kernel/2.6.29.6-aldebaran-rt/arch/arm/plat-orion/gpio.c

   1 /*
   2  * arch/arm/plat-orion/gpio.c
   3  *
   4  * Marvell Orion SoC GPIO handling.
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2.  This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/irq.h>
  14 #include <linux/module.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/bitops.h>
  17 #include <linux/io.h>
  18 #include <asm/gpio.h>
  19
  20 static DEFINE_SPINLOCK(gpio_lock);
  21 static const char *gpio_label[GPIO_MAX];  /* non null for allocated GPIOs */
  22 static unsigned long gpio_valid[BITS_TO_LONGS(GPIO_MAX)];
  23
  24 static inline void __set_direction(unsigned pin, int input)
  25 {
  26         u32 u;
  27
  28         u = readl(GPIO_IO_CONF(pin));
  29         if (input)
  30                 u |= 1 << (pin & 31);
  31         else
  32                 u &= ~(1 << (pin & 31));
  33         writel(u, GPIO_IO_CONF(pin));
  34 }
  35
  36 static void __set_level(unsigned pin, int high)
  37 {
  38         u32 u;
  39
  40         u = readl(GPIO_OUT(pin));
  41         if (high)
  42                 u |= 1 << (pin & 31);
  43         else
  44                 u &= ~(1 << (pin & 31));
  45         writel(u, GPIO_OUT(pin));
  46 }
  47
  48
  49 /*
  50  * GENERIC_GPIO primitives.
  51  */
  52 int gpio_direction_input(unsigned pin)
  53 {
  54         unsigned long flags;
  55
  56         if (pin >= GPIO_MAX || !test_bit(pin, gpio_valid)) {
  57                 pr_debug("%s: invalid GPIO %d\n", __func__, pin);
  58                 return -EINVAL;
  59         }
  60
  61         spin_lock_irqsave(&gpio_lock, flags);
  62
  63         /*
  64          * Some callers might not have used gpio_request(),
  65          * so flag this pin as requested now.
  66          */
  67         if (gpio_label[pin] == NULL)
  68                 gpio_label[pin] = "?";
  69
  70         /*
  71          * Configure GPIO direction.
  72          */
  73         __set_direction(pin, 1);
  74
  75         spin_unlock_irqrestore(&gpio_lock, flags);
  76
  77         return 0;
  78 }
  79 EXPORT_SYMBOL(gpio_direction_input);
  80
  81 int gpio_direction_output(unsigned pin, int value)
  82 {
  83         unsigned long flags;
  84         u32 u;
  85
  86         if (pin >= GPIO_MAX || !test_bit(pin, gpio_valid)) {
  87                 pr_debug("%s: invalid GPIO %d\n", __func__, pin);
  88                 return -EINVAL;
  89         }
  90
  91         spin_lock_irqsave(&gpio_lock, flags);
  92
  93         /*
  94          * Some callers might not have used gpio_request(),
  95          * so flag this pin as requested now.
  96          */
  97         if (gpio_label[pin] == NULL)
  98                 gpio_label[pin] = "?";
  99
 100         /*
 101          * Disable blinking.
 102          */
 103         u = readl(GPIO_BLINK_EN(pin));
 104         u &= ~(1 << (pin & 31));
 105         writel(u, GPIO_BLINK_EN(pin));
 106
 107         /*
 108          * Configure GPIO output value.
 109          */
 110         __set_level(pin, value);
 111
 112         /*
 113          * Configure GPIO direction.
 114          */
 115         __set_direction(pin, 0);
 116
 117         spin_unlock_irqrestore(&gpio_lock, flags);
 118
 119         return 0;
 120 }
 121 EXPORT_SYMBOL(gpio_direction_output);
 122
 123 int gpio_get_value(unsigned pin)
 124 {
 125         int val;
 126
 127         if (readl(GPIO_IO_CONF(pin)) & (1 << (pin & 31)))
 128                 val = readl(GPIO_DATA_IN(pin)) ^ readl(GPIO_IN_POL(pin));
 129         else
 130                 val = readl(GPIO_OUT(pin));
 131
 132         return (val >> (pin & 31)) & 1;
 133 }
 134 EXPORT_SYMBOL(gpio_get_value);
 135
 136 void gpio_set_value(unsigned pin, int value)
 137 {
 138         unsigned long flags;
 139         u32 u;
 140
 141         spin_lock_irqsave(&gpio_lock, flags);
 142
 143         /*
 144          * Disable blinking.
 145          */
 146         u = readl(GPIO_BLINK_EN(pin));
 147         u &= ~(1 << (pin & 31));
 148         writel(u, GPIO_BLINK_EN(pin));
 149
 150         /*
 151          * Configure GPIO output value.
 152          */
 153         __set_level(pin, value);
 154
 155         spin_unlock_irqrestore(&gpio_lock, flags);
 156 }
 157 EXPORT_SYMBOL(gpio_set_value);
 158
 159 int gpio_request(unsigned pin, const char *label)
 160 {
 161         unsigned long flags;
 162         int ret;
 163
 164         if (pin >= GPIO_MAX || !test_bit(pin, gpio_valid)) {
 165                 pr_debug("%s: invalid GPIO %d\n", __func__, pin);
 166                 return -EINVAL;
 167         }
 168
 169         spin_lock_irqsave(&gpio_lock, flags);
 170         if (gpio_label[pin] == NULL) {
 171                 gpio_label[pin] = label ? label : "?";
 172                 ret = 0;
 173         } else {
 174                 pr_debug("%s: GPIO %d already used as %s\n",
 175                          __func__, pin, gpio_label[pin]);
 176                 ret = -EBUSY;
 177         }
 178         spin_unlock_irqrestore(&gpio_lock, flags);
 179
 180         return ret;
 181 }
 182 EXPORT_SYMBOL(gpio_request);
 183
 184 void gpio_free(unsigned pin)
 185 {
 186         if (pin >= GPIO_MAX || !test_bit(pin, gpio_valid)) {
 187                 pr_debug("%s: invalid GPIO %d\n", __func__, pin);
 188                 return;
 189         }
 190
 191         if (gpio_label[pin] == NULL)
 192                 pr_warning("%s: GPIO %d already freed\n", __func__, pin);
 193         else
 194                 gpio_label[pin] = NULL;
 195 }
 196 EXPORT_SYMBOL(gpio_free);
 197
 198
 199 /*
 200  * Orion-specific GPIO API extensions.
 201  */
 202 void __init orion_gpio_set_unused(unsigned pin)
 203 {
 204         /*
 205          * Configure as output, drive low.
 206          */
 207         __set_level(pin, 0);
 208         __set_direction(pin, 0);
 209 }
 210
 211 void __init orion_gpio_set_valid(unsigned pin, int valid)
 212 {
 213         if (valid)
 214                 __set_bit(pin, gpio_valid);
 215         else
 216                 __clear_bit(pin, gpio_valid);
 217 }
 218
 219 void orion_gpio_set_blink(unsigned pin, int blink)
 220 {
 221         unsigned long flags;
 222         u32 u;
 223
 224         spin_lock_irqsave(&gpio_lock, flags);
 225
 226         /*
 227          * Set output value to zero.
 228          */
 229         __set_level(pin, 0);
 230
 231         u = readl(GPIO_BLINK_EN(pin));
 232         if (blink)
 233                 u |= 1 << (pin & 31);
 234         else
 235                 u &= ~(1 << (pin & 31));
 236         writel(u, GPIO_BLINK_EN(pin));
 237
 238         spin_unlock_irqrestore(&gpio_lock, flags);
 239 }
 240 EXPORT_SYMBOL(orion_gpio_set_blink);
 241
 242
 243 /*****************************************************************************
 244  * Orion GPIO IRQ
 245  *
 246  * GPIO_IN_POL register controls whether GPIO_DATA_IN will hold the same
 247  * value of the line or the opposite value.
 248  *
 249  * Level IRQ handlers: DATA_IN is used directly as cause register.
 250  *                     Interrupt are masked by LEVEL_MASK registers.
 251  * Edge IRQ handlers:  Change in DATA_IN are latched in EDGE_CAUSE.
 252  *                     Interrupt are masked by EDGE_MASK registers.
 253  * Both-edge handlers: Similar to regular Edge handlers, but also swaps
 254  *                     the polarity to catch the next line transaction.
 255  *                     This is a race condition that might not perfectly
 256  *                     work on some use cases.
 257  *
 258  * Every eight GPIO lines are grouped (OR'ed) before going up to main
 259  * cause register.
 260  *
 261  *                    EDGE  cause    mask
 262  *        data-in   /--------| |-----| |----\
 263  *     -----| |-----                         ---- to main cause reg
 264  *           X      \----------------| |----/
 265  *        polarity    LEVEL          mask
 266  *
 267  ****************************************************************************/
 268
 269 static void gpio_irq_ack(u32 irq)
 270 {
 271         int type = irq_desc[irq].status & IRQ_TYPE_SENSE_MASK;
 272         if (type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING)) {
 273                 int pin = irq_to_gpio(irq);
 274                 writel(~(1 << (pin & 31)), GPIO_EDGE_CAUSE(pin));
 275         }
 276 }
 277
 278 static void gpio_irq_mask(u32 irq)
 279 {
 280         int pin = irq_to_gpio(irq);
 281         int type = irq_desc[irq].status & IRQ_TYPE_SENSE_MASK;
 282         u32 reg = (type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING)) ?
 283                 GPIO_EDGE_MASK(pin) : GPIO_LEVEL_MASK(pin);
 284         u32 u = readl(reg);
 285         u &= ~(1 << (pin & 31));
 286         writel(u, reg);
 287 }
 288
 289 static void gpio_irq_unmask(u32 irq)
 290 {
 291         int pin = irq_to_gpio(irq);
 292         int type = irq_desc[irq].status & IRQ_TYPE_SENSE_MASK;
 293         u32 reg = (type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING)) ?
 294                 GPIO_EDGE_MASK(pin) : GPIO_LEVEL_MASK(pin);
 295         u32 u = readl(reg);
 296         u |= 1 << (pin & 31);
 297         writel(u, reg);
 298 }
 299
 300 static int gpio_irq_set_type(u32 irq, u32 type)
 301 {
 302         int pin = irq_to_gpio(irq);
 303         struct irq_desc *desc;
 304         u32 u;
 305
 306         u = readl(GPIO_IO_CONF(pin)) & (1 << (pin & 31));
 307         if (!u) {
 308                 printk(KERN_ERR "orion gpio_irq_set_type failed "
 309                                 "(irq %d, pin %d).\n", irq, pin);
 310                 return -EINVAL;
 311         }
 312
 313         desc = irq_desc + irq;
 314
 315         /*
 316          * Set edge/level type.
 317          */
 318         if (type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING)) {
 319                 desc->handle_irq = handle_edge_irq;
 320         } else if (type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) {
 321                 desc->handle_irq = handle_level_irq;
 322         } else {
 323                 printk(KERN_ERR "failed to set irq=%d (type=%d)\n", irq, type);
 324                 return -EINVAL;
 325         }
 326
 327         /*
 328          * Configure interrupt polarity.
 329          */
 330         if (type == IRQ_TYPE_EDGE_RISING || type == IRQ_TYPE_LEVEL_HIGH) {
 331                 u = readl(GPIO_IN_POL(pin));
 332                 u &= ~(1 << (pin & 31));
 333                 writel(u, GPIO_IN_POL(pin));
 334         } else if (type == IRQ_TYPE_EDGE_FALLING || type == IRQ_TYPE_LEVEL_LOW) {
 335                 u = readl(GPIO_IN_POL(pin));
 336                 u |= 1 << (pin & 31);
 337                 writel(u, GPIO_IN_POL(pin));
 338         } else if (type == IRQ_TYPE_EDGE_BOTH) {
 339                 u32 v;
 340
 341                 v = readl(GPIO_IN_POL(pin)) ^ readl(GPIO_DATA_IN(pin));
 342
 343                 /*
 344                  * set initial polarity based on current input level
 345                  */
 346                 u = readl(GPIO_IN_POL(pin));
 347                 if (v & (1 << (pin & 31)))
 348                         u |= 1 << (pin & 31);           /* falling */
 349                 else
 350                         u &= ~(1 << (pin & 31));        /* rising */
 351                 writel(u, GPIO_IN_POL(pin));
 352         }
 353
 354         desc->status = (desc->status & ~IRQ_TYPE_SENSE_MASK) | type;
 355
 356         return 0;
 357 }
 358
 359 struct irq_chip orion_gpio_irq_chip = {
 360         .name           = "orion_gpio",
 361         .ack            = gpio_irq_ack,
 362         .mask           = gpio_irq_mask,
 363         .unmask         = gpio_irq_unmask,
 364         .set_type       = gpio_irq_set_type,
 365 };
 366
 367 void orion_gpio_irq_handler(int pinoff)
 368 {
 369         u32 cause;
 370         int pin;
 371
 372         cause = readl(GPIO_DATA_IN(pinoff)) & readl(GPIO_LEVEL_MASK(pinoff));
 373         cause |= readl(GPIO_EDGE_CAUSE(pinoff)) & readl(GPIO_EDGE_MASK(pinoff));
 374
 375         for (pin = pinoff; pin < pinoff + 8; pin++) {
 376                 int irq = gpio_to_irq(pin);
 377                 struct irq_desc *desc = irq_desc + irq;
 378
 379                 if (!(cause & (1 << (pin & 31))))
 380                         continue;
 381
 382                 if ((desc->status & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_BOTH) {
 383                         /* Swap polarity (race with GPIO line) */
 384                         u32 polarity;
 385
 386                         polarity = readl(GPIO_IN_POL(pin));
 387                         polarity ^= 1 << (pin & 31);
 388                         writel(polarity, GPIO_IN_POL(pin));
 389                 }
 390                 desc_handle_irq(irq, desc);
 391         }
 392 }