gpio: grgpio: Add device driver for GRGPIO cores

This driver supports GRGPIO gpio cores available in the GRLIB VHDL IP
core library from Aeroflex Gaisler.
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/gpio/gpio-grgpio.txt

+Aeroflex Gaisler GRGPIO General Purpose I/O cores.
+
+The GRGPIO GPIO core is available in the GRLIB VHDL IP core library.
+
+Note: In the ordinary environment for the GRGPIO core, a Leon SPARC system,
+these properties are built from information in the AMBA plug&play.
+
+Required properties:
+
+- name : Should be "GAISLER_GPIO" or "01_01a"
+
+- reg : Address and length of the register set for the device
+
+- interrupts : Interrupt numbers for this device
+
+Optional properties:
+
+- nbits : The number of gpio lines. If not present driver assumes 32 lines.
+
+For further information look in the documentation for the GLIB IP core library:
+http://www.gaisler.com/products/grlib/grip.pdf

drivers/gpio/Kconfig

@@ -309,6 +309,15 @@ config GPIO_LYNXPOINT
 	  driver for GPIO functionality on Intel Lynxpoint PCH chipset
 	  Requires ACPI device enumeration code to set up a platform device.
 
+config GPIO_GRGPIO
+	tristate "Aeroflex Gaisler GRGPIO support"
+	depends on OF
+	select GPIO_GENERIC
+	select IRQ_DOMAIN
+	help
+	  Select this to support Aeroflex Gaisler GRGPIO cores from the GRLIB
+	  VHDL IP core library.
+
 comment "I2C GPIO expanders:"
 
 config GPIO_ARIZONA

drivers/gpio/Makefile

@@ -25,6 +25,7 @@ obj-$(CONFIG_ARCH_DAVINCI)	+= gpio-davinci.o
 obj-$(CONFIG_GPIO_EM)		+= gpio-em.o
 obj-$(CONFIG_GPIO_EP93XX)	+= gpio-ep93xx.o
 obj-$(CONFIG_GPIO_GE_FPGA)	+= gpio-ge.o
+obj-$(CONFIG_GPIO_GRGPIO)	+= gpio-grgpio.o
 obj-$(CONFIG_GPIO_ICH)		+= gpio-ich.o
 obj-$(CONFIG_GPIO_IT8761E)	+= gpio-it8761e.o
 obj-$(CONFIG_GPIO_JANZ_TTL)	+= gpio-janz-ttl.o

drivers/gpio/gpio-grgpio.c

+/*
+ * Driver for Aeroflex Gaisler GRGPIO General Purpose I/O cores.
+ *
+ * 2013 (c) Aeroflex Gaisler AB
+ *
+ * This driver supports the GRGPIO GPIO core available in the GRLIB VHDL
+ * IP core library.
+ *
+ * Full documentation of the GRGPIO core can be found here:
+ * http://www.gaisler.com/products/grlib/grip.pdf
+ *
+ * See "Documentation/devicetree/bindings/gpio/gpio-grgpio.txt" for
+ * information on open firmware properties.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * Contributors: Andreas Larsson <andreas@gaisler.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/basic_mmio_gpio.h>
+
+#define GRGPIO_MAX_NGPIO 32
+
+#define GRGPIO_DATA		0x00
+#define GRGPIO_OUTPUT		0x04
+#define GRGPIO_DIR		0x08
+#define GRGPIO_IMASK		0x0c
+#define GRGPIO_IPOL		0x10
+#define GRGPIO_IEDGE		0x14
+#define GRGPIO_BYPASS		0x18
+#define GRGPIO_IMAP_BASE	0x20
+
+struct grgpio_priv {
+	struct bgpio_chip bgc;
+	void __iomem *regs;
+	struct device *dev;
+};
+
+static inline struct grgpio_priv *grgpio_gc_to_priv(struct gpio_chip *gc)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+	return container_of(bgc, struct grgpio_priv, bgc);
+}
+
+static int grgpio_probe(struct platform_device *ofdev)
+{
+	struct device_node *np = ofdev->dev.of_node;
+	void  __iomem *regs;
+	struct gpio_chip *gc;
+	struct bgpio_chip *bgc;
+	struct grgpio_priv *priv;
+	struct resource *res;
+	int err;
+	u32 prop;
+
+	priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
+	regs = devm_ioremap_resource(&ofdev->dev, res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	bgc = &priv->bgc;
+	err = bgpio_init(bgc, &ofdev->dev, 4, regs + GRGPIO_DATA,
+			 regs + GRGPIO_OUTPUT, NULL, regs + GRGPIO_DIR, NULL,
+			 BGPIOF_BIG_ENDIAN_BYTE_ORDER);
+	if (err) {
+		dev_err(&ofdev->dev, "bgpio_init() failed\n");
+		return err;
+	}
+
+	priv->regs = regs;
+	priv->dev = &ofdev->dev;
+
+	gc = &bgc->gc;
+	gc->of_node = np;
+	gc->owner = THIS_MODULE;
+	gc->label = np->full_name;
+	gc->base = -1;
+
+	err = of_property_read_u32(np, "nbits", &prop);
+	if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) {
+		gc->ngpio = GRGPIO_MAX_NGPIO;
+		dev_dbg(&ofdev->dev,
+			"No or invalid nbits property: assume %d\n", gc->ngpio);
+	} else {
+		gc->ngpio = prop;
+	}
+
+	platform_set_drvdata(ofdev, priv);
+
+	err = gpiochip_add(gc);
+	if (err) {
+		dev_err(&ofdev->dev, "Could not add gpiochip\n");
+		return err;
+	}
+
+	dev_info(&ofdev->dev, "regs=0x%p, base=%d, ngpio=%d\n",
+		 priv->regs, gc->base, gc->ngpio);
+
+	return 0;
+}
+
+static int grgpio_remove(struct platform_device *ofdev)
+{
+	struct grgpio_priv *priv = platform_get_drvdata(ofdev);
+
+	return gpiochip_remove(&priv->bgc.gc);
+}
+
+static struct of_device_id grgpio_match[] = {
+	{.name = "GAISLER_GPIO"},
+	{.name = "01_01a"},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, grgpio_match);
+
+static struct platform_driver grgpio_driver = {
+	.driver = {
+		.name = "grgpio",
+		.owner = THIS_MODULE,
+		.of_match_table = grgpio_match,
+	},
+	.probe = grgpio_probe,
+	.remove = grgpio_remove,
+};
+module_platform_driver(grgpio_driver);
+
+MODULE_AUTHOR("Aeroflex Gaisler AB.");
+MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO");
+MODULE_LICENSE("GPL");