--- /dev/null
+/*
+ * 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");
projects / GitHub / exynos8895 / android_kernel_samsung_universal8895.git / commitdiff