xref: /openbmc/linux/drivers/gpio/gpio-htc-egpio.c (revision 4c79e98b) 
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_data/gpio-htc-egpio.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/init.h>
21 
22 struct 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 
30 struct 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 
52 static 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 
57 static 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 
66 static 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 
73 static 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. */
80 static 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 
87 static 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 
94 static 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 
101 static 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 
120 int 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 }
132 EXPORT_SYMBOL(htc_egpio_get_wakeup_irq);
133 
134 static inline int egpio_pos(struct egpio_info *ei, int bit)
135 {
136 	return bit >> ei->reg_shift;
137 }
138 
139 static 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 
148 static 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 = gpiochip_get_data(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 	if (test_bit(offset, &egpio->is_out)) {
164 		return !!(egpio->cached_values & (1 << offset));
165 	} else {
166 		value = egpio_readw(ei, reg);
167 		pr_debug("readw(%p + %x) = %x\n",
168 			 ei->base_addr, reg << ei->bus_shift, value);
169 		return !!(value & bit);
170 	}
171 }
172 
173 static int egpio_direction_input(struct gpio_chip *chip, unsigned offset)
174 {
175 	struct egpio_chip *egpio;
176 
177 	egpio = gpiochip_get_data(chip);
178 	return test_bit(offset, &egpio->is_out) ? -EINVAL : 0;
179 }
180 
181 
182 /*
183  * Output pins
184  */
185 
186 static void egpio_set(struct gpio_chip *chip, unsigned offset, int value)
187 {
188 	unsigned long     flag;
189 	struct egpio_chip *egpio;
190 	struct egpio_info *ei;
191 	unsigned          bit;
192 	int               pos;
193 	int               reg;
194 	int               shift;
195 
196 	pr_debug("egpio_set(%s, %d(%d), %d)\n",
197 			chip->label, offset, offset+chip->base, value);
198 
199 	egpio = gpiochip_get_data(chip);
200 	ei    = dev_get_drvdata(egpio->dev);
201 	bit   = egpio_bit(ei, offset);
202 	pos   = egpio_pos(ei, offset);
203 	reg   = egpio->reg_start + pos;
204 	shift = pos << ei->reg_shift;
205 
206 	pr_debug("egpio %s: reg %d = 0x%04x\n", value ? "set" : "clear",
207 			reg, (egpio->cached_values >> shift) & ei->reg_mask);
208 
209 	spin_lock_irqsave(&ei->lock, flag);
210 	if (value)
211 		egpio->cached_values |= (1 << offset);
212 	else
213 		egpio->cached_values &= ~(1 << offset);
214 	egpio_writew((egpio->cached_values >> shift) & ei->reg_mask, ei, reg);
215 	spin_unlock_irqrestore(&ei->lock, flag);
216 }
217 
218 static int egpio_direction_output(struct gpio_chip *chip,
219 					unsigned offset, int value)
220 {
221 	struct egpio_chip *egpio;
222 
223 	egpio = gpiochip_get_data(chip);
224 	if (test_bit(offset, &egpio->is_out)) {
225 		egpio_set(chip, offset, value);
226 		return 0;
227 	} else {
228 		return -EINVAL;
229 	}
230 }
231 
232 static int egpio_get_direction(struct gpio_chip *chip, unsigned offset)
233 {
234 	struct egpio_chip *egpio;
235 
236 	egpio = gpiochip_get_data(chip);
237 
238 	return !test_bit(offset, &egpio->is_out);
239 }
240 
241 static void egpio_write_cache(struct egpio_info *ei)
242 {
243 	int               i;
244 	struct egpio_chip *egpio;
245 	int               shift;
246 
247 	for (i = 0; i < ei->nchips; i++) {
248 		egpio = &(ei->chip[i]);
249 		if (!egpio->is_out)
250 			continue;
251 
252 		for (shift = 0; shift < egpio->chip.ngpio;
253 				shift += (1<<ei->reg_shift)) {
254 
255 			int reg = egpio->reg_start + egpio_pos(ei, shift);
256 
257 			if (!((egpio->is_out >> shift) & ei->reg_mask))
258 				continue;
259 
260 			pr_debug("EGPIO: setting %x to %x, was %x\n", reg,
261 				(egpio->cached_values >> shift) & ei->reg_mask,
262 				egpio_readw(ei, reg));
263 
264 			egpio_writew((egpio->cached_values >> shift)
265 					& ei->reg_mask, ei, reg);
266 		}
267 	}
268 }
269 
270 
271 /*
272  * Setup
273  */
274 
275 static int __init egpio_probe(struct platform_device *pdev)
276 {
277 	struct htc_egpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
278 	struct resource   *res;
279 	struct egpio_info *ei;
280 	struct gpio_chip  *chip;
281 	unsigned int      irq, irq_end;
282 	int               i;
283 	int               ret;
284 
285 	/* Initialize ei data structure. */
286 	ei = devm_kzalloc(&pdev->dev, sizeof(*ei), GFP_KERNEL);
287 	if (!ei)
288 		return -ENOMEM;
289 
290 	spin_lock_init(&ei->lock);
291 
292 	/* Find chained irq */
293 	ret = -EINVAL;
294 	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
295 	if (res)
296 		ei->chained_irq = res->start;
297 
298 	/* Map egpio chip into virtual address space. */
299 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
300 	if (!res)
301 		goto fail;
302 	ei->base_addr = devm_ioremap_nocache(&pdev->dev, res->start,
303 					     resource_size(res));
304 	if (!ei->base_addr)
305 		goto fail;
306 	pr_debug("EGPIO phys=%08x virt=%p\n", (u32)res->start, ei->base_addr);
307 
308 	if ((pdata->bus_width != 16) && (pdata->bus_width != 32))
309 		goto fail;
310 	ei->bus_shift = fls(pdata->bus_width - 1) - 3;
311 	pr_debug("bus_shift = %d\n", ei->bus_shift);
312 
313 	if ((pdata->reg_width != 8) && (pdata->reg_width != 16))
314 		goto fail;
315 	ei->reg_shift = fls(pdata->reg_width - 1);
316 	pr_debug("reg_shift = %d\n", ei->reg_shift);
317 
318 	ei->reg_mask = (1 << pdata->reg_width) - 1;
319 
320 	platform_set_drvdata(pdev, ei);
321 
322 	ei->nchips = pdata->num_chips;
323 	ei->chip = devm_kzalloc(&pdev->dev,
324 				sizeof(struct egpio_chip) * ei->nchips,
325 				GFP_KERNEL);
326 	if (!ei->chip) {
327 		ret = -ENOMEM;
328 		goto fail;
329 	}
330 	for (i = 0; i < ei->nchips; i++) {
331 		ei->chip[i].reg_start = pdata->chip[i].reg_start;
332 		ei->chip[i].cached_values = pdata->chip[i].initial_values;
333 		ei->chip[i].is_out = pdata->chip[i].direction;
334 		ei->chip[i].dev = &(pdev->dev);
335 		chip = &(ei->chip[i].chip);
336 		chip->label           = "htc-egpio";
337 		chip->parent          = &pdev->dev;
338 		chip->owner           = THIS_MODULE;
339 		chip->get             = egpio_get;
340 		chip->set             = egpio_set;
341 		chip->direction_input = egpio_direction_input;
342 		chip->direction_output = egpio_direction_output;
343 		chip->get_direction   = egpio_get_direction;
344 		chip->base            = pdata->chip[i].gpio_base;
345 		chip->ngpio           = pdata->chip[i].num_gpios;
346 
347 		gpiochip_add_data(chip, &ei->chip[i]);
348 	}
349 
350 	/* Set initial pin values */
351 	egpio_write_cache(ei);
352 
353 	ei->irq_start = pdata->irq_base;
354 	ei->nirqs = pdata->num_irqs;
355 	ei->ack_register = pdata->ack_register;
356 
357 	if (ei->chained_irq) {
358 		/* Setup irq handlers */
359 		ei->ack_write = 0xFFFF;
360 		if (pdata->invert_acks)
361 			ei->ack_write = 0;
362 		irq_end = ei->irq_start + ei->nirqs;
363 		for (irq = ei->irq_start; irq < irq_end; irq++) {
364 			irq_set_chip_and_handler(irq, &egpio_muxed_chip,
365 						 handle_simple_irq);
366 			irq_set_chip_data(irq, ei);
367 			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
368 		}
369 		irq_set_irq_type(ei->chained_irq, IRQ_TYPE_EDGE_RISING);
370 		irq_set_chained_handler_and_data(ei->chained_irq,
371 						 egpio_handler, ei);
372 		ack_irqs(ei);
373 
374 		device_init_wakeup(&pdev->dev, 1);
375 	}
376 
377 	return 0;
378 
379 fail:
380 	printk(KERN_ERR "EGPIO failed to setup\n");
381 	return ret;
382 }
383 
384 #ifdef CONFIG_PM
385 static int egpio_suspend(struct platform_device *pdev, pm_message_t state)
386 {
387 	struct egpio_info *ei = platform_get_drvdata(pdev);
388 
389 	if (ei->chained_irq && device_may_wakeup(&pdev->dev))
390 		enable_irq_wake(ei->chained_irq);
391 	return 0;
392 }
393 
394 static int egpio_resume(struct platform_device *pdev)
395 {
396 	struct egpio_info *ei = platform_get_drvdata(pdev);
397 
398 	if (ei->chained_irq && device_may_wakeup(&pdev->dev))
399 		disable_irq_wake(ei->chained_irq);
400 
401 	/* Update registers from the cache, in case
402 	   the CPLD was powered off during suspend */
403 	egpio_write_cache(ei);
404 	return 0;
405 }
406 #else
407 #define egpio_suspend NULL
408 #define egpio_resume NULL
409 #endif
410 
411 
412 static struct platform_driver egpio_driver = {
413 	.driver = {
414 		.name = "htc-egpio",
415 		.suppress_bind_attrs = true,
416 	},
417 	.suspend      = egpio_suspend,
418 	.resume       = egpio_resume,
419 };
420 
421 static int __init egpio_init(void)
422 {
423 	return platform_driver_probe(&egpio_driver, egpio_probe);
424 }
425 /* start early for dependencies */
426 subsys_initcall(egpio_init);
427