diff options
Diffstat (limited to 'drivers/gpio/gpio-vx855.c')
| -rw-r--r-- | drivers/gpio/gpio-vx855.c | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-vx855.c b/drivers/gpio/gpio-vx855.c new file mode 100644 index 0000000..ef5aabd --- /dev/null +++ b/drivers/gpio/gpio-vx855.c @@ -0,0 +1,333 @@ +/* + * 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/slab.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"); |
