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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Aspeed 24XX/25XX I2C Interrupt Controller.
   4  *
   5  *  Copyright (C) 2012-2017 ASPEED Technology Inc.
   6  *  Copyright 2017 IBM Corporation
   7  *  Copyright 2017 Google, Inc.
   8  */
   9
  10 #include <linux/irq.h>
  11 #include <linux/irqchip.h>
  12 #include <linux/irqchip/chained_irq.h>
  13 #include <linux/irqdomain.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/io.h>
  17
  18
  19 #define ASPEED_I2C_IC_NUM_BUS 14
  20
  21 struct aspeed_i2c_ic {
  22         void __iomem            *base;
  23         int                     parent_irq;
  24         struct irq_domain       *irq_domain;
  25 };
  26
  27 /*
  28  * The aspeed chip provides a single hardware interrupt for all of the I2C
  29  * busses, so we use a dummy interrupt chip to translate this single interrupt
  30  * into multiple interrupts, each associated with a single I2C bus.
  31  */
  32 static void aspeed_i2c_ic_irq_handler(struct irq_desc *desc)
  33 {
  34         struct aspeed_i2c_ic *i2c_ic = irq_desc_get_handler_data(desc);
  35         struct irq_chip *chip = irq_desc_get_chip(desc);
  36         unsigned long bit, status;
  37
  38         chained_irq_enter(chip, desc);
  39         status = readl(i2c_ic->base);
  40         for_each_set_bit(bit, &status, ASPEED_I2C_IC_NUM_BUS)
  41                 generic_handle_domain_irq(i2c_ic->irq_domain, bit);
  42
  43         chained_irq_exit(chip, desc);
  44 }
  45
  46 /*
  47  * Set simple handler and mark IRQ as valid. Nothing interesting to do here
  48  * since we are using a dummy interrupt chip.
  49  */
  50 static int aspeed_i2c_ic_map_irq_domain(struct irq_domain *domain,
  51                                         unsigned int irq, irq_hw_number_t hwirq)
  52 {
  53         irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
  54         irq_set_chip_data(irq, domain->host_data);
  55
  56         return 0;
  57 }
  58
  59 static const struct irq_domain_ops aspeed_i2c_ic_irq_domain_ops = {
  60         .map = aspeed_i2c_ic_map_irq_domain,
  61 };
  62
  63 static int __init aspeed_i2c_ic_of_init(struct device_node *node,
  64                                         struct device_node *parent)
  65 {
  66         struct aspeed_i2c_ic *i2c_ic;
  67         int ret = 0;
  68
  69         i2c_ic = kzalloc(sizeof(*i2c_ic), GFP_KERNEL);
  70         if (!i2c_ic)
  71                 return -ENOMEM;
  72
  73         i2c_ic->base = of_iomap(node, 0);
  74         if (!i2c_ic->base) {
  75                 ret = -ENOMEM;
  76                 goto err_free_ic;
  77         }
  78
  79         i2c_ic->parent_irq = irq_of_parse_and_map(node, 0);
  80         if (!i2c_ic->parent_irq) {
  81                 ret = -EINVAL;
  82                 goto err_iounmap;
  83         }
  84
  85         i2c_ic->irq_domain = irq_domain_add_linear(node, ASPEED_I2C_IC_NUM_BUS,
  86                                                    &aspeed_i2c_ic_irq_domain_ops,
  87                                                    NULL);
  88         if (!i2c_ic->irq_domain) {
  89                 ret = -ENOMEM;
  90                 goto err_iounmap;
  91         }
  92
  93         i2c_ic->irq_domain->name = "aspeed-i2c-domain";
  94
  95         irq_set_chained_handler_and_data(i2c_ic->parent_irq,
  96                                          aspeed_i2c_ic_irq_handler, i2c_ic);
  97
  98         pr_info("i2c controller registered, irq %d\n", i2c_ic->parent_irq);
  99
 100         return 0;
 101
 102 err_iounmap:
 103         iounmap(i2c_ic->base);
 104 err_free_ic:
 105         kfree(i2c_ic);
 106         return ret;
 107 }
 108
 109 IRQCHIP_DECLARE(ast2400_i2c_ic, "aspeed,ast2400-i2c-ic", aspeed_i2c_ic_of_init);
 110 IRQCHIP_DECLARE(ast2500_i2c_ic, "aspeed,ast2500-i2c-ic", aspeed_i2c_ic_of_init);