Quelle  irq-aspeed-i2c-ic.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Aspeed 24XX/25XX I2C Interrupt Controller.
 *
 *  Copyright (C) 2012-2017 ASPEED Technology Inc.
 *  Copyright 2017 IBM Corporation
 *  Copyright 2017 Google, Inc.
 */

#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/io.h>


#define ASPEED_I2C_IC_NUM_BUS 14

struct aspeed_i2c_ic {
 void __iomem  *base;
 int   parent_irq;
 struct irq_domain *irq_domain;
};

/*
 * The aspeed chip provides a single hardware interrupt for all of the I2C
 * busses, so we use a dummy interrupt chip to translate this single interrupt
 * into multiple interrupts, each associated with a single I2C bus.
 */
static void aspeed_i2c_ic_irq_handler(struct irq_desc *desc)
{
 struct aspeed_i2c_ic *i2c_ic = irq_desc_get_handler_data(desc);
 struct irq_chip *chip = irq_desc_get_chip(desc);
 unsigned long bit, status;

 chained_irq_enter(chip, desc);
 status = readl(i2c_ic->base);
 for_each_set_bit(bit, &status, ASPEED_I2C_IC_NUM_BUS)
  generic_handle_domain_irq(i2c_ic->irq_domain, bit);

 chained_irq_exit(chip, desc);
}

/*
 * Set simple handler and mark IRQ as valid. Nothing interesting to do here
 * since we are using a dummy interrupt chip.
 */
static int aspeed_i2c_ic_map_irq_domain(struct irq_domain *domain,
     unsigned int irq, irq_hw_number_t hwirq)
{
 irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
 irq_set_chip_data(irq, domain->host_data);

 return 0;
}

static const struct irq_domain_ops aspeed_i2c_ic_irq_domain_ops = {
 .map = aspeed_i2c_ic_map_irq_domain,
};

static int __init aspeed_i2c_ic_of_init(struct device_node *node,
     struct device_node *parent)
{
 struct aspeed_i2c_ic *i2c_ic;
 int ret = 0;

 i2c_ic = kzalloc(sizeof(*i2c_ic), GFP_KERNEL);
 if (!i2c_ic)
  return -ENOMEM;

 i2c_ic->base = of_iomap(node, 0);
 if (!i2c_ic->base) {
  ret = -ENOMEM;
  goto err_free_ic;
 }

 i2c_ic->parent_irq = irq_of_parse_and_map(node, 0);
 if (!i2c_ic->parent_irq) {
  ret = -EINVAL;
  goto err_iounmap;
 }

 i2c_ic->irq_domain = irq_domain_create_linear(of_fwnode_handle(node), ASPEED_I2C_IC_NUM_BUS,
         &aspeed_i2c_ic_irq_domain_ops,
         NULL);
 if (!i2c_ic->irq_domain) {
  ret = -ENOMEM;
  goto err_iounmap;
 }

 i2c_ic->irq_domain->name = "aspeed-i2c-domain";

 irq_set_chained_handler_and_data(i2c_ic->parent_irq,
      aspeed_i2c_ic_irq_handler, i2c_ic);

 pr_info("i2c controller registered, irq %d\n", i2c_ic->parent_irq);

 return 0;

err_iounmap:
 iounmap(i2c_ic->base);
err_free_ic:
 kfree(i2c_ic);
 return ret;
}

IRQCHIP_DECLARE(ast2400_i2c_ic, "aspeed,ast2400-i2c-ic", aspeed_i2c_ic_of_init);
IRQCHIP_DECLARE(ast2500_i2c_ic, "aspeed,ast2500-i2c-ic", aspeed_i2c_ic_of_init);