1/*
2 * Multiplexed-IRQs driver for TS-4800's FPGA
3 *
4 * Copyright (c) 2015 - Savoir-faire Linux
5 *
6 * This file is licensed under the terms of the GNU General Public
7 * License version 2. This program is licensed "as is" without any
8 * warranty of any kind, whether express or implied.
9 */
10
11#include <linux/interrupt.h>
12#include <linux/io.h>
13#include <linux/irq.h>
14#include <linux/irqchip.h>
15#include <linux/irqchip/chained_irq.h>
16#include <linux/irqdomain.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20#include <linux/of_irq.h>
21#include <linux/platform_device.h>
22#include <linux/seq_file.h>
23
24#define IRQ_MASK        0x4
25#define IRQ_STATUS      0x8
26
27struct ts4800_irq_data {
28	void __iomem            *base;
29	struct platform_device	*pdev;
30	struct irq_domain       *domain;
31};
32
33static void ts4800_irq_mask(struct irq_data *d)
34{
35	struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d);
36	u16 reg = readw(data->base + IRQ_MASK);
37	u16 mask = 1 << d->hwirq;
38
39	writew(reg | mask, data->base + IRQ_MASK);
40}
41
42static void ts4800_irq_unmask(struct irq_data *d)
43{
44	struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d);
45	u16 reg = readw(data->base + IRQ_MASK);
46	u16 mask = 1 << d->hwirq;
47
48	writew(reg & ~mask, data->base + IRQ_MASK);
49}
50
51static void ts4800_irq_print_chip(struct irq_data *d, struct seq_file *p)
52{
53	struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d);
54
55	seq_printf(p, "%s", dev_name(&data->pdev->dev));
56}
57
58static const struct irq_chip ts4800_chip = {
59	.irq_mask	= ts4800_irq_mask,
60	.irq_unmask	= ts4800_irq_unmask,
61	.irq_print_chip	= ts4800_irq_print_chip,
62};
63
64static int ts4800_irqdomain_map(struct irq_domain *d, unsigned int irq,
65				irq_hw_number_t hwirq)
66{
67	struct ts4800_irq_data *data = d->host_data;
68
69	irq_set_chip_and_handler(irq, &ts4800_chip, handle_simple_irq);
70	irq_set_chip_data(irq, data);
71	irq_set_noprobe(irq);
72
73	return 0;
74}
75
76static const struct irq_domain_ops ts4800_ic_ops = {
77	.map = ts4800_irqdomain_map,
78	.xlate = irq_domain_xlate_onecell,
79};
80
81static void ts4800_ic_chained_handle_irq(struct irq_desc *desc)
82{
83	struct ts4800_irq_data *data = irq_desc_get_handler_data(desc);
84	struct irq_chip *chip = irq_desc_get_chip(desc);
85	u16 status = readw(data->base + IRQ_STATUS);
86
87	chained_irq_enter(chip, desc);
88
89	if (unlikely(status == 0)) {
90		handle_bad_irq(desc);
91		goto out;
92	}
93
94	do {
95		unsigned int bit = __ffs(status);
96
97		generic_handle_domain_irq(data->domain, bit);
98		status &= ~(1 << bit);
99	} while (status);
100
101out:
102	chained_irq_exit(chip, desc);
103}
104
105static int ts4800_ic_probe(struct platform_device *pdev)
106{
107	struct device_node *node = pdev->dev.of_node;
108	struct ts4800_irq_data *data;
109	int parent_irq;
110
111	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
112	if (!data)
113		return -ENOMEM;
114
115	data->pdev = pdev;
116	data->base = devm_platform_ioremap_resource(pdev, 0);
117	if (IS_ERR(data->base))
118		return PTR_ERR(data->base);
119
120	writew(0xFFFF, data->base + IRQ_MASK);
121
122	parent_irq = irq_of_parse_and_map(node, 0);
123	if (!parent_irq) {
124		dev_err(&pdev->dev, "failed to get parent IRQ\n");
125		return -EINVAL;
126	}
127
128	data->domain = irq_domain_add_linear(node, 8, &ts4800_ic_ops, data);
129	if (!data->domain) {
130		dev_err(&pdev->dev, "cannot add IRQ domain\n");
131		return -ENOMEM;
132	}
133
134	irq_set_chained_handler_and_data(parent_irq,
135					 ts4800_ic_chained_handle_irq, data);
136
137	platform_set_drvdata(pdev, data);
138
139	return 0;
140}
141
142static void ts4800_ic_remove(struct platform_device *pdev)
143{
144	struct ts4800_irq_data *data = platform_get_drvdata(pdev);
145
146	irq_domain_remove(data->domain);
147}
148
149static const struct of_device_id ts4800_ic_of_match[] = {
150	{ .compatible = "technologic,ts4800-irqc", },
151	{},
152};
153MODULE_DEVICE_TABLE(of, ts4800_ic_of_match);
154
155static struct platform_driver ts4800_ic_driver = {
156	.probe		= ts4800_ic_probe,
157	.remove_new	= ts4800_ic_remove,
158	.driver = {
159		.name		= "ts4800-irqc",
160		.of_match_table	= ts4800_ic_of_match,
161	},
162};
163module_platform_driver(ts4800_ic_driver);
164
165MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
166MODULE_LICENSE("GPL v2");
167MODULE_ALIAS("platform:ts4800_irqc");
168