drivers/gpio/gpio-104-idi-48.c

   1 /*
   2  * GPIO driver for the ACCES 104-IDI-48 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  * This driver supports the following ACCES devices: 104-IDI-48A,
  15  * 104-IDI-48AC, 104-IDI-48B, and 104-IDI-48BC.
  16  */
  17 #include <linux/bitops.h>
  18 #include <linux/device.h>
  19 #include <linux/errno.h>
  20 #include <linux/gpio/driver.h>
  21 #include <linux/io.h>
  22 #include <linux/ioport.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/irqdesc.h>
  25 #include <linux/isa.h>
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/spinlock.h>
  30
  31 #define IDI_48_EXTENT 8
  32 #define MAX_NUM_IDI_48 max_num_isa_dev(IDI_48_EXTENT)
  33
  34 static unsigned int base[MAX_NUM_IDI_48];
  35 static unsigned int num_idi_48;
  36 module_param_hw_array(base, uint, ioport, &num_idi_48, 0);
  37 MODULE_PARM_DESC(base, "ACCES 104-IDI-48 base addresses");
  38
  39 static unsigned int irq[MAX_NUM_IDI_48];
  40 module_param_hw_array(irq, uint, irq, NULL, 0);
  41 MODULE_PARM_DESC(irq, "ACCES 104-IDI-48 interrupt line numbers");
  42
  43 /**
  44  * struct idi_48_gpio - GPIO device private data structure
  45  * @chip:       instance of the gpio_chip
  46  * @lock:       synchronization lock to prevent I/O race conditions
  47  * @ack_lock:   synchronization lock to prevent IRQ handler race conditions
  48  * @irq_mask:   input bits affected by interrupts
  49  * @base:       base port address of the GPIO device
  50  * @cos_enb:    Change-Of-State IRQ enable boundaries mask
  51  */
  52 struct idi_48_gpio {
  53         struct gpio_chip chip;
  54         raw_spinlock_t lock;
  55         spinlock_t ack_lock;
  56         unsigned char irq_mask[6];
  57         unsigned base;
  58         unsigned char cos_enb;
  59 };
  60
  61 static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
  62 {
  63         return 1;
  64 }
  65
  66 static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  67 {
  68         return 0;
  69 }
  70
  71 static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
  72 {
  73         struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
  74         unsigned i;
  75         const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
  76         unsigned base_offset;
  77         unsigned mask;
  78
  79         for (i = 0; i < 48; i += 8)
  80                 if (offset < i + 8) {
  81                         base_offset = register_offset[i / 8];
  82                         mask = BIT(offset - i);
  83
  84                         return !!(inb(idi48gpio->base + base_offset) & mask);
  85                 }
  86
  87         /* The following line should never execute since offset < 48 */
  88         return 0;
  89 }
  90
  91 static void idi_48_irq_ack(struct irq_data *data)
  92 {
  93 }
  94
  95 static void idi_48_irq_mask(struct irq_data *data)
  96 {
  97         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
  98         struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
  99         const unsigned offset = irqd_to_hwirq(data);
 100         unsigned i;
 101         unsigned mask;
 102         unsigned boundary;
 103         unsigned long flags;
 104
 105         for (i = 0; i < 48; i += 8)
 106                 if (offset < i + 8) {
 107                         mask = BIT(offset - i);
 108                         boundary = i / 8;
 109
 110                         idi48gpio->irq_mask[boundary] &= ~mask;
 111
 112                         if (!idi48gpio->irq_mask[boundary]) {
 113                                 idi48gpio->cos_enb &= ~BIT(boundary);
 114
 115                                 raw_spin_lock_irqsave(&idi48gpio->lock, flags);
 116
 117                                 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
 118
 119                                 raw_spin_unlock_irqrestore(&idi48gpio->lock,
 120                                                            flags);
 121                         }
 122
 123                         return;
 124                 }
 125 }
 126
 127 static void idi_48_irq_unmask(struct irq_data *data)
 128 {
 129         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 130         struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
 131         const unsigned offset = irqd_to_hwirq(data);
 132         unsigned i;
 133         unsigned mask;
 134         unsigned boundary;
 135         unsigned prev_irq_mask;
 136         unsigned long flags;
 137
 138         for (i = 0; i < 48; i += 8)
 139                 if (offset < i + 8) {
 140                         mask = BIT(offset - i);
 141                         boundary = i / 8;
 142                         prev_irq_mask = idi48gpio->irq_mask[boundary];
 143
 144                         idi48gpio->irq_mask[boundary] |= mask;
 145
 146                         if (!prev_irq_mask) {
 147                                 idi48gpio->cos_enb |= BIT(boundary);
 148
 149                                 raw_spin_lock_irqsave(&idi48gpio->lock, flags);
 150
 151                                 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
 152
 153                                 raw_spin_unlock_irqrestore(&idi48gpio->lock,
 154                                                            flags);
 155                         }
 156
 157                         return;
 158                 }
 159 }
 160
 161 static int idi_48_irq_set_type(struct irq_data *data, unsigned flow_type)
 162 {
 163         /* The only valid irq types are none and both-edges */
 164         if (flow_type != IRQ_TYPE_NONE &&
 165                 (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
 166                 return -EINVAL;
 167
 168         return 0;
 169 }
 170
 171 static struct irq_chip idi_48_irqchip = {
 172         .name = "104-idi-48",
 173         .irq_ack = idi_48_irq_ack,
 174         .irq_mask = idi_48_irq_mask,
 175         .irq_unmask = idi_48_irq_unmask,
 176         .irq_set_type = idi_48_irq_set_type
 177 };
 178
 179 static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
 180 {
 181         struct idi_48_gpio *const idi48gpio = dev_id;
 182         unsigned long cos_status;
 183         unsigned long boundary;
 184         unsigned long irq_mask;
 185         unsigned long bit_num;
 186         unsigned long gpio;
 187         struct gpio_chip *const chip = &idi48gpio->chip;
 188
 189         spin_lock(&idi48gpio->ack_lock);
 190
 191         raw_spin_lock(&idi48gpio->lock);
 192
 193         cos_status = inb(idi48gpio->base + 7);
 194
 195         raw_spin_unlock(&idi48gpio->lock);
 196
 197         /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
 198         if (cos_status & BIT(6)) {
 199                 spin_unlock(&idi48gpio->ack_lock);
 200                 return IRQ_NONE;
 201         }
 202
 203         /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
 204         cos_status &= 0x3F;
 205
 206         for_each_set_bit(boundary, &cos_status, 6) {
 207                 irq_mask = idi48gpio->irq_mask[boundary];
 208
 209                 for_each_set_bit(bit_num, &irq_mask, 8) {
 210                         gpio = bit_num + boundary * 8;
 211
 212                         generic_handle_irq(irq_find_mapping(chip->irqdomain,
 213                                 gpio));
 214                 }
 215         }
 216
 217         spin_unlock(&idi48gpio->ack_lock);
 218
 219         return IRQ_HANDLED;
 220 }
 221
 222 #define IDI48_NGPIO 48
 223 static const char *idi48_names[IDI48_NGPIO] = {
 224         "Bit 0 A", "Bit 1 A", "Bit 2 A", "Bit 3 A", "Bit 4 A", "Bit 5 A",
 225         "Bit 6 A", "Bit 7 A", "Bit 8 A", "Bit 9 A", "Bit 10 A", "Bit 11 A",
 226         "Bit 12 A", "Bit 13 A", "Bit 14 A", "Bit 15 A", "Bit 16 A", "Bit 17 A",
 227         "Bit 18 A", "Bit 19 A", "Bit 20 A", "Bit 21 A", "Bit 22 A", "Bit 23 A",
 228         "Bit 0 B", "Bit 1 B", "Bit 2 B", "Bit 3 B", "Bit 4 B", "Bit 5 B",
 229         "Bit 6 B", "Bit 7 B", "Bit 8 B", "Bit 9 B", "Bit 10 B", "Bit 11 B",
 230         "Bit 12 B", "Bit 13 B", "Bit 14 B", "Bit 15 B", "Bit 16 B", "Bit 17 B",
 231         "Bit 18 B", "Bit 19 B", "Bit 20 B", "Bit 21 B", "Bit 22 B", "Bit 23 B"
 232 };
 233
 234 static int idi_48_probe(struct device *dev, unsigned int id)
 235 {
 236         struct idi_48_gpio *idi48gpio;
 237         const char *const name = dev_name(dev);
 238         int err;
 239
 240         idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
 241         if (!idi48gpio)
 242                 return -ENOMEM;
 243
 244         if (!devm_request_region(dev, base[id], IDI_48_EXTENT, name)) {
 245                 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
 246                         base[id], base[id] + IDI_48_EXTENT);
 247                 return -EBUSY;
 248         }
 249
 250         idi48gpio->chip.label = name;
 251         idi48gpio->chip.parent = dev;
 252         idi48gpio->chip.owner = THIS_MODULE;
 253         idi48gpio->chip.base = -1;
 254         idi48gpio->chip.ngpio = IDI48_NGPIO;
 255         idi48gpio->chip.names = idi48_names;
 256         idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
 257         idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
 258         idi48gpio->chip.get = idi_48_gpio_get;
 259         idi48gpio->base = base[id];
 260
 261         raw_spin_lock_init(&idi48gpio->lock);
 262         spin_lock_init(&idi48gpio->ack_lock);
 263
 264         err = devm_gpiochip_add_data(dev, &idi48gpio->chip, idi48gpio);
 265         if (err) {
 266                 dev_err(dev, "GPIO registering failed (%d)\n", err);
 267                 return err;
 268         }
 269
 270         /* Disable IRQ by default */
 271         outb(0, base[id] + 7);
 272         inb(base[id] + 7);
 273
 274         err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0,
 275                 handle_edge_irq, IRQ_TYPE_NONE);
 276         if (err) {
 277                 dev_err(dev, "Could not add irqchip (%d)\n", err);
 278                 return err;
 279         }
 280
 281         err = devm_request_irq(dev, irq[id], idi_48_irq_handler, IRQF_SHARED,
 282                 name, idi48gpio);
 283         if (err) {
 284                 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
 285                 return err;
 286         }
 287
 288         return 0;
 289 }
 290
 291 static struct isa_driver idi_48_driver = {
 292         .probe = idi_48_probe,
 293         .driver = {
 294                 .name = "104-idi-48"
 295         },
 296 };
 297 module_isa_driver(idi_48_driver, num_idi_48);
 298
 299 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 300 MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
 301 MODULE_LICENSE("GPL v2");