[PATCH v11] gpio: add a driver for the Synopsys DesignWare APB GPIO block

[PATCH v11] gpio: add a driver for the Synopsys DesignWare APB GPIO block

[Alan Tull]

From: Jamie Iles <jamie@jamieiles.com>

The Synopsys DesignWare block is used in some ARM devices (picoxcell)
and can be configured to provide multiple banks of GPIO pins.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Alan Tull <atull@altera.com>
Reviewed-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

v11: - Use NULL when checking existence of 'interrupts' property
     - Bindings descriptions cleanup
v10: - in documentation nr-gpio -> nr-gpios
v9:  - cleanup in dt bindings doc
     - use of_get_child_count()
v8:  - remove socfpga.dtsi changes
     - minor cleanup in devicetree documentation
v7:  - use irq_generic_chip
     - support one irq per gpio line or one irq for many
     - s/bank/port/ and other cleanup
v6:  - (atull) squash the set of patches
     - use linear irq domain
     - build fixes. Original driver was reviewed on v3.2.
     - Fix setting irq edge type for 'rising' and 'both'.
     - Support as a loadable module.
     - Use bgpio_chip's spinlock during register access.
     - Clean up register names to match spec
     - s/bank/port/ because register names use the word 'port'
     - s/nr-gpio/nr-gpios/
     - don't get/put the of_node
     - remove signoffs/acked-by's because of changes
     - other cleanup
v5:  - handle sparse bank population correctly
v3:  - depend on rather than select IRQ_DOMAIN
     - split IRQ support into a separate patch
v2:  - use Rob Herring's irqdomain in generic irq chip patches
     - use reg property to indicate bank index
     - support irqs on both edges based on LinusW's u300 driver
---
 .../devicetree/bindings/gpio/snps-dwapb-gpio.txt   |   58 +++
 drivers/gpio/Kconfig                               |    9 +
 drivers/gpio/Makefile                              |    1 +
 drivers/gpio/gpio-dwapb.c                          |  415 ++++++++++++++++++++
 4 files changed, 483 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
 create mode 100644 drivers/gpio/gpio-dwapb.c

diff --git a/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
new file mode 100644
index 0000000..38c2224
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
@@ -0,0 +1,58 @@
+* Synopsys DesignWare APB GPIO controller
+
+Required properties:
+- compatible : Should contain "snps,dw-apb-gpio"
+- reg : Address and length of the register set for the device.
+- #address-cells : should be 1 (for addressing port subnodes).
+- #size-cells : should be 0 (port subnodes).
+
+The GPIO controller has a configurable number of ports, each of which are
+represented as child nodes with the following properties:
+
+Required properties:
+- compatible : "snps,dw-apb-gpio-port"
+- gpio-controller : Marks the device node as a gpio controller.
+- #gpio-cells : Should be 1.  It is the pin number.
+- reg : The integer port index of the port, a single cell.
+
+Optional properties:
+- interrupt-controller : The first port may be configured to be an interrupt
+controller.
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt.  Shall be set to 2.  The first cell defines the interrupt number,
+  the second encodes the triger flags encoded as described in
+  Documentation/devicetree/bindings/interrupts.txt
+- interrupt-parent : The parent interrupt controller.
+- interrupts : The interrupts to the parent controller raised when GPIOs
+  generate the interrupts.  The number of interrupts depends on the hardware
+  configuration of the DesignWare IP block.
+- snps,nr-gpios : The number of pins in the port, a single cell.
+
+Example:
+
+gpio: gpio@20000 {
+	compatible = "snps,dw-apb-gpio";
+	reg = <0x20000 0x1000>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	porta: gpio-controller@0 {
+		compatible = "snps,dw-apb-gpio-port";
+		gpio-controller;
+		#gpio-cells = <2>;
+		snps,nr-gpios = <8>;
+		reg = <0>;
+		interrupt-controller;
+		#interrupt-cells = <2>;
+		interrupt-parent = <&vic1>;
+		interrupts = <0>, <1>, <2>, <3>, <4>, <5>, <6>, <7>;
+	};
+
+	portb: gpio-controller@1 {
+		compatible = "snps,dw-apb-gpio-port";
+		gpio-controller;
+		#gpio-cells = <2>;
+		snps,nr-gpios = <8>;
+		reg = <1>;
+	};
+};
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 6973387..b72cd85 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -128,6 +128,15 @@ config GPIO_GENERIC_PLATFORM
 	help
 	  Say yes here to support basic platform_device memory-mapped GPIO controllers.
 
+config GPIO_DWAPB
+	tristate "Synopsys DesignWare APB GPIO driver"
+	select GPIO_GENERIC
+	select GENERIC_IRQ_CHIP
+	depends on OF_GPIO && IRQ_DOMAIN
+	help
+	  Say Y or M here to build support for the Synopsys DesignWare APB
+	  GPIO block.
+
 config GPIO_IT8761E
 	tristate "IT8761E GPIO support"
 	depends on X86  # unconditional access to IO space.
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 5d50179..2d09f04 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_GPIO_CS5535)	+= gpio-cs5535.o
 obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o
 obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o
+obj-$(CONFIG_GPIO_DWAPB)	+= gpio-dwapb.o
 obj-$(CONFIG_GPIO_EM)		+= gpio-em.o
 obj-$(CONFIG_GPIO_EP93XX)	+= gpio-ep93xx.o
 obj-$(CONFIG_GPIO_F7188X)	+= gpio-f7188x.o
diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
new file mode 100644
index 0000000..a689c2b
--- /dev/null
+++ b/drivers/gpio/gpio-dwapb.c
@@ -0,0 +1,415 @@
+/*
+ * Copyright (c) 2011 Jamie Iles
+ *
+ * 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.
+ *
+ * All enquiries to support@picochip.com
+ */
+#include <linux/basic_mmio_gpio.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#define GPIO_SWPORTA_DR		0x00
+#define GPIO_SWPORTA_DDR	0x04
+#define GPIO_SWPORTB_DR		0x0c
+#define GPIO_SWPORTB_DDR	0x10
+#define GPIO_SWPORTC_DR		0x18
+#define GPIO_SWPORTC_DDR	0x1c
+#define GPIO_SWPORTD_DR		0x24
+#define GPIO_SWPORTD_DDR	0x28
+#define GPIO_INTEN		0x30
+#define GPIO_INTMASK		0x34
+#define GPIO_INTTYPE_LEVEL	0x38
+#define GPIO_INT_POLARITY	0x3c
+#define GPIO_INTSTATUS		0x40
+#define GPIO_PORTA_EOI		0x4c
+#define GPIO_EXT_PORTA		0x50
+#define GPIO_EXT_PORTB		0x54
+#define GPIO_EXT_PORTC		0x58
+#define GPIO_EXT_PORTD		0x5c
+
+#define DWAPB_MAX_PORTS		4
+#define GPIO_EXT_PORT_SIZE	(GPIO_EXT_PORTB - GPIO_EXT_PORTA)
+#define GPIO_SWPORT_DR_SIZE	(GPIO_SWPORTB_DR - GPIO_SWPORTA_DR)
+#define GPIO_SWPORT_DDR_SIZE	(GPIO_SWPORTB_DDR - GPIO_SWPORTA_DDR)
+
+struct dwapb_gpio;
+
+struct dwapb_gpio_port {
+	struct bgpio_chip	bgc;
+	bool			is_registered;
+	struct dwapb_gpio	*gpio;
+};
+
+struct dwapb_gpio {
+	struct	device		*dev;
+	void __iomem		*regs;
+	struct dwapb_gpio_port	*ports;
+	unsigned int		nr_ports;
+	struct irq_domain	*domain;
+};
+
+static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+	struct dwapb_gpio_port *port = container_of(bgc, struct
+						    dwapb_gpio_port, bgc);
+	struct dwapb_gpio *gpio = port->gpio;
+
+	return irq_create_mapping(gpio->domain, offset);
+}
+
+static void dwapb_toggle_trigger(struct dwapb_gpio *gpio, unsigned int offs)
+{
+	u32 v = readl(gpio->regs + GPIO_INT_POLARITY);
+
+	if (gpio_get_value(gpio->ports[0].bgc.gc.base + offs))
+		v &= ~BIT(offs);
+	else
+		v |= BIT(offs);
+
+	writel(v, gpio->regs + GPIO_INT_POLARITY);
+}
+
+static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
+{
+	struct dwapb_gpio *gpio = irq_get_handler_data(irq);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	u32 irq_status = readl_relaxed(gpio->regs + GPIO_INTSTATUS);
+
+	while (irq_status) {
+		int hwirq = fls(irq_status) - 1;
+		int gpio_irq = irq_find_mapping(gpio->domain, hwirq);
+
+		generic_handle_irq(gpio_irq);
+		irq_status &= ~BIT(hwirq);
+
+		if ((irq_get_trigger_type(gpio_irq) & IRQ_TYPE_SENSE_MASK)
+			== IRQ_TYPE_EDGE_BOTH)
+			dwapb_toggle_trigger(gpio, hwirq);
+	}
+
+	if (chip->irq_eoi)
+		chip->irq_eoi(irq_desc_get_irq_data(desc));
+}
+
+static void dwapb_irq_enable(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct dwapb_gpio *gpio = gc->private;
+	struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+	val = readl(gpio->regs + GPIO_INTEN);
+	val |= BIT(d->hwirq);
+	writel(val, gpio->regs + GPIO_INTEN);
+	spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void dwapb_irq_disable(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct dwapb_gpio *gpio = gc->private;
+	struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+	val = readl(gpio->regs + GPIO_INTEN);
+	val &= ~BIT(d->hwirq);
+	writel(val, gpio->regs + GPIO_INTEN);
+	spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static int dwapb_irq_set_type(struct irq_data *d, u32 type)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct dwapb_gpio *gpio = gc->private;
+	struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+	int bit = d->hwirq;
+	unsigned long level, polarity, flags;
+
+	if (type & ~(IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING |
+		     IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+		return -EINVAL;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+	level = readl(gpio->regs + GPIO_INTTYPE_LEVEL);
+	polarity = readl(gpio->regs + GPIO_INT_POLARITY);
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_BOTH:
+		level |= BIT(bit);
+		dwapb_toggle_trigger(gpio, bit);
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		level |= BIT(bit);
+		polarity |= BIT(bit);
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		level |= BIT(bit);
+		polarity &= ~BIT(bit);
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		level &= ~BIT(bit);
+		polarity |= BIT(bit);
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		level &= ~BIT(bit);
+		polarity &= ~BIT(bit);
+		break;
+	}
+
+	writel(level, gpio->regs + GPIO_INTTYPE_LEVEL);
+	writel(polarity, gpio->regs + GPIO_INT_POLARITY);
+	spin_unlock_irqrestore(&bgc->lock, flags);
+
+	return 0;
+}
+
+static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
+				 struct dwapb_gpio_port *port)
+{
+	struct gpio_chip *gc = &port->bgc.gc;
+	struct device_node *node =  gc->of_node;
+	struct irq_chip_generic	*irq_gc;
+	unsigned int hwirq, ngpio = gc->ngpio;
+	struct irq_chip_type *ct;
+	int reg, err, irq;
+
+	if (of_get_property(node, "interrupts", NULL) == NULL)
+		return;
+
+	gpio->domain = irq_domain_add_linear(node, ngpio, &irq_generic_chip_ops,
+					     gpio);
+	if (!gpio->domain)
+		return;
+
+	err = irq_alloc_domain_generic_chips(gpio->domain, ngpio, 1,
+					     "gpio-dwapb", handle_level_irq,
+					     IRQ_NOREQUEST, 0,
+					     IRQ_GC_INIT_NESTED_LOCK);
+	if (err) {
+		dev_info(gpio->dev, "irq_alloc_domain_generic_chips failed\n");
+		irq_domain_remove(gpio->domain);
+		gpio->domain = NULL;
+		return;
+	}
+
+	for (hwirq = 0 ; hwirq < ngpio ; hwirq++) {
+		irq_gc = irq_get_domain_generic_chip(gpio->domain, hwirq);
+		if (!irq_gc) {
+			irq_domain_remove(gpio->domain);
+			gpio->domain = NULL;
+			return;
+		}
+
+		irq_gc->reg_base = gpio->regs;
+		irq_gc->private = gpio;
+
+		ct = irq_gc->chip_types;
+		ct->chip.irq_ack = irq_gc_ack_set_bit;
+		ct->chip.irq_mask = irq_gc_mask_set_bit;
+		ct->chip.irq_unmask = irq_gc_mask_clr_bit;
+		ct->chip.irq_set_type = dwapb_irq_set_type;
+		ct->chip.irq_enable = dwapb_irq_enable;
+		ct->chip.irq_disable = dwapb_irq_disable;
+		ct->regs.ack = GPIO_PORTA_EOI;
+		ct->regs.mask = GPIO_INTMASK;
+
+		irq_setup_generic_chip(irq_gc, IRQ_MSK(port->bgc.gc.ngpio),
+				IRQ_GC_INIT_NESTED_LOCK, IRQ_NOREQUEST, 0);
+
+		irq = irq_of_parse_and_map(node, hwirq);
+		if (!irq && (hwirq == 0)) {
+			dev_warn(gpio->dev, "no irq for bank %s\n",
+				port->bgc.gc.of_node->full_name);
+			return;
+		} else if (!irq)
+			break;
+
+		irq_set_chained_handler(irq, dwapb_irq_handler);
+		irq_set_handler_data(irq, gpio);
+	}
+	port->bgc.gc.to_irq = dwapb_gpio_to_irq;
+}
+
+static void dwapb_irq_teardown(struct dwapb_gpio *gpio)
+{
+	struct dwapb_gpio_port *port = &gpio->ports[0];
+	struct gpio_chip *gc = &port->bgc.gc;
+	unsigned int ngpio = gc->ngpio;
+	irq_hw_number_t hwirq;
+
+	if (!gpio->domain)
+		return;
+
+	for (hwirq = 0 ; hwirq < ngpio ; hwirq++)
+		irq_dispose_mapping(irq_find_mapping(gpio->domain, hwirq));
+
+	irq_domain_remove(gpio->domain);
+	gpio->domain = NULL;
+}
+
+static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
+			       struct device_node *port_np,
+			       unsigned int offs)
+{
+	struct dwapb_gpio_port *port;
+	u32 port_idx, ngpio;
+	void __iomem *dat, *set, *dirout;
+	int err;
+
+	if (of_property_read_u32(port_np, "reg", &port_idx) ||
+		port_idx >= DWAPB_MAX_PORTS) {
+		dev_err(gpio->dev, "missing/invalid port index for %s\n",
+			port_np->full_name);
+		return -EINVAL;
+	}
+
+	port = &gpio->ports[offs];
+	port->gpio = gpio;
+
+	if (of_property_read_u32(port_np, "snps,nr-gpios", &ngpio)) {
+		dev_info(gpio->dev, "failed to get number of gpios for %s\n",
+			 port_np->full_name);
+		ngpio = 32;
+	}
+
+	dat = gpio->regs + GPIO_EXT_PORTA + (port_idx * GPIO_EXT_PORT_SIZE);
+	set = gpio->regs + GPIO_SWPORTA_DR + (port_idx * GPIO_SWPORT_DR_SIZE);
+	dirout = gpio->regs + GPIO_SWPORTA_DDR +
+		(port_idx * GPIO_SWPORT_DDR_SIZE);
+
+	err = bgpio_init(&port->bgc, gpio->dev, 4, dat, set, NULL, dirout,
+			 NULL, false);
+	if (err) {
+		dev_err(gpio->dev, "failed to init gpio chip for %s\n",
+			port_np->full_name);
+		return err;
+	}
+
+	port->bgc.gc.ngpio = ngpio;
+	port->bgc.gc.of_node = port_np;
+
+	/*
+	 * Only port A can provide interrupts in all configurations of the IP.
+	 */
+	if (port_idx == 0 &&
+	    of_property_read_bool(port_np, "interrupt-controller"))
+		dwapb_configure_irqs(gpio, port);
+
+	err = gpiochip_add(&port->bgc.gc);
+	if (err)
+		dev_err(gpio->dev, "failed to register gpiochip for %s\n",
+			port_np->full_name);
+	else
+		port->is_registered = true;
+
+	return err;
+}
+
+static void dwapb_gpio_unregister(struct dwapb_gpio *gpio)
+{
+	unsigned int m;
+
+	for (m = 0; m < gpio->nr_ports; ++m)
+		if (gpio->ports[m].is_registered)
+			WARN_ON(gpiochip_remove(&gpio->ports[m].bgc.gc));
+}
+
+static int dwapb_gpio_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct dwapb_gpio *gpio;
+	struct device_node *np;
+	int err;
+	unsigned int offs = 0;
+
+	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+	gpio->dev = &pdev->dev;
+
+	gpio->nr_ports = of_get_child_count(pdev->dev.of_node);
+	if (!gpio->nr_ports) {
+		err = -EINVAL;
+		goto out_err;
+	}
+	gpio->ports = devm_kzalloc(&pdev->dev, gpio->nr_ports *
+				   sizeof(*gpio->ports), GFP_KERNEL);
+	if (!gpio->ports) {
+		err = -ENOMEM;
+		goto out_err;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	gpio->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(gpio->regs)) {
+		err = PTR_ERR(gpio->regs);
+		goto out_err;
+	}
+
+	for_each_child_of_node(pdev->dev.of_node, np) {
+		err = dwapb_gpio_add_port(gpio, np, offs++);
+		if (err)
+			goto out_unregister;
+	}
+	platform_set_drvdata(pdev, gpio);
+
+	return 0;
+
+out_unregister:
+	dwapb_gpio_unregister(gpio);
+	dwapb_irq_teardown(gpio);
+
+out_err:
+	return err;
+}
+
+static int dwapb_gpio_remove(struct platform_device *pdev)
+{
+	struct dwapb_gpio *gpio = platform_get_drvdata(pdev);
+
+	dwapb_gpio_unregister(gpio);
+	dwapb_irq_teardown(gpio);
+
+	return 0;
+}
+
+static const struct of_device_id dwapb_of_match[] = {
+	{ .compatible = "snps,dw-apb-gpio" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dwapb_of_match);
+
+static struct platform_driver dwapb_gpio_driver = {
+	.driver		= {
+		.name	= "gpio-dwapb",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(dwapb_of_match),
+	},
+	.probe		= dwapb_gpio_probe,
+	.remove		= dwapb_gpio_remove,
+};
+
+module_platform_driver(dwapb_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jamie Iles");
+MODULE_DESCRIPTION("Synopsys DesignWare APB GPIO driver");
-- 
1.7.9.5

[PATCH v11] gpio: add a driver for the Synopsys DesignWare APB GPIO block

[Alan Tull]

From: Jamie Iles <jamie@jamieiles.com>

The Synopsys DesignWare block is used in some ARM devices (picoxcell)
and can be configured to provide multiple banks of GPIO pins.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Alan Tull <atull@altera.com>
Reviewed-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

v11: - Use NULL when checking existence of 'interrupts' property
     - Bindings descriptions cleanup
v10: - in documentation nr-gpio -> nr-gpios
v9:  - cleanup in dt bindings doc
     - use of_get_child_count()
v8:  - remove socfpga.dtsi changes
     - minor cleanup in devicetree documentation
v7:  - use irq_generic_chip
     - support one irq per gpio line or one irq for many
     - s/bank/port/ and other cleanup
v6:  - (atull) squash the set of patches
     - use linear irq domain
     - build fixes. Original driver was reviewed on v3.2.
     - Fix setting irq edge type for 'rising' and 'both'.
     - Support as a loadable module.
     - Use bgpio_chip's spinlock during register access.
     - Clean up register names to match spec
     - s/bank/port/ because register names use the word 'port'
     - s/nr-gpio/nr-gpios/
     - don't get/put the of_node
     - remove signoffs/acked-by's because of changes
     - other cleanup
v5:  - handle sparse bank population correctly
v3:  - depend on rather than select IRQ_DOMAIN
     - split IRQ support into a separate patch
v2:  - use Rob Herring's irqdomain in generic irq chip patches
     - use reg property to indicate bank index
     - support irqs on both edges based on LinusW's u300 driver
---
 .../devicetree/bindings/gpio/snps-dwapb-gpio.txt   |   58 +++
 drivers/gpio/Kconfig                               |    9 +
 drivers/gpio/Makefile                              |    1 +
 drivers/gpio/gpio-dwapb.c                          |  415 ++++++++++++++++++++
 4 files changed, 483 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
 create mode 100644 drivers/gpio/gpio-dwapb.c

diff --git a/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
new file mode 100644
index 0000000..38c2224
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt
@@ -0,0 +1,58 @@
+* Synopsys DesignWare APB GPIO controller
+
+Required properties:
+- compatible : Should contain "snps,dw-apb-gpio"
+- reg : Address and length of the register set for the device.
+- #address-cells : should be 1 (for addressing port subnodes).
+- #size-cells : should be 0 (port subnodes).
+
+The GPIO controller has a configurable number of ports, each of which are
+represented as child nodes with the following properties:
+
+Required properties:
+- compatible : "snps,dw-apb-gpio-port"
+- gpio-controller : Marks the device node as a gpio controller.
+- #gpio-cells : Should be 1.  It is the pin number.
+- reg : The integer port index of the port, a single cell.
+
+Optional properties:
+- interrupt-controller : The first port may be configured to be an interrupt
+controller.
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt.  Shall be set to 2.  The first cell defines the interrupt number,
+  the second encodes the triger flags encoded as described in
+  Documentation/devicetree/bindings/interrupts.txt
+- interrupt-parent : The parent interrupt controller.
+- interrupts : The interrupts to the parent controller raised when GPIOs
+  generate the interrupts.  The number of interrupts depends on the hardware
+  configuration of the DesignWare IP block.
+- snps,nr-gpios : The number of pins in the port, a single cell.
+
+Example:
+
+gpio: gpio@20000 {
+	compatible = "snps,dw-apb-gpio";
+	reg = <0x20000 0x1000>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	porta: gpio-controller@0 {
+		compatible = "snps,dw-apb-gpio-port";
+		gpio-controller;
+		#gpio-cells = <2>;
+		snps,nr-gpios = <8>;
+		reg = <0>;
+		interrupt-controller;
+		#interrupt-cells = <2>;
+		interrupt-parent = <&vic1>;
+		interrupts = <0>, <1>, <2>, <3>, <4>, <5>, <6>, <7>;
+	};
+
+	portb: gpio-controller@1 {
+		compatible = "snps,dw-apb-gpio-port";
+		gpio-controller;
+		#gpio-cells = <2>;
+		snps,nr-gpios = <8>;
+		reg = <1>;
+	};
+};
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 6973387..b72cd85 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -128,6 +128,15 @@ config GPIO_GENERIC_PLATFORM
 	help
 	  Say yes here to support basic platform_device memory-mapped GPIO controllers.
 
+config GPIO_DWAPB
+	tristate "Synopsys DesignWare APB GPIO driver"
+	select GPIO_GENERIC
+	select GENERIC_IRQ_CHIP
+	depends on OF_GPIO && IRQ_DOMAIN
+	help
+	  Say Y or M here to build support for the Synopsys DesignWare APB
+	  GPIO block.
+
 config GPIO_IT8761E
 	tristate "IT8761E GPIO support"
 	depends on X86  # unconditional access to IO space.
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 5d50179..2d09f04 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_GPIO_CS5535)	+= gpio-cs5535.o
 obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o
 obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o
+obj-$(CONFIG_GPIO_DWAPB)	+= gpio-dwapb.o
 obj-$(CONFIG_GPIO_EM)		+= gpio-em.o
 obj-$(CONFIG_GPIO_EP93XX)	+= gpio-ep93xx.o
 obj-$(CONFIG_GPIO_F7188X)	+= gpio-f7188x.o
diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
new file mode 100644
index 0000000..a689c2b
--- /dev/null
+++ b/drivers/gpio/gpio-dwapb.c
@@ -0,0 +1,415 @@
+/*
+ * Copyright (c) 2011 Jamie Iles
+ *
+ * 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.
+ *
+ * All enquiries to support@picochip.com
+ */
+#include <linux/basic_mmio_gpio.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#define GPIO_SWPORTA_DR		0x00
+#define GPIO_SWPORTA_DDR	0x04
+#define GPIO_SWPORTB_DR		0x0c
+#define GPIO_SWPORTB_DDR	0x10
+#define GPIO_SWPORTC_DR		0x18
+#define GPIO_SWPORTC_DDR	0x1c
+#define GPIO_SWPORTD_DR		0x24
+#define GPIO_SWPORTD_DDR	0x28
+#define GPIO_INTEN		0x30
+#define GPIO_INTMASK		0x34
+#define GPIO_INTTYPE_LEVEL	0x38
+#define GPIO_INT_POLARITY	0x3c
+#define GPIO_INTSTATUS		0x40
+#define GPIO_PORTA_EOI		0x4c
+#define GPIO_EXT_PORTA		0x50
+#define GPIO_EXT_PORTB		0x54
+#define GPIO_EXT_PORTC		0x58
+#define GPIO_EXT_PORTD		0x5c
+
+#define DWAPB_MAX_PORTS		4
+#define GPIO_EXT_PORT_SIZE	(GPIO_EXT_PORTB - GPIO_EXT_PORTA)
+#define GPIO_SWPORT_DR_SIZE	(GPIO_SWPORTB_DR - GPIO_SWPORTA_DR)
+#define GPIO_SWPORT_DDR_SIZE	(GPIO_SWPORTB_DDR - GPIO_SWPORTA_DDR)
+
+struct dwapb_gpio;
+
+struct dwapb_gpio_port {
+	struct bgpio_chip	bgc;
+	bool			is_registered;
+	struct dwapb_gpio	*gpio;
+};
+
+struct dwapb_gpio {
+	struct	device		*dev;
+	void __iomem		*regs;
+	struct dwapb_gpio_port	*ports;
+	unsigned int		nr_ports;
+	struct irq_domain	*domain;
+};
+
+static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+	struct dwapb_gpio_port *port = container_of(bgc, struct
+						    dwapb_gpio_port, bgc);
+	struct dwapb_gpio *gpio = port->gpio;
+
+	return irq_create_mapping(gpio->domain, offset);
+}
+
+static void dwapb_toggle_trigger(struct dwapb_gpio *gpio, unsigned int offs)
+{
+	u32 v = readl(gpio->regs + GPIO_INT_POLARITY);
+
+	if (gpio_get_value(gpio->ports[0].bgc.gc.base + offs))
+		v &= ~BIT(offs);
+	else
+		v |= BIT(offs);
+
+	writel(v, gpio->regs + GPIO_INT_POLARITY);
+}
+
+static void dwapb_irq_handler(u32 irq, struct irq_desc *desc)
+{
+	struct dwapb_gpio *gpio = irq_get_handler_data(irq);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	u32 irq_status = readl_relaxed(gpio->regs + GPIO_INTSTATUS);
+
+	while (irq_status) {
+		int hwirq = fls(irq_status) - 1;
+		int gpio_irq = irq_find_mapping(gpio->domain, hwirq);
+
+		generic_handle_irq(gpio_irq);
+		irq_status &= ~BIT(hwirq);
+
+		if ((irq_get_trigger_type(gpio_irq) & IRQ_TYPE_SENSE_MASK)
+			== IRQ_TYPE_EDGE_BOTH)
+			dwapb_toggle_trigger(gpio, hwirq);
+	}
+
+	if (chip->irq_eoi)
+		chip->irq_eoi(irq_desc_get_irq_data(desc));
+}
+
+static void dwapb_irq_enable(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct dwapb_gpio *gpio = gc->private;
+	struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+	val = readl(gpio->regs + GPIO_INTEN);
+	val |= BIT(d->hwirq);
+	writel(val, gpio->regs + GPIO_INTEN);
+	spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static void dwapb_irq_disable(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct dwapb_gpio *gpio = gc->private;
+	struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+	val = readl(gpio->regs + GPIO_INTEN);
+	val &= ~BIT(d->hwirq);
+	writel(val, gpio->regs + GPIO_INTEN);
+	spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
+static int dwapb_irq_set_type(struct irq_data *d, u32 type)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct dwapb_gpio *gpio = gc->private;
+	struct bgpio_chip *bgc = &gpio->ports[0].bgc;
+	int bit = d->hwirq;
+	unsigned long level, polarity, flags;
+
+	if (type & ~(IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING |
+		     IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+		return -EINVAL;
+
+	spin_lock_irqsave(&bgc->lock, flags);
+	level = readl(gpio->regs + GPIO_INTTYPE_LEVEL);
+	polarity = readl(gpio->regs + GPIO_INT_POLARITY);
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_BOTH:
+		level |= BIT(bit);
+		dwapb_toggle_trigger(gpio, bit);
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		level |= BIT(bit);
+		polarity |= BIT(bit);
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		level |= BIT(bit);
+		polarity &= ~BIT(bit);
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		level &= ~BIT(bit);
+		polarity |= BIT(bit);
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		level &= ~BIT(bit);
+		polarity &= ~BIT(bit);
+		break;
+	}
+
+	writel(level, gpio->regs + GPIO_INTTYPE_LEVEL);
+	writel(polarity, gpio->regs + GPIO_INT_POLARITY);
+	spin_unlock_irqrestore(&bgc->lock, flags);
+
+	return 0;
+}
+
+static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
+				 struct dwapb_gpio_port *port)
+{
+	struct gpio_chip *gc = &port->bgc.gc;
+	struct device_node *node =  gc->of_node;
+	struct irq_chip_generic	*irq_gc;
+	unsigned int hwirq, ngpio = gc->ngpio;
+	struct irq_chip_type *ct;
+	int reg, err, irq;
+
+	if (of_get_property(node, "interrupts", NULL) == NULL)
+		return;
+
+	gpio->domain = irq_domain_add_linear(node, ngpio, &irq_generic_chip_ops,
+					     gpio);
+	if (!gpio->domain)
+		return;
+
+	err = irq_alloc_domain_generic_chips(gpio->domain, ngpio, 1,
+					     "gpio-dwapb", handle_level_irq,
+					     IRQ_NOREQUEST, 0,
+					     IRQ_GC_INIT_NESTED_LOCK);
+	if (err) {
+		dev_info(gpio->dev, "irq_alloc_domain_generic_chips failed\n");
+		irq_domain_remove(gpio->domain);
+		gpio->domain = NULL;
+		return;
+	}
+
+	for (hwirq = 0 ; hwirq < ngpio ; hwirq++) {
+		irq_gc = irq_get_domain_generic_chip(gpio->domain, hwirq);
+		if (!irq_gc) {
+			irq_domain_remove(gpio->domain);
+			gpio->domain = NULL;
+			return;
+		}
+
+		irq_gc->reg_base = gpio->regs;
+		irq_gc->private = gpio;
+
+		ct = irq_gc->chip_types;
+		ct->chip.irq_ack = irq_gc_ack_set_bit;
+		ct->chip.irq_mask = irq_gc_mask_set_bit;
+		ct->chip.irq_unmask = irq_gc_mask_clr_bit;
+		ct->chip.irq_set_type = dwapb_irq_set_type;
+		ct->chip.irq_enable = dwapb_irq_enable;
+		ct->chip.irq_disable = dwapb_irq_disable;
+		ct->regs.ack = GPIO_PORTA_EOI;
+		ct->regs.mask = GPIO_INTMASK;
+
+		irq_setup_generic_chip(irq_gc, IRQ_MSK(port->bgc.gc.ngpio),
+				IRQ_GC_INIT_NESTED_LOCK, IRQ_NOREQUEST, 0);
+
+		irq = irq_of_parse_and_map(node, hwirq);
+		if (!irq && (hwirq == 0)) {
+			dev_warn(gpio->dev, "no irq for bank %s\n",
+				port->bgc.gc.of_node->full_name);
+			return;
+		} else if (!irq)
+			break;
+
+		irq_set_chained_handler(irq, dwapb_irq_handler);
+		irq_set_handler_data(irq, gpio);
+	}
+	port->bgc.gc.to_irq = dwapb_gpio_to_irq;
+}
+
+static void dwapb_irq_teardown(struct dwapb_gpio *gpio)
+{
+	struct dwapb_gpio_port *port = &gpio->ports[0];
+	struct gpio_chip *gc = &port->bgc.gc;
+	unsigned int ngpio = gc->ngpio;
+	irq_hw_number_t hwirq;
+
+	if (!gpio->domain)
+		return;
+
+	for (hwirq = 0 ; hwirq < ngpio ; hwirq++)
+		irq_dispose_mapping(irq_find_mapping(gpio->domain, hwirq));
+
+	irq_domain_remove(gpio->domain);
+	gpio->domain = NULL;
+}
+
+static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
+			       struct device_node *port_np,
+			       unsigned int offs)
+{
+	struct dwapb_gpio_port *port;
+	u32 port_idx, ngpio;
+	void __iomem *dat, *set, *dirout;
+	int err;
+
+	if (of_property_read_u32(port_np, "reg", &port_idx) ||
+		port_idx >= DWAPB_MAX_PORTS) {
+		dev_err(gpio->dev, "missing/invalid port index for %s\n",
+			port_np->full_name);
+		return -EINVAL;
+	}
+
+	port = &gpio->ports[offs];
+	port->gpio = gpio;
+
+	if (of_property_read_u32(port_np, "snps,nr-gpios", &ngpio)) {
+		dev_info(gpio->dev, "failed to get number of gpios for %s\n",
+			 port_np->full_name);
+		ngpio = 32;
+	}
+
+	dat = gpio->regs + GPIO_EXT_PORTA + (port_idx * GPIO_EXT_PORT_SIZE);
+	set = gpio->regs + GPIO_SWPORTA_DR + (port_idx * GPIO_SWPORT_DR_SIZE);
+	dirout = gpio->regs + GPIO_SWPORTA_DDR +
+		(port_idx * GPIO_SWPORT_DDR_SIZE);
+
+	err = bgpio_init(&port->bgc, gpio->dev, 4, dat, set, NULL, dirout,
+			 NULL, false);
+	if (err) {
+		dev_err(gpio->dev, "failed to init gpio chip for %s\n",
+			port_np->full_name);
+		return err;
+	}
+
+	port->bgc.gc.ngpio = ngpio;
+	port->bgc.gc.of_node = port_np;
+
+	/*
+	 * Only port A can provide interrupts in all configurations of the IP.
+	 */
+	if (port_idx == 0 &&
+	    of_property_read_bool(port_np, "interrupt-controller"))
+		dwapb_configure_irqs(gpio, port);
+
+	err = gpiochip_add(&port->bgc.gc);
+	if (err)
+		dev_err(gpio->dev, "failed to register gpiochip for %s\n",
+			port_np->full_name);
+	else
+		port->is_registered = true;
+
+	return err;
+}
+
+static void dwapb_gpio_unregister(struct dwapb_gpio *gpio)
+{
+	unsigned int m;
+
+	for (m = 0; m < gpio->nr_ports; ++m)
+		if (gpio->ports[m].is_registered)
+			WARN_ON(gpiochip_remove(&gpio->ports[m].bgc.gc));
+}
+
+static int dwapb_gpio_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct dwapb_gpio *gpio;
+	struct device_node *np;
+	int err;
+	unsigned int offs = 0;
+
+	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+	gpio->dev = &pdev->dev;
+
+	gpio->nr_ports = of_get_child_count(pdev->dev.of_node);
+	if (!gpio->nr_ports) {
+		err = -EINVAL;
+		goto out_err;
+	}
+	gpio->ports = devm_kzalloc(&pdev->dev, gpio->nr_ports *
+				   sizeof(*gpio->ports), GFP_KERNEL);
+	if (!gpio->ports) {
+		err = -ENOMEM;
+		goto out_err;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	gpio->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(gpio->regs)) {
+		err = PTR_ERR(gpio->regs);
+		goto out_err;
+	}
+
+	for_each_child_of_node(pdev->dev.of_node, np) {
+		err = dwapb_gpio_add_port(gpio, np, offs++);
+		if (err)
+			goto out_unregister;
+	}
+	platform_set_drvdata(pdev, gpio);
+
+	return 0;
+
+out_unregister:
+	dwapb_gpio_unregister(gpio);
+	dwapb_irq_teardown(gpio);
+
+out_err:
+	return err;
+}
+
+static int dwapb_gpio_remove(struct platform_device *pdev)
+{
+	struct dwapb_gpio *gpio = platform_get_drvdata(pdev);
+
+	dwapb_gpio_unregister(gpio);
+	dwapb_irq_teardown(gpio);
+
+	return 0;
+}
+
+static const struct of_device_id dwapb_of_match[] = {
+	{ .compatible = "snps,dw-apb-gpio" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dwapb_of_match);
+
+static struct platform_driver dwapb_gpio_driver = {
+	.driver		= {
+		.name	= "gpio-dwapb",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(dwapb_of_match),
+	},
+	.probe		= dwapb_gpio_probe,
+	.remove		= dwapb_gpio_remove,
+};
+
+module_platform_driver(dwapb_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jamie Iles");
+MODULE_DESCRIPTION("Synopsys DesignWare APB GPIO driver");
-- 
1.7.9.5

Re: [PATCH v11] gpio: add a driver for the Synopsys DesignWare APB GPIO block

[Linus Walleij]

Hi Alan, this is starting to look good. I's like an ACK from a DT
maintainer on the bindings but can't see anything really controversial
about them.

On Thu, Feb 6, 2014 at 11:06 PM, Alan Tull <delicious.quinoa@gmail.com> wrote:

> +static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
> +{
> +       struct bgpio_chip *bgc = to_bgpio_chip(gc);
> +       struct dwapb_gpio_port *port = container_of(bgc, struct
> +                                                   dwapb_gpio_port, bgc);
> +       struct dwapb_gpio *gpio = port->gpio;
> +
> +       return irq_create_mapping(gpio->domain, offset);
> +}

I think you want to call irq_find_mapping() here. irq_create_mapping()
should be called for all valid IRQs on probe() instead.

> +               ct = irq_gc->chip_types;
> +               ct->chip.irq_ack = irq_gc_ack_set_bit;
> +               ct->chip.irq_mask = irq_gc_mask_set_bit;
> +               ct->chip.irq_unmask = irq_gc_mask_clr_bit;
> +               ct->chip.irq_set_type = dwapb_irq_set_type;
> +               ct->chip.irq_enable = dwapb_irq_enable;
> +               ct->chip.irq_disable = dwapb_irq_disable;
> +               ct->regs.ack = GPIO_PORTA_EOI;
> +               ct->regs.mask = GPIO_INTMASK;

Please add .startup() and .shutdown() callbacks marking the
respective lines as IRQs, compare to recent patches in the
GPIO subsystem such as this:
http://marc.info/?l=linux-gpio&m=138546100215235&w=2

You probably want to call irq_create_mapping() for each
valid IRQ after registering the chip in this function.

Yours,
Linus Walleij

Re: [PATCH v11] gpio: add a driver for the Synopsys DesignWare APB GPIO block

[delicious quinoa]

On Mon, Feb 10, 2014 at 5:06 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
> Hi Alan, this is starting to look good. I's like an ACK from a DT
> maintainer on the bindings but can't see anything really controversial
> about them.
>
> On Thu, Feb 6, 2014 at 11:06 PM, Alan Tull <delicious.quinoa@gmail.com> wrote:
>
>> +static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
>> +{
>> +       struct bgpio_chip *bgc = to_bgpio_chip(gc);
>> +       struct dwapb_gpio_port *port = container_of(bgc, struct
>> +                                                   dwapb_gpio_port, bgc);
>> +       struct dwapb_gpio *gpio = port->gpio;
>> +
>> +       return irq_create_mapping(gpio->domain, offset);
>> +}
>
> I think you want to call irq_find_mapping() here. irq_create_mapping()
> should be called for all valid IRQs on probe() instead.
>
>> +               ct = irq_gc->chip_types;
>> +               ct->chip.irq_ack = irq_gc_ack_set_bit;
>> +               ct->chip.irq_mask = irq_gc_mask_set_bit;
>> +               ct->chip.irq_unmask = irq_gc_mask_clr_bit;
>> +               ct->chip.irq_set_type = dwapb_irq_set_type;
>> +               ct->chip.irq_enable = dwapb_irq_enable;
>> +               ct->chip.irq_disable = dwapb_irq_disable;
>> +               ct->regs.ack = GPIO_PORTA_EOI;
>> +               ct->regs.mask = GPIO_INTMASK;
>
> Please add .startup() and .shutdown() callbacks marking the
> respective lines as IRQs, compare to recent patches in the
> GPIO subsystem such as this:
> http://marc.info/?l=linux-gpio&m=138546100215235&w=2
>
> You probably want to call irq_create_mapping() for each
> valid IRQ after registering the chip in this function.

Hi Linus,

Thanks for the feedback.  I am working on making these changes.  The
startup/shutdown were easy to add.

I am wondering about the change in usage of
irq_find_mapping/irq_create_mapping.  It seems like all the GPIO
drivers that use irq domains do it the way I was doing it (that's
where I got the idea in the first place): irq_create_mapping is used
in the to_irq() function.  I guess this is a general direction all the
other drivers will be encouraged to go in also?

Regards,
Alan


>
> Yours,
> Linus Walleij

Re: [PATCH v11] gpio: add a driver for the Synopsys DesignWare APB GPIO block

[Linus Walleij]

On Wed, Feb 12, 2014 at 5:17 PM, delicious quinoa
<delicious.quinoa@gmail.com> wrote:

> I am wondering about the change in usage of
> irq_find_mapping/irq_create_mapping.  It seems like all the GPIO
> drivers that use irq domains do it the way I was doing it

It is a well known problems that the kernel contain many bad
examples. When in doubt ask for a good example to be provided.

In gpio-omap.c you will find that this is done in the probe()
path.

> (that's
> where I got the idea in the first place): irq_create_mapping is used
> in the to_irq() function.  I guess this is a general direction all the
> other drivers will be encouraged to go in also?

Yes. The reason is that it should be possible to reques an IRQ
from an irqchip no matter whether the gpio_to_irq() function
was called first, as the APIs are orthogonal.

Yours,
Linus Walleij

Re: [PATCH v11] gpio: add a driver for the Synopsys DesignWare APB GPIO block

[delicious quinoa]

On Mon, Feb 24, 2014 at 6:20 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Wed, Feb 12, 2014 at 5:17 PM, delicious quinoa
> <delicious.quinoa@gmail.com> wrote:
>
>> I am wondering about the change in usage of
>> irq_find_mapping/irq_create_mapping.  It seems like all the GPIO
>> drivers that use irq domains do it the way I was doing it
>
> It is a well known problems that the kernel contain many bad
> examples. When in doubt ask for a good example to be provided.
>
> In gpio-omap.c you will find that this is done in the probe()
> path.
>
>> (that's
>> where I got the idea in the first place): irq_create_mapping is used
>> in the to_irq() function.  I guess this is a general direction all the
>> other drivers will be encouraged to go in also?
>
> Yes. The reason is that it should be possible to reques an IRQ
> from an irqchip no matter whether the gpio_to_irq() function
> was called first, as the APIs are orthogonal.
>
> Yours,
> Linus Walleij

Hi Linus,

Thanks, I made these changes and can see them working for me.

The thing that is currently holding me up is that the DesignWare IP
can be configured to have one irq exiting for the many gpios on port A
or one gpio exiting for each gpio.  I am trying to figure out how to
support both cases with the simplest code.  Currently support works
for the one irq case.

Alan