1 /*
2  * Timberdale FPGA GPIO driver
3  * Copyright (c) 2009 Intel Corporation
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,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17  */
18 
19 /* Supports:
20  * Timberdale FPGA GPIO
21  */
22 
23 #include <linux/module.h>
24 #include <linux/gpio.h>
25 #include <linux/platform_device.h>
26 #include <linux/irq.h>
27 #include <linux/io.h>
28 #include <linux/timb_gpio.h>
29 #include <linux/interrupt.h>
30 #include <linux/slab.h>
31 
32 #define DRIVER_NAME "timb-gpio"
33 
34 #define TGPIOVAL	0x00
35 #define TGPIODIR	0x04
36 #define TGPIO_IER	0x08
37 #define TGPIO_ISR	0x0c
38 #define TGPIO_IPR	0x10
39 #define TGPIO_ICR	0x14
40 #define TGPIO_FLR	0x18
41 #define TGPIO_LVR	0x1c
42 #define TGPIO_VER	0x20
43 #define TGPIO_BFLR	0x24
44 
45 struct timbgpio {
46 	void __iomem		*membase;
47 	spinlock_t		lock; /* mutual exclusion */
48 	struct gpio_chip	gpio;
49 	int			irq_base;
50 	unsigned long		last_ier;
51 };
52 
53 static int timbgpio_update_bit(struct gpio_chip *gpio, unsigned index,
54 	unsigned offset, bool enabled)
55 {
56 	struct timbgpio *tgpio = container_of(gpio, struct timbgpio, gpio);
57 	u32 reg;
58 
59 	spin_lock(&tgpio->lock);
60 	reg = ioread32(tgpio->membase + offset);
61 
62 	if (enabled)
63 		reg |= (1 << index);
64 	else
65 		reg &= ~(1 << index);
66 
67 	iowrite32(reg, tgpio->membase + offset);
68 	spin_unlock(&tgpio->lock);
69 
70 	return 0;
71 }
72 
73 static int timbgpio_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
74 {
75 	return timbgpio_update_bit(gpio, nr, TGPIODIR, true);
76 }
77 
78 static int timbgpio_gpio_get(struct gpio_chip *gpio, unsigned nr)
79 {
80 	struct timbgpio *tgpio = container_of(gpio, struct timbgpio, gpio);
81 	u32 value;
82 
83 	value = ioread32(tgpio->membase + TGPIOVAL);
84 	return (value & (1 << nr)) ? 1 : 0;
85 }
86 
87 static int timbgpio_gpio_direction_output(struct gpio_chip *gpio,
88 						unsigned nr, int val)
89 {
90 	return timbgpio_update_bit(gpio, nr, TGPIODIR, false);
91 }
92 
93 static void timbgpio_gpio_set(struct gpio_chip *gpio,
94 				unsigned nr, int val)
95 {
96 	timbgpio_update_bit(gpio, nr, TGPIOVAL, val != 0);
97 }
98 
99 static int timbgpio_to_irq(struct gpio_chip *gpio, unsigned offset)
100 {
101 	struct timbgpio *tgpio = container_of(gpio, struct timbgpio, gpio);
102 
103 	if (tgpio->irq_base <= 0)
104 		return -EINVAL;
105 
106 	return tgpio->irq_base + offset;
107 }
108 
109 /*
110  * GPIO IRQ
111  */
112 static void timbgpio_irq_disable(struct irq_data *d)
113 {
114 	struct timbgpio *tgpio = irq_data_get_irq_chip_data(d);
115 	int offset = d->irq - tgpio->irq_base;
116 	unsigned long flags;
117 
118 	spin_lock_irqsave(&tgpio->lock, flags);
119 	tgpio->last_ier &= ~(1UL << offset);
120 	iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
121 	spin_unlock_irqrestore(&tgpio->lock, flags);
122 }
123 
124 static void timbgpio_irq_enable(struct irq_data *d)
125 {
126 	struct timbgpio *tgpio = irq_data_get_irq_chip_data(d);
127 	int offset = d->irq - tgpio->irq_base;
128 	unsigned long flags;
129 
130 	spin_lock_irqsave(&tgpio->lock, flags);
131 	tgpio->last_ier |= 1UL << offset;
132 	iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
133 	spin_unlock_irqrestore(&tgpio->lock, flags);
134 }
135 
136 static int timbgpio_irq_type(struct irq_data *d, unsigned trigger)
137 {
138 	struct timbgpio *tgpio = irq_data_get_irq_chip_data(d);
139 	int offset = d->irq - tgpio->irq_base;
140 	unsigned long flags;
141 	u32 lvr, flr, bflr = 0;
142 	u32 ver;
143 	int ret = 0;
144 
145 	if (offset < 0 || offset > tgpio->gpio.ngpio)
146 		return -EINVAL;
147 
148 	ver = ioread32(tgpio->membase + TGPIO_VER);
149 
150 	spin_lock_irqsave(&tgpio->lock, flags);
151 
152 	lvr = ioread32(tgpio->membase + TGPIO_LVR);
153 	flr = ioread32(tgpio->membase + TGPIO_FLR);
154 	if (ver > 2)
155 		bflr = ioread32(tgpio->membase + TGPIO_BFLR);
156 
157 	if (trigger & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) {
158 		bflr &= ~(1 << offset);
159 		flr &= ~(1 << offset);
160 		if (trigger & IRQ_TYPE_LEVEL_HIGH)
161 			lvr |= 1 << offset;
162 		else
163 			lvr &= ~(1 << offset);
164 	}
165 
166 	if ((trigger & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH) {
167 		if (ver < 3) {
168 			ret = -EINVAL;
169 			goto out;
170 		} else {
171 			flr |= 1 << offset;
172 			bflr |= 1 << offset;
173 		}
174 	} else {
175 		bflr &= ~(1 << offset);
176 		flr |= 1 << offset;
177 		if (trigger & IRQ_TYPE_EDGE_FALLING)
178 			lvr &= ~(1 << offset);
179 		else
180 			lvr |= 1 << offset;
181 	}
182 
183 	iowrite32(lvr, tgpio->membase + TGPIO_LVR);
184 	iowrite32(flr, tgpio->membase + TGPIO_FLR);
185 	if (ver > 2)
186 		iowrite32(bflr, tgpio->membase + TGPIO_BFLR);
187 
188 	iowrite32(1 << offset, tgpio->membase + TGPIO_ICR);
189 
190 out:
191 	spin_unlock_irqrestore(&tgpio->lock, flags);
192 	return ret;
193 }
194 
195 static void timbgpio_irq(unsigned int irq, struct irq_desc *desc)
196 {
197 	struct timbgpio *tgpio = irq_get_handler_data(irq);
198 	unsigned long ipr;
199 	int offset;
200 
201 	desc->irq_data.chip->irq_ack(irq_get_irq_data(irq));
202 	ipr = ioread32(tgpio->membase + TGPIO_IPR);
203 	iowrite32(ipr, tgpio->membase + TGPIO_ICR);
204 
205 	/*
206 	 * Some versions of the hardware trash the IER register if more than
207 	 * one interrupt is received simultaneously.
208 	 */
209 	iowrite32(0, tgpio->membase + TGPIO_IER);
210 
211 	for_each_set_bit(offset, &ipr, tgpio->gpio.ngpio)
212 		generic_handle_irq(timbgpio_to_irq(&tgpio->gpio, offset));
213 
214 	iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
215 }
216 
217 static struct irq_chip timbgpio_irqchip = {
218 	.name		= "GPIO",
219 	.irq_enable	= timbgpio_irq_enable,
220 	.irq_disable	= timbgpio_irq_disable,
221 	.irq_set_type	= timbgpio_irq_type,
222 };
223 
224 static int timbgpio_probe(struct platform_device *pdev)
225 {
226 	int err, i;
227 	struct gpio_chip *gc;
228 	struct timbgpio *tgpio;
229 	struct resource *iomem;
230 	struct timbgpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
231 	int irq = platform_get_irq(pdev, 0);
232 
233 	if (!pdata || pdata->nr_pins > 32) {
234 		err = -EINVAL;
235 		goto err_mem;
236 	}
237 
238 	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
239 	if (!iomem) {
240 		err = -EINVAL;
241 		goto err_mem;
242 	}
243 
244 	tgpio = kzalloc(sizeof(*tgpio), GFP_KERNEL);
245 	if (!tgpio) {
246 		err = -EINVAL;
247 		goto err_mem;
248 	}
249 	tgpio->irq_base = pdata->irq_base;
250 
251 	spin_lock_init(&tgpio->lock);
252 
253 	if (!request_mem_region(iomem->start, resource_size(iomem),
254 		DRIVER_NAME)) {
255 		err = -EBUSY;
256 		goto err_request;
257 	}
258 
259 	tgpio->membase = ioremap(iomem->start, resource_size(iomem));
260 	if (!tgpio->membase) {
261 		err = -ENOMEM;
262 		goto err_ioremap;
263 	}
264 
265 	gc = &tgpio->gpio;
266 
267 	gc->label = dev_name(&pdev->dev);
268 	gc->owner = THIS_MODULE;
269 	gc->dev = &pdev->dev;
270 	gc->direction_input = timbgpio_gpio_direction_input;
271 	gc->get = timbgpio_gpio_get;
272 	gc->direction_output = timbgpio_gpio_direction_output;
273 	gc->set = timbgpio_gpio_set;
274 	gc->to_irq = (irq >= 0 && tgpio->irq_base > 0) ? timbgpio_to_irq : NULL;
275 	gc->dbg_show = NULL;
276 	gc->base = pdata->gpio_base;
277 	gc->ngpio = pdata->nr_pins;
278 	gc->can_sleep = false;
279 
280 	err = gpiochip_add(gc);
281 	if (err)
282 		goto err_chipadd;
283 
284 	platform_set_drvdata(pdev, tgpio);
285 
286 	/* make sure to disable interrupts */
287 	iowrite32(0x0, tgpio->membase + TGPIO_IER);
288 
289 	if (irq < 0 || tgpio->irq_base <= 0)
290 		return 0;
291 
292 	for (i = 0; i < pdata->nr_pins; i++) {
293 		irq_set_chip_and_handler(tgpio->irq_base + i,
294 			&timbgpio_irqchip, handle_simple_irq);
295 		irq_set_chip_data(tgpio->irq_base + i, tgpio);
296 #ifdef CONFIG_ARM
297 		set_irq_flags(tgpio->irq_base + i, IRQF_VALID | IRQF_PROBE);
298 #endif
299 	}
300 
301 	irq_set_handler_data(irq, tgpio);
302 	irq_set_chained_handler(irq, timbgpio_irq);
303 
304 	return 0;
305 
306 err_chipadd:
307 	iounmap(tgpio->membase);
308 err_ioremap:
309 	release_mem_region(iomem->start, resource_size(iomem));
310 err_request:
311 	kfree(tgpio);
312 err_mem:
313 	printk(KERN_ERR DRIVER_NAME": Failed to register GPIOs: %d\n", err);
314 
315 	return err;
316 }
317 
318 static int timbgpio_remove(struct platform_device *pdev)
319 {
320 	int err;
321 	struct timbgpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
322 	struct timbgpio *tgpio = platform_get_drvdata(pdev);
323 	struct resource *iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
324 	int irq = platform_get_irq(pdev, 0);
325 
326 	if (irq >= 0 && tgpio->irq_base > 0) {
327 		int i;
328 		for (i = 0; i < pdata->nr_pins; i++) {
329 			irq_set_chip(tgpio->irq_base + i, NULL);
330 			irq_set_chip_data(tgpio->irq_base + i, NULL);
331 		}
332 
333 		irq_set_handler(irq, NULL);
334 		irq_set_handler_data(irq, NULL);
335 	}
336 
337 	err = gpiochip_remove(&tgpio->gpio);
338 	if (err)
339 		printk(KERN_ERR DRIVER_NAME": failed to remove gpio_chip\n");
340 
341 	iounmap(tgpio->membase);
342 	release_mem_region(iomem->start, resource_size(iomem));
343 	kfree(tgpio);
344 
345 	return 0;
346 }
347 
348 static struct platform_driver timbgpio_platform_driver = {
349 	.driver = {
350 		.name	= DRIVER_NAME,
351 		.owner	= THIS_MODULE,
352 	},
353 	.probe		= timbgpio_probe,
354 	.remove		= timbgpio_remove,
355 };
356 
357 /*--------------------------------------------------------------------------*/
358 
359 module_platform_driver(timbgpio_platform_driver);
360 
361 MODULE_DESCRIPTION("Timberdale GPIO driver");
362 MODULE_LICENSE("GPL v2");
363 MODULE_AUTHOR("Mocean Laboratories");
364 MODULE_ALIAS("platform:"DRIVER_NAME);
365 
366