drivers/gpio/gpio-msm-v2.c

   1 /* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 and
   5  * only version 2 as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  15  * 02110-1301, USA.
  16  *
  17  */
  18 #define pr_fmt(fmt) "%s: " fmt, __func__
  19
  20 #include <linux/bitmap.h>
  21 #include <linux/bitops.h>
  22 #include <linux/err.h>
  23 #include <linux/gpio.h>
  24 #include <linux/init.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/io.h>
  27 #include <linux/irqchip/chained_irq.h>
  28 #include <linux/irq.h>
  29 #include <linux/irqdomain.h>
  30 #include <linux/module.h>
  31 #include <linux/of_address.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/slab.h>
  35
  36 #define MAX_NR_GPIO 300
  37
  38 /* Bits of interest in the GPIO_IN_OUT register.
  39  */
  40 enum {
  41         GPIO_IN  = 0,
  42         GPIO_OUT = 1
  43 };
  44
  45 /* Bits of interest in the GPIO_INTR_STATUS register.
  46  */
  47 enum {
  48         INTR_STATUS = 0,
  49 };
  50
  51 /* Bits of interest in the GPIO_CFG register.
  52  */
  53 enum {
  54         GPIO_OE = 9,
  55 };
  56
  57 /* Bits of interest in the GPIO_INTR_CFG register.
  58  * When a GPIO triggers, two separate decisions are made, controlled
  59  * by two separate flags.
  60  *
  61  * - First, INTR_RAW_STATUS_EN controls whether or not the GPIO_INTR_STATUS
  62  * register for that GPIO will be updated to reflect the triggering of that
  63  * gpio.  If this bit is 0, this register will not be updated.
  64  * - Second, INTR_ENABLE controls whether an interrupt is triggered.
  65  *
  66  * If INTR_ENABLE is set and INTR_RAW_STATUS_EN is NOT set, an interrupt
  67  * can be triggered but the status register will not reflect it.
  68  */
  69 enum {
  70         INTR_ENABLE        = 0,
  71         INTR_POL_CTL       = 1,
  72         INTR_DECT_CTL      = 2,
  73         INTR_RAW_STATUS_EN = 3,
  74 };
  75
  76 /* Codes of interest in GPIO_INTR_CFG_SU.
  77  */
  78 enum {
  79         TARGET_PROC_SCORPION = 4,
  80         TARGET_PROC_NONE     = 7,
  81 };
  82
  83 /**
  84  * struct msm_gpio_dev: the MSM8660 SoC GPIO device structure
  85  *
  86  * @enabled_irqs: a bitmap used to optimize the summary-irq handler.  By
  87  * keeping track of which gpios are unmasked as irq sources, we avoid
  88  * having to do readl calls on hundreds of iomapped registers each time
  89  * the summary interrupt fires in order to locate the active interrupts.
  90  *
  91  * @wake_irqs: a bitmap for tracking which interrupt lines are enabled
  92  * as wakeup sources.  When the device is suspended, interrupts which are
  93  * not wakeup sources are disabled.
  94  *
  95  * @dual_edge_irqs: a bitmap used to track which irqs are configured
  96  * as dual-edge, as this is not supported by the hardware and requires
  97  * some special handling in the driver.
  98  */
  99 struct msm_gpio_dev {
 100         struct gpio_chip gpio_chip;
 101         DECLARE_BITMAP(enabled_irqs, MAX_NR_GPIO);
 102         DECLARE_BITMAP(wake_irqs, MAX_NR_GPIO);
 103         DECLARE_BITMAP(dual_edge_irqs, MAX_NR_GPIO);
 104         struct irq_domain *domain;
 105         int summary_irq;
 106         void __iomem *msm_tlmm_base;
 107 };
 108
 109 static struct msm_gpio_dev msm_gpio;
 110
 111 #define GPIO_INTR_CFG_SU(gpio)    (msm_gpio.msm_tlmm_base + 0x0400 + \
 112                                                                 (0x04 * (gpio)))
 113 #define GPIO_CONFIG(gpio)         (msm_gpio.msm_tlmm_base + 0x1000 + \
 114                                                                 (0x10 * (gpio)))
 115 #define GPIO_IN_OUT(gpio)         (msm_gpio.msm_tlmm_base + 0x1004 + \
 116                                                                 (0x10 * (gpio)))
 117 #define GPIO_INTR_CFG(gpio)       (msm_gpio.msm_tlmm_base + 0x1008 + \
 118                                                                 (0x10 * (gpio)))
 119 #define GPIO_INTR_STATUS(gpio)    (msm_gpio.msm_tlmm_base + 0x100c + \
 120                                                                 (0x10 * (gpio)))
 121
 122 static DEFINE_SPINLOCK(tlmm_lock);
 123
 124 static inline struct msm_gpio_dev *to_msm_gpio_dev(struct gpio_chip *chip)
 125 {
 126         return container_of(chip, struct msm_gpio_dev, gpio_chip);
 127 }
 128
 129 static inline void set_gpio_bits(unsigned n, void __iomem *reg)
 130 {
 131         writel(readl(reg) | n, reg);
 132 }
 133
 134 static inline void clear_gpio_bits(unsigned n, void __iomem *reg)
 135 {
 136         writel(readl(reg) & ~n, reg);
 137 }
 138
 139 static int msm_gpio_get(struct gpio_chip *chip, unsigned offset)
 140 {
 141         return readl(GPIO_IN_OUT(offset)) & BIT(GPIO_IN);
 142 }
 143
 144 static void msm_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
 145 {
 146         writel(val ? BIT(GPIO_OUT) : 0, GPIO_IN_OUT(offset));
 147 }
 148
 149 static int msm_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 150 {
 151         unsigned long irq_flags;
 152
 153         spin_lock_irqsave(&tlmm_lock, irq_flags);
 154         clear_gpio_bits(BIT(GPIO_OE), GPIO_CONFIG(offset));
 155         spin_unlock_irqrestore(&tlmm_lock, irq_flags);
 156         return 0;
 157 }
 158
 159 static int msm_gpio_direction_output(struct gpio_chip *chip,
 160                                 unsigned offset,
 161                                 int val)
 162 {
 163         unsigned long irq_flags;
 164
 165         spin_lock_irqsave(&tlmm_lock, irq_flags);
 166         msm_gpio_set(chip, offset, val);
 167         set_gpio_bits(BIT(GPIO_OE), GPIO_CONFIG(offset));
 168         spin_unlock_irqrestore(&tlmm_lock, irq_flags);
 169         return 0;
 170 }
 171
 172 static int msm_gpio_request(struct gpio_chip *chip, unsigned offset)
 173 {
 174         return 0;
 175 }
 176
 177 static void msm_gpio_free(struct gpio_chip *chip, unsigned offset)
 178 {
 179         return;
 180 }
 181
 182 static int msm_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 183 {
 184         struct msm_gpio_dev *g_dev = to_msm_gpio_dev(chip);
 185         struct irq_domain *domain = g_dev->domain;
 186
 187         return irq_create_mapping(domain, offset);
 188 }
 189
 190 /* For dual-edge interrupts in software, since the hardware has no
 191  * such support:
 192  *
 193  * At appropriate moments, this function may be called to flip the polarity
 194  * settings of both-edge irq lines to try and catch the next edge.
 195  *
 196  * The attempt is considered successful if:
 197  * - the status bit goes high, indicating that an edge was caught, or
 198  * - the input value of the gpio doesn't change during the attempt.
 199  * If the value changes twice during the process, that would cause the first
 200  * test to fail but would force the second, as two opposite
 201  * transitions would cause a detection no matter the polarity setting.
 202  *
 203  * The do-loop tries to sledge-hammer closed the timing hole between
 204  * the initial value-read and the polarity-write - if the line value changes
 205  * during that window, an interrupt is lost, the new polarity setting is
 206  * incorrect, and the first success test will fail, causing a retry.
 207  *
 208  * Algorithm comes from Google's msmgpio driver, see mach-msm/gpio.c.
 209  */
 210 static void msm_gpio_update_dual_edge_pos(unsigned gpio)
 211 {
 212         int loop_limit = 100;
 213         unsigned val, val2, intstat;
 214
 215         do {
 216                 val = readl(GPIO_IN_OUT(gpio)) & BIT(GPIO_IN);
 217                 if (val)
 218                         clear_gpio_bits(BIT(INTR_POL_CTL), GPIO_INTR_CFG(gpio));
 219                 else
 220                         set_gpio_bits(BIT(INTR_POL_CTL), GPIO_INTR_CFG(gpio));
 221                 val2 = readl(GPIO_IN_OUT(gpio)) & BIT(GPIO_IN);
 222                 intstat = readl(GPIO_INTR_STATUS(gpio)) & BIT(INTR_STATUS);
 223                 if (intstat || val == val2)
 224                         return;
 225         } while (loop_limit-- > 0);
 226         pr_err("%s: dual-edge irq failed to stabilize, "
 227                "interrupts dropped. %#08x != %#08x\n",
 228                __func__, val, val2);
 229 }
 230
 231 static void msm_gpio_irq_ack(struct irq_data *d)
 232 {
 233         int gpio = d->hwirq;
 234
 235         writel(BIT(INTR_STATUS), GPIO_INTR_STATUS(gpio));
 236         if (test_bit(gpio, msm_gpio.dual_edge_irqs))
 237                 msm_gpio_update_dual_edge_pos(gpio);
 238 }
 239
 240 static void msm_gpio_irq_mask(struct irq_data *d)
 241 {
 242         unsigned long irq_flags;
 243         int gpio = d->hwirq;
 244
 245         spin_lock_irqsave(&tlmm_lock, irq_flags);
 246         writel(TARGET_PROC_NONE, GPIO_INTR_CFG_SU(gpio));
 247         clear_gpio_bits(BIT(INTR_RAW_STATUS_EN) | BIT(INTR_ENABLE), GPIO_INTR_CFG(gpio));
 248         __clear_bit(gpio, msm_gpio.enabled_irqs);
 249         spin_unlock_irqrestore(&tlmm_lock, irq_flags);
 250 }
 251
 252 static void msm_gpio_irq_unmask(struct irq_data *d)
 253 {
 254         unsigned long irq_flags;
 255         int gpio = d->hwirq;
 256
 257         spin_lock_irqsave(&tlmm_lock, irq_flags);
 258         __set_bit(gpio, msm_gpio.enabled_irqs);
 259         set_gpio_bits(BIT(INTR_RAW_STATUS_EN) | BIT(INTR_ENABLE), GPIO_INTR_CFG(gpio));
 260         writel(TARGET_PROC_SCORPION, GPIO_INTR_CFG_SU(gpio));
 261         spin_unlock_irqrestore(&tlmm_lock, irq_flags);
 262 }
 263
 264 static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int flow_type)
 265 {
 266         unsigned long irq_flags;
 267         int gpio = d->hwirq;
 268         uint32_t bits;
 269
 270         spin_lock_irqsave(&tlmm_lock, irq_flags);
 271
 272         bits = readl(GPIO_INTR_CFG(gpio));
 273
 274         if (flow_type & IRQ_TYPE_EDGE_BOTH) {
 275                 bits |= BIT(INTR_DECT_CTL);
 276                 irq_set_handler_locked(d, handle_edge_irq);
 277                 if ((flow_type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
 278                         __set_bit(gpio, msm_gpio.dual_edge_irqs);
 279                 else
 280                         __clear_bit(gpio, msm_gpio.dual_edge_irqs);
 281         } else {
 282                 bits &= ~BIT(INTR_DECT_CTL);
 283                 irq_set_handler_locked(d, handle_level_irq);
 284                 __clear_bit(gpio, msm_gpio.dual_edge_irqs);
 285         }
 286
 287         if (flow_type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_LEVEL_HIGH))
 288                 bits |= BIT(INTR_POL_CTL);
 289         else
 290                 bits &= ~BIT(INTR_POL_CTL);
 291
 292         writel(bits, GPIO_INTR_CFG(gpio));
 293
 294         if ((flow_type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
 295                 msm_gpio_update_dual_edge_pos(gpio);
 296
 297         spin_unlock_irqrestore(&tlmm_lock, irq_flags);
 298
 299         return 0;
 300 }
 301
 302 /*
 303  * When the summary IRQ is raised, any number of GPIO lines may be high.
 304  * It is the job of the summary handler to find all those GPIO lines
 305  * which have been set as summary IRQ lines and which are triggered,
 306  * and to call their interrupt handlers.
 307  */
 308 static void msm_summary_irq_handler(struct irq_desc *desc)
 309 {
 310         unsigned long i;
 311         struct irq_chip *chip = irq_desc_get_chip(desc);
 312
 313         chained_irq_enter(chip, desc);
 314
 315         for_each_set_bit(i, msm_gpio.enabled_irqs, MAX_NR_GPIO) {
 316                 if (readl(GPIO_INTR_STATUS(i)) & BIT(INTR_STATUS))
 317                         generic_handle_irq(irq_find_mapping(msm_gpio.domain,
 318                                                                 i));
 319         }
 320
 321         chained_irq_exit(chip, desc);
 322 }
 323
 324 static int msm_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
 325 {
 326         int gpio = d->hwirq;
 327
 328         if (on) {
 329                 if (bitmap_empty(msm_gpio.wake_irqs, MAX_NR_GPIO))
 330                         irq_set_irq_wake(msm_gpio.summary_irq, 1);
 331                 set_bit(gpio, msm_gpio.wake_irqs);
 332         } else {
 333                 clear_bit(gpio, msm_gpio.wake_irqs);
 334                 if (bitmap_empty(msm_gpio.wake_irqs, MAX_NR_GPIO))
 335                         irq_set_irq_wake(msm_gpio.summary_irq, 0);
 336         }
 337
 338         return 0;
 339 }
 340
 341 static struct irq_chip msm_gpio_irq_chip = {
 342         .name           = "msmgpio",
 343         .irq_mask       = msm_gpio_irq_mask,
 344         .irq_unmask     = msm_gpio_irq_unmask,
 345         .irq_ack        = msm_gpio_irq_ack,
 346         .irq_set_type   = msm_gpio_irq_set_type,
 347         .irq_set_wake   = msm_gpio_irq_set_wake,
 348 };
 349
 350 static struct lock_class_key msm_gpio_lock_class;
 351
 352 static int msm_gpio_irq_domain_map(struct irq_domain *d, unsigned int irq,
 353                                    irq_hw_number_t hwirq)
 354 {
 355         irq_set_lockdep_class(irq, &msm_gpio_lock_class);
 356         irq_set_chip_and_handler(irq, &msm_gpio_irq_chip,
 357                         handle_level_irq);
 358
 359         return 0;
 360 }
 361
 362 static const struct irq_domain_ops msm_gpio_irq_domain_ops = {
 363         .xlate = irq_domain_xlate_twocell,
 364         .map = msm_gpio_irq_domain_map,
 365 };
 366
 367 static int msm_gpio_probe(struct platform_device *pdev)
 368 {
 369         int ret, ngpio;
 370         struct resource *res;
 371
 372         if (of_property_read_u32(pdev->dev.of_node, "ngpio", &ngpio)) {
 373                 dev_err(&pdev->dev, "%s: ngpio property missing\n", __func__);
 374                 return -EINVAL;
 375         }
 376
 377         if (ngpio > MAX_NR_GPIO)
 378                 WARN(1, "ngpio exceeds the MAX_NR_GPIO. Increase MAX_NR_GPIO\n");
 379
 380         bitmap_zero(msm_gpio.enabled_irqs, MAX_NR_GPIO);
 381         bitmap_zero(msm_gpio.wake_irqs, MAX_NR_GPIO);
 382         bitmap_zero(msm_gpio.dual_edge_irqs, MAX_NR_GPIO);
 383
 384         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 385         msm_gpio.msm_tlmm_base = devm_ioremap_resource(&pdev->dev, res);
 386         if (IS_ERR(msm_gpio.msm_tlmm_base))
 387                 return PTR_ERR(msm_gpio.msm_tlmm_base);
 388
 389         msm_gpio.gpio_chip.ngpio = ngpio;
 390         msm_gpio.gpio_chip.label = pdev->name;
 391         msm_gpio.gpio_chip.dev = &pdev->dev;
 392         msm_gpio.gpio_chip.base = 0;
 393         msm_gpio.gpio_chip.direction_input = msm_gpio_direction_input;
 394         msm_gpio.gpio_chip.direction_output = msm_gpio_direction_output;
 395         msm_gpio.gpio_chip.get = msm_gpio_get;
 396         msm_gpio.gpio_chip.set = msm_gpio_set;
 397         msm_gpio.gpio_chip.to_irq = msm_gpio_to_irq;
 398         msm_gpio.gpio_chip.request = msm_gpio_request;
 399         msm_gpio.gpio_chip.free = msm_gpio_free;
 400
 401         ret = gpiochip_add(&msm_gpio.gpio_chip);
 402         if (ret < 0) {
 403                 dev_err(&pdev->dev, "gpiochip_add failed with error %d\n", ret);
 404                 return ret;
 405         }
 406
 407         msm_gpio.summary_irq = platform_get_irq(pdev, 0);
 408         if (msm_gpio.summary_irq < 0) {
 409                 dev_err(&pdev->dev, "No Summary irq defined for msmgpio\n");
 410                 return msm_gpio.summary_irq;
 411         }
 412
 413         msm_gpio.domain = irq_domain_add_linear(pdev->dev.of_node, ngpio,
 414                                                 &msm_gpio_irq_domain_ops,
 415                                                 &msm_gpio);
 416         if (!msm_gpio.domain)
 417                 return -ENODEV;
 418
 419         irq_set_chained_handler(msm_gpio.summary_irq, msm_summary_irq_handler);
 420
 421         return 0;
 422 }
 423
 424 static const struct of_device_id msm_gpio_of_match[] = {
 425         { .compatible = "qcom,msm-gpio", },
 426         { },
 427 };
 428 MODULE_DEVICE_TABLE(of, msm_gpio_of_match);
 429
 430 static int msm_gpio_remove(struct platform_device *dev)
 431 {
 432         gpiochip_remove(&msm_gpio.gpio_chip);
 433
 434         irq_set_handler(msm_gpio.summary_irq, NULL);
 435
 436         return 0;
 437 }
 438
 439 static struct platform_driver msm_gpio_driver = {
 440         .probe = msm_gpio_probe,
 441         .remove = msm_gpio_remove,
 442         .driver = {
 443                 .name = "msmgpio",
 444                 .of_match_table = msm_gpio_of_match,
 445         },
 446 };
 447
 448 module_platform_driver(msm_gpio_driver)
 449
 450 MODULE_AUTHOR("Gregory Bean <gbean@codeaurora.org>");
 451 MODULE_DESCRIPTION("Driver for Qualcomm MSM TLMMv2 SoC GPIOs");
 452 MODULE_LICENSE("GPL v2");
 453 MODULE_ALIAS("platform:msmgpio");