1 /*
2  * Conexant Digicolor SoCs IRQ chip driver
3  *
4  * Author: Baruch Siach <baruch@tkos.co.il>
5  *
6  * Copyright (C) 2014 Paradox Innovation Ltd.
7  *
8  * This file is licensed under the terms of the GNU General Public
9  * License version 2.  This program is licensed "as is" without any
10  * warranty of any kind, whether express or implied.
11  */
12 
13 #include <linux/io.h>
14 #include <linux/irq.h>
15 #include <linux/irqchip.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/of_irq.h>
19 #include <linux/mfd/syscon.h>
20 #include <linux/regmap.h>
21 
22 #include <asm/exception.h>
23 
24 #define UC_IRQ_CONTROL		0x04
25 
26 #define IC_FLAG_CLEAR_LO	0x00
27 #define IC_FLAG_CLEAR_XLO	0x04
28 #define IC_INT0ENABLE_LO	0x10
29 #define IC_INT0ENABLE_XLO	0x14
30 #define IC_INT0STATUS_LO	0x18
31 #define IC_INT0STATUS_XLO	0x1c
32 
33 static struct irq_domain *digicolor_irq_domain;
34 
35 static void __exception_irq_entry digicolor_handle_irq(struct pt_regs *regs)
36 {
37 	struct irq_domain_chip_generic *dgc = digicolor_irq_domain->gc;
38 	struct irq_chip_generic *gc = dgc->gc[0];
39 	u32 status, hwirq;
40 
41 	do {
42 		status = irq_reg_readl(gc, IC_INT0STATUS_LO);
43 		if (status) {
44 			hwirq = ffs(status) - 1;
45 		} else {
46 			status = irq_reg_readl(gc, IC_INT0STATUS_XLO);
47 			if (status)
48 				hwirq = ffs(status) - 1 + 32;
49 			else
50 				return;
51 		}
52 
53 		generic_handle_domain_irq(digicolor_irq_domain, hwirq);
54 	} while (1);
55 }
56 
57 static void __init digicolor_set_gc(void __iomem *reg_base, unsigned irq_base,
58 				    unsigned en_reg, unsigned ack_reg)
59 {
60 	struct irq_chip_generic *gc;
61 
62 	gc = irq_get_domain_generic_chip(digicolor_irq_domain, irq_base);
63 	gc->reg_base = reg_base;
64 	gc->chip_types[0].regs.ack = ack_reg;
65 	gc->chip_types[0].regs.mask = en_reg;
66 	gc->chip_types[0].chip.irq_ack = irq_gc_ack_set_bit;
67 	gc->chip_types[0].chip.irq_mask = irq_gc_mask_clr_bit;
68 	gc->chip_types[0].chip.irq_unmask = irq_gc_mask_set_bit;
69 }
70 
71 static int __init digicolor_of_init(struct device_node *node,
72 				struct device_node *parent)
73 {
74 	void __iomem *reg_base;
75 	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
76 	struct regmap *ucregs;
77 	int ret;
78 
79 	reg_base = of_iomap(node, 0);
80 	if (!reg_base) {
81 		pr_err("%pOF: unable to map IC registers\n", node);
82 		return -ENXIO;
83 	}
84 
85 	/* disable all interrupts */
86 	writel(0, reg_base + IC_INT0ENABLE_LO);
87 	writel(0, reg_base + IC_INT0ENABLE_XLO);
88 
89 	ucregs = syscon_regmap_lookup_by_phandle(node, "syscon");
90 	if (IS_ERR(ucregs)) {
91 		pr_err("%pOF: unable to map UC registers\n", node);
92 		return PTR_ERR(ucregs);
93 	}
94 	/* channel 1, regular IRQs */
95 	regmap_write(ucregs, UC_IRQ_CONTROL, 1);
96 
97 	digicolor_irq_domain =
98 		irq_domain_add_linear(node, 64, &irq_generic_chip_ops, NULL);
99 	if (!digicolor_irq_domain) {
100 		pr_err("%pOF: unable to create IRQ domain\n", node);
101 		return -ENOMEM;
102 	}
103 
104 	ret = irq_alloc_domain_generic_chips(digicolor_irq_domain, 32, 1,
105 					     "digicolor_irq", handle_level_irq,
106 					     clr, 0, 0);
107 	if (ret) {
108 		pr_err("%pOF: unable to allocate IRQ gc\n", node);
109 		return ret;
110 	}
111 
112 	digicolor_set_gc(reg_base, 0, IC_INT0ENABLE_LO, IC_FLAG_CLEAR_LO);
113 	digicolor_set_gc(reg_base, 32, IC_INT0ENABLE_XLO, IC_FLAG_CLEAR_XLO);
114 
115 	set_handle_irq(digicolor_handle_irq);
116 
117 	return 0;
118 }
119 IRQCHIP_DECLARE(conexant_digicolor_ic, "cnxt,cx92755-ic", digicolor_of_init);
120