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
23#define IRQ_MASK 0x4
24#define IRQ_STATUS 0x8
25
26struct ts4800_irq_data {
27 void __iomem *base;
28 struct irq_domain *domain;
29 struct irq_chip irq_chip;
30};
31
32static void ts4800_irq_mask(struct irq_data *d)
33{
34 struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d);
35 u16 reg = readw(data->base + IRQ_MASK);
36 u16 mask = 1 << d->hwirq;
37
38 writew(reg | mask, data->base + IRQ_MASK);
39}
40
41static void ts4800_irq_unmask(struct irq_data *d)
42{
43 struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d);
44 u16 reg = readw(data->base + IRQ_MASK);
45 u16 mask = 1 << d->hwirq;
46
47 writew(reg & ~mask, data->base + IRQ_MASK);
48}
49
50static int ts4800_irqdomain_map(struct irq_domain *d, unsigned int irq,
51 irq_hw_number_t hwirq)
52{
53 struct ts4800_irq_data *data = d->host_data;
54
55 irq_set_chip_and_handler(irq, &data->irq_chip, handle_simple_irq);
56 irq_set_chip_data(irq, data);
57 irq_set_noprobe(irq);
58
59 return 0;
60}
61
62static const struct irq_domain_ops ts4800_ic_ops = {
63 .map = ts4800_irqdomain_map,
64 .xlate = irq_domain_xlate_onecell,
65};
66
67static void ts4800_ic_chained_handle_irq(struct irq_desc *desc)
68{
69 struct ts4800_irq_data *data = irq_desc_get_handler_data(desc);
70 struct irq_chip *chip = irq_desc_get_chip(desc);
71 u16 status = readw(data->base + IRQ_STATUS);
72
73 chained_irq_enter(chip, desc);
74
75 if (unlikely(status == 0)) {
76 handle_bad_irq(desc);
77 goto out;
78 }
79
80 do {
81 unsigned int bit = __ffs(status);
82 int irq = irq_find_mapping(data->domain, bit);
83
84 status &= ~(1 << bit);
85 generic_handle_irq(irq);
86 } while (status);
87
88out:
89 chained_irq_exit(chip, desc);
90}
91
92static int ts4800_ic_probe(struct platform_device *pdev)
93{
94 struct device_node *node = pdev->dev.of_node;
95 struct ts4800_irq_data *data;
96 struct irq_chip *irq_chip;
97 struct resource *res;
98 int parent_irq;
99
100 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
101 if (!data)
102 return -ENOMEM;
103
104 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
105 data->base = devm_ioremap_resource(&pdev->dev, res);
106 if (IS_ERR(data->base))
107 return PTR_ERR(data->base);
108
109 writew(0xFFFF, data->base + IRQ_MASK);
110
111 parent_irq = irq_of_parse_and_map(node, 0);
112 if (!parent_irq) {
113 dev_err(&pdev->dev, "failed to get parent IRQ\n");
114 return -EINVAL;
115 }
116
117 irq_chip = &data->irq_chip;
118 irq_chip->name = dev_name(&pdev->dev);
119 irq_chip->irq_mask = ts4800_irq_mask;
120 irq_chip->irq_unmask = ts4800_irq_unmask;
121
122 data->domain = irq_domain_add_linear(node, 8, &ts4800_ic_ops, data);
123 if (!data->domain) {
124 dev_err(&pdev->dev, "cannot add IRQ domain\n");
125 return -ENOMEM;
126 }
127
128 irq_set_chained_handler_and_data(parent_irq,
129 ts4800_ic_chained_handle_irq, data);
130
131 platform_set_drvdata(pdev, data);
132
133 return 0;
134}
135
136static int ts4800_ic_remove(struct platform_device *pdev)
137{
138 struct ts4800_irq_data *data = platform_get_drvdata(pdev);
139
140 irq_domain_remove(data->domain);
141
142 return 0;
143}
144
145static const struct of_device_id ts4800_ic_of_match[] = {
146 { .compatible = "technologic,ts4800-irqc", },
147 {},
148};
149MODULE_DEVICE_TABLE(of, ts4800_ic_of_match);
150
151static struct platform_driver ts4800_ic_driver = {
152 .probe = ts4800_ic_probe,
153 .remove = ts4800_ic_remove,
154 .driver = {
155 .name = "ts4800-irqc",
156 .of_match_table = ts4800_ic_of_match,
157 },
158};
159module_platform_driver(ts4800_ic_driver);
160
161MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
162MODULE_LICENSE("GPL v2");
163MODULE_ALIAS("platform:ts4800_irqc");
164