gpio: Add VIA VX855 GPIO driver

This is needed for supporting the upcoming VX855 camera and OLPC DCON drivers, as well as the advanced viafb features on non-OLPC hardware based on this chip. Based on earlier work by Harald Welte. Signed-off-by: Daniel Drake <dsd@laptop.org> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

gpio: Add VIA VX855 GPIO driver
This is needed for supporting the upcoming VX855 camera and OLPC DCON drivers, as well as the advanced viafb features on non-OLPC hardware based on this chip. Based on earlier work by Harald Welte. Signed-off-by: Daniel Drake <dsd@laptop.org> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Daniel Drake · Samuel Ortiz
1 parent 375fc77ba9
Showing 3 changed files with 345 additions and 0 deletions Side-by-side Diff
drivers/gpio/Kconfig
drivers/gpio/Makefile
drivers/gpio/vx855_gpio.c
@@ -116,6 +116,18 @@
 	  This driver can also be built as a module. If so, the module
 	  will be called sch-gpio.
  
+config GPIO_VX855
+	tristate "VIA VX855/VX875 GPIO"
+	depends on GPIOLIB
+	select MFD_CORE
+	select MFD_VX855
+	help
+	  Support access to the VX855/VX875 GPIO lines through the gpio library.
+
+	  This driver provides common support for accessing the device,
+	  additional drivers must be enabled in order to use the
+	  functionality of the device.
+
 comment "I2C GPIO expanders:"
  
 config GPIO_MAX7300
@@ -40,4 +40,5 @@
 obj-$(CONFIG_GPIO_RDC321X)	+= rdc321x-gpio.o
 obj-$(CONFIG_GPIO_JANZ_TTL)	+= janz-ttl.o
 obj-$(CONFIG_GPIO_SX150X)	+= sx150x.o
+obj-$(CONFIG_GPIO_VX855)	+= vx855_gpio.o
+/*
+ * Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO
+ *
+ * Copyright (C) 2009 VIA Technologies, Inc.
+ * Copyright (C) 2010 One Laptop per Child
+ * Author: Harald Welte <HaraldWelte@viatech.com>
+ * All rights reserved.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gpio.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/pci.h>
+#include <linux/io.h>
+
+#define MODULE_NAME "vx855_gpio"
+
+/* The VX855 south bridge has the following GPIO pins:
+ *	GPI 0...13	General Purpose Input
+ *	GPO 0...12	General Purpose Output
+ *	GPIO 0...14	General Purpose I/O (Open-Drain)
+ */
+
+#define NR_VX855_GPI	14
+#define NR_VX855_GPO	13
+#define NR_VX855_GPIO	15
+
+#define NR_VX855_GPInO	(NR_VX855_GPI + NR_VX855_GPO)
+#define NR_VX855_GP	(NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO)
+
+struct vx855_gpio {
+	struct gpio_chip gpio;
+	spinlock_t lock;
+	u32 io_gpi;
+	u32 io_gpo;
+	bool gpi_reserved;
+	bool gpo_reserved;
+};
+
+/* resolve a GPIx into the corresponding bit position */
+static inline u_int32_t gpi_i_bit(int i)
+{
+	if (i < 10)
+		return 1 << i;
+	else
+		return 1 << (i + 14);
+}
+
+static inline u_int32_t gpo_o_bit(int i)
+{
+	if (i < 11)
+		return 1 << i;
+	else
+		return 1 << (i + 14);
+}
+
+static inline u_int32_t gpio_i_bit(int i)
+{
+	if (i < 14)
+		return 1 << (i + 10);
+	else
+		return 1 << (i + 14);
+}
+
+static inline u_int32_t gpio_o_bit(int i)
+{
+	if (i < 14)
+		return 1 << (i + 11);
+	else
+		return 1 << (i + 13);
+}
+
+/* Mapping betwee numeric GPIO ID and the actual GPIO hardware numbering:
+ * 0..13	GPI 0..13
+ * 14..26	GPO 0..12
+ * 27..41	GPIO 0..14
+ */
+
+static int vx855gpio_direction_input(struct gpio_chip *gpio,
+				     unsigned int nr)
+{
+	struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
+	unsigned long flags;
+	u_int32_t reg_out;
+
+	/* Real GPI bits are always in input direction */
+	if (nr < NR_VX855_GPI)
+		return 0;
+
+	/* Real GPO bits cannot be put in output direction */
+	if (nr < NR_VX855_GPInO)
+		return -EINVAL;
+
+	/* Open Drain GPIO have to be set to one */
+	spin_lock_irqsave(&vg->lock, flags);
+	reg_out = inl(vg->io_gpo);
+	reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
+	outl(reg_out, vg->io_gpo);
+	spin_unlock_irqrestore(&vg->lock, flags);
+
+	return 0;
+}
+
+static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr)
+{
+	struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
+	u_int32_t reg_in;
+	int ret = 0;
+
+	if (nr < NR_VX855_GPI) {
+		reg_in = inl(vg->io_gpi);
+		if (reg_in & gpi_i_bit(nr))
+			ret = 1;
+	} else if (nr < NR_VX855_GPInO) {
+		/* GPO don't have an input bit, we need to read it
+		 * back from the output register */
+		reg_in = inl(vg->io_gpo);
+		if (reg_in & gpo_o_bit(nr - NR_VX855_GPI))
+			ret = 1;
+	} else {
+		reg_in = inl(vg->io_gpi);
+		if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO))
+			ret = 1;
+	}
+
+	return ret;
+}
+
+static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr,
+			  int val)
+{
+	struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
+	unsigned long flags;
+	u_int32_t reg_out;
+
+	/* True GPI cannot be switched to output mode */
+	if (nr < NR_VX855_GPI)
+		return;
+
+	spin_lock_irqsave(&vg->lock, flags);
+	reg_out = inl(vg->io_gpo);
+	if (nr < NR_VX855_GPInO) {
+		if (val)
+			reg_out |= gpo_o_bit(nr - NR_VX855_GPI);
+		else
+			reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI);
+	} else {
+		if (val)
+			reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
+		else
+			reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO);
+	}
+	outl(reg_out, vg->io_gpo);
+	spin_unlock_irqrestore(&vg->lock, flags);
+}
+
+static int vx855gpio_direction_output(struct gpio_chip *gpio,
+				      unsigned int nr, int val)
+{
+	/* True GPI cannot be switched to output mode */
+	if (nr < NR_VX855_GPI)
+		return -EINVAL;
+
+	/* True GPO don't need to be switched to output mode,
+	 * and GPIO are open-drain, i.e. also need no switching,
+	 * so all we do is set the level */
+	vx855gpio_set(gpio, nr, val);
+
+	return 0;
+}
+
+static const char *vx855gpio_names[NR_VX855_GP] = {
+	"VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4",
+	"VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9",
+	"VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13",
+	"VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4",
+	"VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9",
+	"VX855_GPO10", "VX855_GPO11", "VX855_GPO12",
+	"VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3",
+	"VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7",
+	"VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11",
+	"VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14"
+};
+
+static void vx855gpio_gpio_setup(struct vx855_gpio *vg)
+{
+	struct gpio_chip *c = &vg->gpio;
+
+	c->label = "VX855 South Bridge";
+	c->owner = THIS_MODULE;
+	c->direction_input = vx855gpio_direction_input;
+	c->direction_output = vx855gpio_direction_output;
+	c->get = vx855gpio_get;
+	c->set = vx855gpio_set;
+	c->dbg_show = NULL;
+	c->base = 0;
+	c->ngpio = NR_VX855_GP;
+	c->can_sleep = 0;
+	c->names = vx855gpio_names;
+}
+
+/* This platform device is ordinarily registered by the vx855 mfd driver */
+static __devinit int vx855gpio_probe(struct platform_device *pdev)
+{
+	struct resource *res_gpi;
+	struct resource *res_gpo;
+	struct vx855_gpio *vg;
+	int ret;
+
+	res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1);
+	if (!res_gpi || !res_gpo)
+		return -EBUSY;
+
+	vg = kzalloc(sizeof(*vg), GFP_KERNEL);
+	if (!vg)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, vg);
+
+	dev_info(&pdev->dev, "found VX855 GPIO controller\n");
+	vg->io_gpi = res_gpi->start;
+	vg->io_gpo = res_gpo->start;
+	spin_lock_init(&vg->lock);
+
+	/*
+	 * A single byte is used to control various GPIO ports on the VX855,
+	 * and in the case of the OLPC XO-1.5, some of those ports are used
+	 * for switches that are interpreted and exposed through ACPI. ACPI
+	 * will have reserved the region, so our own reservation will not
+	 * succeed. Ignore and continue.
+	 */
+
+	if (!request_region(res_gpi->start, resource_size(res_gpi),
+			MODULE_NAME "_gpi"))
+		dev_warn(&pdev->dev,
+			"GPI I/O resource busy, probably claimed by ACPI\n");
+	else
+		vg->gpi_reserved = true;
+
+	if (!request_region(res_gpo->start, resource_size(res_gpo),
+			MODULE_NAME "_gpo"))
+		dev_warn(&pdev->dev,
+			"GPO I/O resource busy, probably claimed by ACPI\n");
+	else
+		vg->gpo_reserved = true;
+
+	vx855gpio_gpio_setup(vg);
+
+	ret = gpiochip_add(&vg->gpio);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register GPIOs\n");
+		goto out_release;
+	}
+
+	return 0;
+
+out_release:
+	if (vg->gpi_reserved)
+		release_region(res_gpi->start, resource_size(res_gpi));
+	if (vg->gpo_reserved)
+		release_region(res_gpi->start, resource_size(res_gpo));
+	platform_set_drvdata(pdev, NULL);
+	kfree(vg);
+	return ret;
+}
+
+static int __devexit vx855gpio_remove(struct platform_device *pdev)
+{
+	struct vx855_gpio *vg = platform_get_drvdata(pdev);
+	struct resource *res;
+
+	if (gpiochip_remove(&vg->gpio))
+		dev_err(&pdev->dev, "unable to remove gpio_chip?\n");
+
+	if (vg->gpi_reserved) {
+		res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+		release_region(res->start, resource_size(res));
+	}
+	if (vg->gpo_reserved) {
+		res = platform_get_resource(pdev, IORESOURCE_IO, 1);
+		release_region(res->start, resource_size(res));
+	}
+
+	platform_set_drvdata(pdev, NULL);
+	kfree(vg);
+	return 0;
+}
+
+static struct platform_driver vx855gpio_driver = {
+	.driver = {
+		.name	= MODULE_NAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= vx855gpio_probe,
+	.remove		= __devexit_p(vx855gpio_remove),
+};
+
+static int vx855gpio_init(void)
+{
+	return platform_driver_register(&vx855gpio_driver);
+}
+module_init(vx855gpio_init);
+
+static void vx855gpio_exit(void)
+{
+	platform_driver_unregister(&vx855gpio_driver);
+}
+module_exit(vx855gpio_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
+MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset");
+MODULE_ALIAS("platform:vx855_gpio");
...	...	@@ -116,6 +116,18 @@
116	116	This driver can also be built as a module. If so, the module
117	117	will be called sch-gpio.
118	118
	119	+config GPIO_VX855
	120	+ tristate "VIA VX855/VX875 GPIO"
	121	+ depends on GPIOLIB
	122	+ select MFD_CORE
	123	+ select MFD_VX855
	124	+ help
	125	+ Support access to the VX855/VX875 GPIO lines through the gpio library.
	126	+
	127	+ This driver provides common support for accessing the device,
	128	+ additional drivers must be enabled in order to use the
	129	+ functionality of the device.
	130	+
119	131	comment "I2C GPIO expanders:"
120	132
121	133	config GPIO_MAX7300
...	...	@@ -40,4 +40,5 @@
40	40	obj-$(CONFIG_GPIO_RDC321X) += rdc321x-gpio.o
41	41	obj-$(CONFIG_GPIO_JANZ_TTL) += janz-ttl.o
42	42	obj-$(CONFIG_GPIO_SX150X) += sx150x.o
	43	+obj-$(CONFIG_GPIO_VX855) += vx855_gpio.o
	1	+/*
	2	+ * Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO
	3	+ *
	4	+ * Copyright (C) 2009 VIA Technologies, Inc.
	5	+ * Copyright (C) 2010 One Laptop per Child
	6	+ * Author: Harald Welte <HaraldWelte@viatech.com>
	7	+ * All rights reserved.
	8	+ *
	9	+ * This program is free software; you can redistribute it and/or
	10	+ * modify it under the terms of the GNU General Public License as
	11	+ * published by the Free Software Foundation; either version 2 of
	12	+ * the License, or (at your option) any later version.
	13	+ *
	14	+ * This program is distributed in the hope that it will be useful,
	15	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	+ * GNU General Public License for more details.
	18	+ *
	19	+ * You should have received a copy of the GNU General Public License
	20	+ * along with this program; if not, write to the Free Software
	21	+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
	22	+ * MA 02111-1307 USA
	23	+ *
	24	+ */
	25	+
	26	+#include <linux/kernel.h>
	27	+#include <linux/module.h>
	28	+#include <linux/gpio.h>
	29	+#include <linux/device.h>
	30	+#include <linux/platform_device.h>
	31	+#include <linux/pci.h>
	32	+#include <linux/io.h>
	33	+
	34	+#define MODULE_NAME "vx855_gpio"
	35	+
	36	+/* The VX855 south bridge has the following GPIO pins:
	37	+ * GPI 0...13 General Purpose Input
	38	+ * GPO 0...12 General Purpose Output
	39	+ * GPIO 0...14 General Purpose I/O (Open-Drain)
	40	+ */
	41	+
	42	+#define NR_VX855_GPI 14
	43	+#define NR_VX855_GPO 13
	44	+#define NR_VX855_GPIO 15
	45	+
	46	+#define NR_VX855_GPInO (NR_VX855_GPI + NR_VX855_GPO)
	47	+#define NR_VX855_GP (NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO)
	48	+
	49	+struct vx855_gpio {
	50	+ struct gpio_chip gpio;
	51	+ spinlock_t lock;
	52	+ u32 io_gpi;
	53	+ u32 io_gpo;
	54	+ bool gpi_reserved;
	55	+ bool gpo_reserved;
	56	+};
	57	+
	58	+/* resolve a GPIx into the corresponding bit position */
	59	+static inline u_int32_t gpi_i_bit(int i)
	60	+{
	61	+ if (i < 10)
	62	+ return 1 << i;
	63	+ else
	64	+ return 1 << (i + 14);
	65	+}
	66	+
	67	+static inline u_int32_t gpo_o_bit(int i)
	68	+{
	69	+ if (i < 11)
	70	+ return 1 << i;
	71	+ else
	72	+ return 1 << (i + 14);
	73	+}
	74	+
	75	+static inline u_int32_t gpio_i_bit(int i)
	76	+{
	77	+ if (i < 14)
	78	+ return 1 << (i + 10);
	79	+ else
	80	+ return 1 << (i + 14);
	81	+}
	82	+
	83	+static inline u_int32_t gpio_o_bit(int i)
	84	+{
	85	+ if (i < 14)
	86	+ return 1 << (i + 11);
	87	+ else
	88	+ return 1 << (i + 13);
	89	+}
	90	+
	91	+/* Mapping betwee numeric GPIO ID and the actual GPIO hardware numbering:
	92	+ * 0..13 GPI 0..13
	93	+ * 14..26 GPO 0..12
	94	+ * 27..41 GPIO 0..14
	95	+ */
	96	+
	97	+static int vx855gpio_direction_input(struct gpio_chip *gpio,
	98	+ unsigned int nr)
	99	+{
	100	+ struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
	101	+ unsigned long flags;
	102	+ u_int32_t reg_out;
	103	+
	104	+ /* Real GPI bits are always in input direction */
	105	+ if (nr < NR_VX855_GPI)
	106	+ return 0;
	107	+
	108	+ /* Real GPO bits cannot be put in output direction */
	109	+ if (nr < NR_VX855_GPInO)
	110	+ return -EINVAL;
	111	+
	112	+ /* Open Drain GPIO have to be set to one */
	113	+ spin_lock_irqsave(&vg->lock, flags);
	114	+ reg_out = inl(vg->io_gpo);
	115	+ reg_out \|= gpio_o_bit(nr - NR_VX855_GPInO);
	116	+ outl(reg_out, vg->io_gpo);
	117	+ spin_unlock_irqrestore(&vg->lock, flags);
	118	+
	119	+ return 0;
	120	+}
	121	+
	122	+static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr)
	123	+{
	124	+ struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
	125	+ u_int32_t reg_in;
	126	+ int ret = 0;
	127	+
	128	+ if (nr < NR_VX855_GPI) {
	129	+ reg_in = inl(vg->io_gpi);
	130	+ if (reg_in & gpi_i_bit(nr))
	131	+ ret = 1;
	132	+ } else if (nr < NR_VX855_GPInO) {
	133	+ /* GPO don't have an input bit, we need to read it
	134	+ * back from the output register */
	135	+ reg_in = inl(vg->io_gpo);
	136	+ if (reg_in & gpo_o_bit(nr - NR_VX855_GPI))
	137	+ ret = 1;
	138	+ } else {
	139	+ reg_in = inl(vg->io_gpi);
	140	+ if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO))
	141	+ ret = 1;
	142	+ }
	143	+
	144	+ return ret;
	145	+}
	146	+
	147	+static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr,
	148	+ int val)
	149	+{
	150	+ struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
	151	+ unsigned long flags;
	152	+ u_int32_t reg_out;
	153	+
	154	+ /* True GPI cannot be switched to output mode */
	155	+ if (nr < NR_VX855_GPI)
	156	+ return;
	157	+
	158	+ spin_lock_irqsave(&vg->lock, flags);
	159	+ reg_out = inl(vg->io_gpo);
	160	+ if (nr < NR_VX855_GPInO) {
	161	+ if (val)
	162	+ reg_out \|= gpo_o_bit(nr - NR_VX855_GPI);
	163	+ else
	164	+ reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI);
	165	+ } else {
	166	+ if (val)
	167	+ reg_out \|= gpio_o_bit(nr - NR_VX855_GPInO);
	168	+ else
	169	+ reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO);
	170	+ }
	171	+ outl(reg_out, vg->io_gpo);
	172	+ spin_unlock_irqrestore(&vg->lock, flags);
	173	+}
	174	+
	175	+static int vx855gpio_direction_output(struct gpio_chip *gpio,
	176	+ unsigned int nr, int val)
	177	+{
	178	+ /* True GPI cannot be switched to output mode */
	179	+ if (nr < NR_VX855_GPI)
	180	+ return -EINVAL;
	181	+
	182	+ /* True GPO don't need to be switched to output mode,
	183	+ * and GPIO are open-drain, i.e. also need no switching,
	184	+ * so all we do is set the level */
	185	+ vx855gpio_set(gpio, nr, val);
	186	+
	187	+ return 0;
	188	+}
	189	+
	190	+static const char *vx855gpio_names[NR_VX855_GP] = {
	191	+ "VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4",
	192	+ "VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9",
	193	+ "VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13",
	194	+ "VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4",
	195	+ "VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9",
	196	+ "VX855_GPO10", "VX855_GPO11", "VX855_GPO12",
	197	+ "VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3",
	198	+ "VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7",
	199	+ "VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11",
	200	+ "VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14"
	201	+};
	202	+
	203	+static void vx855gpio_gpio_setup(struct vx855_gpio *vg)
	204	+{
	205	+ struct gpio_chip *c = &vg->gpio;
	206	+
	207	+ c->label = "VX855 South Bridge";
	208	+ c->owner = THIS_MODULE;
	209	+ c->direction_input = vx855gpio_direction_input;
	210	+ c->direction_output = vx855gpio_direction_output;
	211	+ c->get = vx855gpio_get;
	212	+ c->set = vx855gpio_set;
	213	+ c->dbg_show = NULL;
	214	+ c->base = 0;
	215	+ c->ngpio = NR_VX855_GP;
	216	+ c->can_sleep = 0;
	217	+ c->names = vx855gpio_names;
	218	+}
	219	+
	220	+/* This platform device is ordinarily registered by the vx855 mfd driver */
	221	+static __devinit int vx855gpio_probe(struct platform_device *pdev)
	222	+{
	223	+ struct resource *res_gpi;
	224	+ struct resource *res_gpo;
	225	+ struct vx855_gpio *vg;
	226	+ int ret;
	227	+
	228	+ res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0);
	229	+ res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1);
	230	+ if (!res_gpi \|\| !res_gpo)
	231	+ return -EBUSY;
	232	+
	233	+ vg = kzalloc(sizeof(*vg), GFP_KERNEL);
	234	+ if (!vg)
	235	+ return -ENOMEM;
	236	+
	237	+ platform_set_drvdata(pdev, vg);
	238	+
	239	+ dev_info(&pdev->dev, "found VX855 GPIO controller\n");
	240	+ vg->io_gpi = res_gpi->start;
	241	+ vg->io_gpo = res_gpo->start;
	242	+ spin_lock_init(&vg->lock);
	243	+
	244	+ /*
	245	+ * A single byte is used to control various GPIO ports on the VX855,
	246	+ * and in the case of the OLPC XO-1.5, some of those ports are used
	247	+ * for switches that are interpreted and exposed through ACPI. ACPI
	248	+ * will have reserved the region, so our own reservation will not
	249	+ * succeed. Ignore and continue.
	250	+ */
	251	+
	252	+ if (!request_region(res_gpi->start, resource_size(res_gpi),
	253	+ MODULE_NAME "_gpi"))
	254	+ dev_warn(&pdev->dev,
	255	+ "GPI I/O resource busy, probably claimed by ACPI\n");
	256	+ else
	257	+ vg->gpi_reserved = true;
	258	+
	259	+ if (!request_region(res_gpo->start, resource_size(res_gpo),
	260	+ MODULE_NAME "_gpo"))
	261	+ dev_warn(&pdev->dev,
	262	+ "GPO I/O resource busy, probably claimed by ACPI\n");
	263	+ else
	264	+ vg->gpo_reserved = true;
	265	+
	266	+ vx855gpio_gpio_setup(vg);
	267	+
	268	+ ret = gpiochip_add(&vg->gpio);
	269	+ if (ret) {
	270	+ dev_err(&pdev->dev, "failed to register GPIOs\n");
	271	+ goto out_release;
	272	+ }
	273	+
	274	+ return 0;
	275	+
	276	+out_release:
	277	+ if (vg->gpi_reserved)
	278	+ release_region(res_gpi->start, resource_size(res_gpi));
	279	+ if (vg->gpo_reserved)
	280	+ release_region(res_gpi->start, resource_size(res_gpo));
	281	+ platform_set_drvdata(pdev, NULL);
	282	+ kfree(vg);
	283	+ return ret;
	284	+}
	285	+
	286	+static int __devexit vx855gpio_remove(struct platform_device *pdev)
	287	+{
	288	+ struct vx855_gpio *vg = platform_get_drvdata(pdev);
	289	+ struct resource *res;
	290	+
	291	+ if (gpiochip_remove(&vg->gpio))
	292	+ dev_err(&pdev->dev, "unable to remove gpio_chip?\n");
	293	+
	294	+ if (vg->gpi_reserved) {
	295	+ res = platform_get_resource(pdev, IORESOURCE_IO, 0);
	296	+ release_region(res->start, resource_size(res));
	297	+ }
	298	+ if (vg->gpo_reserved) {
	299	+ res = platform_get_resource(pdev, IORESOURCE_IO, 1);
	300	+ release_region(res->start, resource_size(res));
	301	+ }
	302	+
	303	+ platform_set_drvdata(pdev, NULL);
	304	+ kfree(vg);
	305	+ return 0;
	306	+}
	307	+
	308	+static struct platform_driver vx855gpio_driver = {
	309	+ .driver = {
	310	+ .name = MODULE_NAME,
	311	+ .owner = THIS_MODULE,
	312	+ },
	313	+ .probe = vx855gpio_probe,
	314	+ .remove = __devexit_p(vx855gpio_remove),
	315	+};
	316	+
	317	+static int vx855gpio_init(void)
	318	+{
	319	+ return platform_driver_register(&vx855gpio_driver);
	320	+}
	321	+module_init(vx855gpio_init);
	322	+
	323	+static void vx855gpio_exit(void)
	324	+{
	325	+ platform_driver_unregister(&vx855gpio_driver);
	326	+}
	327	+module_exit(vx855gpio_exit);
	328	+
	329	+MODULE_LICENSE("GPL");
	330	+MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
	331	+MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset");
	332	+MODULE_ALIAS("platform:vx855_gpio");