drivers/irqchip/irq-aspeed-i2c-ic.c

   1 /*
   2  *  Aspeed 24XX/25XX I2C Interrupt Controller.
   3  *
   4  *  Copyright (C) 2012-2017 ASPEED Technology Inc.
   5  *  Copyright 2017 IBM Corporation
   6  *  Copyright 2017 Google, Inc.
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License version 2 as
  10  *  published by the Free Software Foundation.
  11  */
  12
  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/of_address.h>
  18 #include <linux/of_irq.h>
  19 #include <linux/io.h>
  20
  21
  22 #define ASPEED_I2C_IC_NUM_BUS 14
  23
  24 struct aspeed_i2c_ic {
  25         void __iomem            *base;
  26         int                     parent_irq;
  27         struct irq_domain       *irq_domain;
  28 };
  29
  30 /*
  31  * The aspeed chip provides a single hardware interrupt for all of the I2C
  32  * busses, so we use a dummy interrupt chip to translate this single interrupt
  33  * into multiple interrupts, each associated with a single I2C bus.
  34  */
  35 static void aspeed_i2c_ic_irq_handler(struct irq_desc *desc)
  36 {
  37         struct aspeed_i2c_ic *i2c_ic = irq_desc_get_handler_data(desc);
  38         struct irq_chip *chip = irq_desc_get_chip(desc);
  39         unsigned long bit, status;
  40         unsigned int bus_irq;
  41
  42         chained_irq_enter(chip, desc);
  43         status = readl(i2c_ic->base);
  44         for_each_set_bit(bit, &status, ASPEED_I2C_IC_NUM_BUS) {
  45                 bus_irq = irq_find_mapping(i2c_ic->irq_domain, bit);
  46                 generic_handle_irq(bus_irq);
  47         }
  48         chained_irq_exit(chip, desc);
  49 }
  50
  51 /*
  52  * Set simple handler and mark IRQ as valid. Nothing interesting to do here
  53  * since we are using a dummy interrupt chip.
  54  */
  55 static int aspeed_i2c_ic_map_irq_domain(struct irq_domain *domain,
  56                                         unsigned int irq, irq_hw_number_t hwirq)
  57 {
  58         irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
  59         irq_set_chip_data(irq, domain->host_data);
  60
  61         return 0;
  62 }
  63
  64 static const struct irq_domain_ops aspeed_i2c_ic_irq_domain_ops = {
  65         .map = aspeed_i2c_ic_map_irq_domain,
  66 };
  67
  68 static int __init aspeed_i2c_ic_of_init(struct device_node *node,
  69                                         struct device_node *parent)
  70 {
  71         struct aspeed_i2c_ic *i2c_ic;
  72         int ret = 0;
  73
  74         i2c_ic = kzalloc(sizeof(*i2c_ic), GFP_KERNEL);
  75         if (!i2c_ic)
  76                 return -ENOMEM;
  77
  78         i2c_ic->base = of_iomap(node, 0);
  79         if (!i2c_ic->base) {
  80                 ret = -ENOMEM;
  81                 goto err_free_ic;
  82         }
  83
  84         i2c_ic->parent_irq = irq_of_parse_and_map(node, 0);
  85         if (i2c_ic->parent_irq < 0) {
  86                 ret = i2c_ic->parent_irq;
  87                 goto err_iounmap;
  88         }
  89
  90         i2c_ic->irq_domain = irq_domain_add_linear(node, ASPEED_I2C_IC_NUM_BUS,
  91                                                    &aspeed_i2c_ic_irq_domain_ops,
  92                                                    NULL);
  93         if (!i2c_ic->irq_domain) {
  94                 ret = -ENOMEM;
  95                 goto err_iounmap;
  96         }
  97
  98         i2c_ic->irq_domain->name = "aspeed-i2c-domain";
  99
 100         irq_set_chained_handler_and_data(i2c_ic->parent_irq,
 101                                          aspeed_i2c_ic_irq_handler, i2c_ic);
 102
 103         pr_info("i2c controller registered, irq %d\n", i2c_ic->parent_irq);
 104
 105         return 0;
 106
 107 err_iounmap:
 108         iounmap(i2c_ic->base);
 109 err_free_ic:
 110         kfree(i2c_ic);
 111         return ret;
 112 }
 113
 114 IRQCHIP_DECLARE(ast2400_i2c_ic, "aspeed,ast2400-i2c-ic", aspeed_i2c_ic_of_init);
 115 IRQCHIP_DECLARE(ast2500_i2c_ic, "aspeed,ast2500-i2c-ic", aspeed_i2c_ic_of_init);