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

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DEFINITIONS

This source file includes following definitions.
  1. idi_48_gpio_get_direction
  2. idi_48_gpio_direction_input
  3. idi_48_gpio_get
  4. idi_48_gpio_get_multiple
  5. idi_48_irq_ack
  6. idi_48_irq_mask
  7. idi_48_irq_unmask
  8. idi_48_irq_set_type
  9. idi_48_irq_handler
  10. idi_48_probe

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * GPIO driver for the ACCES 104-IDI-48 family
   4  * Copyright (C) 2015 William Breathitt Gray
   5  *
   6  * This driver supports the following ACCES devices: 104-IDI-48A,
   7  * 104-IDI-48AC, 104-IDI-48B, and 104-IDI-48BC.
   8  */
   9 #include <linux/bitmap.h>
  10 #include <linux/bitops.h>
  11 #include <linux/device.h>
  12 #include <linux/errno.h>
  13 #include <linux/gpio/driver.h>
  14 #include <linux/io.h>
  15 #include <linux/ioport.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/irqdesc.h>
  18 #include <linux/isa.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/spinlock.h>
  23 
  24 #define IDI_48_EXTENT 8
  25 #define MAX_NUM_IDI_48 max_num_isa_dev(IDI_48_EXTENT)
  26 
  27 static unsigned int base[MAX_NUM_IDI_48];
  28 static unsigned int num_idi_48;
  29 module_param_hw_array(base, uint, ioport, &num_idi_48, 0);
  30 MODULE_PARM_DESC(base, "ACCES 104-IDI-48 base addresses");
  31 
  32 static unsigned int irq[MAX_NUM_IDI_48];
  33 module_param_hw_array(irq, uint, irq, NULL, 0);
  34 MODULE_PARM_DESC(irq, "ACCES 104-IDI-48 interrupt line numbers");
  35 
  36 /**
  37  * struct idi_48_gpio - GPIO device private data structure
  38  * @chip:       instance of the gpio_chip
  39  * @lock:       synchronization lock to prevent I/O race conditions
  40  * @ack_lock:   synchronization lock to prevent IRQ handler race conditions
  41  * @irq_mask:   input bits affected by interrupts
  42  * @base:       base port address of the GPIO device
  43  * @cos_enb:    Change-Of-State IRQ enable boundaries mask
  44  */
  45 struct idi_48_gpio {
  46         struct gpio_chip chip;
  47         raw_spinlock_t lock;
  48         spinlock_t ack_lock;
  49         unsigned char irq_mask[6];
  50         unsigned base;
  51         unsigned char cos_enb;
  52 };
  53 
  54 static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
  55 {
  56         return 1;
  57 }
  58 
  59 static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  60 {
  61         return 0;
  62 }
  63 
  64 static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
  65 {
  66         struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
  67         unsigned i;
  68         const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
  69         unsigned base_offset;
  70         unsigned mask;
  71 
  72         for (i = 0; i < 48; i += 8)
  73                 if (offset < i + 8) {
  74                         base_offset = register_offset[i / 8];
  75                         mask = BIT(offset - i);
  76 
  77                         return !!(inb(idi48gpio->base + base_offset) & mask);
  78                 }
  79 
  80         /* The following line should never execute since offset < 48 */
  81         return 0;
  82 }
  83 
  84 static int idi_48_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
  85         unsigned long *bits)
  86 {
  87         struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
  88         size_t i;
  89         static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
  90         const unsigned int gpio_reg_size = 8;
  91         unsigned int bits_offset;
  92         size_t word_index;
  93         unsigned int word_offset;
  94         unsigned long word_mask;
  95         const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
  96         unsigned long port_state;
  97 
  98         /* clear bits array to a clean slate */
  99         bitmap_zero(bits, chip->ngpio);
 100 
 101         /* get bits are evaluated a gpio port register at a time */
 102         for (i = 0; i < ARRAY_SIZE(ports); i++) {
 103                 /* gpio offset in bits array */
 104                 bits_offset = i * gpio_reg_size;
 105 
 106                 /* word index for bits array */
 107                 word_index = BIT_WORD(bits_offset);
 108 
 109                 /* gpio offset within current word of bits array */
 110                 word_offset = bits_offset % BITS_PER_LONG;
 111 
 112                 /* mask of get bits for current gpio within current word */
 113                 word_mask = mask[word_index] & (port_mask << word_offset);
 114                 if (!word_mask) {
 115                         /* no get bits in this port so skip to next one */
 116                         continue;
 117                 }
 118 
 119                 /* read bits from current gpio port */
 120                 port_state = inb(idi48gpio->base + ports[i]);
 121 
 122                 /* store acquired bits at respective bits array offset */
 123                 bits[word_index] |= (port_state << word_offset) & word_mask;
 124         }
 125 
 126         return 0;
 127 }
 128 
 129 static void idi_48_irq_ack(struct irq_data *data)
 130 {
 131 }
 132 
 133 static void idi_48_irq_mask(struct irq_data *data)
 134 {
 135         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 136         struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
 137         const unsigned offset = irqd_to_hwirq(data);
 138         unsigned i;
 139         unsigned mask;
 140         unsigned boundary;
 141         unsigned long flags;
 142 
 143         for (i = 0; i < 48; i += 8)
 144                 if (offset < i + 8) {
 145                         mask = BIT(offset - i);
 146                         boundary = i / 8;
 147 
 148                         idi48gpio->irq_mask[boundary] &= ~mask;
 149 
 150                         if (!idi48gpio->irq_mask[boundary]) {
 151                                 idi48gpio->cos_enb &= ~BIT(boundary);
 152 
 153                                 raw_spin_lock_irqsave(&idi48gpio->lock, flags);
 154 
 155                                 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
 156 
 157                                 raw_spin_unlock_irqrestore(&idi48gpio->lock,
 158                                                            flags);
 159                         }
 160 
 161                         return;
 162                 }
 163 }
 164 
 165 static void idi_48_irq_unmask(struct irq_data *data)
 166 {
 167         struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
 168         struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
 169         const unsigned offset = irqd_to_hwirq(data);
 170         unsigned i;
 171         unsigned mask;
 172         unsigned boundary;
 173         unsigned prev_irq_mask;
 174         unsigned long flags;
 175 
 176         for (i = 0; i < 48; i += 8)
 177                 if (offset < i + 8) {
 178                         mask = BIT(offset - i);
 179                         boundary = i / 8;
 180                         prev_irq_mask = idi48gpio->irq_mask[boundary];
 181 
 182                         idi48gpio->irq_mask[boundary] |= mask;
 183 
 184                         if (!prev_irq_mask) {
 185                                 idi48gpio->cos_enb |= BIT(boundary);
 186 
 187                                 raw_spin_lock_irqsave(&idi48gpio->lock, flags);
 188 
 189                                 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
 190 
 191                                 raw_spin_unlock_irqrestore(&idi48gpio->lock,
 192                                                            flags);
 193                         }
 194 
 195                         return;
 196                 }
 197 }
 198 
 199 static int idi_48_irq_set_type(struct irq_data *data, unsigned flow_type)
 200 {
 201         /* The only valid irq types are none and both-edges */
 202         if (flow_type != IRQ_TYPE_NONE &&
 203                 (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
 204                 return -EINVAL;
 205 
 206         return 0;
 207 }
 208 
 209 static struct irq_chip idi_48_irqchip = {
 210         .name = "104-idi-48",
 211         .irq_ack = idi_48_irq_ack,
 212         .irq_mask = idi_48_irq_mask,
 213         .irq_unmask = idi_48_irq_unmask,
 214         .irq_set_type = idi_48_irq_set_type
 215 };
 216 
 217 static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
 218 {
 219         struct idi_48_gpio *const idi48gpio = dev_id;
 220         unsigned long cos_status;
 221         unsigned long boundary;
 222         unsigned long irq_mask;
 223         unsigned long bit_num;
 224         unsigned long gpio;
 225         struct gpio_chip *const chip = &idi48gpio->chip;
 226 
 227         spin_lock(&idi48gpio->ack_lock);
 228 
 229         raw_spin_lock(&idi48gpio->lock);
 230 
 231         cos_status = inb(idi48gpio->base + 7);
 232 
 233         raw_spin_unlock(&idi48gpio->lock);
 234 
 235         /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
 236         if (cos_status & BIT(6)) {
 237                 spin_unlock(&idi48gpio->ack_lock);
 238                 return IRQ_NONE;
 239         }
 240 
 241         /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
 242         cos_status &= 0x3F;
 243 
 244         for_each_set_bit(boundary, &cos_status, 6) {
 245                 irq_mask = idi48gpio->irq_mask[boundary];
 246 
 247                 for_each_set_bit(bit_num, &irq_mask, 8) {
 248                         gpio = bit_num + boundary * 8;
 249 
 250                         generic_handle_irq(irq_find_mapping(chip->irq.domain,
 251                                 gpio));
 252                 }
 253         }
 254 
 255         spin_unlock(&idi48gpio->ack_lock);
 256 
 257         return IRQ_HANDLED;
 258 }
 259 
 260 #define IDI48_NGPIO 48
 261 static const char *idi48_names[IDI48_NGPIO] = {
 262         "Bit 0 A", "Bit 1 A", "Bit 2 A", "Bit 3 A", "Bit 4 A", "Bit 5 A",
 263         "Bit 6 A", "Bit 7 A", "Bit 8 A", "Bit 9 A", "Bit 10 A", "Bit 11 A",
 264         "Bit 12 A", "Bit 13 A", "Bit 14 A", "Bit 15 A", "Bit 16 A", "Bit 17 A",
 265         "Bit 18 A", "Bit 19 A", "Bit 20 A", "Bit 21 A", "Bit 22 A", "Bit 23 A",
 266         "Bit 0 B", "Bit 1 B", "Bit 2 B", "Bit 3 B", "Bit 4 B", "Bit 5 B",
 267         "Bit 6 B", "Bit 7 B", "Bit 8 B", "Bit 9 B", "Bit 10 B", "Bit 11 B",
 268         "Bit 12 B", "Bit 13 B", "Bit 14 B", "Bit 15 B", "Bit 16 B", "Bit 17 B",
 269         "Bit 18 B", "Bit 19 B", "Bit 20 B", "Bit 21 B", "Bit 22 B", "Bit 23 B"
 270 };
 271 
 272 static int idi_48_probe(struct device *dev, unsigned int id)
 273 {
 274         struct idi_48_gpio *idi48gpio;
 275         const char *const name = dev_name(dev);
 276         int err;
 277 
 278         idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
 279         if (!idi48gpio)
 280                 return -ENOMEM;
 281 
 282         if (!devm_request_region(dev, base[id], IDI_48_EXTENT, name)) {
 283                 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
 284                         base[id], base[id] + IDI_48_EXTENT);
 285                 return -EBUSY;
 286         }
 287 
 288         idi48gpio->chip.label = name;
 289         idi48gpio->chip.parent = dev;
 290         idi48gpio->chip.owner = THIS_MODULE;
 291         idi48gpio->chip.base = -1;
 292         idi48gpio->chip.ngpio = IDI48_NGPIO;
 293         idi48gpio->chip.names = idi48_names;
 294         idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
 295         idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
 296         idi48gpio->chip.get = idi_48_gpio_get;
 297         idi48gpio->chip.get_multiple = idi_48_gpio_get_multiple;
 298         idi48gpio->base = base[id];
 299 
 300         raw_spin_lock_init(&idi48gpio->lock);
 301         spin_lock_init(&idi48gpio->ack_lock);
 302 
 303         err = devm_gpiochip_add_data(dev, &idi48gpio->chip, idi48gpio);
 304         if (err) {
 305                 dev_err(dev, "GPIO registering failed (%d)\n", err);
 306                 return err;
 307         }
 308 
 309         /* Disable IRQ by default */
 310         outb(0, base[id] + 7);
 311         inb(base[id] + 7);
 312 
 313         err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0,
 314                 handle_edge_irq, IRQ_TYPE_NONE);
 315         if (err) {
 316                 dev_err(dev, "Could not add irqchip (%d)\n", err);
 317                 return err;
 318         }
 319 
 320         err = devm_request_irq(dev, irq[id], idi_48_irq_handler, IRQF_SHARED,
 321                 name, idi48gpio);
 322         if (err) {
 323                 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
 324                 return err;
 325         }
 326 
 327         return 0;
 328 }
 329 
 330 static struct isa_driver idi_48_driver = {
 331         .probe = idi_48_probe,
 332         .driver = {
 333                 .name = "104-idi-48"
 334         },
 335 };
 336 module_isa_driver(idi_48_driver, num_idi_48);
 337 
 338 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 339 MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
 340 MODULE_LICENSE("GPL v2");

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