drivers/irqchip/irq-ts4800.c

   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 void 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
 149 static const struct of_device_id ts4800_ic_of_match[] = {
 150         { .compatible = "technologic,ts4800-irqc", },
 151         {},
 152 };
 153 MODULE_DEVICE_TABLE(of, ts4800_ic_of_match);
 154
 155 static struct platform_driver ts4800_ic_driver = {
 156         .probe          = ts4800_ic_probe,
 157         .remove         = ts4800_ic_remove,
 158         .driver = {
 159                 .name           = "ts4800-irqc",
 160                 .of_match_table = ts4800_ic_of_match,
 161         },
 162 };
 163 module_platform_driver(ts4800_ic_driver);
 164
 165 MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
 166 MODULE_DESCRIPTION("Multiplexed-IRQs driver for TS-4800's FPGA");
 167 MODULE_LICENSE("GPL v2");
 168 MODULE_ALIAS("platform:ts4800_irqc");