drivers/leds/leds-bcm6328.c

   1 /*
   2  * Driver for BCM6328 memory-mapped LEDs, based on leds-syscon.c
   3  *
   4  * Copyright 2015 Álvaro Fernández Rojas <noltari@gmail.com>
   5  * Copyright 2015 Jonas Gorski <jogo@openwrt.org>
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  */
  12 #include <linux/io.h>
  13 #include <linux/leds.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/spinlock.h>
  18
  19 #define BCM6328_REG_INIT                0x00
  20 #define BCM6328_REG_MODE_HI             0x04
  21 #define BCM6328_REG_MODE_LO             0x08
  22 #define BCM6328_REG_HWDIS               0x0c
  23 #define BCM6328_REG_STROBE              0x10
  24 #define BCM6328_REG_LNKACTSEL_HI        0x14
  25 #define BCM6328_REG_LNKACTSEL_LO        0x18
  26 #define BCM6328_REG_RBACK               0x1c
  27 #define BCM6328_REG_SERMUX              0x20
  28
  29 #define BCM6328_LED_MAX_COUNT           24
  30 #define BCM6328_LED_DEF_DELAY           500
  31 #define BCM6328_LED_INTERVAL_MS         20
  32
  33 #define BCM6328_LED_INTV_MASK           0x3f
  34 #define BCM6328_LED_FAST_INTV_SHIFT     6
  35 #define BCM6328_LED_FAST_INTV_MASK      (BCM6328_LED_INTV_MASK << \
  36                                          BCM6328_LED_FAST_INTV_SHIFT)
  37 #define BCM6328_SERIAL_LED_EN           BIT(12)
  38 #define BCM6328_SERIAL_LED_MUX          BIT(13)
  39 #define BCM6328_SERIAL_LED_CLK_NPOL     BIT(14)
  40 #define BCM6328_SERIAL_LED_DATA_PPOL    BIT(15)
  41 #define BCM6328_SERIAL_LED_SHIFT_DIR    BIT(16)
  42 #define BCM6328_LED_SHIFT_TEST          BIT(30)
  43 #define BCM6328_LED_TEST                BIT(31)
  44 #define BCM6328_INIT_MASK               (BCM6328_SERIAL_LED_EN | \
  45                                          BCM6328_SERIAL_LED_MUX | \
  46                                          BCM6328_SERIAL_LED_CLK_NPOL | \
  47                                          BCM6328_SERIAL_LED_DATA_PPOL | \
  48                                          BCM6328_SERIAL_LED_SHIFT_DIR)
  49
  50 #define BCM6328_LED_MODE_MASK           3
  51 #define BCM6328_LED_MODE_ON             0
  52 #define BCM6328_LED_MODE_FAST           1
  53 #define BCM6328_LED_MODE_BLINK          2
  54 #define BCM6328_LED_MODE_OFF            3
  55 #define BCM6328_LED_SHIFT(X)            ((X) << 1)
  56
  57 /**
  58  * struct bcm6328_led - state container for bcm6328 based LEDs
  59  * @cdev: LED class device for this LED
  60  * @mem: memory resource
  61  * @lock: memory lock
  62  * @pin: LED pin number
  63  * @blink_leds: blinking LEDs
  64  * @blink_delay: blinking delay
  65  * @active_low: LED is active low
  66  */
  67 struct bcm6328_led {
  68         struct led_classdev cdev;
  69         void __iomem *mem;
  70         spinlock_t *lock;
  71         unsigned long pin;
  72         unsigned long *blink_leds;
  73         unsigned long *blink_delay;
  74         bool active_low;
  75 };
  76
  77 static void bcm6328_led_write(void __iomem *reg, unsigned long data)
  78 {
  79 #ifdef CONFIG_CPU_BIG_ENDIAN
  80         iowrite32be(data, reg);
  81 #else
  82         writel(data, reg);
  83 #endif
  84 }
  85
  86 static unsigned long bcm6328_led_read(void __iomem *reg)
  87 {
  88 #ifdef CONFIG_CPU_BIG_ENDIAN
  89         return ioread32be(reg);
  90 #else
  91         return readl(reg);
  92 #endif
  93 }
  94
  95 /**
  96  * LEDMode 64 bits / 24 LEDs
  97  * bits [31:0] -> LEDs 8-23
  98  * bits [47:32] -> LEDs 0-7
  99  * bits [63:48] -> unused
 100  */
 101 static unsigned long bcm6328_pin2shift(unsigned long pin)
 102 {
 103         if (pin < 8)
 104                 return pin + 16; /* LEDs 0-7 (bits 47:32) */
 105         else
 106                 return pin - 8; /* LEDs 8-23 (bits 31:0) */
 107 }
 108
 109 static void bcm6328_led_mode(struct bcm6328_led *led, unsigned long value)
 110 {
 111         void __iomem *mode;
 112         unsigned long val, shift;
 113
 114         shift = bcm6328_pin2shift(led->pin);
 115         if (shift / 16)
 116                 mode = led->mem + BCM6328_REG_MODE_HI;
 117         else
 118                 mode = led->mem + BCM6328_REG_MODE_LO;
 119
 120         val = bcm6328_led_read(mode);
 121         val &= ~(BCM6328_LED_MODE_MASK << BCM6328_LED_SHIFT(shift % 16));
 122         val |= (value << BCM6328_LED_SHIFT(shift % 16));
 123         bcm6328_led_write(mode, val);
 124 }
 125
 126 static void bcm6328_led_set(struct led_classdev *led_cdev,
 127                             enum led_brightness value)
 128 {
 129         struct bcm6328_led *led =
 130                 container_of(led_cdev, struct bcm6328_led, cdev);
 131         unsigned long flags;
 132
 133         spin_lock_irqsave(led->lock, flags);
 134         *(led->blink_leds) &= ~BIT(led->pin);
 135         if ((led->active_low && value == LED_OFF) ||
 136             (!led->active_low && value != LED_OFF))
 137                 bcm6328_led_mode(led, BCM6328_LED_MODE_ON);
 138         else
 139                 bcm6328_led_mode(led, BCM6328_LED_MODE_OFF);
 140         spin_unlock_irqrestore(led->lock, flags);
 141 }
 142
 143 static unsigned long bcm6328_blink_delay(unsigned long delay)
 144 {
 145         unsigned long bcm6328_delay;
 146
 147         bcm6328_delay = delay + BCM6328_LED_INTERVAL_MS / 2;
 148         bcm6328_delay = bcm6328_delay / BCM6328_LED_INTERVAL_MS;
 149         if (bcm6328_delay == 0)
 150                 bcm6328_delay = 1;
 151
 152         return bcm6328_delay;
 153 }
 154
 155 static int bcm6328_blink_set(struct led_classdev *led_cdev,
 156                              unsigned long *delay_on, unsigned long *delay_off)
 157 {
 158         struct bcm6328_led *led =
 159                 container_of(led_cdev, struct bcm6328_led, cdev);
 160         unsigned long delay, flags;
 161         int rc;
 162
 163         if (!*delay_on)
 164                 *delay_on = BCM6328_LED_DEF_DELAY;
 165         if (!*delay_off)
 166                 *delay_off = BCM6328_LED_DEF_DELAY;
 167
 168         delay = bcm6328_blink_delay(*delay_on);
 169         if (delay != bcm6328_blink_delay(*delay_off)) {
 170                 dev_dbg(led_cdev->dev,
 171                         "fallback to soft blinking (delay_on != delay_off)\n");
 172                 return -EINVAL;
 173         }
 174
 175         if (delay > BCM6328_LED_INTV_MASK) {
 176                 dev_dbg(led_cdev->dev,
 177                         "fallback to soft blinking (delay > %ums)\n",
 178                         BCM6328_LED_INTV_MASK * BCM6328_LED_INTERVAL_MS);
 179                 return -EINVAL;
 180         }
 181
 182         spin_lock_irqsave(led->lock, flags);
 183         if (*(led->blink_leds) == 0 ||
 184             *(led->blink_leds) == BIT(led->pin) ||
 185             *(led->blink_delay) == delay) {
 186                 unsigned long val;
 187
 188                 *(led->blink_leds) |= BIT(led->pin);
 189                 *(led->blink_delay) = delay;
 190
 191                 val = bcm6328_led_read(led->mem + BCM6328_REG_INIT);
 192                 val &= ~BCM6328_LED_FAST_INTV_MASK;
 193                 val |= (delay << BCM6328_LED_FAST_INTV_SHIFT);
 194                 bcm6328_led_write(led->mem + BCM6328_REG_INIT, val);
 195
 196                 bcm6328_led_mode(led, BCM6328_LED_MODE_BLINK);
 197                 rc = 0;
 198         } else {
 199                 dev_dbg(led_cdev->dev,
 200                         "fallback to soft blinking (delay already set)\n");
 201                 rc = -EINVAL;
 202         }
 203         spin_unlock_irqrestore(led->lock, flags);
 204
 205         return rc;
 206 }
 207
 208 static int bcm6328_hwled(struct device *dev, struct device_node *nc, u32 reg,
 209                          void __iomem *mem, spinlock_t *lock)
 210 {
 211         int i, cnt;
 212         unsigned long flags, val;
 213
 214         spin_lock_irqsave(lock, flags);
 215         val = bcm6328_led_read(mem + BCM6328_REG_HWDIS);
 216         val &= ~BIT(reg);
 217         bcm6328_led_write(mem + BCM6328_REG_HWDIS, val);
 218         spin_unlock_irqrestore(lock, flags);
 219
 220         /* Only LEDs 0-7 can be activity/link controlled */
 221         if (reg >= 8)
 222                 return 0;
 223
 224         cnt = of_property_count_elems_of_size(nc, "brcm,link-signal-sources",
 225                                               sizeof(u32));
 226         for (i = 0; i < cnt; i++) {
 227                 u32 sel;
 228                 void __iomem *addr;
 229
 230                 if (reg < 4)
 231                         addr = mem + BCM6328_REG_LNKACTSEL_LO;
 232                 else
 233                         addr = mem + BCM6328_REG_LNKACTSEL_HI;
 234
 235                 of_property_read_u32_index(nc, "brcm,link-signal-sources", i,
 236                                            &sel);
 237
 238                 if (reg / 4 != sel / 4) {
 239                         dev_warn(dev, "invalid link signal source\n");
 240                         continue;
 241                 }
 242
 243                 spin_lock_irqsave(lock, flags);
 244                 val = bcm6328_led_read(addr);
 245                 val |= (BIT(reg % 4) << (((sel % 4) * 4) + 16));
 246                 bcm6328_led_write(addr, val);
 247                 spin_unlock_irqrestore(lock, flags);
 248         }
 249
 250         cnt = of_property_count_elems_of_size(nc,
 251                                               "brcm,activity-signal-sources",
 252                                               sizeof(u32));
 253         for (i = 0; i < cnt; i++) {
 254                 u32 sel;
 255                 void __iomem *addr;
 256
 257                 if (reg < 4)
 258                         addr = mem + BCM6328_REG_LNKACTSEL_LO;
 259                 else
 260                         addr = mem + BCM6328_REG_LNKACTSEL_HI;
 261
 262                 of_property_read_u32_index(nc, "brcm,activity-signal-sources",
 263                                            i, &sel);
 264
 265                 if (reg / 4 != sel / 4) {
 266                         dev_warn(dev, "invalid activity signal source\n");
 267                         continue;
 268                 }
 269
 270                 spin_lock_irqsave(lock, flags);
 271                 val = bcm6328_led_read(addr);
 272                 val |= (BIT(reg % 4) << ((sel % 4) * 4));
 273                 bcm6328_led_write(addr, val);
 274                 spin_unlock_irqrestore(lock, flags);
 275         }
 276
 277         return 0;
 278 }
 279
 280 static int bcm6328_led(struct device *dev, struct device_node *nc, u32 reg,
 281                        void __iomem *mem, spinlock_t *lock,
 282                        unsigned long *blink_leds, unsigned long *blink_delay)
 283 {
 284         struct bcm6328_led *led;
 285         const char *state;
 286         int rc;
 287
 288         led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
 289         if (!led)
 290                 return -ENOMEM;
 291
 292         led->pin = reg;
 293         led->mem = mem;
 294         led->lock = lock;
 295         led->blink_leds = blink_leds;
 296         led->blink_delay = blink_delay;
 297
 298         if (of_property_read_bool(nc, "active-low"))
 299                 led->active_low = true;
 300
 301         led->cdev.name = of_get_property(nc, "label", NULL) ? : nc->name;
 302         led->cdev.default_trigger = of_get_property(nc,
 303                                                     "linux,default-trigger",
 304                                                     NULL);
 305
 306         if (!of_property_read_string(nc, "default-state", &state)) {
 307                 if (!strcmp(state, "on")) {
 308                         led->cdev.brightness = LED_FULL;
 309                 } else if (!strcmp(state, "keep")) {
 310                         void __iomem *mode;
 311                         unsigned long val, shift;
 312
 313                         shift = bcm6328_pin2shift(led->pin);
 314                         if (shift / 16)
 315                                 mode = mem + BCM6328_REG_MODE_HI;
 316                         else
 317                                 mode = mem + BCM6328_REG_MODE_LO;
 318
 319                         val = bcm6328_led_read(mode) >>
 320                               BCM6328_LED_SHIFT(shift % 16);
 321                         val &= BCM6328_LED_MODE_MASK;
 322                         if ((led->active_low && val == BCM6328_LED_MODE_OFF) ||
 323                             (!led->active_low && val == BCM6328_LED_MODE_ON))
 324                                 led->cdev.brightness = LED_FULL;
 325                         else
 326                                 led->cdev.brightness = LED_OFF;
 327                 } else {
 328                         led->cdev.brightness = LED_OFF;
 329                 }
 330         } else {
 331                 led->cdev.brightness = LED_OFF;
 332         }
 333
 334         bcm6328_led_set(&led->cdev, led->cdev.brightness);
 335
 336         led->cdev.brightness_set = bcm6328_led_set;
 337         led->cdev.blink_set = bcm6328_blink_set;
 338
 339         rc = led_classdev_register(dev, &led->cdev);
 340         if (rc < 0)
 341                 return rc;
 342
 343         dev_dbg(dev, "registered LED %s\n", led->cdev.name);
 344
 345         return 0;
 346 }
 347
 348 static int bcm6328_leds_probe(struct platform_device *pdev)
 349 {
 350         struct device *dev = &pdev->dev;
 351         struct device_node *np = pdev->dev.of_node;
 352         struct device_node *child;
 353         struct resource *mem_r;
 354         void __iomem *mem;
 355         spinlock_t *lock; /* memory lock */
 356         unsigned long val, *blink_leds, *blink_delay;
 357
 358         mem_r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 359         if (!mem_r)
 360                 return -EINVAL;
 361
 362         mem = devm_ioremap_resource(dev, mem_r);
 363         if (IS_ERR(mem))
 364                 return PTR_ERR(mem);
 365
 366         lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
 367         if (!lock)
 368                 return -ENOMEM;
 369
 370         blink_leds = devm_kzalloc(dev, sizeof(*blink_leds), GFP_KERNEL);
 371         if (!blink_leds)
 372                 return -ENOMEM;
 373
 374         blink_delay = devm_kzalloc(dev, sizeof(*blink_delay), GFP_KERNEL);
 375         if (!blink_delay)
 376                 return -ENOMEM;
 377
 378         spin_lock_init(lock);
 379
 380         bcm6328_led_write(mem + BCM6328_REG_HWDIS, ~0);
 381         bcm6328_led_write(mem + BCM6328_REG_LNKACTSEL_HI, 0);
 382         bcm6328_led_write(mem + BCM6328_REG_LNKACTSEL_LO, 0);
 383
 384         val = bcm6328_led_read(mem + BCM6328_REG_INIT);
 385         val &= ~(BCM6328_INIT_MASK);
 386         if (of_property_read_bool(np, "brcm,serial-leds"))
 387                 val |= BCM6328_SERIAL_LED_EN;
 388         if (of_property_read_bool(np, "brcm,serial-mux"))
 389                 val |= BCM6328_SERIAL_LED_MUX;
 390         if (of_property_read_bool(np, "brcm,serial-clk-low"))
 391                 val |= BCM6328_SERIAL_LED_CLK_NPOL;
 392         if (!of_property_read_bool(np, "brcm,serial-dat-low"))
 393                 val |= BCM6328_SERIAL_LED_DATA_PPOL;
 394         if (!of_property_read_bool(np, "brcm,serial-shift-inv"))
 395                 val |= BCM6328_SERIAL_LED_SHIFT_DIR;
 396         bcm6328_led_write(mem + BCM6328_REG_INIT, val);
 397
 398         for_each_available_child_of_node(np, child) {
 399                 int rc;
 400                 u32 reg;
 401
 402                 if (of_property_read_u32(child, "reg", &reg))
 403                         continue;
 404
 405                 if (reg >= BCM6328_LED_MAX_COUNT) {
 406                         dev_err(dev, "invalid LED (%u >= %d)\n", reg,
 407                                 BCM6328_LED_MAX_COUNT);
 408                         continue;
 409                 }
 410
 411                 if (of_property_read_bool(child, "brcm,hardware-controlled"))
 412                         rc = bcm6328_hwled(dev, child, reg, mem, lock);
 413                 else
 414                         rc = bcm6328_led(dev, child, reg, mem, lock,
 415                                          blink_leds, blink_delay);
 416
 417                 if (rc < 0) {
 418                         of_node_put(child);
 419                         return rc;
 420                 }
 421         }
 422
 423         return 0;
 424 }
 425
 426 static const struct of_device_id bcm6328_leds_of_match[] = {
 427         { .compatible = "brcm,bcm6328-leds", },
 428         { },
 429 };
 430 MODULE_DEVICE_TABLE(of, bcm6328_leds_of_match);
 431
 432 static struct platform_driver bcm6328_leds_driver = {
 433         .probe = bcm6328_leds_probe,
 434         .driver = {
 435                 .name = "leds-bcm6328",
 436                 .of_match_table = bcm6328_leds_of_match,
 437         },
 438 };
 439
 440 module_platform_driver(bcm6328_leds_driver);
 441
 442 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
 443 MODULE_AUTHOR("Jonas Gorski <jogo@openwrt.org>");
 444 MODULE_DESCRIPTION("LED driver for BCM6328 controllers");
 445 MODULE_LICENSE("GPL v2");
 446 MODULE_ALIAS("platform:leds-bcm6328");