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 23 #define IRQ_MASK 0x4 24 #define IRQ_STATUS 0x8 25 26 struct ts4800_irq_data { 27 void __iomem *base; 28 struct irq_domain *domain; 29 struct irq_chip irq_chip; 30 }; 31 32 static void ts4800_irq_mask(struct irq_data *d) 33 { 34 struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d); 35 u16 reg = readw(data->base + IRQ_MASK); 36 u16 mask = 1 << d->hwirq; 37 38 writew(reg | mask, data->base + IRQ_MASK); 39 } 40 41 static void ts4800_irq_unmask(struct irq_data *d) 42 { 43 struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d); 44 u16 reg = readw(data->base + IRQ_MASK); 45 u16 mask = 1 << d->hwirq; 46 47 writew(reg & ~mask, data->base + IRQ_MASK); 48 } 49 50 static int ts4800_irqdomain_map(struct irq_domain *d, unsigned int irq, 51 irq_hw_number_t hwirq) 52 { 53 struct ts4800_irq_data *data = d->host_data; 54 55 irq_set_chip_and_handler(irq, &data->irq_chip, handle_simple_irq); 56 irq_set_chip_data(irq, data); 57 irq_set_noprobe(irq); 58 59 return 0; 60 } 61 62 struct irq_domain_ops ts4800_ic_ops = { 63 .map = ts4800_irqdomain_map, 64 .xlate = irq_domain_xlate_onecell, 65 }; 66 67 static void ts4800_ic_chained_handle_irq(struct irq_desc *desc) 68 { 69 struct ts4800_irq_data *data = irq_desc_get_handler_data(desc); 70 struct irq_chip *chip = irq_desc_get_chip(desc); 71 u16 status = readw(data->base + IRQ_STATUS); 72 73 chained_irq_enter(chip, desc); 74 75 if (unlikely(status == 0)) { 76 handle_bad_irq(desc); 77 goto out; 78 } 79 80 do { 81 unsigned int bit = __ffs(status); 82 int irq = irq_find_mapping(data->domain, bit); 83 84 status &= ~(1 << bit); 85 generic_handle_irq(irq); 86 } while (status); 87 88 out: 89 chained_irq_exit(chip, desc); 90 } 91 92 static int ts4800_ic_probe(struct platform_device *pdev) 93 { 94 struct device_node *node = pdev->dev.of_node; 95 struct ts4800_irq_data *data; 96 struct irq_chip *irq_chip; 97 struct resource *res; 98 int parent_irq; 99 100 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 101 if (!data) 102 return -ENOMEM; 103 104 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 105 data->base = devm_ioremap_resource(&pdev->dev, res); 106 if (IS_ERR(data->base)) 107 return PTR_ERR(data->base); 108 109 writew(0xFFFF, data->base + IRQ_MASK); 110 111 parent_irq = irq_of_parse_and_map(node, 0); 112 if (!parent_irq) { 113 dev_err(&pdev->dev, "failed to get parent IRQ\n"); 114 return -EINVAL; 115 } 116 117 irq_chip = &data->irq_chip; 118 irq_chip->name = dev_name(&pdev->dev); 119 irq_chip->irq_mask = ts4800_irq_mask; 120 irq_chip->irq_unmask = ts4800_irq_unmask; 121 122 data->domain = irq_domain_add_linear(node, 8, &ts4800_ic_ops, data); 123 if (!data->domain) { 124 dev_err(&pdev->dev, "cannot add IRQ domain\n"); 125 return -ENOMEM; 126 } 127 128 irq_set_chained_handler_and_data(parent_irq, 129 ts4800_ic_chained_handle_irq, data); 130 131 platform_set_drvdata(pdev, data); 132 133 return 0; 134 } 135 136 static int ts4800_ic_remove(struct platform_device *pdev) 137 { 138 struct ts4800_irq_data *data = platform_get_drvdata(pdev); 139 140 irq_domain_remove(data->domain); 141 142 return 0; 143 } 144 145 static const struct of_device_id ts4800_ic_of_match[] = { 146 { .compatible = "technologic,ts4800-irqc", }, 147 {}, 148 }; 149 MODULE_DEVICE_TABLE(of, ts4800_ic_of_match); 150 151 static struct platform_driver ts4800_ic_driver = { 152 .probe = ts4800_ic_probe, 153 .remove = ts4800_ic_remove, 154 .driver = { 155 .name = "ts4800-irqc", 156 .of_match_table = ts4800_ic_of_match, 157 }, 158 }; 159 module_platform_driver(ts4800_ic_driver); 160 161 MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>"); 162 MODULE_LICENSE("GPL v2"); 163 MODULE_ALIAS("platform:ts4800_irqc"); 164