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
27 struct ts4800_irq_data {
28 void __iomem *base;
29 struct platform_device *pdev;
30 struct irq_domain *domain;
31 };
32
ts4800_irq_mask(struct irq_data * d)33 static 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
ts4800_irq_unmask(struct irq_data * d)42 static 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
ts4800_irq_print_chip(struct irq_data * d,struct seq_file * p)51 static 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
58 static 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
ts4800_irqdomain_map(struct irq_domain * d,unsigned int irq,irq_hw_number_t hwirq)64 static 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
76 static const struct irq_domain_ops ts4800_ic_ops = {
77 .map = ts4800_irqdomain_map,
78 .xlate = irq_domain_xlate_onecell,
79 };
80
ts4800_ic_chained_handle_irq(struct irq_desc * desc)81 static 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
101 out:
102 chained_irq_exit(chip, desc);
103 }
104
ts4800_ic_probe(struct platform_device * pdev)105 static 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
ts4800_ic_remove(struct platform_device * pdev)142 static 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
149 static const struct of_device_id ts4800_ic_of_match[] = {
150 { .compatible = "technologic,ts4800-irqc", },
151 {},
152 };
153 MODULE_DEVICE_TABLE(of, ts4800_ic_of_match);
154
155 static 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 };
163 module_platform_driver(ts4800_ic_driver);
164
165 MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
166 MODULE_DESCRIPTION("Multiplexed-IRQs driver for TS-4800's FPGA");
167 MODULE_LICENSE("GPL v2");
168 MODULE_ALIAS("platform:ts4800_irqc");
169