1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Aspeed 24XX/25XX I2C Interrupt Controller.
4 *
5 * Copyright (C) 2012-2017 ASPEED Technology Inc.
6 * Copyright 2017 IBM Corporation
7 * Copyright 2017 Google, Inc.
8 */
9
10 #include <linux/irq.h>
11 #include <linux/irqchip.h>
12 #include <linux/irqchip/chained_irq.h>
13 #include <linux/irqdomain.h>
14 #include <linux/of_address.h>
15 #include <linux/of_irq.h>
16 #include <linux/io.h>
17
18
19 #define ASPEED_I2C_IC_NUM_BUS 14
20
21 struct aspeed_i2c_ic {
22 void __iomem *base;
23 int parent_irq;
24 struct irq_domain *irq_domain;
25 };
26
27 /*
28 * The aspeed chip provides a single hardware interrupt for all of the I2C
29 * busses, so we use a dummy interrupt chip to translate this single interrupt
30 * into multiple interrupts, each associated with a single I2C bus.
31 */
aspeed_i2c_ic_irq_handler(struct irq_desc * desc)32 static void aspeed_i2c_ic_irq_handler(struct irq_desc *desc)
33 {
34 struct aspeed_i2c_ic *i2c_ic = irq_desc_get_handler_data(desc);
35 struct irq_chip *chip = irq_desc_get_chip(desc);
36 unsigned long bit, status;
37 unsigned int bus_irq;
38
39 chained_irq_enter(chip, desc);
40 status = readl(i2c_ic->base);
41 for_each_set_bit(bit, &status, ASPEED_I2C_IC_NUM_BUS) {
42 bus_irq = irq_find_mapping(i2c_ic->irq_domain, bit);
43 generic_handle_irq(bus_irq);
44 }
45 chained_irq_exit(chip, desc);
46 }
47
48 /*
49 * Set simple handler and mark IRQ as valid. Nothing interesting to do here
50 * since we are using a dummy interrupt chip.
51 */
aspeed_i2c_ic_map_irq_domain(struct irq_domain * domain,unsigned int irq,irq_hw_number_t hwirq)52 static int aspeed_i2c_ic_map_irq_domain(struct irq_domain *domain,
53 unsigned int irq, irq_hw_number_t hwirq)
54 {
55 irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
56 irq_set_chip_data(irq, domain->host_data);
57
58 return 0;
59 }
60
61 static const struct irq_domain_ops aspeed_i2c_ic_irq_domain_ops = {
62 .map = aspeed_i2c_ic_map_irq_domain,
63 };
64
aspeed_i2c_ic_of_init(struct device_node * node,struct device_node * parent)65 static int __init aspeed_i2c_ic_of_init(struct device_node *node,
66 struct device_node *parent)
67 {
68 struct aspeed_i2c_ic *i2c_ic;
69 int ret = 0;
70
71 i2c_ic = kzalloc(sizeof(*i2c_ic), GFP_KERNEL);
72 if (!i2c_ic)
73 return -ENOMEM;
74
75 i2c_ic->base = of_iomap(node, 0);
76 if (!i2c_ic->base) {
77 ret = -ENOMEM;
78 goto err_free_ic;
79 }
80
81 i2c_ic->parent_irq = irq_of_parse_and_map(node, 0);
82 if (i2c_ic->parent_irq < 0) {
83 ret = i2c_ic->parent_irq;
84 goto err_iounmap;
85 }
86
87 i2c_ic->irq_domain = irq_domain_add_linear(node, ASPEED_I2C_IC_NUM_BUS,
88 &aspeed_i2c_ic_irq_domain_ops,
89 NULL);
90 if (!i2c_ic->irq_domain) {
91 ret = -ENOMEM;
92 goto err_iounmap;
93 }
94
95 i2c_ic->irq_domain->name = "aspeed-i2c-domain";
96
97 irq_set_chained_handler_and_data(i2c_ic->parent_irq,
98 aspeed_i2c_ic_irq_handler, i2c_ic);
99
100 pr_info("i2c controller registered, irq %d\n", i2c_ic->parent_irq);
101
102 return 0;
103
104 err_iounmap:
105 iounmap(i2c_ic->base);
106 err_free_ic:
107 kfree(i2c_ic);
108 return ret;
109 }
110
111 IRQCHIP_DECLARE(ast2400_i2c_ic, "aspeed,ast2400-i2c-ic", aspeed_i2c_ic_of_init);
112 IRQCHIP_DECLARE(ast2500_i2c_ic, "aspeed,ast2500-i2c-ic", aspeed_i2c_ic_of_init);
113
