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 
38 	chained_irq_enter(chip, desc);
39 	status = readl(i2c_ic->base);
40 	for_each_set_bit(bit, &status, ASPEED_I2C_IC_NUM_BUS)
41 		generic_handle_domain_irq(i2c_ic->irq_domain, bit);
42 
43 	chained_irq_exit(chip, desc);
44 }
45 
46 /*
47  * Set simple handler and mark IRQ as valid. Nothing interesting to do here
48  * since we are using a dummy interrupt chip.
49  */
aspeed_i2c_ic_map_irq_domain(struct irq_domain * domain,unsigned int irq,irq_hw_number_t hwirq)50 static int aspeed_i2c_ic_map_irq_domain(struct irq_domain *domain,
51 					unsigned int irq, irq_hw_number_t hwirq)
52 {
53 	irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
54 	irq_set_chip_data(irq, domain->host_data);
55 
56 	return 0;
57 }
58 
59 static const struct irq_domain_ops aspeed_i2c_ic_irq_domain_ops = {
60 	.map = aspeed_i2c_ic_map_irq_domain,
61 };
62 
aspeed_i2c_ic_of_init(struct device_node * node,struct device_node * parent)63 static int __init aspeed_i2c_ic_of_init(struct device_node *node,
64 					struct device_node *parent)
65 {
66 	struct aspeed_i2c_ic *i2c_ic;
67 	int ret = 0;
68 
69 	i2c_ic = kzalloc(sizeof(*i2c_ic), GFP_KERNEL);
70 	if (!i2c_ic)
71 		return -ENOMEM;
72 
73 	i2c_ic->base = of_iomap(node, 0);
74 	if (!i2c_ic->base) {
75 		ret = -ENOMEM;
76 		goto err_free_ic;
77 	}
78 
79 	i2c_ic->parent_irq = irq_of_parse_and_map(node, 0);
80 	if (!i2c_ic->parent_irq) {
81 		ret = -EINVAL;
82 		goto err_iounmap;
83 	}
84 
85 	i2c_ic->irq_domain = irq_domain_add_linear(node, ASPEED_I2C_IC_NUM_BUS,
86 						   &aspeed_i2c_ic_irq_domain_ops,
87 						   NULL);
88 	if (!i2c_ic->irq_domain) {
89 		ret = -ENOMEM;
90 		goto err_iounmap;
91 	}
92 
93 	i2c_ic->irq_domain->name = "aspeed-i2c-domain";
94 
95 	irq_set_chained_handler_and_data(i2c_ic->parent_irq,
96 					 aspeed_i2c_ic_irq_handler, i2c_ic);
97 
98 	pr_info("i2c controller registered, irq %d\n", i2c_ic->parent_irq);
99 
100 	return 0;
101 
102 err_iounmap:
103 	iounmap(i2c_ic->base);
104 err_free_ic:
105 	kfree(i2c_ic);
106 	return ret;
107 }
108 
109 IRQCHIP_DECLARE(ast2400_i2c_ic, "aspeed,ast2400-i2c-ic", aspeed_i2c_ic_of_init);
110 IRQCHIP_DECLARE(ast2500_i2c_ic, "aspeed,ast2500-i2c-ic", aspeed_i2c_ic_of_init);
111