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authorBrendan Higgins <brendanhiggins@google.com>2017-06-02 18:29:49 -0700
committerMarc Zyngier <marc.zyngier@arm.com>2017-06-22 14:15:00 +0100
commitf48e699ddf7056f83bb8e2dbe3c2ae8d1ff1a31a (patch)
treeacdac0e97e8286bee1ebdb30e21aa8f8e9013a1e /drivers/irqchip/irq-aspeed-i2c-ic.c
parent0a56f9eebe6320980b68c60c852436cbf2a14b61 (diff)
irqchip/aspeed-i2c-ic: Add I2C IRQ controller for Aspeed
The Aspeed 24XX/25XX chips share a single hardware interrupt across 14 separate I2C busses. This adds a dummy irqchip which maps the single hardware interrupt to software interrupts for each of the busses. Signed-off-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'drivers/irqchip/irq-aspeed-i2c-ic.c')
-rw-r--r--drivers/irqchip/irq-aspeed-i2c-ic.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-aspeed-i2c-ic.c b/drivers/irqchip/irq-aspeed-i2c-ic.c
new file mode 100644
index 000000000000..815b88dd18f2
--- /dev/null
+++ b/drivers/irqchip/irq-aspeed-i2c-ic.c
@@ -0,0 +1,115 @@
+/*
+ * Aspeed 24XX/25XX I2C Interrupt Controller.
+ *
+ * Copyright (C) 2012-2017 ASPEED Technology Inc.
+ * Copyright 2017 IBM Corporation
+ * Copyright 2017 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#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;
+ unsigned int bus_irq;
+
+ chained_irq_enter(chip, desc);
+ status = readl(i2c_ic->base);
+ for_each_set_bit(bit, &status, ASPEED_I2C_IC_NUM_BUS) {
+ bus_irq = irq_find_mapping(i2c_ic->irq_domain, bit);
+ generic_handle_irq(bus_irq);
+ }
+ 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 (IS_ERR(i2c_ic->base)) {
+ ret = PTR_ERR(i2c_ic->base);
+ goto err_free_ic;
+ }
+
+ i2c_ic->parent_irq = irq_of_parse_and_map(node, 0);
+ if (i2c_ic->parent_irq < 0) {
+ ret = i2c_ic->parent_irq;
+ goto err_iounmap;
+ }
+
+ i2c_ic->irq_domain = irq_domain_add_linear(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);