irqchip: mtk-sysirq: Add sysirq interrupt polarity support

Mediatek SoCs have interrupt polarity support in sysirq which
allows to invert polarity for given interrupt. Add this support
using hierarchy irq domain.

Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Link: https://lkml.kernel.org/r/1416902662-19281-3-git-send-email-yingjoe.chen@mediatek.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

2 files changed, 164 insertions, 0 deletions

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index ec3621d5ca87..2029e79c07a9 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -39,3 +39,4 @@ obj-$(CONFIG_IRQ_CROSSBAR)		+= irq-crossbar.o
 obj-$(CONFIG_BRCMSTB_L2_IRQ)            += irq-brcmstb-l2.o \
                                            irq-bcm7120-l2.o
 obj-$(CONFIG_KEYSTONE_IRQ)              += irq-keystone.o
+obj-$(CONFIG_ARCH_MEDIATEK)             += irq-mtk-sysirq.o
diff --git a/drivers/irqchip/irq-mtk-sysirq.c b/drivers/irqchip/irq-mtk-sysirq.c
new file mode 100644
index 000000000000..7e342df6a62f
--- /dev/null
+++ b/drivers/irqchip/irq-mtk-sysirq.c
@@ -0,0 +1,163 @@
+/*
+ * Copyright (c) 2014 MediaTek Inc.
+ * Author: Joe.C <yingjoe.chen@mediatek.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "irqchip.h"
+
+#define MT6577_SYS_INTPOL_NUM   (224)
+
+struct mtk_sysirq_chip_data {
+        spinlock_t lock;
+        void __iomem *intpol_base;
+};
+
+static int mtk_sysirq_set_type(struct irq_data *data, unsigned int type)
+{
+        irq_hw_number_t hwirq = data->hwirq;
+        struct mtk_sysirq_chip_data *chip_data = data->chip_data;
+        u32 offset, reg_index, value;
+        unsigned long flags;
+        int ret;
+
+        offset = hwirq & 0x1f;
+        reg_index = hwirq >> 5;
+
+        spin_lock_irqsave(&chip_data->lock, flags);
+        value = readl_relaxed(chip_data->intpol_base + reg_index * 4);
+        if (type == IRQ_TYPE_LEVEL_LOW || type == IRQ_TYPE_EDGE_FALLING) {
+                if (type == IRQ_TYPE_LEVEL_LOW)
+                        type = IRQ_TYPE_LEVEL_HIGH;
+                else
+                        type = IRQ_TYPE_EDGE_RISING;
+                value |= (1 << offset);
+        } else {
+                value &= ~(1 << offset);
+        }
+        writel(value, chip_data->intpol_base + reg_index * 4);
+
+        data = data->parent_data;
+        ret = data->chip->irq_set_type(data, type);
+        spin_unlock_irqrestore(&chip_data->lock, flags);
+        return ret;
+}
+
+static struct irq_chip mtk_sysirq_chip = {
+        .name                   = "MT_SYSIRQ",
+        .irq_mask               = irq_chip_mask_parent,
+        .irq_unmask             = irq_chip_unmask_parent,
+        .irq_eoi                = irq_chip_eoi_parent,
+        .irq_set_type           = mtk_sysirq_set_type,
+        .irq_retrigger          = irq_chip_retrigger_hierarchy,
+        .irq_set_affinity       = irq_chip_set_affinity_parent,
+};
+
+static int mtk_sysirq_domain_xlate(struct irq_domain *d,
+                                   struct device_node *controller,
+                                   const u32 *intspec, unsigned int intsize,
+                                   unsigned long *out_hwirq,
+                                   unsigned int *out_type)
+{
+        if (intsize != 3)
+                return -EINVAL;
+
+        /* sysirq doesn't support PPI */
+        if (intspec[0])
+                return -EINVAL;
+
+        *out_hwirq = intspec[1];
+        *out_type = intspec[2] & IRQ_TYPE_SENSE_MASK;
+        return 0;
+}
+
+static int mtk_sysirq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+                                   unsigned int nr_irqs, void *arg)
+{
+        int i;
+        irq_hw_number_t hwirq;
+        struct of_phandle_args *irq_data = arg;
+        struct of_phandle_args gic_data = *irq_data;
+
+        if (irq_data->args_count != 3)
+                return -EINVAL;
+
+        /* sysirq doesn't support PPI */
+        if (irq_data->args[0])
+                return -EINVAL;
+
+        hwirq = irq_data->args[1];
+        for (i = 0; i < nr_irqs; i++)
+                irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+                                              &mtk_sysirq_chip,
+                                              domain->host_data);
+
+        gic_data.np = domain->parent->of_node;
+        return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &gic_data);
+}
+
+static struct irq_domain_ops sysirq_domain_ops = {
+        .xlate = mtk_sysirq_domain_xlate,
+        .alloc = mtk_sysirq_domain_alloc,
+        .free = irq_domain_free_irqs_common,
+};
+
+static int __init mtk_sysirq_of_init(struct device_node *node,
+                                     struct device_node *parent)
+{
+        struct irq_domain *domain, *domain_parent;
+        struct mtk_sysirq_chip_data *chip_data;
+        int ret = 0;
+
+        domain_parent = irq_find_host(parent);
+        if (!domain_parent) {
+                pr_err("mtk_sysirq: interrupt-parent not found\n");
+                return -EINVAL;
+        }
+
+        chip_data = kzalloc(sizeof(*chip_data), GFP_KERNEL);
+        if (!chip_data)
+                return -ENOMEM;
+
+        chip_data->intpol_base = of_io_request_and_map(node, 0, "intpol");
+        if (!chip_data->intpol_base) {
+                pr_err("mtk_sysirq: unable to map sysirq register\n");
+                ret = -ENOMEM;
+                goto out_free;
+        }
+
+        domain = irq_domain_add_hierarchy(domain_parent, 0,
+                                          MT6577_SYS_INTPOL_NUM, node,
+                                          &sysirq_domain_ops, chip_data);
+        if (!domain) {
+                ret = -ENOMEM;
+                goto out_unmap;
+        }
+        spin_lock_init(&chip_data->lock);
+
+        return 0;
+
+out_unmap:
+        iounmap(chip_data->intpol_base);
+out_free:
+        kfree(chip_data);
+        return ret;
+}
+IRQCHIP_DECLARE(mtk_sysirq, "mediatek,mt6577-sysirq", mtk_sysirq_of_init);