drivers/gpio/gpio-104-idio-16.c

   1 /*
   2  * GPIO driver for the ACCES 104-IDIO-16 family
   3  * Copyright (C) 2015 William Breathitt Gray
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  */
  14 #include <linux/bitops.h>
  15 #include <linux/device.h>
  16 #include <linux/errno.h>
  17 #include <linux/gpio/driver.h>
  18 #include <linux/io.h>
  19 #include <linux/ioport.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/irqdesc.h>
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/spinlock.h>
  27
  28 static unsigned idio_16_base;
  29 module_param(idio_16_base, uint, 0);
  30 MODULE_PARM_DESC(idio_16_base, "ACCES 104-IDIO-16 base address");
  31 static unsigned idio_16_irq;
  32 module_param(idio_16_irq, uint, 0);
  33 MODULE_PARM_DESC(idio_16_irq, "ACCES 104-IDIO-16 interrupt line number");
  34
  35 /**
  36  * struct idio_16_gpio - GPIO device private data structure
  37  * @chip:       instance of the gpio_chip
  38  * @lock:       synchronization lock to prevent I/O race conditions
  39  * @irq_mask:   I/O bits affected by interrupts
  40  * @base:       base port address of the GPIO device
  41  * @irq:        Interrupt line number
  42  * @out_state:  output bits state
  43  */
  44 struct idio_16_gpio {
  45         struct gpio_chip chip;
  46         spinlock_t lock;
  47         unsigned long irq_mask;
  48         unsigned base;
  49         unsigned irq;
  50         unsigned out_state;
  51 };
  52
  53 static int idio_16_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
  54 {
  55         if (offset > 15)
  56                 return 1;
  57
  58         return 0;
  59 }
  60
  61 static int idio_16_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  62 {
  63         return 0;
  64 }
  65
  66 static int idio_16_gpio_direction_output(struct gpio_chip *chip,
  67         unsigned offset, int value)
  68 {
  69         chip->set(chip, offset, value);
  70         return 0;
  71 }
  72
  73 static int idio_16_gpio_get(struct gpio_chip *chip, unsigned offset)
  74 {
  75         struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
  76         const unsigned mask = BIT(offset-16);
  77
  78         if (offset < 16)
  79                 return -EINVAL;
  80
  81         if (offset < 24)
  82                 return !!(inb(idio16gpio->base + 1) & mask);
  83
  84         return !!(inb(idio16gpio->base + 5) & (mask>>8));
  85 }
  86
  87 static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  88 {
  89         struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
  90         const unsigned mask = BIT(offset);
  91         unsigned long flags;
  92
  93         if (offset > 15)
  94                 return;
  95
  96         spin_lock_irqsave(&idio16gpio->lock, flags);
  97
  98         if (value)
  99                 idio16gpio->out_state |= mask;
 100         else
 101                 idio16gpio->out_state &= ~mask;
 102
 103         if (offset > 7)
 104                 outb(idio16gpio->out_state >> 8, idio16gpio->base + 4);
 105         else
 106                 outb(idio16gpio->out_state, idio16gpio->base);
 107
 108         spin_unlock_irqrestore(&idio16gpio->lock, flags);
 109 }
 110
 111 static void idio_16_irq_ack(struct irq_data *data)
 112 {
 113 }
 114
 115 static void idio_16_irq_mask(struct irq_data *data)
 116 {
 117         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 118         struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
 119         const unsigned long mask = BIT(irqd_to_hwirq(data));
 120         unsigned long flags;
 121
 122         idio16gpio->irq_mask &= ~mask;
 123
 124         if (!idio16gpio->irq_mask) {
 125                 spin_lock_irqsave(&idio16gpio->lock, flags);
 126
 127                 outb(0, idio16gpio->base + 2);
 128
 129                 spin_unlock_irqrestore(&idio16gpio->lock, flags);
 130         }
 131 }
 132
 133 static void idio_16_irq_unmask(struct irq_data *data)
 134 {
 135         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 136         struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
 137         const unsigned long mask = BIT(irqd_to_hwirq(data));
 138         const unsigned long prev_irq_mask = idio16gpio->irq_mask;
 139         unsigned long flags;
 140
 141         idio16gpio->irq_mask |= mask;
 142
 143         if (!prev_irq_mask) {
 144                 spin_lock_irqsave(&idio16gpio->lock, flags);
 145
 146                 inb(idio16gpio->base + 2);
 147
 148                 spin_unlock_irqrestore(&idio16gpio->lock, flags);
 149         }
 150 }
 151
 152 static int idio_16_irq_set_type(struct irq_data *data, unsigned flow_type)
 153 {
 154         /* The only valid irq types are none and both-edges */
 155         if (flow_type != IRQ_TYPE_NONE &&
 156                 (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
 157                 return -EINVAL;
 158
 159         return 0;
 160 }
 161
 162 static struct irq_chip idio_16_irqchip = {
 163         .name = "104-idio-16",
 164         .irq_ack = idio_16_irq_ack,
 165         .irq_mask = idio_16_irq_mask,
 166         .irq_unmask = idio_16_irq_unmask,
 167         .irq_set_type = idio_16_irq_set_type
 168 };
 169
 170 static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
 171 {
 172         struct idio_16_gpio *const idio16gpio = dev_id;
 173         struct gpio_chip *const chip = &idio16gpio->chip;
 174         int gpio;
 175
 176         for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
 177                 generic_handle_irq(irq_find_mapping(chip->irqdomain, gpio));
 178
 179         spin_lock(&idio16gpio->lock);
 180
 181         outb(0, idio16gpio->base + 1);
 182
 183         spin_unlock(&idio16gpio->lock);
 184
 185         return IRQ_HANDLED;
 186 }
 187
 188 static int __init idio_16_probe(struct platform_device *pdev)
 189 {
 190         struct device *dev = &pdev->dev;
 191         struct idio_16_gpio *idio16gpio;
 192         const unsigned base = idio_16_base;
 193         const unsigned extent = 8;
 194         const char *const name = dev_name(dev);
 195         int err;
 196         const unsigned irq = idio_16_irq;
 197
 198         idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
 199         if (!idio16gpio)
 200                 return -ENOMEM;
 201
 202         if (!devm_request_region(dev, base, extent, name)) {
 203                 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
 204                         base, base + extent);
 205                 return -EBUSY;
 206         }
 207
 208         idio16gpio->chip.label = name;
 209         idio16gpio->chip.parent = dev;
 210         idio16gpio->chip.owner = THIS_MODULE;
 211         idio16gpio->chip.base = -1;
 212         idio16gpio->chip.ngpio = 32;
 213         idio16gpio->chip.get_direction = idio_16_gpio_get_direction;
 214         idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
 215         idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
 216         idio16gpio->chip.get = idio_16_gpio_get;
 217         idio16gpio->chip.set = idio_16_gpio_set;
 218         idio16gpio->base = base;
 219         idio16gpio->irq = irq;
 220         idio16gpio->out_state = 0xFFFF;
 221
 222         spin_lock_init(&idio16gpio->lock);
 223
 224         dev_set_drvdata(dev, idio16gpio);
 225
 226         err = gpiochip_add_data(&idio16gpio->chip, idio16gpio);
 227         if (err) {
 228                 dev_err(dev, "GPIO registering failed (%d)\n", err);
 229                 return err;
 230         }
 231
 232         /* Disable IRQ by default */
 233         outb(0, base + 2);
 234         outb(0, base + 1);
 235
 236         err = gpiochip_irqchip_add(&idio16gpio->chip, &idio_16_irqchip, 0,
 237                 handle_edge_irq, IRQ_TYPE_NONE);
 238         if (err) {
 239                 dev_err(dev, "Could not add irqchip (%d)\n", err);
 240                 goto err_gpiochip_remove;
 241         }
 242
 243         err = request_irq(irq, idio_16_irq_handler, 0, name, idio16gpio);
 244         if (err) {
 245                 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
 246                 goto err_gpiochip_remove;
 247         }
 248
 249         return 0;
 250
 251 err_gpiochip_remove:
 252         gpiochip_remove(&idio16gpio->chip);
 253         return err;
 254 }
 255
 256 static int idio_16_remove(struct platform_device *pdev)
 257 {
 258         struct idio_16_gpio *const idio16gpio = platform_get_drvdata(pdev);
 259
 260         free_irq(idio16gpio->irq, idio16gpio);
 261         gpiochip_remove(&idio16gpio->chip);
 262
 263         return 0;
 264 }
 265
 266 static struct platform_device *idio_16_device;
 267
 268 static struct platform_driver idio_16_driver = {
 269         .driver = {
 270                 .name = "104-idio-16"
 271         },
 272         .remove = idio_16_remove
 273 };
 274
 275 static void __exit idio_16_exit(void)
 276 {
 277         platform_device_unregister(idio_16_device);
 278         platform_driver_unregister(&idio_16_driver);
 279 }
 280
 281 static int __init idio_16_init(void)
 282 {
 283         int err;
 284
 285         idio_16_device = platform_device_alloc(idio_16_driver.driver.name, -1);
 286         if (!idio_16_device)
 287                 return -ENOMEM;
 288
 289         err = platform_device_add(idio_16_device);
 290         if (err)
 291                 goto err_platform_device;
 292
 293         err = platform_driver_probe(&idio_16_driver, idio_16_probe);
 294         if (err)
 295                 goto err_platform_driver;
 296
 297         return 0;
 298
 299 err_platform_driver:
 300         platform_device_del(idio_16_device);
 301 err_platform_device:
 302         platform_device_put(idio_16_device);
 303         return err;
 304 }
 305
 306 module_init(idio_16_init);
 307 module_exit(idio_16_exit);
 308
 309 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 310 MODULE_DESCRIPTION("ACCES 104-IDIO-16 GPIO driver");
 311 MODULE_LICENSE("GPL v2");