1/*
2 * Support for the GPIO/IRQ expander chips present on several HTC phones.
3 * These are implemented in CPLD chips present on the board.
4 *
5 * Copyright (c) 2007 Kevin O'Connor <kevin@koconnor.net>
6 * Copyright (c) 2007 Philipp Zabel <philipp.zabel@gmail.com>
7 *
8 * This file may be distributed under the terms of the GNU GPL license.
9 */
10
11#include <linux/kernel.h>
12#include <linux/errno.h>
13#include <linux/interrupt.h>
14#include <linux/irq.h>
15#include <linux/io.h>
16#include <linux/spinlock.h>
17#include <linux/platform_device.h>
18#include <linux/slab.h>
19#include <linux/module.h>
20#include <linux/mfd/htc-egpio.h>
21
22struct egpio_chip {
23	int              reg_start;
24	int              cached_values;
25	unsigned long    is_out;
26	struct device    *dev;
27	struct gpio_chip chip;
28};
29
30struct egpio_info {
31	spinlock_t        lock;
32
33	/* iomem info */
34	void __iomem      *base_addr;
35	int               bus_shift;	/* byte shift */
36	int               reg_shift;	/* bit shift */
37	int               reg_mask;
38
39	/* irq info */
40	int               ack_register;
41	int               ack_write;
42	u16               irqs_enabled;
43	uint              irq_start;
44	int               nirqs;
45	uint              chained_irq;
46
47	/* egpio info */
48	struct egpio_chip *chip;
49	int               nchips;
50};
51
52static inline void egpio_writew(u16 value, struct egpio_info *ei, int reg)
53{
54	writew(value, ei->base_addr + (reg << ei->bus_shift));
55}
56
57static inline u16 egpio_readw(struct egpio_info *ei, int reg)
58{
59	return readw(ei->base_addr + (reg << ei->bus_shift));
60}
61
62/*
63 * IRQs
64 */
65
66static inline void ack_irqs(struct egpio_info *ei)
67{
68	egpio_writew(ei->ack_write, ei, ei->ack_register);
69	pr_debug("EGPIO ack - write %x to base+%x\n",
70			ei->ack_write, ei->ack_register << ei->bus_shift);
71}
72
73static void egpio_ack(struct irq_data *data)
74{
75}
76
77/* There does not appear to be a way to proactively mask interrupts
78 * on the egpio chip itself.  So, we simply ignore interrupts that
79 * aren't desired. */
80static void egpio_mask(struct irq_data *data)
81{
82	struct egpio_info *ei = irq_data_get_irq_chip_data(data);
83	ei->irqs_enabled &= ~(1 << (data->irq - ei->irq_start));
84	pr_debug("EGPIO mask %d %04x\n", data->irq, ei->irqs_enabled);
85}
86
87static void egpio_unmask(struct irq_data *data)
88{
89	struct egpio_info *ei = irq_data_get_irq_chip_data(data);
90	ei->irqs_enabled |= 1 << (data->irq - ei->irq_start);
91	pr_debug("EGPIO unmask %d %04x\n", data->irq, ei->irqs_enabled);
92}
93
94static struct irq_chip egpio_muxed_chip = {
95	.name		= "htc-egpio",
96	.irq_ack	= egpio_ack,
97	.irq_mask	= egpio_mask,
98	.irq_unmask	= egpio_unmask,
99};
100
101static void egpio_handler(struct irq_desc *desc)
102{
103	struct egpio_info *ei = irq_desc_get_handler_data(desc);
104	int irqpin;
105
106	/* Read current pins. */
107	unsigned long readval = egpio_readw(ei, ei->ack_register);
108	pr_debug("IRQ reg: %x\n", (unsigned int)readval);
109	/* Ack/unmask interrupts. */
110	ack_irqs(ei);
111	/* Process all set pins. */
112	readval &= ei->irqs_enabled;
113	for_each_set_bit(irqpin, &readval, ei->nirqs) {
114		/* Run irq handler */
115		pr_debug("got IRQ %d\n", irqpin);
116		generic_handle_irq(ei->irq_start + irqpin);
117	}
118}
119
120int htc_egpio_get_wakeup_irq(struct device *dev)
121{
122	struct egpio_info *ei = dev_get_drvdata(dev);
123
124	/* Read current pins. */
125	u16 readval = egpio_readw(ei, ei->ack_register);
126	/* Ack/unmask interrupts. */
127	ack_irqs(ei);
128	/* Return first set pin. */
129	readval &= ei->irqs_enabled;
130	return ei->irq_start + ffs(readval) - 1;
131}
132EXPORT_SYMBOL(htc_egpio_get_wakeup_irq);
133
134static inline int egpio_pos(struct egpio_info *ei, int bit)
135{
136	return bit >> ei->reg_shift;
137}
138
139static inline int egpio_bit(struct egpio_info *ei, int bit)
140{
141	return 1 << (bit & ((1 << ei->reg_shift)-1));
142}
143
144/*
145 * Input pins
146 */
147
148static int egpio_get(struct gpio_chip *chip, unsigned offset)
149{
150	struct egpio_chip *egpio;
151	struct egpio_info *ei;
152	unsigned           bit;
153	int                reg;
154	int                value;
155
156	pr_debug("egpio_get_value(%d)\n", chip->base + offset);
157
158	egpio = container_of(chip, struct egpio_chip, chip);
159	ei    = dev_get_drvdata(egpio->dev);
160	bit   = egpio_bit(ei, offset);
161	reg   = egpio->reg_start + egpio_pos(ei, offset);
162
163	value = egpio_readw(ei, reg);
164	pr_debug("readw(%p + %x) = %x\n",
165			ei->base_addr, reg << ei->bus_shift, value);
166	return value & bit;
167}
168
169static int egpio_direction_input(struct gpio_chip *chip, unsigned offset)
170{
171	struct egpio_chip *egpio;
172
173	egpio = container_of(chip, struct egpio_chip, chip);
174	return test_bit(offset, &egpio->is_out) ? -EINVAL : 0;
175}
176
177
178/*
179 * Output pins
180 */
181
182static void egpio_set(struct gpio_chip *chip, unsigned offset, int value)
183{
184	unsigned long     flag;
185	struct egpio_chip *egpio;
186	struct egpio_info *ei;
187	unsigned          bit;
188	int               pos;
189	int               reg;
190	int               shift;
191
192	pr_debug("egpio_set(%s, %d(%d), %d)\n",
193			chip->label, offset, offset+chip->base, value);
194
195	egpio = container_of(chip, struct egpio_chip, chip);
196	ei    = dev_get_drvdata(egpio->dev);
197	bit   = egpio_bit(ei, offset);
198	pos   = egpio_pos(ei, offset);
199	reg   = egpio->reg_start + pos;
200	shift = pos << ei->reg_shift;
201
202	pr_debug("egpio %s: reg %d = 0x%04x\n", value ? "set" : "clear",
203			reg, (egpio->cached_values >> shift) & ei->reg_mask);
204
205	spin_lock_irqsave(&ei->lock, flag);
206	if (value)
207		egpio->cached_values |= (1 << offset);
208	else
209		egpio->cached_values &= ~(1 << offset);
210	egpio_writew((egpio->cached_values >> shift) & ei->reg_mask, ei, reg);
211	spin_unlock_irqrestore(&ei->lock, flag);
212}
213
214static int egpio_direction_output(struct gpio_chip *chip,
215					unsigned offset, int value)
216{
217	struct egpio_chip *egpio;
218
219	egpio = container_of(chip, struct egpio_chip, chip);
220	if (test_bit(offset, &egpio->is_out)) {
221		egpio_set(chip, offset, value);
222		return 0;
223	} else {
224		return -EINVAL;
225	}
226}
227
228static void egpio_write_cache(struct egpio_info *ei)
229{
230	int               i;
231	struct egpio_chip *egpio;
232	int               shift;
233
234	for (i = 0; i < ei->nchips; i++) {
235		egpio = &(ei->chip[i]);
236		if (!egpio->is_out)
237			continue;
238
239		for (shift = 0; shift < egpio->chip.ngpio;
240				shift += (1<<ei->reg_shift)) {
241
242			int reg = egpio->reg_start + egpio_pos(ei, shift);
243
244			if (!((egpio->is_out >> shift) & ei->reg_mask))
245				continue;
246
247			pr_debug("EGPIO: setting %x to %x, was %x\n", reg,
248				(egpio->cached_values >> shift) & ei->reg_mask,
249				egpio_readw(ei, reg));
250
251			egpio_writew((egpio->cached_values >> shift)
252					& ei->reg_mask, ei, reg);
253		}
254	}
255}
256
257
258/*
259 * Setup
260 */
261
262static int __init egpio_probe(struct platform_device *pdev)
263{
264	struct htc_egpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
265	struct resource   *res;
266	struct egpio_info *ei;
267	struct gpio_chip  *chip;
268	unsigned int      irq, irq_end;
269	int               i;
270	int               ret;
271
272	/* Initialize ei data structure. */
273	ei = devm_kzalloc(&pdev->dev, sizeof(*ei), GFP_KERNEL);
274	if (!ei)
275		return -ENOMEM;
276
277	spin_lock_init(&ei->lock);
278
279	/* Find chained irq */
280	ret = -EINVAL;
281	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
282	if (res)
283		ei->chained_irq = res->start;
284
285	/* Map egpio chip into virtual address space. */
286	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
287	if (!res)
288		goto fail;
289	ei->base_addr = devm_ioremap_nocache(&pdev->dev, res->start,
290					     resource_size(res));
291	if (!ei->base_addr)
292		goto fail;
293	pr_debug("EGPIO phys=%08x virt=%p\n", (u32)res->start, ei->base_addr);
294
295	if ((pdata->bus_width != 16) && (pdata->bus_width != 32))
296		goto fail;
297	ei->bus_shift = fls(pdata->bus_width - 1) - 3;
298	pr_debug("bus_shift = %d\n", ei->bus_shift);
299
300	if ((pdata->reg_width != 8) && (pdata->reg_width != 16))
301		goto fail;
302	ei->reg_shift = fls(pdata->reg_width - 1);
303	pr_debug("reg_shift = %d\n", ei->reg_shift);
304
305	ei->reg_mask = (1 << pdata->reg_width) - 1;
306
307	platform_set_drvdata(pdev, ei);
308
309	ei->nchips = pdata->num_chips;
310	ei->chip = devm_kzalloc(&pdev->dev,
311				sizeof(struct egpio_chip) * ei->nchips,
312				GFP_KERNEL);
313	if (!ei->chip) {
314		ret = -ENOMEM;
315		goto fail;
316	}
317	for (i = 0; i < ei->nchips; i++) {
318		ei->chip[i].reg_start = pdata->chip[i].reg_start;
319		ei->chip[i].cached_values = pdata->chip[i].initial_values;
320		ei->chip[i].is_out = pdata->chip[i].direction;
321		ei->chip[i].dev = &(pdev->dev);
322		chip = &(ei->chip[i].chip);
323		chip->label           = "htc-egpio";
324		chip->dev             = &pdev->dev;
325		chip->owner           = THIS_MODULE;
326		chip->get             = egpio_get;
327		chip->set             = egpio_set;
328		chip->direction_input = egpio_direction_input;
329		chip->direction_output = egpio_direction_output;
330		chip->base            = pdata->chip[i].gpio_base;
331		chip->ngpio           = pdata->chip[i].num_gpios;
332
333		gpiochip_add(chip);
334	}
335
336	/* Set initial pin values */
337	egpio_write_cache(ei);
338
339	ei->irq_start = pdata->irq_base;
340	ei->nirqs = pdata->num_irqs;
341	ei->ack_register = pdata->ack_register;
342
343	if (ei->chained_irq) {
344		/* Setup irq handlers */
345		ei->ack_write = 0xFFFF;
346		if (pdata->invert_acks)
347			ei->ack_write = 0;
348		irq_end = ei->irq_start + ei->nirqs;
349		for (irq = ei->irq_start; irq < irq_end; irq++) {
350			irq_set_chip_and_handler(irq, &egpio_muxed_chip,
351						 handle_simple_irq);
352			irq_set_chip_data(irq, ei);
353			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
354		}
355		irq_set_irq_type(ei->chained_irq, IRQ_TYPE_EDGE_RISING);
356		irq_set_chained_handler_and_data(ei->chained_irq,
357						 egpio_handler, ei);
358		ack_irqs(ei);
359
360		device_init_wakeup(&pdev->dev, 1);
361	}
362
363	return 0;
364
365fail:
366	printk(KERN_ERR "EGPIO failed to setup\n");
367	return ret;
368}
369
370static int __exit egpio_remove(struct platform_device *pdev)
371{
372	struct egpio_info *ei = platform_get_drvdata(pdev);
373	unsigned int      irq, irq_end;
374
375	if (ei->chained_irq) {
376		irq_end = ei->irq_start + ei->nirqs;
377		for (irq = ei->irq_start; irq < irq_end; irq++) {
378			irq_set_chip_and_handler(irq, NULL, NULL);
379			irq_set_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
380		}
381		irq_set_chained_handler(ei->chained_irq, NULL);
382		device_init_wakeup(&pdev->dev, 0);
383	}
384
385	return 0;
386}
387
388#ifdef CONFIG_PM
389static int egpio_suspend(struct platform_device *pdev, pm_message_t state)
390{
391	struct egpio_info *ei = platform_get_drvdata(pdev);
392
393	if (ei->chained_irq && device_may_wakeup(&pdev->dev))
394		enable_irq_wake(ei->chained_irq);
395	return 0;
396}
397
398static int egpio_resume(struct platform_device *pdev)
399{
400	struct egpio_info *ei = platform_get_drvdata(pdev);
401
402	if (ei->chained_irq && device_may_wakeup(&pdev->dev))
403		disable_irq_wake(ei->chained_irq);
404
405	/* Update registers from the cache, in case
406	   the CPLD was powered off during suspend */
407	egpio_write_cache(ei);
408	return 0;
409}
410#else
411#define egpio_suspend NULL
412#define egpio_resume NULL
413#endif
414
415
416static struct platform_driver egpio_driver = {
417	.driver = {
418		.name = "htc-egpio",
419	},
420	.remove       = __exit_p(egpio_remove),
421	.suspend      = egpio_suspend,
422	.resume       = egpio_resume,
423};
424
425static int __init egpio_init(void)
426{
427	return platform_driver_probe(&egpio_driver, egpio_probe);
428}
429
430static void __exit egpio_exit(void)
431{
432	platform_driver_unregister(&egpio_driver);
433}
434
435/* start early for dependencies */
436subsys_initcall(egpio_init);
437module_exit(egpio_exit)
438
439MODULE_LICENSE("GPL");
440MODULE_AUTHOR("Kevin O'Connor <kevin@koconnor.net>");
441