linux/drivers/irqchip/irq-ts4800.c
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   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
  26struct ts4800_irq_data {
  27        void __iomem            *base;
  28        struct irq_domain       *domain;
  29        struct irq_chip         irq_chip;
  30};
  31
  32static 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
  41static 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
  50static 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
  62static const struct irq_domain_ops ts4800_ic_ops = {
  63        .map = ts4800_irqdomain_map,
  64        .xlate = irq_domain_xlate_onecell,
  65};
  66
  67static 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
  83                generic_handle_domain_irq(data->domain, bit);
  84                status &= ~(1 << bit);
  85        } while (status);
  86
  87out:
  88        chained_irq_exit(chip, desc);
  89}
  90
  91static int ts4800_ic_probe(struct platform_device *pdev)
  92{
  93        struct device_node *node = pdev->dev.of_node;
  94        struct ts4800_irq_data *data;
  95        struct irq_chip *irq_chip;
  96        struct resource *res;
  97        int parent_irq;
  98
  99        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 100        if (!data)
 101                return -ENOMEM;
 102
 103        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 104        data->base = devm_ioremap_resource(&pdev->dev, res);
 105        if (IS_ERR(data->base))
 106                return PTR_ERR(data->base);
 107
 108        writew(0xFFFF, data->base + IRQ_MASK);
 109
 110        parent_irq = irq_of_parse_and_map(node, 0);
 111        if (!parent_irq) {
 112                dev_err(&pdev->dev, "failed to get parent IRQ\n");
 113                return -EINVAL;
 114        }
 115
 116        irq_chip = &data->irq_chip;
 117        irq_chip->name = dev_name(&pdev->dev);
 118        irq_chip->irq_mask = ts4800_irq_mask;
 119        irq_chip->irq_unmask = ts4800_irq_unmask;
 120
 121        data->domain = irq_domain_add_linear(node, 8, &ts4800_ic_ops, data);
 122        if (!data->domain) {
 123                dev_err(&pdev->dev, "cannot add IRQ domain\n");
 124                return -ENOMEM;
 125        }
 126
 127        irq_set_chained_handler_and_data(parent_irq,
 128                                         ts4800_ic_chained_handle_irq, data);
 129
 130        platform_set_drvdata(pdev, data);
 131
 132        return 0;
 133}
 134
 135static int ts4800_ic_remove(struct platform_device *pdev)
 136{
 137        struct ts4800_irq_data *data = platform_get_drvdata(pdev);
 138
 139        irq_domain_remove(data->domain);
 140
 141        return 0;
 142}
 143
 144static const struct of_device_id ts4800_ic_of_match[] = {
 145        { .compatible = "technologic,ts4800-irqc", },
 146        {},
 147};
 148MODULE_DEVICE_TABLE(of, ts4800_ic_of_match);
 149
 150static struct platform_driver ts4800_ic_driver = {
 151        .probe  = ts4800_ic_probe,
 152        .remove = ts4800_ic_remove,
 153        .driver = {
 154                .name = "ts4800-irqc",
 155                .of_match_table = ts4800_ic_of_match,
 156        },
 157};
 158module_platform_driver(ts4800_ic_driver);
 159
 160MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
 161MODULE_LICENSE("GPL v2");
 162MODULE_ALIAS("platform:ts4800_irqc");
 163