ICP DAS LP-8x4x contains FPGA chip. The chip functions as an interrupt
source providing 16 additional interrupts among other things. The
interrupt lines are muxed to a GPIO pin of a 2nd level PXA-GPIO
interrupt controller. GPIO pins of the 2nd level controller are in turn
muxed to a CPU interrupt line.
Until pxa is completely converted to device tree, it is impossible
to use IRQCHIP_DECLARE() and the irqdomain needs to added manually.
Drivers for the on-CPU IRQs and GPIO-IRQs are loaded using
postcore_initcall(). We need to have all irq domain drivers loaded prior
to DT parsing in order to allow normal initialization of IRQ resources
with DT.
Signed-off-by: Sergei Ianovich <ynvich@xxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
CC: Arnd Bergmann <arnd@xxxxxxxx>
CC: Rob Herring <robh@xxxxxxxxxx>
CC: Marc Zyngier <marc.zyngier@xxxxxxx>
v5..v6
fixes according to Rob Herring review comments:
* drop wildcards in binding and file names
* rename alias 'fpga'->'fpga_irq'
fixes according to Marc Zyngier review comments:
* use writeb/readb not iowrite8/ioread8
* redefine 2nd mask using inversion on 1st
* add comments
v4..v5
* constify struct of_device_id
* drop irq number from handler signature
v3.2..v4
* move DTS binding to a different patch (8/21)
v3.1..v3.2
fixes to apply Linus Walleij's "Reviewed-by":
* add kerneldoc comment for state container struct
* rename irq -> hwirq for clarity
* drop overzealous error checks from the hotpaths
v3..v3.1
fixes according to Linus Walleij review comments:
* update commit message
* use state container instead of global variables
* get hardware irq nums from irq_data, don't calculate them
* use BIT() macro
* add defines for system irq register masks
* replace cycle control variable with break
* use better names for resource variables
* add a linear domain instead of a legacy one
* use irq_create_mapping() instead of irq_alloc_desc()
v2..v3
* no changes (except number 09/16 -> 11/21)
v0..v2
* extract irqchip and move to drivers/irqchip/
* use device tree
* use devm helpers where possible
---
.../interrupt-controller/icpdas-lp8x4x-irq.txt | 49 ++++
drivers/irqchip/Kconfig | 5 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-lp8841.c | 246 +++++++++++++++++++++
4 files changed, 301 insertions(+)
create mode 100644 Documentation/devicetree/bindings/interrupt-controller/icpdas-lp8x4x-irq.txt
create mode 100644 drivers/irqchip/irq-lp8841.c
diff --git a/Documentation/devicetree/bindings/interrupt-controller/icpdas-lp8x4x-irq.txt b/Documentation/devicetree/bindings/interrupt-controller/icpdas-lp8x4x-irq.txt
new file mode 100644
index 0000000..a72109b
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/icpdas-lp8x4x-irq.txt
@@ -0,0 +1,49 @@
+ICP DAS LP-8841 FPGA Interrupt Controller
+
+ICP DAS LP-8841 contains FPGA chip. The chip functions as a interrupt
+source providing 16 additional interrupts among other things.
+
+Required properties:
+- compatible : should be "icpdas,lp8x4x-irq"
+
+- reg: physical base address of the controller and length of memory mapped
+ region.
+
+- interrupt-controller : identifies the node as an interrupt controller
+
+- #interrupt-cells : should be 1
+
+- interrupts : should provide interrupt
+
+Optional properties:
+
+- interrupt-parent : should provide a link to interrupt controller either
+ explicitly and implicitly from a parent node
+
+Example:
+
+fpgairq: irq@9006 {
+ compatible = "icpdas,lp8841-irq";
+ reg = <0x9006 0x16>;
+ interrupt-parent = <&gpio>;
+ interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
+ #interrupt-cells = <1>;
+ interrupt-controller;
+ status = "okay";
+};
+
+serial@9050 {
+ compatible = "icpdas,lp8841-uart";
+ reg = <0x9050 0x10
+ 0x9030 0x02>;
+ interrupts = <13>;
+ status = "okay";
+};
+
+serial@9060 {
+ compatible = "icpdas,lp8841-uart";
+ reg = <0x9060 0x10
+ 0x9032 0x02>;
+ interrupts = <14>;
+ status = "okay";
+};
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index fb50911..786073b 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -218,3 +218,8 @@ config IRQ_MXS
def_bool y if MACH_ASM9260 || ARCH_MXS
select IRQ_DOMAIN
select STMP_DEVICE
+
+config LP8841_IRQ
+ bool
+ def_bool y if MACH_PXA27X_DT
+ select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 18caacb..05313d1 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_ARCH_SA1100) += irq-sa11x0.o
obj-$(CONFIG_INGENIC_IRQ) += irq-ingenic.o
obj-$(CONFIG_IMX_GPCV2) += irq-imx-gpcv2.o
obj-$(CONFIG_PIC32_EVIC) += irq-pic32-evic.o
+obj-$(CONFIG_LP8841_IRQ) += irq-lp8841.o
diff --git a/drivers/irqchip/irq-lp8841.c b/drivers/irqchip/irq-lp8841.c
new file mode 100644
index 0000000..6a019f0
--- /dev/null
+++ b/drivers/irqchip/irq-lp8841.c
@@ -0,0 +1,246 @@
+/*
+ * linux/drivers/irqchip/irq-lp8841.c
+ *
+ * Support for ICP DAS LP-8841 FPGA irq
+ * Copyright (C) 2013 Sergei Ianovich <ynvich@xxxxxxxxx>
+ *
+ * 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 or any later version.
+ */
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#define MODULE_NAME "irq-lp8841"
+
+#define EOI 0x00000000
+#define INSINT 0x00000002
+#define ENSYSINT 0x00000004
+#define PRIMINT 0x00000006
+#define PRIMINT_MASK 0xe0
+#define SECOINT 0x00000008
+#define SECOINT_MASK (~(u8)PRIMINT_MASK)
+#define ENRISEINT 0x0000000A
+#define CLRRISEINT 0x0000000C
+#define ENHILVINT 0x0000000E
+#define CLRHILVINT 0x00000010
+#define ENFALLINT 0x00000012
+#define CLRFALLINT 0x00000014
+#define IRQ_MEM_SIZE 0x00000016
+#define LP8841_NUM_IRQ_DEFAULT 16
+
+/**
+ * struct lp8841_irq_data - LP8841 custom irq controller state container
+ * @base: base IO memory address
+ * @irq_domain: Interrupt translation domain; responsible for mapping
+ * between hwirq number and linux irq number
+ * @irq_sys_enabled: mask keeping track of interrupts enabled in the
+ * register which vendor calls 'system'
+ * @irq_high_enabled: mask keeping track of interrupts enabled in the
+ * register which vendor calls 'high'
+ *
+ * The structure implements State Container from
+ * Documentation/driver-model/design-patterns.txt
+ */
+
+struct lp8841_irq_data {
+ void *base;
+ struct irq_domain *domain;
+ unsigned char irq_sys_enabled;
+ unsigned char irq_high_enabled;
+};
+
+static void lp8841_mask_irq(struct irq_data *d)
+{
+ unsigned mask;
+ unsigned long hwirq = d->hwirq;
+ struct lp8841_irq_data *host = irq_data_get_irq_chip_data(d);
+
+ if (hwirq < 8) {
+ host->irq_high_enabled &= ~BIT(hwirq);
+
+ mask = readb(host->base + ENHILVINT);
+ mask &= ~BIT(hwirq);
+ writeb(mask, host->base + ENHILVINT);
+ } else {
+ hwirq -= 8;
+ host->irq_sys_enabled &= ~BIT(hwirq);
+
+ mask = readb(host->base + ENSYSINT);
+ mask &= ~BIT(hwirq);
+ writeb(mask, host->base + ENSYSINT);
+ }
+}
+
+static void lp8841_unmask_irq(struct irq_data *d)
+{
+ unsigned mask;
+ unsigned long hwirq = d->hwirq;
+ struct lp8841_irq_data *host = irq_data_get_irq_chip_data(d);
+
+ if (hwirq < 8) {
+ host->irq_high_enabled |= BIT(hwirq);
+ mask = readb(host->base + CLRHILVINT);
+ mask |= BIT(hwirq);
+ writeb(mask, host->base + CLRHILVINT);
+
+ mask = readb(host->base + ENHILVINT);
+ mask |= BIT(hwirq);
+ writeb(mask, host->base + ENHILVINT);
+ } else {
+ hwirq -= 8;
+ host->irq_sys_enabled |= BIT(hwirq);
+
+ mask = readb(host->base + SECOINT);
+ mask |= BIT(hwirq);
+ writeb(mask, host->base + SECOINT);
+
+ mask = readb(host->base + ENSYSINT);
+ mask |= BIT(hwirq);
+ writeb(mask, host->base + ENSYSINT);
+ }
+}
+
+static struct irq_chip lp8841_irq_chip = {
+ .name = "FPGA",
+ .irq_ack = lp8841_mask_irq,
+ .irq_mask = lp8841_mask_irq,
+ .irq_mask_ack = lp8841_mask_irq,
+ .irq_unmask = lp8841_unmask_irq,
+};
+
+static void lp8841_irq_handler(struct irq_desc *desc)
+{
+ int n;
+ unsigned long mask;
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct lp8841_irq_data *host = irq_desc_get_handler_data(desc);
+
+ chained_irq_enter(chip, desc);
+
+ for (;;) {
+ mask = readb(host->base + CLRHILVINT) & 0xff;
+ /* load two registers into a single byte */
+ mask |= (readb(host->base + SECOINT) & SECOINT_MASK) << 8;
+ mask |= (readb(host->base + PRIMINT) & PRIMINT_MASK) << 8;
+ if (mask == 0)
+ break;
+ for_each_set_bit(n, &mask, BITS_PER_LONG)
+ generic_handle_irq(irq_find_mapping(host->domain, n));
+ }
+
+ writeb(0, host->base + EOI);
+ chained_irq_exit(chip, desc);
+}
+
+static int lp8841_irq_domain_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hw)
+{
+ struct lp8841_irq_data *host = d->host_data;
+ int err;
+
+ err = irq_set_chip_data(irq, host);
+ if (err < 0)
+ return err;
+
+ irq_set_chip_and_handler(irq, &lp8841_irq_chip, handle_level_irq);
+ irq_set_probe(irq);
+ return 0;
+}
+
+const struct irq_domain_ops lp8841_irq_domain_ops = {
+ .map = lp8841_irq_domain_map,
+ .xlate = irq_domain_xlate_onecell,
+};
+
+static const struct of_device_id lp8841_irq_dt_ids[] = {
+ { .compatible = "icpdas,lp8841-irq", },
+ {}
+};
+
+/*
+ * REVISIT probing will need to rewritten when PXA is converted to DT
+ */
+
+static int lp8841_irq_probe(struct platform_device *pdev)
+{
+ struct resource *res_mem;
+ int irq;
+ struct device_node *np = pdev->dev.of_node;
+ struct lp8841_irq_data *host;
+ int i, err;
+
+ irq = platform_get_irq(pdev, 0);
+ if (IS_ERR_VALUE(irq)) {
+ dev_err(&pdev->dev, "bad irq %i\n", irq);
+ return irq;
+ }
+
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res_mem || resource_size(res_mem) < IRQ_MEM_SIZE) {
+ dev_err(&pdev->dev, "bad IOmem %p\n", res_mem);
+ if (res_mem)
+ dev_err(&pdev->dev, "bad start %p or size %u\n",
+ (void *) res_mem->start,
+ resource_size(res_mem));
+ return -ENODEV;
+ }
+
+ host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
+ if (!host)
+ return -ENOMEM;
+
+ host->base = devm_ioremap_resource(&pdev->dev, res_mem);
+ if (!host->base) {
+ dev_err(&pdev->dev, "Failed to ioremap %p\n", host->base);
+ return -EFAULT;
+ }
+
+ host->domain = irq_domain_add_linear(np, LP8841_NUM_IRQ_DEFAULT,
+ &lp8841_irq_domain_ops, host);
+ if (!host->domain) {
+ dev_err(&pdev->dev, "Failed to add IRQ domain\n");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < LP8841_NUM_IRQ_DEFAULT; i++) {
+ err = irq_create_mapping(host->domain, i);
+ if (err < 0)
+ dev_err(&pdev->dev, "Failed to map IRQ %i\n", i);
+ }
+
+ /* Initialize chip registers */
+ writeb(0, host->base + CLRRISEINT);
+ writeb(0, host->base + ENRISEINT);
+ writeb(0, host->base + CLRFALLINT);
+ writeb(0, host->base + ENFALLINT);
+ writeb(0, host->base + CLRHILVINT);
+ writeb(0, host->base + ENHILVINT);
+ writeb(0, host->base + ENSYSINT);
+ writeb(0, host->base + SECOINT);
+
+ irq_set_handler_data(irq, host);
+ irq_set_chained_handler(irq, lp8841_irq_handler);
+
+ pr_info(MODULE_NAME ": %i IRQs\n", LP8841_NUM_IRQ_DEFAULT);
+ return 0;
+}
+
+static struct platform_driver lp8841_irq_driver = {
+ .probe = lp8841_irq_probe,
+ .driver = {
+ .name = MODULE_NAME,
+ .of_match_table = lp8841_irq_dt_ids,
+ },
+};
+
+static int __init lp8841_irq_init(void)
+{
+ return platform_driver_register(&lp8841_irq_driver);
+}
+device_initcall(lp8841_irq_init);
--
2.7.0
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