// SPDX-License-Identifier: GPL-2.0+ /* * 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. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/gpio/driver.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; }; /* 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 = gpiochip_get_data(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 = gpiochip_get_data(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 = gpiochip_get_data(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 int vx855gpio_set_config(struct gpio_chip *gpio, unsigned int nr, unsigned long config) { enum pin_config_param param = pinconf_to_config_param(config); /* The GPI cannot be single-ended */ if (nr < NR_VX855_GPI) return -EINVAL; /* The GPO's are push-pull */ if (nr < NR_VX855_GPInO) { if (param != PIN_CONFIG_DRIVE_PUSH_PULL) return -ENOTSUPP; return 0; } /* The GPIO's are open drain */ if (param != PIN_CONFIG_DRIVE_OPEN_DRAIN) return -ENOTSUPP; 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->set_config = vx855gpio_set_config, c->dbg_show = NULL; c->base = 0; c->ngpio = NR_VX855_GP; c->can_sleep = false; c->names = vx855gpio_names; } /* This platform device is ordinarily registered by the vx855 mfd driver */ static int vx855gpio_probe(struct platform_device *pdev) { struct resource *res_gpi; struct resource *res_gpo; struct vx855_gpio *vg; 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 = devm_kzalloc(&pdev->dev, 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 (!devm_request_region(&pdev->dev, res_gpi->start, resource_size(res_gpi), MODULE_NAME "_gpi")) dev_warn(&pdev->dev, "GPI I/O resource busy, probably claimed by ACPI\n"); if (!devm_request_region(&pdev->dev, res_gpo->start, resource_size(res_gpo), MODULE_NAME "_gpo")) dev_warn(&pdev->dev, "GPO I/O resource busy, probably claimed by ACPI\n"); vx855gpio_gpio_setup(vg); return devm_gpiochip_add_data(&pdev->dev, &vg->gpio, vg); } static struct platform_driver vx855gpio_driver = { .driver = { .name = MODULE_NAME, }, .probe = vx855gpio_probe, }; module_platform_driver(vx855gpio_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>"); MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset"); MODULE_ALIAS("platform:vx855_gpio");