1/*
  2 * TI LP8788 MFD - interrupt handler
  3 *
  4 * Copyright 2012 Texas Instruments
  5 *
  6 * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 *
 12 */
 13
 14#include <linux/delay.h>
 15#include <linux/err.h>
 16#include <linux/interrupt.h>
 17#include <linux/irq.h>
 18#include <linux/irqdomain.h>
 19#include <linux/device.h>
 20#include <linux/mfd/lp8788.h>
 21#include <linux/module.h>
 22#include <linux/slab.h>
 23
 24/* register address */
 25#define LP8788_INT_1			0x00
 26#define LP8788_INTEN_1			0x03
 27
 28#define BASE_INTEN_ADDR			LP8788_INTEN_1
 29#define SIZE_REG			8
 30#define NUM_REGS			3
 31
 32/*
 33 * struct lp8788_irq_data
 34 * @lp               : used for accessing to lp8788 registers
 35 * @irq_lock         : mutex for enabling/disabling the interrupt
 36 * @domain           : IRQ domain for handling nested interrupt
 37 * @enabled          : status of enabled interrupt
 38 */
 39struct lp8788_irq_data {
 40	struct lp8788 *lp;
 41	struct mutex irq_lock;
 42	struct irq_domain *domain;
 43	int enabled[LP8788_INT_MAX];
 44};
 45
 46static inline u8 _irq_to_addr(enum lp8788_int_id id)
 47{
 48	return id / SIZE_REG;
 49}
 50
 51static inline u8 _irq_to_enable_addr(enum lp8788_int_id id)
 52{
 53	return _irq_to_addr(id) + BASE_INTEN_ADDR;
 54}
 55
 56static inline u8 _irq_to_mask(enum lp8788_int_id id)
 57{
 58	return 1 << (id % SIZE_REG);
 59}
 60
 61static inline u8 _irq_to_val(enum lp8788_int_id id, int enable)
 62{
 63	return enable << (id % SIZE_REG);
 64}
 65
 66static void lp8788_irq_enable(struct irq_data *data)
 67{
 68	struct lp8788_irq_data *irqd = irq_data_get_irq_chip_data(data);
 69	irqd->enabled[data->hwirq] = 1;
 70}
 71
 72static void lp8788_irq_disable(struct irq_data *data)
 73{
 74	struct lp8788_irq_data *irqd = irq_data_get_irq_chip_data(data);
 75	irqd->enabled[data->hwirq] = 0;
 76}
 77
 78static void lp8788_irq_bus_lock(struct irq_data *data)
 79{
 80	struct lp8788_irq_data *irqd = irq_data_get_irq_chip_data(data);
 81
 82	mutex_lock(&irqd->irq_lock);
 83}
 84
 85static void lp8788_irq_bus_sync_unlock(struct irq_data *data)
 86{
 87	struct lp8788_irq_data *irqd = irq_data_get_irq_chip_data(data);
 88	enum lp8788_int_id irq = data->hwirq;
 89	u8 addr, mask, val;
 90
 91	addr = _irq_to_enable_addr(irq);
 92	mask = _irq_to_mask(irq);
 93	val = _irq_to_val(irq, irqd->enabled[irq]);
 94
 95	lp8788_update_bits(irqd->lp, addr, mask, val);
 96
 97	mutex_unlock(&irqd->irq_lock);
 98}
 99
100static struct irq_chip lp8788_irq_chip = {
101	.name			= "lp8788",
102	.irq_enable		= lp8788_irq_enable,
103	.irq_disable		= lp8788_irq_disable,
104	.irq_bus_lock		= lp8788_irq_bus_lock,
105	.irq_bus_sync_unlock	= lp8788_irq_bus_sync_unlock,
106};
107
108static irqreturn_t lp8788_irq_handler(int irq, void *ptr)
109{
110	struct lp8788_irq_data *irqd = ptr;
111	struct lp8788 *lp = irqd->lp;
112	u8 status[NUM_REGS], addr, mask;
113	bool handled;
114	int i;
115
116	if (lp8788_read_multi_bytes(lp, LP8788_INT_1, status, NUM_REGS))
117		return IRQ_NONE;
118
119	for (i = 0 ; i < LP8788_INT_MAX ; i++) {
120		addr = _irq_to_addr(i);
121		mask = _irq_to_mask(i);
122
123		/* reporting only if the irq is enabled */
124		if (status[addr] & mask) {
125			handle_nested_irq(irq_find_mapping(irqd->domain, i));
126			handled = true;
127		}
128	}
129
130	return handled ? IRQ_HANDLED : IRQ_NONE;
131}
132
133static int lp8788_irq_map(struct irq_domain *d, unsigned int virq,
134			irq_hw_number_t hwirq)
135{
136	struct lp8788_irq_data *irqd = d->host_data;
137	struct irq_chip *chip = &lp8788_irq_chip;
138
139	irq_set_chip_data(virq, irqd);
140	irq_set_chip_and_handler(virq, chip, handle_edge_irq);
141	irq_set_nested_thread(virq, 1);
142
143#ifdef CONFIG_ARM
144	set_irq_flags(virq, IRQF_VALID);
145#else
146	irq_set_noprobe(virq);
147#endif
148
149	return 0;
150}
151
152static struct irq_domain_ops lp8788_domain_ops = {
153	.map = lp8788_irq_map,
154};
155
156int lp8788_irq_init(struct lp8788 *lp, int irq)
157{
158	struct lp8788_irq_data *irqd;
159	int ret;
160
161	if (irq <= 0) {
162		dev_warn(lp->dev, "invalid irq number: %d\n", irq);
163		return 0;
164	}
165
166	irqd = devm_kzalloc(lp->dev, sizeof(*irqd), GFP_KERNEL);
167	if (!irqd)
168		return -ENOMEM;
169
170	irqd->lp = lp;
171	irqd->domain = irq_domain_add_linear(lp->dev->of_node, LP8788_INT_MAX,
172					&lp8788_domain_ops, irqd);
173	if (!irqd->domain) {
174		dev_err(lp->dev, "failed to add irq domain err\n");
175		return -EINVAL;
176	}
177
178	lp->irqdm = irqd->domain;
179	mutex_init(&irqd->irq_lock);
180
181	ret = request_threaded_irq(irq, NULL, lp8788_irq_handler,
182				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
183				"lp8788-irq", irqd);
184	if (ret) {
185		dev_err(lp->dev, "failed to create a thread for IRQ_N\n");
186		return ret;
187	}
188
189	lp->irq = irq;
190
191	return 0;
192}
193
194void lp8788_irq_exit(struct lp8788 *lp)
195{
196	if (lp->irq)
197		free_irq(lp->irq, lp->irqdm);
198}