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(addr: data->base + IRQ_MASK);
37 u16 mask = 1 << d->hwirq;
38
39 writew(val: reg | mask, addr: 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(addr: data->base + IRQ_MASK);
46 u16 mask = 1 << d->hwirq;
47
48 writew(val: reg & ~mask, addr: 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_puts(m: p, s: dev_name(dev: &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, chip: &ts4800_chip, handle: 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(addr: 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(domain: data->domain, hwirq: 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(dev: &pdev->dev, size: sizeof(*data), GFP_KERNEL);
112 if (!data)
113 return -ENOMEM;
114
115 data->pdev = pdev;
116 data->base = devm_platform_ioremap_resource(pdev, index: 0);
117 if (IS_ERR(ptr: data->base))
118 return PTR_ERR(ptr: data->base);
119
120 writew(val: 0xFFFF, addr: data->base + IRQ_MASK);
121
122 parent_irq = irq_of_parse_and_map(node, index: 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_create_linear(dev_fwnode(&pdev->dev), size: 8, ops: &ts4800_ic_ops, host_data: 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(irq: parent_irq,
135 handle: 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(domain: 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 = 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_DESCRIPTION("Multiplexed-IRQs driver for TS-4800's FPGA");
167MODULE_LICENSE("GPL v2");
168

source code of linux/drivers/irqchip/irq-ts4800.c