1// SPDX-License-Identifier: GPL-2.0+ 2/* 3 * Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO 4 * 5 * Copyright (C) 2009 VIA Technologies, Inc. 6 * Copyright (C) 2010 One Laptop per Child 7 * Author: Harald Welte <HaraldWelte@viatech.com> 8 * All rights reserved. 9 */ 10#include <linux/kernel.h> 11#include <linux/module.h> 12#include <linux/gpio/driver.h> 13#include <linux/slab.h> 14#include <linux/device.h> 15#include <linux/platform_device.h> 16#include <linux/pci.h> 17#include <linux/io.h> 18 19#define MODULE_NAME "vx855_gpio" 20 21/* The VX855 south bridge has the following GPIO pins: 22 * GPI 0...13 General Purpose Input 23 * GPO 0...12 General Purpose Output 24 * GPIO 0...14 General Purpose I/O (Open-Drain) 25 */ 26 27#define NR_VX855_GPI 14 28#define NR_VX855_GPO 13 29#define NR_VX855_GPIO 15 30 31#define NR_VX855_GPInO (NR_VX855_GPI + NR_VX855_GPO) 32#define NR_VX855_GP (NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO) 33 34struct vx855_gpio { 35 struct gpio_chip gpio; 36 spinlock_t lock; 37 u32 io_gpi; 38 u32 io_gpo; 39}; 40 41/* resolve a GPIx into the corresponding bit position */ 42static inline u_int32_t gpi_i_bit(int i) 43{ 44 if (i < 10) 45 return 1 << i; 46 else 47 return 1 << (i + 14); 48} 49 50static inline u_int32_t gpo_o_bit(int i) 51{ 52 if (i < 11) 53 return 1 << i; 54 else 55 return 1 << (i + 14); 56} 57 58static inline u_int32_t gpio_i_bit(int i) 59{ 60 if (i < 14) 61 return 1 << (i + 10); 62 else 63 return 1 << (i + 14); 64} 65 66static inline u_int32_t gpio_o_bit(int i) 67{ 68 if (i < 14) 69 return 1 << (i + 11); 70 else 71 return 1 << (i + 13); 72} 73 74/* Mapping between numeric GPIO ID and the actual GPIO hardware numbering: 75 * 0..13 GPI 0..13 76 * 14..26 GPO 0..12 77 * 27..41 GPIO 0..14 78 */ 79 80static int vx855gpio_direction_input(struct gpio_chip *gpio, 81 unsigned int nr) 82{ 83 struct vx855_gpio *vg = gpiochip_get_data(gpio); 84 unsigned long flags; 85 u_int32_t reg_out; 86 87 /* Real GPI bits are always in input direction */ 88 if (nr < NR_VX855_GPI) 89 return 0; 90 91 /* Real GPO bits cannot be put in output direction */ 92 if (nr < NR_VX855_GPInO) 93 return -EINVAL; 94 95 /* Open Drain GPIO have to be set to one */ 96 spin_lock_irqsave(&vg->lock, flags); 97 reg_out = inl(vg->io_gpo); 98 reg_out |= gpio_o_bit(nr - NR_VX855_GPInO); 99 outl(reg_out, vg->io_gpo); 100 spin_unlock_irqrestore(&vg->lock, flags); 101 102 return 0; 103} 104 105static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr) 106{ 107 struct vx855_gpio *vg = gpiochip_get_data(gpio); 108 u_int32_t reg_in; 109 int ret = 0; 110 111 if (nr < NR_VX855_GPI) { 112 reg_in = inl(vg->io_gpi); 113 if (reg_in & gpi_i_bit(nr)) 114 ret = 1; 115 } else if (nr < NR_VX855_GPInO) { 116 /* GPO don't have an input bit, we need to read it 117 * back from the output register */ 118 reg_in = inl(vg->io_gpo); 119 if (reg_in & gpo_o_bit(nr - NR_VX855_GPI)) 120 ret = 1; 121 } else { 122 reg_in = inl(vg->io_gpi); 123 if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO)) 124 ret = 1; 125 } 126 127 return ret; 128} 129 130static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr, 131 int val) 132{ 133 struct vx855_gpio *vg = gpiochip_get_data(gpio); 134 unsigned long flags; 135 u_int32_t reg_out; 136 137 /* True GPI cannot be switched to output mode */ 138 if (nr < NR_VX855_GPI) 139 return; 140 141 spin_lock_irqsave(&vg->lock, flags); 142 reg_out = inl(vg->io_gpo); 143 if (nr < NR_VX855_GPInO) { 144 if (val) 145 reg_out |= gpo_o_bit(nr - NR_VX855_GPI); 146 else 147 reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI); 148 } else { 149 if (val) 150 reg_out |= gpio_o_bit(nr - NR_VX855_GPInO); 151 else 152 reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO); 153 } 154 outl(reg_out, vg->io_gpo); 155 spin_unlock_irqrestore(&vg->lock, flags); 156} 157 158static int vx855gpio_direction_output(struct gpio_chip *gpio, 159 unsigned int nr, int val) 160{ 161 /* True GPI cannot be switched to output mode */ 162 if (nr < NR_VX855_GPI) 163 return -EINVAL; 164 165 /* True GPO don't need to be switched to output mode, 166 * and GPIO are open-drain, i.e. also need no switching, 167 * so all we do is set the level */ 168 vx855gpio_set(gpio, nr, val); 169 170 return 0; 171} 172 173static int vx855gpio_set_config(struct gpio_chip *gpio, unsigned int nr, 174 unsigned long config) 175{ 176 enum pin_config_param param = pinconf_to_config_param(config); 177 178 /* The GPI cannot be single-ended */ 179 if (nr < NR_VX855_GPI) 180 return -EINVAL; 181 182 /* The GPO's are push-pull */ 183 if (nr < NR_VX855_GPInO) { 184 if (param != PIN_CONFIG_DRIVE_PUSH_PULL) 185 return -ENOTSUPP; 186 return 0; 187 } 188 189 /* The GPIO's are open drain */ 190 if (param != PIN_CONFIG_DRIVE_OPEN_DRAIN) 191 return -ENOTSUPP; 192 193 return 0; 194} 195 196static const char *vx855gpio_names[NR_VX855_GP] = { 197 "VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4", 198 "VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9", 199 "VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13", 200 "VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4", 201 "VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9", 202 "VX855_GPO10", "VX855_GPO11", "VX855_GPO12", 203 "VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3", 204 "VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7", 205 "VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11", 206 "VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14" 207}; 208 209static void vx855gpio_gpio_setup(struct vx855_gpio *vg) 210{ 211 struct gpio_chip *c = &vg->gpio; 212 213 c->label = "VX855 South Bridge"; 214 c->owner = THIS_MODULE; 215 c->direction_input = vx855gpio_direction_input; 216 c->direction_output = vx855gpio_direction_output; 217 c->get = vx855gpio_get; 218 c->set = vx855gpio_set; 219 c->set_config = vx855gpio_set_config; 220 c->dbg_show = NULL; 221 c->base = 0; 222 c->ngpio = NR_VX855_GP; 223 c->can_sleep = false; 224 c->names = vx855gpio_names; 225} 226 227/* This platform device is ordinarily registered by the vx855 mfd driver */ 228static int vx855gpio_probe(struct platform_device *pdev) 229{ 230 struct resource *res_gpi; 231 struct resource *res_gpo; 232 struct vx855_gpio *vg; 233 234 res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0); 235 res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1); 236 if (!res_gpi || !res_gpo) 237 return -EBUSY; 238 239 vg = devm_kzalloc(&pdev->dev, sizeof(*vg), GFP_KERNEL); 240 if (!vg) 241 return -ENOMEM; 242 243 dev_info(&pdev->dev, "found VX855 GPIO controller\n"); 244 vg->io_gpi = res_gpi->start; 245 vg->io_gpo = res_gpo->start; 246 spin_lock_init(&vg->lock); 247 248 /* 249 * A single byte is used to control various GPIO ports on the VX855, 250 * and in the case of the OLPC XO-1.5, some of those ports are used 251 * for switches that are interpreted and exposed through ACPI. ACPI 252 * will have reserved the region, so our own reservation will not 253 * succeed. Ignore and continue. 254 */ 255 256 if (!devm_request_region(&pdev->dev, res_gpi->start, 257 resource_size(res_gpi), MODULE_NAME "_gpi")) 258 dev_warn(&pdev->dev, 259 "GPI I/O resource busy, probably claimed by ACPI\n"); 260 261 if (!devm_request_region(&pdev->dev, res_gpo->start, 262 resource_size(res_gpo), MODULE_NAME "_gpo")) 263 dev_warn(&pdev->dev, 264 "GPO I/O resource busy, probably claimed by ACPI\n"); 265 266 vx855gpio_gpio_setup(vg); 267 268 return devm_gpiochip_add_data(&pdev->dev, &vg->gpio, vg); 269} 270 271static struct platform_driver vx855gpio_driver = { 272 .driver = { 273 .name = MODULE_NAME, 274 }, 275 .probe = vx855gpio_probe, 276}; 277 278module_platform_driver(vx855gpio_driver); 279 280MODULE_LICENSE("GPL"); 281MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>"); 282MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset"); 283MODULE_ALIAS("platform:vx855_gpio"); 284