1/*
2 * Generic EP93xx GPIO handling
3 *
4 * Copyright (c) 2008 Ryan Mallon
5 * Copyright (c) 2011 H Hartley Sweeten <hsweeten@visionengravers.com>
6 *
7 * Based on code originally from:
8 *  linux/arch/arm/mach-ep93xx/core.c
9 *
10 *  This program is free software; you can redistribute it and/or modify
11 *  it under the terms of the GNU General Public License version 2 as
12 *  published by the Free Software Foundation.
13 */
14
15#include <linux/init.h>
16#include <linux/module.h>
17#include <linux/platform_device.h>
18#include <linux/io.h>
19#include <linux/gpio.h>
20#include <linux/irq.h>
21#include <linux/slab.h>
22#include <linux/basic_mmio_gpio.h>
23
24#include <mach/hardware.h>
25#include <mach/gpio-ep93xx.h>
26
27#define irq_to_gpio(irq)	((irq) - gpio_to_irq(0))
28
29struct ep93xx_gpio {
30	void __iomem		*mmio_base;
31	struct bgpio_chip	bgc[8];
32};
33
34/*************************************************************************
35 * Interrupt handling for EP93xx on-chip GPIOs
36 *************************************************************************/
37static unsigned char gpio_int_unmasked[3];
38static unsigned char gpio_int_enabled[3];
39static unsigned char gpio_int_type1[3];
40static unsigned char gpio_int_type2[3];
41static unsigned char gpio_int_debounce[3];
42
43/* Port ordering is: A B F */
44static const u8 int_type1_register_offset[3]	= { 0x90, 0xac, 0x4c };
45static const u8 int_type2_register_offset[3]	= { 0x94, 0xb0, 0x50 };
46static const u8 eoi_register_offset[3]		= { 0x98, 0xb4, 0x54 };
47static const u8 int_en_register_offset[3]	= { 0x9c, 0xb8, 0x58 };
48static const u8 int_debounce_register_offset[3]	= { 0xa8, 0xc4, 0x64 };
49
50static void ep93xx_gpio_update_int_params(unsigned port)
51{
52	BUG_ON(port > 2);
53
54	writeb_relaxed(0, EP93XX_GPIO_REG(int_en_register_offset[port]));
55
56	writeb_relaxed(gpio_int_type2[port],
57		EP93XX_GPIO_REG(int_type2_register_offset[port]));
58
59	writeb_relaxed(gpio_int_type1[port],
60		EP93XX_GPIO_REG(int_type1_register_offset[port]));
61
62	writeb(gpio_int_unmasked[port] & gpio_int_enabled[port],
63		EP93XX_GPIO_REG(int_en_register_offset[port]));
64}
65
66static void ep93xx_gpio_int_debounce(unsigned int irq, bool enable)
67{
68	int line = irq_to_gpio(irq);
69	int port = line >> 3;
70	int port_mask = 1 << (line & 7);
71
72	if (enable)
73		gpio_int_debounce[port] |= port_mask;
74	else
75		gpio_int_debounce[port] &= ~port_mask;
76
77	writeb(gpio_int_debounce[port],
78		EP93XX_GPIO_REG(int_debounce_register_offset[port]));
79}
80
81static void ep93xx_gpio_ab_irq_handler(struct irq_desc *desc)
82{
83	unsigned char status;
84	int i;
85
86	status = readb(EP93XX_GPIO_A_INT_STATUS);
87	for (i = 0; i < 8; i++) {
88		if (status & (1 << i)) {
89			int gpio_irq = gpio_to_irq(EP93XX_GPIO_LINE_A(0)) + i;
90			generic_handle_irq(gpio_irq);
91		}
92	}
93
94	status = readb(EP93XX_GPIO_B_INT_STATUS);
95	for (i = 0; i < 8; i++) {
96		if (status & (1 << i)) {
97			int gpio_irq = gpio_to_irq(EP93XX_GPIO_LINE_B(0)) + i;
98			generic_handle_irq(gpio_irq);
99		}
100	}
101}
102
103static void ep93xx_gpio_f_irq_handler(struct irq_desc *desc)
104{
105	/*
106	 * map discontiguous hw irq range to continuous sw irq range:
107	 *
108	 *  IRQ_EP93XX_GPIO{0..7}MUX -> gpio_to_irq(EP93XX_GPIO_LINE_F({0..7})
109	 */
110	unsigned int irq = irq_desc_get_irq(desc);
111	int port_f_idx = ((irq + 1) & 7) ^ 4; /* {19..22,47..50} -> {0..7} */
112	int gpio_irq = gpio_to_irq(EP93XX_GPIO_LINE_F(0)) + port_f_idx;
113
114	generic_handle_irq(gpio_irq);
115}
116
117static void ep93xx_gpio_irq_ack(struct irq_data *d)
118{
119	int line = irq_to_gpio(d->irq);
120	int port = line >> 3;
121	int port_mask = 1 << (line & 7);
122
123	if (irqd_get_trigger_type(d) == IRQ_TYPE_EDGE_BOTH) {
124		gpio_int_type2[port] ^= port_mask; /* switch edge direction */
125		ep93xx_gpio_update_int_params(port);
126	}
127
128	writeb(port_mask, EP93XX_GPIO_REG(eoi_register_offset[port]));
129}
130
131static void ep93xx_gpio_irq_mask_ack(struct irq_data *d)
132{
133	int line = irq_to_gpio(d->irq);
134	int port = line >> 3;
135	int port_mask = 1 << (line & 7);
136
137	if (irqd_get_trigger_type(d) == IRQ_TYPE_EDGE_BOTH)
138		gpio_int_type2[port] ^= port_mask; /* switch edge direction */
139
140	gpio_int_unmasked[port] &= ~port_mask;
141	ep93xx_gpio_update_int_params(port);
142
143	writeb(port_mask, EP93XX_GPIO_REG(eoi_register_offset[port]));
144}
145
146static void ep93xx_gpio_irq_mask(struct irq_data *d)
147{
148	int line = irq_to_gpio(d->irq);
149	int port = line >> 3;
150
151	gpio_int_unmasked[port] &= ~(1 << (line & 7));
152	ep93xx_gpio_update_int_params(port);
153}
154
155static void ep93xx_gpio_irq_unmask(struct irq_data *d)
156{
157	int line = irq_to_gpio(d->irq);
158	int port = line >> 3;
159
160	gpio_int_unmasked[port] |= 1 << (line & 7);
161	ep93xx_gpio_update_int_params(port);
162}
163
164/*
165 * gpio_int_type1 controls whether the interrupt is level (0) or
166 * edge (1) triggered, while gpio_int_type2 controls whether it
167 * triggers on low/falling (0) or high/rising (1).
168 */
169static int ep93xx_gpio_irq_type(struct irq_data *d, unsigned int type)
170{
171	const int gpio = irq_to_gpio(d->irq);
172	const int port = gpio >> 3;
173	const int port_mask = 1 << (gpio & 7);
174	irq_flow_handler_t handler;
175
176	gpio_direction_input(gpio);
177
178	switch (type) {
179	case IRQ_TYPE_EDGE_RISING:
180		gpio_int_type1[port] |= port_mask;
181		gpio_int_type2[port] |= port_mask;
182		handler = handle_edge_irq;
183		break;
184	case IRQ_TYPE_EDGE_FALLING:
185		gpio_int_type1[port] |= port_mask;
186		gpio_int_type2[port] &= ~port_mask;
187		handler = handle_edge_irq;
188		break;
189	case IRQ_TYPE_LEVEL_HIGH:
190		gpio_int_type1[port] &= ~port_mask;
191		gpio_int_type2[port] |= port_mask;
192		handler = handle_level_irq;
193		break;
194	case IRQ_TYPE_LEVEL_LOW:
195		gpio_int_type1[port] &= ~port_mask;
196		gpio_int_type2[port] &= ~port_mask;
197		handler = handle_level_irq;
198		break;
199	case IRQ_TYPE_EDGE_BOTH:
200		gpio_int_type1[port] |= port_mask;
201		/* set initial polarity based on current input level */
202		if (gpio_get_value(gpio))
203			gpio_int_type2[port] &= ~port_mask; /* falling */
204		else
205			gpio_int_type2[port] |= port_mask; /* rising */
206		handler = handle_edge_irq;
207		break;
208	default:
209		return -EINVAL;
210	}
211
212	irq_set_handler_locked(d, handler);
213
214	gpio_int_enabled[port] |= port_mask;
215
216	ep93xx_gpio_update_int_params(port);
217
218	return 0;
219}
220
221static struct irq_chip ep93xx_gpio_irq_chip = {
222	.name		= "GPIO",
223	.irq_ack	= ep93xx_gpio_irq_ack,
224	.irq_mask_ack	= ep93xx_gpio_irq_mask_ack,
225	.irq_mask	= ep93xx_gpio_irq_mask,
226	.irq_unmask	= ep93xx_gpio_irq_unmask,
227	.irq_set_type	= ep93xx_gpio_irq_type,
228};
229
230static void ep93xx_gpio_init_irq(void)
231{
232	int gpio_irq;
233
234	for (gpio_irq = gpio_to_irq(0);
235	     gpio_irq <= gpio_to_irq(EP93XX_GPIO_LINE_MAX_IRQ); ++gpio_irq) {
236		irq_set_chip_and_handler(gpio_irq, &ep93xx_gpio_irq_chip,
237					 handle_level_irq);
238		irq_clear_status_flags(gpio_irq, IRQ_NOREQUEST);
239	}
240
241	irq_set_chained_handler(IRQ_EP93XX_GPIO_AB,
242				ep93xx_gpio_ab_irq_handler);
243	irq_set_chained_handler(IRQ_EP93XX_GPIO0MUX,
244				ep93xx_gpio_f_irq_handler);
245	irq_set_chained_handler(IRQ_EP93XX_GPIO1MUX,
246				ep93xx_gpio_f_irq_handler);
247	irq_set_chained_handler(IRQ_EP93XX_GPIO2MUX,
248				ep93xx_gpio_f_irq_handler);
249	irq_set_chained_handler(IRQ_EP93XX_GPIO3MUX,
250				ep93xx_gpio_f_irq_handler);
251	irq_set_chained_handler(IRQ_EP93XX_GPIO4MUX,
252				ep93xx_gpio_f_irq_handler);
253	irq_set_chained_handler(IRQ_EP93XX_GPIO5MUX,
254				ep93xx_gpio_f_irq_handler);
255	irq_set_chained_handler(IRQ_EP93XX_GPIO6MUX,
256				ep93xx_gpio_f_irq_handler);
257	irq_set_chained_handler(IRQ_EP93XX_GPIO7MUX,
258				ep93xx_gpio_f_irq_handler);
259}
260
261
262/*************************************************************************
263 * gpiolib interface for EP93xx on-chip GPIOs
264 *************************************************************************/
265struct ep93xx_gpio_bank {
266	const char	*label;
267	int		data;
268	int		dir;
269	int		base;
270	bool		has_debounce;
271};
272
273#define EP93XX_GPIO_BANK(_label, _data, _dir, _base, _debounce)	\
274	{							\
275		.label		= _label,			\
276		.data		= _data,			\
277		.dir		= _dir,				\
278		.base		= _base,			\
279		.has_debounce	= _debounce,			\
280	}
281
282static struct ep93xx_gpio_bank ep93xx_gpio_banks[] = {
283	EP93XX_GPIO_BANK("A", 0x00, 0x10, 0, true),
284	EP93XX_GPIO_BANK("B", 0x04, 0x14, 8, true),
285	EP93XX_GPIO_BANK("C", 0x08, 0x18, 40, false),
286	EP93XX_GPIO_BANK("D", 0x0c, 0x1c, 24, false),
287	EP93XX_GPIO_BANK("E", 0x20, 0x24, 32, false),
288	EP93XX_GPIO_BANK("F", 0x30, 0x34, 16, true),
289	EP93XX_GPIO_BANK("G", 0x38, 0x3c, 48, false),
290	EP93XX_GPIO_BANK("H", 0x40, 0x44, 56, false),
291};
292
293static int ep93xx_gpio_set_debounce(struct gpio_chip *chip,
294				    unsigned offset, unsigned debounce)
295{
296	int gpio = chip->base + offset;
297	int irq = gpio_to_irq(gpio);
298
299	if (irq < 0)
300		return -EINVAL;
301
302	ep93xx_gpio_int_debounce(irq, debounce ? true : false);
303
304	return 0;
305}
306
307/*
308 * Map GPIO A0..A7  (0..7)  to irq 64..71,
309 *          B0..B7  (7..15) to irq 72..79, and
310 *          F0..F7 (16..24) to irq 80..87.
311 */
312static int ep93xx_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
313{
314	int gpio = chip->base + offset;
315
316	if (gpio > EP93XX_GPIO_LINE_MAX_IRQ)
317		return -EINVAL;
318
319	return 64 + gpio;
320}
321
322static int ep93xx_gpio_add_bank(struct bgpio_chip *bgc, struct device *dev,
323	void __iomem *mmio_base, struct ep93xx_gpio_bank *bank)
324{
325	void __iomem *data = mmio_base + bank->data;
326	void __iomem *dir =  mmio_base + bank->dir;
327	int err;
328
329	err = bgpio_init(bgc, dev, 1, data, NULL, NULL, dir, NULL, 0);
330	if (err)
331		return err;
332
333	bgc->gc.label = bank->label;
334	bgc->gc.base = bank->base;
335
336	if (bank->has_debounce) {
337		bgc->gc.set_debounce = ep93xx_gpio_set_debounce;
338		bgc->gc.to_irq = ep93xx_gpio_to_irq;
339	}
340
341	return gpiochip_add(&bgc->gc);
342}
343
344static int ep93xx_gpio_probe(struct platform_device *pdev)
345{
346	struct ep93xx_gpio *ep93xx_gpio;
347	struct resource *res;
348	int i;
349	struct device *dev = &pdev->dev;
350
351	ep93xx_gpio = devm_kzalloc(dev, sizeof(struct ep93xx_gpio), GFP_KERNEL);
352	if (!ep93xx_gpio)
353		return -ENOMEM;
354
355	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
356	ep93xx_gpio->mmio_base = devm_ioremap_resource(dev, res);
357	if (IS_ERR(ep93xx_gpio->mmio_base))
358		return PTR_ERR(ep93xx_gpio->mmio_base);
359
360	for (i = 0; i < ARRAY_SIZE(ep93xx_gpio_banks); i++) {
361		struct bgpio_chip *bgc = &ep93xx_gpio->bgc[i];
362		struct ep93xx_gpio_bank *bank = &ep93xx_gpio_banks[i];
363
364		if (ep93xx_gpio_add_bank(bgc, &pdev->dev,
365					 ep93xx_gpio->mmio_base, bank))
366			dev_warn(&pdev->dev, "Unable to add gpio bank %s\n",
367				bank->label);
368	}
369
370	ep93xx_gpio_init_irq();
371
372	return 0;
373}
374
375static struct platform_driver ep93xx_gpio_driver = {
376	.driver		= {
377		.name	= "gpio-ep93xx",
378	},
379	.probe		= ep93xx_gpio_probe,
380};
381
382static int __init ep93xx_gpio_init(void)
383{
384	return platform_driver_register(&ep93xx_gpio_driver);
385}
386postcore_initcall(ep93xx_gpio_init);
387
388MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com> "
389		"H Hartley Sweeten <hsweeten@visionengravers.com>");
390MODULE_DESCRIPTION("EP93XX GPIO driver");
391MODULE_LICENSE("GPL");
392