189 out_state |= *mask & *bits;
190 iowrite8(out_state, &idio16gpio->reg->out0_7);
191 }
192
193 /* shift to next output line word */
194 *mask >>= 8;
195
196 /* process output lines 8-15 */
197 if (*mask & 0xFF) {
198 *bits >>= 8;
199 out_state = ioread8(&idio16gpio->reg->out8_15) & ~*mask;
200 out_state |= *mask & *bits;
201 iowrite8(out_state, &idio16gpio->reg->out8_15);
202 }
203
204 raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
205 }
206
idio_16_irq_ack(struct irq_data * data)207 static void idio_16_irq_ack(struct irq_data *data)
208 {
209 }
210
idio_16_irq_mask(struct irq_data * data)211 static void idio_16_irq_mask(struct irq_data *data)
212 {
213 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
214 struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
215 const unsigned long mask = BIT(irqd_to_hwirq(data));
216 unsigned long flags;
217
218 idio16gpio->irq_mask &= ~mask;
219
220 if (!idio16gpio->irq_mask) {
221 raw_spin_lock_irqsave(&idio16gpio->lock, flags);
222
223 iowrite8(0, &idio16gpio->reg->irq_ctl);
224
225 raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
226 }
227 }
228
idio_16_irq_unmask(struct irq_data * data)229 static void idio_16_irq_unmask(struct irq_data *data)
230 {
231 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
232 struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
233 const unsigned long mask = BIT(irqd_to_hwirq(data));
234 const unsigned long prev_irq_mask = idio16gpio->irq_mask;
235 unsigned long flags;
236
237 idio16gpio->irq_mask |= mask;
238
239 if (!prev_irq_mask) {
240 raw_spin_lock_irqsave(&idio16gpio->lock, flags);
241
242 ioread8(&idio16gpio->reg->irq_ctl);
243
244 raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
245 }
246 }
247
idio_16_irq_set_type(struct irq_data * data,unsigned int flow_type)248 static int idio_16_irq_set_type(struct irq_data *data, unsigned int flow_type)
249 {
250 /* The only valid irq types are none and both-edges */
251 if (flow_type != IRQ_TYPE_NONE &&
252 (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
253 return -EINVAL;
254
255 return 0;
256 }
257
258 static struct irq_chip idio_16_irqchip = {
259 .name = "pci-idio-16",
260 .irq_ack = idio_16_irq_ack,
261 .irq_mask = idio_16_irq_mask,
262 .irq_unmask = idio_16_irq_unmask,
263 .irq_set_type = idio_16_irq_set_type
264 };
265
idio_16_irq_handler(int irq,void * dev_id)266 static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
267 {
268 struct idio_16_gpio *const idio16gpio = dev_id;
269 unsigned int irq_status;
270 struct gpio_chip *const chip = &idio16gpio->chip;
271 int gpio;
272
273 raw_spin_lock(&idio16gpio->lock);
274
275 irq_status = ioread8(&idio16gpio->reg->irq_status);
276
277 raw_spin_unlock(&idio16gpio->lock);
278
279 /* Make sure our device generated IRQ */
280 if (!(irq_status & 0x3) || !(irq_status & 0x4))
281 return IRQ_NONE;
282
283 for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
284 generic_handle_irq(irq_find_mapping(chip->irq.domain, gpio));
285
286 raw_spin_lock(&idio16gpio->lock);
287
288 /* Clear interrupt */
289 iowrite8(0, &idio16gpio->reg->in0_7);
290
291 raw_spin_unlock(&idio16gpio->lock);
292
293 return IRQ_HANDLED;
294 }
295
296 #define IDIO_16_NGPIO 32
297 static const char *idio_16_names[IDIO_16_NGPIO] = {
298 "OUT0", "OUT1", "OUT2", "OUT3", "OUT4", "OUT5", "OUT6", "OUT7",
299 "OUT8", "OUT9", "OUT10", "OUT11", "OUT12", "OUT13", "OUT14", "OUT15",
300 "IIN0", "IIN1", "IIN2", "IIN3", "IIN4", "IIN5", "IIN6", "IIN7",
301 "IIN8", "IIN9", "IIN10", "IIN11", "IIN12", "IIN13", "IIN14", "IIN15"
302 };
303
idio_16_probe(struct pci_dev * pdev,const struct pci_device_id * id)304 static int idio_16_probe(struct pci_dev *pdev, const struct pci_device_id *id)
305 {
306 struct device *const dev = &pdev->dev;
307 struct idio_16_gpio *idio16gpio;
308 int err;
309 const size_t pci_bar_index = 2;
310 const char *const name = pci_name(pdev);
311
312 idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
313 if (!idio16gpio)
314 return -ENOMEM;
315
316 err = pcim_enable_device(pdev);
317 if (err) {
318 dev_err(dev, "Failed to enable PCI device (%d)\n", err);
319 return err;
320 }
321
322 err = pcim_iomap_regions(pdev, BIT(pci_bar_index), name);
323 if (err) {
324 dev_err(dev, "Unable to map PCI I/O addresses (%d)\n", err);
325 return err;
326 }
327
328 idio16gpio->reg = pcim_iomap_table(pdev)[pci_bar_index];
329
330 /* Deactivate input filters */
331 iowrite8(0, &idio16gpio->reg->filter_ctl);
332
333 idio16gpio->chip.label = name;
334 idio16gpio->chip.parent = dev;
335 idio16gpio->chip.owner = THIS_MODULE;
336 idio16gpio->chip.base = -1;
337 idio16gpio->chip.ngpio = IDIO_16_NGPIO;
338 idio16gpio->chip.names = idio_16_names;
339 idio16gpio->chip.get_direction = idio_16_gpio_get_direction;
340 idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
341 idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
342 idio16gpio->chip.get = idio_16_gpio_get;
343 idio16gpio->chip.get_multiple = idio_16_gpio_get_multiple;
344 idio16gpio->chip.set = idio_16_gpio_set;
345 idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
346
347 raw_spin_lock_init(&idio16gpio->lock);
348
349 err = devm_gpiochip_add_data(dev, &idio16gpio->chip, idio16gpio);
350 if (err) {
351 dev_err(dev, "GPIO registering failed (%d)\n", err);
352 return err;
353 }
354
355 /* Disable IRQ by default and clear any pending interrupt */
356 iowrite8(0, &idio16gpio->reg->irq_ctl);
357 iowrite8(0, &idio16gpio->reg->in0_7);
358
359 err = gpiochip_irqchip_add(&idio16gpio->chip, &idio_16_irqchip, 0,
360 handle_edge_irq, IRQ_TYPE_NONE);
361 if (err) {
362 dev_err(dev, "Could not add irqchip (%d)\n", err);
363 return err;
364 }
365
366 err = devm_request_irq(dev, pdev->irq, idio_16_irq_handler, IRQF_SHARED,
367 name, idio16gpio);
368 if (err) {
369 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
370 return err;
371 }
372
373 return 0;
374 }
375
376 static const struct pci_device_id idio_16_pci_dev_id[] = {
377 { PCI_DEVICE(0x494F, 0x0DC8) }, { 0 }
378 };
379 MODULE_DEVICE_TABLE(pci, idio_16_pci_dev_id);
380
381 static struct pci_driver idio_16_driver = {
382 .name = "pci-idio-16",
383 .id_table = idio_16_pci_dev_id,
384 .probe = idio_16_probe
385 };
386
387 module_pci_driver(idio_16_driver);
388
389 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
390 MODULE_DESCRIPTION("ACCES PCI-IDIO-16 GPIO driver");
391 MODULE_LICENSE("GPL v2");
392
