1 /*
2 * Aspeed 24XX/25XX I2C Interrupt Controller.
3 *
4 * Copyright (C) 2012-2017 ASPEED Technology Inc.
5 * Copyright 2017 IBM Corporation
6 * Copyright 2017 Google, Inc.
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 #include <linux/irq.h>
14 #include <linux/irqchip.h>
15 #include <linux/irqchip/chained_irq.h>
16 #include <linux/irqdomain.h>
17 #include <linux/of_address.h>
18 #include <linux/of_irq.h>
19 #include <linux/io.h>
20
21
22 #define ASPEED_I2C_IC_NUM_BUS 14
23
24 struct aspeed_i2c_ic {
25 void __iomem *base;
26 int parent_irq;
27 struct irq_domain *irq_domain;
28 };
29
30 /*
31 * The aspeed chip provides a single hardware interrupt for all of the I2C
32 * busses, so we use a dummy interrupt chip to translate this single interrupt
33 * into multiple interrupts, each associated with a single I2C bus.
34 */
aspeed_i2c_ic_irq_handler(struct irq_desc * desc)35 static void aspeed_i2c_ic_irq_handler(struct irq_desc *desc)
36 {
37 struct aspeed_i2c_ic *i2c_ic = irq_desc_get_handler_data(desc);
38 struct irq_chip *chip = irq_desc_get_chip(desc);
39 unsigned long bit, status;
40 unsigned int bus_irq;
41
42 chained_irq_enter(chip, desc);
43 status = readl(i2c_ic->base);
44 for_each_set_bit(bit, &status, ASPEED_I2C_IC_NUM_BUS) {
45 bus_irq = irq_find_mapping(i2c_ic->irq_domain, bit);
46 generic_handle_irq(bus_irq);
47 }
48 chained_irq_exit(chip, desc);
49 }
50
51 /*
52 * Set simple handler and mark IRQ as valid. Nothing interesting to do here
53 * since we are using a dummy interrupt chip.
54 */
aspeed_i2c_ic_map_irq_domain(struct irq_domain * domain,unsigned int irq,irq_hw_number_t hwirq)55 static int aspeed_i2c_ic_map_irq_domain(struct irq_domain *domain,
56 unsigned int irq, irq_hw_number_t hwirq)
57 {
58 irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
59 irq_set_chip_data(irq, domain->host_data);
60
61 return 0;
62 }
63
64 static const struct irq_domain_ops aspeed_i2c_ic_irq_domain_ops = {
65 .map = aspeed_i2c_ic_map_irq_domain,
66 };
67
aspeed_i2c_ic_of_init(struct device_node * node,struct device_node * parent)68 static int __init aspeed_i2c_ic_of_init(struct device_node *node,
69 struct device_node *parent)
70 {
71 struct aspeed_i2c_ic *i2c_ic;
72 int ret = 0;
73
74 i2c_ic = kzalloc(sizeof(*i2c_ic), GFP_KERNEL);
75 if (!i2c_ic)
76 return -ENOMEM;
77
78 i2c_ic->base = of_iomap(node, 0);
79 if (!i2c_ic->base) {
80 ret = -ENOMEM;
81 goto err_free_ic;
82 }
83
84 i2c_ic->parent_irq = irq_of_parse_and_map(node, 0);
85 if (!i2c_ic->parent_irq) {
86 ret = -EINVAL;
87 goto err_iounmap;
88 }
89
90 i2c_ic->irq_domain = irq_domain_add_linear(node, ASPEED_I2C_IC_NUM_BUS,
91 &aspeed_i2c_ic_irq_domain_ops,
92 NULL);
93 if (!i2c_ic->irq_domain) {
94 ret = -ENOMEM;
95 goto err_iounmap;
96 }
97
98 i2c_ic->irq_domain->name = "aspeed-i2c-domain";
99
100 irq_set_chained_handler_and_data(i2c_ic->parent_irq,
101 aspeed_i2c_ic_irq_handler, i2c_ic);
102
103 pr_info("i2c controller registered, irq %d\n", i2c_ic->parent_irq);
104
105 return 0;
106
107 err_iounmap:
108 iounmap(i2c_ic->base);
109 err_free_ic:
110 kfree(i2c_ic);
111 return ret;
112 }
113
114 IRQCHIP_DECLARE(ast2400_i2c_ic, "aspeed,ast2400-i2c-ic", aspeed_i2c_ic_of_init);
115 IRQCHIP_DECLARE(ast2500_i2c_ic, "aspeed,ast2500-i2c-ic", aspeed_i2c_ic_of_init);
116