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 #include <linux/seq_file.h> 23 24 #define IRQ_MASK 0x4 25 #define IRQ_STATUS 0x8 26 27 struct ts4800_irq_data { 28 void __iomem *base; 29 struct platform_device *pdev; 30 struct irq_domain *domain; 31 }; 32 33 static void ts4800_irq_mask(struct irq_data *d) 34 { 35 struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d); 36 u16 reg = readw(data->base + IRQ_MASK); 37 u16 mask = 1 << d->hwirq; 38 39 writew(reg | mask, data->base + IRQ_MASK); 40 } 41 42 static void ts4800_irq_unmask(struct irq_data *d) 43 { 44 struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d); 45 u16 reg = readw(data->base + IRQ_MASK); 46 u16 mask = 1 << d->hwirq; 47 48 writew(reg & ~mask, data->base + IRQ_MASK); 49 } 50 51 static void ts4800_irq_print_chip(struct irq_data *d, struct seq_file *p) 52 { 53 struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d); 54 55 seq_printf(p, "%s", dev_name(&data->pdev->dev)); 56 } 57 58 static const struct irq_chip ts4800_chip = { 59 .irq_mask = ts4800_irq_mask, 60 .irq_unmask = ts4800_irq_unmask, 61 .irq_print_chip = ts4800_irq_print_chip, 62 }; 63 64 static int ts4800_irqdomain_map(struct irq_domain *d, unsigned int irq, 65 irq_hw_number_t hwirq) 66 { 67 struct ts4800_irq_data *data = d->host_data; 68 69 irq_set_chip_and_handler(irq, &ts4800_chip, handle_simple_irq); 70 irq_set_chip_data(irq, data); 71 irq_set_noprobe(irq); 72 73 return 0; 74 } 75 76 static const struct irq_domain_ops ts4800_ic_ops = { 77 .map = ts4800_irqdomain_map, 78 .xlate = irq_domain_xlate_onecell, 79 }; 80 81 static void ts4800_ic_chained_handle_irq(struct irq_desc *desc) 82 { 83 struct ts4800_irq_data *data = irq_desc_get_handler_data(desc); 84 struct irq_chip *chip = irq_desc_get_chip(desc); 85 u16 status = readw(data->base + IRQ_STATUS); 86 87 chained_irq_enter(chip, desc); 88 89 if (unlikely(status == 0)) { 90 handle_bad_irq(desc); 91 goto out; 92 } 93 94 do { 95 unsigned int bit = __ffs(status); 96 97 generic_handle_domain_irq(data->domain, bit); 98 status &= ~(1 << bit); 99 } while (status); 100 101 out: 102 chained_irq_exit(chip, desc); 103 } 104 105 static int ts4800_ic_probe(struct platform_device *pdev) 106 { 107 struct device_node *node = pdev->dev.of_node; 108 struct ts4800_irq_data *data; 109 int parent_irq; 110 111 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 112 if (!data) 113 return -ENOMEM; 114 115 data->pdev = pdev; 116 data->base = devm_platform_ioremap_resource(pdev, 0); 117 if (IS_ERR(data->base)) 118 return PTR_ERR(data->base); 119 120 writew(0xFFFF, data->base + IRQ_MASK); 121 122 parent_irq = irq_of_parse_and_map(node, 0); 123 if (!parent_irq) { 124 dev_err(&pdev->dev, "failed to get parent IRQ\n"); 125 return -EINVAL; 126 } 127 128 data->domain = irq_domain_add_linear(node, 8, &ts4800_ic_ops, data); 129 if (!data->domain) { 130 dev_err(&pdev->dev, "cannot add IRQ domain\n"); 131 return -ENOMEM; 132 } 133 134 irq_set_chained_handler_and_data(parent_irq, 135 ts4800_ic_chained_handle_irq, data); 136 137 platform_set_drvdata(pdev, data); 138 139 return 0; 140 } 141 142 static int ts4800_ic_remove(struct platform_device *pdev) 143 { 144 struct ts4800_irq_data *data = platform_get_drvdata(pdev); 145 146 irq_domain_remove(data->domain); 147 148 return 0; 149 } 150 151 static const struct of_device_id ts4800_ic_of_match[] = { 152 { .compatible = "technologic,ts4800-irqc", }, 153 {}, 154 }; 155 MODULE_DEVICE_TABLE(of, ts4800_ic_of_match); 156 157 static struct platform_driver ts4800_ic_driver = { 158 .probe = ts4800_ic_probe, 159 .remove = ts4800_ic_remove, 160 .driver = { 161 .name = "ts4800-irqc", 162 .of_match_table = ts4800_ic_of_match, 163 }, 164 }; 165 module_platform_driver(ts4800_ic_driver); 166 167 MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>"); 168 MODULE_LICENSE("GPL v2"); 169 MODULE_ALIAS("platform:ts4800_irqc"); 170