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Subject[PATCH v6 2/5] irqchip/aspeed-i2c-ic: Add I2C IRQ controller for Aspeed
Date
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>
---
Added in v6:
- Pulled "aspeed_i2c_controller" out into a interrupt controller since that is
what it actually does.
---
drivers/irqchip/Makefile | 2 +-
drivers/irqchip/irq-aspeed-i2c-ic.c | 102 ++++++++++++++++++++++++++++++++++++
2 files changed, 103 insertions(+), 1 deletion(-)
create mode 100644 drivers/irqchip/irq-aspeed-i2c-ic.c

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 152bc40b6762..c136c2bd1761 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -74,6 +74,6 @@ obj-$(CONFIG_MVEBU_ODMI) += irq-mvebu-odmi.o
obj-$(CONFIG_MVEBU_PIC) += irq-mvebu-pic.o
obj-$(CONFIG_LS_SCFG_MSI) += irq-ls-scfg-msi.o
obj-$(CONFIG_EZNPS_GIC) += irq-eznps.o
-obj-$(CONFIG_ARCH_ASPEED) += irq-aspeed-vic.o
+obj-$(CONFIG_ARCH_ASPEED) += irq-aspeed-vic.o irq-aspeed-i2c-ic.o
obj-$(CONFIG_STM32_EXTI) += irq-stm32-exti.o
obj-$(CONFIG_QCOM_IRQ_COMBINER) += qcom-irq-combiner.o
diff --git a/drivers/irqchip/irq-aspeed-i2c-ic.c b/drivers/irqchip/irq-aspeed-i2c-ic.c
new file mode 100644
index 000000000000..59c50b28dec0
--- /dev/null
+++ b/drivers/irqchip/irq-aspeed-i2c-ic.c
@@ -0,0 +1,102 @@
+/*
+ * 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;
+
+ 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))
+ return PTR_ERR(i2c_ic->base);
+
+ i2c_ic->parent_irq = irq_of_parse_and_map(node, 0);
+ if (i2c_ic->parent_irq < 0)
+ return i2c_ic->parent_irq;
+
+ 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)
+ return -ENOMEM;
+
+ i2c_ic->irq_domain->name = "ast-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;
+}
+
+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);
--
2.12.2.564.g063fe858b8-goog
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