drivers/gpio/gpio-altera.c

   1 /*
   2  * Copyright (C) 2013 Altera Corporation
   3  * Based on gpio-mpc8xxx.c
   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 as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/io.h>
  20 #include <linux/of_gpio.h>
  21 #include <linux/platform_device.h>
  22
  23 #define ALTERA_GPIO_MAX_NGPIO           32
  24 #define ALTERA_GPIO_DATA                0x0
  25 #define ALTERA_GPIO_DIR                 0x4
  26 #define ALTERA_GPIO_IRQ_MASK            0x8
  27 #define ALTERA_GPIO_EDGE_CAP            0xc
  28
  29 /**
  30 * struct altera_gpio_chip
  31 * @mmchip               : memory mapped chip structure.
  32 * @gpio_lock            : synchronization lock so that new irq/set/get requests
  33                           will be blocked until the current one completes.
  34 * @interrupt_trigger    : specifies the hardware configured IRQ trigger type
  35                           (rising, falling, both, high)
  36 * @mapped_irq           : kernel mapped irq number.
  37 */
  38 struct altera_gpio_chip {
  39         struct of_mm_gpio_chip mmchip;
  40         spinlock_t gpio_lock;
  41         int interrupt_trigger;
  42         int mapped_irq;
  43 };
  44
  45 static struct altera_gpio_chip *to_altera(struct gpio_chip *gc)
  46 {
  47         return container_of(gc, struct altera_gpio_chip, mmchip.gc);
  48 }
  49
  50 static void altera_gpio_irq_unmask(struct irq_data *d)
  51 {
  52         struct altera_gpio_chip *altera_gc;
  53         struct of_mm_gpio_chip *mm_gc;
  54         unsigned long flags;
  55         u32 intmask;
  56
  57         altera_gc = to_altera(irq_data_get_irq_chip_data(d));
  58         mm_gc = &altera_gc->mmchip;
  59
  60         spin_lock_irqsave(&altera_gc->gpio_lock, flags);
  61         intmask = readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
  62         /* Set ALTERA_GPIO_IRQ_MASK bit to unmask */
  63         intmask |= BIT(irqd_to_hwirq(d));
  64         writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
  65         spin_unlock_irqrestore(&altera_gc->gpio_lock, flags);
  66 }
  67
  68 static void altera_gpio_irq_mask(struct irq_data *d)
  69 {
  70         struct altera_gpio_chip *altera_gc;
  71         struct of_mm_gpio_chip *mm_gc;
  72         unsigned long flags;
  73         u32 intmask;
  74
  75         altera_gc = to_altera(irq_data_get_irq_chip_data(d));
  76         mm_gc = &altera_gc->mmchip;
  77
  78         spin_lock_irqsave(&altera_gc->gpio_lock, flags);
  79         intmask = readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
  80         /* Clear ALTERA_GPIO_IRQ_MASK bit to mask */
  81         intmask &= ~BIT(irqd_to_hwirq(d));
  82         writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
  83         spin_unlock_irqrestore(&altera_gc->gpio_lock, flags);
  84 }
  85
  86 /**
  87  * This controller's IRQ type is synthesized in hardware, so this function
  88  * just checks if the requested set_type matches the synthesized IRQ type
  89  */
  90 static int altera_gpio_irq_set_type(struct irq_data *d,
  91                                    unsigned int type)
  92 {
  93         struct altera_gpio_chip *altera_gc;
  94
  95         altera_gc = to_altera(irq_data_get_irq_chip_data(d));
  96
  97         if (type == IRQ_TYPE_NONE)
  98                 return 0;
  99         if (type == IRQ_TYPE_LEVEL_HIGH &&
 100                 altera_gc->interrupt_trigger == IRQ_TYPE_LEVEL_HIGH)
 101                 return 0;
 102         if (type == IRQ_TYPE_EDGE_RISING &&
 103                 altera_gc->interrupt_trigger == IRQ_TYPE_EDGE_RISING)
 104                 return 0;
 105         if (type == IRQ_TYPE_EDGE_FALLING &&
 106                 altera_gc->interrupt_trigger == IRQ_TYPE_EDGE_FALLING)
 107                 return 0;
 108         if (type == IRQ_TYPE_EDGE_BOTH &&
 109                 altera_gc->interrupt_trigger == IRQ_TYPE_EDGE_BOTH)
 110                 return 0;
 111
 112         return -EINVAL;
 113 }
 114
 115 static unsigned int altera_gpio_irq_startup(struct irq_data *d)
 116 {
 117         altera_gpio_irq_unmask(d);
 118
 119         return 0;
 120 }
 121
 122 static struct irq_chip altera_irq_chip = {
 123         .name           = "altera-gpio",
 124         .irq_mask       = altera_gpio_irq_mask,
 125         .irq_unmask     = altera_gpio_irq_unmask,
 126         .irq_set_type   = altera_gpio_irq_set_type,
 127         .irq_startup    = altera_gpio_irq_startup,
 128         .irq_shutdown   = altera_gpio_irq_mask,
 129 };
 130
 131 static int altera_gpio_get(struct gpio_chip *gc, unsigned offset)
 132 {
 133         struct of_mm_gpio_chip *mm_gc;
 134
 135         mm_gc = to_of_mm_gpio_chip(gc);
 136
 137         return !!(readl(mm_gc->regs + ALTERA_GPIO_DATA) & BIT(offset));
 138 }
 139
 140 static void altera_gpio_set(struct gpio_chip *gc, unsigned offset, int value)
 141 {
 142         struct of_mm_gpio_chip *mm_gc;
 143         struct altera_gpio_chip *chip;
 144         unsigned long flags;
 145         unsigned int data_reg;
 146
 147         mm_gc = to_of_mm_gpio_chip(gc);
 148         chip = container_of(mm_gc, struct altera_gpio_chip, mmchip);
 149
 150         spin_lock_irqsave(&chip->gpio_lock, flags);
 151         data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA);
 152         if (value)
 153                 data_reg |= BIT(offset);
 154         else
 155                 data_reg &= ~BIT(offset);
 156         writel(data_reg, mm_gc->regs + ALTERA_GPIO_DATA);
 157         spin_unlock_irqrestore(&chip->gpio_lock, flags);
 158 }
 159
 160 static int altera_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
 161 {
 162         struct of_mm_gpio_chip *mm_gc;
 163         struct altera_gpio_chip *chip;
 164         unsigned long flags;
 165         unsigned int gpio_ddr;
 166
 167         mm_gc = to_of_mm_gpio_chip(gc);
 168         chip = container_of(mm_gc, struct altera_gpio_chip, mmchip);
 169
 170         spin_lock_irqsave(&chip->gpio_lock, flags);
 171         /* Set pin as input, assumes software controlled IP */
 172         gpio_ddr = readl(mm_gc->regs + ALTERA_GPIO_DIR);
 173         gpio_ddr &= ~BIT(offset);
 174         writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR);
 175         spin_unlock_irqrestore(&chip->gpio_lock, flags);
 176
 177         return 0;
 178 }
 179
 180 static int altera_gpio_direction_output(struct gpio_chip *gc,
 181                 unsigned offset, int value)
 182 {
 183         struct of_mm_gpio_chip *mm_gc;
 184         struct altera_gpio_chip *chip;
 185         unsigned long flags;
 186         unsigned int data_reg, gpio_ddr;
 187
 188         mm_gc = to_of_mm_gpio_chip(gc);
 189         chip = container_of(mm_gc, struct altera_gpio_chip, mmchip);
 190
 191         spin_lock_irqsave(&chip->gpio_lock, flags);
 192         /* Sets the GPIO value */
 193         data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA);
 194         if (value)
 195                 data_reg |= BIT(offset);
 196         else
 197                 data_reg &= ~BIT(offset);
 198         writel(data_reg, mm_gc->regs + ALTERA_GPIO_DATA);
 199
 200         /* Set pin as output, assumes software controlled IP */
 201         gpio_ddr = readl(mm_gc->regs + ALTERA_GPIO_DIR);
 202         gpio_ddr |= BIT(offset);
 203         writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR);
 204         spin_unlock_irqrestore(&chip->gpio_lock, flags);
 205
 206         return 0;
 207 }
 208
 209 static void altera_gpio_irq_edge_handler(struct irq_desc *desc)
 210 {
 211         struct altera_gpio_chip *altera_gc;
 212         struct irq_chip *chip;
 213         struct of_mm_gpio_chip *mm_gc;
 214         struct irq_domain *irqdomain;
 215         unsigned long status;
 216         int i;
 217
 218         altera_gc = to_altera(irq_desc_get_handler_data(desc));
 219         chip = irq_desc_get_chip(desc);
 220         mm_gc = &altera_gc->mmchip;
 221         irqdomain = altera_gc->mmchip.gc.irqdomain;
 222
 223         chained_irq_enter(chip, desc);
 224
 225         while ((status =
 226               (readl(mm_gc->regs + ALTERA_GPIO_EDGE_CAP) &
 227               readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK)))) {
 228                 writel(status, mm_gc->regs + ALTERA_GPIO_EDGE_CAP);
 229                 for_each_set_bit(i, &status, mm_gc->gc.ngpio) {
 230                         generic_handle_irq(irq_find_mapping(irqdomain, i));
 231                 }
 232         }
 233
 234         chained_irq_exit(chip, desc);
 235 }
 236
 237
 238 static void altera_gpio_irq_leveL_high_handler(struct irq_desc *desc)
 239 {
 240         struct altera_gpio_chip *altera_gc;
 241         struct irq_chip *chip;
 242         struct of_mm_gpio_chip *mm_gc;
 243         struct irq_domain *irqdomain;
 244         unsigned long status;
 245         int i;
 246
 247         altera_gc = to_altera(irq_desc_get_handler_data(desc));
 248         chip = irq_desc_get_chip(desc);
 249         mm_gc = &altera_gc->mmchip;
 250         irqdomain = altera_gc->mmchip.gc.irqdomain;
 251
 252         chained_irq_enter(chip, desc);
 253
 254         status = readl(mm_gc->regs + ALTERA_GPIO_DATA);
 255         status &= readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
 256
 257         for_each_set_bit(i, &status, mm_gc->gc.ngpio) {
 258                 generic_handle_irq(irq_find_mapping(irqdomain, i));
 259         }
 260         chained_irq_exit(chip, desc);
 261 }
 262
 263 static int altera_gpio_probe(struct platform_device *pdev)
 264 {
 265         struct device_node *node = pdev->dev.of_node;
 266         int reg, ret;
 267         struct altera_gpio_chip *altera_gc;
 268
 269         altera_gc = devm_kzalloc(&pdev->dev, sizeof(*altera_gc), GFP_KERNEL);
 270         if (!altera_gc)
 271                 return -ENOMEM;
 272
 273         spin_lock_init(&altera_gc->gpio_lock);
 274
 275         if (of_property_read_u32(node, "altr,ngpio", &reg))
 276                 /* By default assume maximum ngpio */
 277                 altera_gc->mmchip.gc.ngpio = ALTERA_GPIO_MAX_NGPIO;
 278         else
 279                 altera_gc->mmchip.gc.ngpio = reg;
 280
 281         if (altera_gc->mmchip.gc.ngpio > ALTERA_GPIO_MAX_NGPIO) {
 282                 dev_warn(&pdev->dev,
 283                         "ngpio is greater than %d, defaulting to %d\n",
 284                         ALTERA_GPIO_MAX_NGPIO, ALTERA_GPIO_MAX_NGPIO);
 285                 altera_gc->mmchip.gc.ngpio = ALTERA_GPIO_MAX_NGPIO;
 286         }
 287
 288         altera_gc->mmchip.gc.direction_input    = altera_gpio_direction_input;
 289         altera_gc->mmchip.gc.direction_output   = altera_gpio_direction_output;
 290         altera_gc->mmchip.gc.get                = altera_gpio_get;
 291         altera_gc->mmchip.gc.set                = altera_gpio_set;
 292         altera_gc->mmchip.gc.owner              = THIS_MODULE;
 293         altera_gc->mmchip.gc.dev                = &pdev->dev;
 294
 295         ret = of_mm_gpiochip_add(node, &altera_gc->mmchip);
 296         if (ret) {
 297                 dev_err(&pdev->dev, "Failed adding memory mapped gpiochip\n");
 298                 return ret;
 299         }
 300
 301         platform_set_drvdata(pdev, altera_gc);
 302
 303         altera_gc->mapped_irq = platform_get_irq(pdev, 0);
 304
 305         if (altera_gc->mapped_irq < 0)
 306                 goto skip_irq;
 307
 308         if (of_property_read_u32(node, "altr,interrupt-type", &reg)) {
 309                 ret = -EINVAL;
 310                 dev_err(&pdev->dev,
 311                         "altr,interrupt-type value not set in device tree\n");
 312                 goto teardown;
 313         }
 314         altera_gc->interrupt_trigger = reg;
 315
 316         ret = gpiochip_irqchip_add(&altera_gc->mmchip.gc, &altera_irq_chip, 0,
 317                 handle_simple_irq, IRQ_TYPE_NONE);
 318
 319         if (ret) {
 320                 dev_info(&pdev->dev, "could not add irqchip\n");
 321                 return ret;
 322         }
 323
 324         gpiochip_set_chained_irqchip(&altera_gc->mmchip.gc,
 325                 &altera_irq_chip,
 326                 altera_gc->mapped_irq,
 327                 altera_gc->interrupt_trigger == IRQ_TYPE_LEVEL_HIGH ?
 328                 altera_gpio_irq_leveL_high_handler :
 329                 altera_gpio_irq_edge_handler);
 330
 331 skip_irq:
 332         return 0;
 333 teardown:
 334         pr_err("%s: registration failed with status %d\n",
 335                 node->full_name, ret);
 336
 337         return ret;
 338 }
 339
 340 static int altera_gpio_remove(struct platform_device *pdev)
 341 {
 342         struct altera_gpio_chip *altera_gc = platform_get_drvdata(pdev);
 343
 344         of_mm_gpiochip_remove(&altera_gc->mmchip);
 345
 346         return 0;
 347 }
 348
 349 static const struct of_device_id altera_gpio_of_match[] = {
 350         { .compatible = "altr,pio-1.0", },
 351         {},
 352 };
 353 MODULE_DEVICE_TABLE(of, altera_gpio_of_match);
 354
 355 static struct platform_driver altera_gpio_driver = {
 356         .driver = {
 357                 .name   = "altera_gpio",
 358                 .of_match_table = of_match_ptr(altera_gpio_of_match),
 359         },
 360         .probe          = altera_gpio_probe,
 361         .remove         = altera_gpio_remove,
 362 };
 363
 364 static int __init altera_gpio_init(void)
 365 {
 366         return platform_driver_register(&altera_gpio_driver);
 367 }
 368 subsys_initcall(altera_gpio_init);
 369
 370 static void __exit altera_gpio_exit(void)
 371 {
 372         platform_driver_unregister(&altera_gpio_driver);
 373 }
 374 module_exit(altera_gpio_exit);
 375
 376 MODULE_AUTHOR("Tien Hock Loh <thloh@altera.com>");
 377 MODULE_DESCRIPTION("Altera GPIO driver");
 378 MODULE_LICENSE("GPL");