1 /*
2 * Copyright (C) 2013 Altera Corporation
3 * Based on gpio-mpc8xxx.c
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 as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #include <linux/io.h>
20 #include <linux/module.h>
21 #include <linux/gpio/driver.h>
22 #include <linux/of_gpio.h> /* For of_mm_gpio_chip */
23 #include <linux/platform_device.h>
24
25 #define ALTERA_GPIO_MAX_NGPIO 32
26 #define ALTERA_GPIO_DATA 0x0
27 #define ALTERA_GPIO_DIR 0x4
28 #define ALTERA_GPIO_IRQ_MASK 0x8
29 #define ALTERA_GPIO_EDGE_CAP 0xc
30
31 /**
32 * struct altera_gpio_chip
33 * @mmchip : memory mapped chip structure.
34 * @gpio_lock : synchronization lock so that new irq/set/get requests
35 will be blocked until the current one completes.
36 * @interrupt_trigger : specifies the hardware configured IRQ trigger type
37 (rising, falling, both, high)
38 * @mapped_irq : kernel mapped irq number.
39 */
40 struct altera_gpio_chip {
41 struct of_mm_gpio_chip mmchip;
42 raw_spinlock_t gpio_lock;
43 int interrupt_trigger;
44 int mapped_irq;
45 };
46
altera_gpio_irq_unmask(struct irq_data * d)47 static void altera_gpio_irq_unmask(struct irq_data *d)
48 {
49 struct altera_gpio_chip *altera_gc;
50 struct of_mm_gpio_chip *mm_gc;
51 unsigned long flags;
52 u32 intmask;
53
54 altera_gc = gpiochip_get_data(irq_data_get_irq_chip_data(d));
55 mm_gc = &altera_gc->mmchip;
56
57 raw_spin_lock_irqsave(&altera_gc->gpio_lock, flags);
58 intmask = readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
59 /* Set ALTERA_GPIO_IRQ_MASK bit to unmask */
60 intmask |= BIT(irqd_to_hwirq(d));
61 writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
62 raw_spin_unlock_irqrestore(&altera_gc->gpio_lock, flags);
63 }
64
altera_gpio_irq_mask(struct irq_data * d)65 static void altera_gpio_irq_mask(struct irq_data *d)
66 {
67 struct altera_gpio_chip *altera_gc;
68 struct of_mm_gpio_chip *mm_gc;
69 unsigned long flags;
70 u32 intmask;
71
72 altera_gc = gpiochip_get_data(irq_data_get_irq_chip_data(d));
73 mm_gc = &altera_gc->mmchip;
74
75 raw_spin_lock_irqsave(&altera_gc->gpio_lock, flags);
76 intmask = readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
77 /* Clear ALTERA_GPIO_IRQ_MASK bit to mask */
78 intmask &= ~BIT(irqd_to_hwirq(d));
79 writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
80 raw_spin_unlock_irqrestore(&altera_gc->gpio_lock, flags);
81 }
82
83 /**
84 * This controller's IRQ type is synthesized in hardware, so this function
85 * just checks if the requested set_type matches the synthesized IRQ type
86 */
altera_gpio_irq_set_type(struct irq_data * d,unsigned int type)87 static int altera_gpio_irq_set_type(struct irq_data *d,
88 unsigned int type)
89 {
90 struct altera_gpio_chip *altera_gc;
91
92 altera_gc = gpiochip_get_data(irq_data_get_irq_chip_data(d));
93
94 if (type == IRQ_TYPE_NONE) {
95 irq_set_handler_locked(d, handle_bad_irq);
96 return 0;
97 }
98 if (type == altera_gc->interrupt_trigger) {
99 if (type == IRQ_TYPE_LEVEL_HIGH)
100 irq_set_handler_locked(d, handle_level_irq);
101 else
102 irq_set_handler_locked(d, handle_simple_irq);
103 return 0;
104 }
105 irq_set_handler_locked(d, handle_bad_irq);
106 return -EINVAL;
107 }
108
altera_gpio_irq_startup(struct irq_data * d)109 static unsigned int altera_gpio_irq_startup(struct irq_data *d)
110 {
111 altera_gpio_irq_unmask(d);
112
113 return 0;
114 }
115
116 static struct irq_chip altera_irq_chip = {
117 .name = "altera-gpio",
118 .irq_mask = altera_gpio_irq_mask,
119 .irq_unmask = altera_gpio_irq_unmask,
120 .irq_set_type = altera_gpio_irq_set_type,
121 .irq_startup = altera_gpio_irq_startup,
122 .irq_shutdown = altera_gpio_irq_mask,
123 };
124
altera_gpio_get(struct gpio_chip * gc,unsigned offset)125 static int altera_gpio_get(struct gpio_chip *gc, unsigned offset)
126 {
127 struct of_mm_gpio_chip *mm_gc;
128
129 mm_gc = to_of_mm_gpio_chip(gc);
130
131 return !!(readl(mm_gc->regs + ALTERA_GPIO_DATA) & BIT(offset));
132 }
133
altera_gpio_set(struct gpio_chip * gc,unsigned offset,int value)134 static void altera_gpio_set(struct gpio_chip *gc, unsigned offset, int value)
135 {
136 struct of_mm_gpio_chip *mm_gc;
137 struct altera_gpio_chip *chip;
138 unsigned long flags;
139 unsigned int data_reg;
140
141 mm_gc = to_of_mm_gpio_chip(gc);
142 chip = gpiochip_get_data(gc);
143
144 raw_spin_lock_irqsave(&chip->gpio_lock, flags);
145 data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA);
146 if (value)
147 data_reg |= BIT(offset);
148 else
149 data_reg &= ~BIT(offset);
150 writel(data_reg, mm_gc->regs + ALTERA_GPIO_DATA);
151 raw_spin_unlock_irqrestore(&chip->gpio_lock, flags);
152 }
153
altera_gpio_direction_input(struct gpio_chip * gc,unsigned offset)154 static int altera_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
155 {
156 struct of_mm_gpio_chip *mm_gc;
157 struct altera_gpio_chip *chip;
158 unsigned long flags;
159 unsigned int gpio_ddr;
160
161 mm_gc = to_of_mm_gpio_chip(gc);
162 chip = gpiochip_get_data(gc);
163
164 raw_spin_lock_irqsave(&chip->gpio_lock, flags);
165 /* Set pin as input, assumes software controlled IP */
166 gpio_ddr = readl(mm_gc->regs + ALTERA_GPIO_DIR);
167 gpio_ddr &= ~BIT(offset);
168 writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR);
169 raw_spin_unlock_irqrestore(&chip->gpio_lock, flags);
170
171 return 0;
172 }
173
altera_gpio_direction_output(struct gpio_chip * gc,unsigned offset,int value)174 static int altera_gpio_direction_output(struct gpio_chip *gc,
175 unsigned offset, int value)
176 {
177 struct of_mm_gpio_chip *mm_gc;
178 struct altera_gpio_chip *chip;
179 unsigned long flags;
180 unsigned int data_reg, gpio_ddr;
181
182 mm_gc = to_of_mm_gpio_chip(gc);
183 chip = gpiochip_get_data(gc);
184
185 raw_spin_lock_irqsave(&chip->gpio_lock, flags);
186 /* Sets the GPIO value */
187 data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA);
188 if (value)
189 data_reg |= BIT(offset);
190 else
191 data_reg &= ~BIT(offset);
192 writel(data_reg, mm_gc->regs + ALTERA_GPIO_DATA);
193
194 /* Set pin as output, assumes software controlled IP */
195 gpio_ddr = readl(mm_gc->regs + ALTERA_GPIO_DIR);
196 gpio_ddr |= BIT(offset);
197 writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR);
198 raw_spin_unlock_irqrestore(&chip->gpio_lock, flags);
199
200 return 0;
201 }
202
altera_gpio_irq_edge_handler(struct irq_desc * desc)203 static void altera_gpio_irq_edge_handler(struct irq_desc *desc)
204 {
205 struct altera_gpio_chip *altera_gc;
206 struct irq_chip *chip;
207 struct of_mm_gpio_chip *mm_gc;
208 struct irq_domain *irqdomain;
209 unsigned long status;
210 int i;
211
212 altera_gc = gpiochip_get_data(irq_desc_get_handler_data(desc));
213 chip = irq_desc_get_chip(desc);
214 mm_gc = &altera_gc->mmchip;
215 irqdomain = altera_gc->mmchip.gc.irq.domain;
216
217 chained_irq_enter(chip, desc);
218
219 while ((status =
220 (readl(mm_gc->regs + ALTERA_GPIO_EDGE_CAP) &
221 readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK)))) {
222 writel(status, mm_gc->regs + ALTERA_GPIO_EDGE_CAP);
223 for_each_set_bit(i, &status, mm_gc->gc.ngpio) {
224 generic_handle_irq(irq_find_mapping(irqdomain, i));
225 }
226 }
227
228 chained_irq_exit(chip, desc);
229 }
230
altera_gpio_irq_leveL_high_handler(struct irq_desc * desc)231 static void altera_gpio_irq_leveL_high_handler(struct irq_desc *desc)
232 {
233 struct altera_gpio_chip *altera_gc;
234 struct irq_chip *chip;
235 struct of_mm_gpio_chip *mm_gc;
236 struct irq_domain *irqdomain;
237 unsigned long status;
238 int i;
239
240 altera_gc = gpiochip_get_data(irq_desc_get_handler_data(desc));
241 chip = irq_desc_get_chip(desc);
242 mm_gc = &altera_gc->mmchip;
243 irqdomain = altera_gc->mmchip.gc.irq.domain;
244
245 chained_irq_enter(chip, desc);
246
247 status = readl(mm_gc->regs + ALTERA_GPIO_DATA);
248 status &= readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
249
250 for_each_set_bit(i, &status, mm_gc->gc.ngpio) {
251 generic_handle_irq(irq_find_mapping(irqdomain, i));
252 }
253 chained_irq_exit(chip, desc);
254 }
255
altera_gpio_probe(struct platform_device * pdev)256 static int altera_gpio_probe(struct platform_device *pdev)
257 {
258 struct device_node *node = pdev->dev.of_node;
259 int reg, ret;
260 struct altera_gpio_chip *altera_gc;
261
262 altera_gc = devm_kzalloc(&pdev->dev, sizeof(*altera_gc), GFP_KERNEL);
263 if (!altera_gc)
264 return -ENOMEM;
265
266 raw_spin_lock_init(&altera_gc->gpio_lock);
267
268 if (of_property_read_u32(node, "altr,ngpio", ®))
269 /* By default assume maximum ngpio */
270 altera_gc->mmchip.gc.ngpio = ALTERA_GPIO_MAX_NGPIO;
271 else
272 altera_gc->mmchip.gc.ngpio = reg;
273
274 if (altera_gc->mmchip.gc.ngpio > ALTERA_GPIO_MAX_NGPIO) {
275 dev_warn(&pdev->dev,
276 "ngpio is greater than %d, defaulting to %d\n",
277 ALTERA_GPIO_MAX_NGPIO, ALTERA_GPIO_MAX_NGPIO);
278 altera_gc->mmchip.gc.ngpio = ALTERA_GPIO_MAX_NGPIO;
279 }
280
281 altera_gc->mmchip.gc.direction_input = altera_gpio_direction_input;
282 altera_gc->mmchip.gc.direction_output = altera_gpio_direction_output;
283 altera_gc->mmchip.gc.get = altera_gpio_get;
284 altera_gc->mmchip.gc.set = altera_gpio_set;
285 altera_gc->mmchip.gc.owner = THIS_MODULE;
286 altera_gc->mmchip.gc.parent = &pdev->dev;
287
288 ret = of_mm_gpiochip_add_data(node, &altera_gc->mmchip, altera_gc);
289 if (ret) {
290 dev_err(&pdev->dev, "Failed adding memory mapped gpiochip\n");
291 return ret;
292 }
293
294 platform_set_drvdata(pdev, altera_gc);
295
296 altera_gc->mapped_irq = platform_get_irq(pdev, 0);
297
298 if (altera_gc->mapped_irq < 0)
299 goto skip_irq;
300
301 if (of_property_read_u32(node, "altr,interrupt-type", ®)) {
302 ret = -EINVAL;
303 dev_err(&pdev->dev,
304 "altr,interrupt-type value not set in device tree\n");
305 goto teardown;
306 }
307 altera_gc->interrupt_trigger = reg;
308
309 ret = gpiochip_irqchip_add(&altera_gc->mmchip.gc, &altera_irq_chip, 0,
310 handle_bad_irq, IRQ_TYPE_NONE);
311
312 if (ret) {
313 dev_err(&pdev->dev, "could not add irqchip\n");
314 goto teardown;
315 }
316
317 gpiochip_set_chained_irqchip(&altera_gc->mmchip.gc,
318 &altera_irq_chip,
319 altera_gc->mapped_irq,
320 altera_gc->interrupt_trigger == IRQ_TYPE_LEVEL_HIGH ?
321 altera_gpio_irq_leveL_high_handler :
322 altera_gpio_irq_edge_handler);
323
324 skip_irq:
325 return 0;
326 teardown:
327 of_mm_gpiochip_remove(&altera_gc->mmchip);
328 pr_err("%pOF: registration failed with status %d\n",
329 node, ret);
330
331 return ret;
332 }
333
altera_gpio_remove(struct platform_device * pdev)334 static int altera_gpio_remove(struct platform_device *pdev)
335 {
336 struct altera_gpio_chip *altera_gc = platform_get_drvdata(pdev);
337
338 of_mm_gpiochip_remove(&altera_gc->mmchip);
339
340 return 0;
341 }
342
343 static const struct of_device_id altera_gpio_of_match[] = {
344 { .compatible = "altr,pio-1.0", },
345 {},
346 };
347 MODULE_DEVICE_TABLE(of, altera_gpio_of_match);
348
349 static struct platform_driver altera_gpio_driver = {
350 .driver = {
351 .name = "altera_gpio",
352 .of_match_table = of_match_ptr(altera_gpio_of_match),
353 },
354 .probe = altera_gpio_probe,
355 .remove = altera_gpio_remove,
356 };
357
altera_gpio_init(void)358 static int __init altera_gpio_init(void)
359 {
360 return platform_driver_register(&altera_gpio_driver);
361 }
362 subsys_initcall(altera_gpio_init);
363
altera_gpio_exit(void)364 static void __exit altera_gpio_exit(void)
365 {
366 platform_driver_unregister(&altera_gpio_driver);
367 }
368 module_exit(altera_gpio_exit);
369
370 MODULE_AUTHOR("Tien Hock Loh <thloh@altera.com>");
371 MODULE_DESCRIPTION("Altera GPIO driver");
372 MODULE_LICENSE("GPL");
373
