drivers/leds/blink/leds-bcm63138.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
   4  */
   5 #include <linux/delay.h>
   6 #include <linux/io.h>
   7 #include <linux/leds.h>
   8 #include <linux/module.h>
   9 #include <linux/of.h>
  10 #include <linux/pinctrl/consumer.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/spinlock.h>
  13
  14 #define BCM63138_MAX_LEDS                               32
  15 #define BCM63138_MAX_BRIGHTNESS                         9
  16
  17 #define BCM63138_LED_BITS                               4                               /* how many bits control a single LED */
  18 #define BCM63138_LED_MASK                               ((1 << BCM63138_LED_BITS) - 1)  /* 0xf */
  19 #define BCM63138_LEDS_PER_REG                           (32 / BCM63138_LED_BITS)        /* 8 */
  20
  21 #define BCM63138_GLB_CTRL                               0x00
  22 #define  BCM63138_GLB_CTRL_SERIAL_LED_DATA_PPOL         0x00000002
  23 #define  BCM63138_GLB_CTRL_SERIAL_LED_EN_POL            0x00000008
  24 #define BCM63138_MASK                                   0x04
  25 #define BCM63138_HW_LED_EN                              0x08
  26 #define BCM63138_SERIAL_LED_SHIFT_SEL                   0x0c
  27 #define BCM63138_FLASH_RATE_CTRL1                       0x10
  28 #define BCM63138_FLASH_RATE_CTRL2                       0x14
  29 #define BCM63138_FLASH_RATE_CTRL3                       0x18
  30 #define BCM63138_FLASH_RATE_CTRL4                       0x1c
  31 #define BCM63138_BRIGHT_CTRL1                           0x20
  32 #define BCM63138_BRIGHT_CTRL2                           0x24
  33 #define BCM63138_BRIGHT_CTRL3                           0x28
  34 #define BCM63138_BRIGHT_CTRL4                           0x2c
  35 #define BCM63138_POWER_LED_CFG                          0x30
  36 #define BCM63138_HW_POLARITY                            0xb4
  37 #define BCM63138_SW_DATA                                0xb8
  38 #define BCM63138_SW_POLARITY                            0xbc
  39 #define BCM63138_PARALLEL_LED_POLARITY                  0xc0
  40 #define BCM63138_SERIAL_LED_POLARITY                    0xc4
  41 #define BCM63138_HW_LED_STATUS                          0xc8
  42 #define BCM63138_FLASH_CTRL_STATUS                      0xcc
  43 #define BCM63138_FLASH_BRT_CTRL                         0xd0
  44 #define BCM63138_FLASH_P_LED_OUT_STATUS                 0xd4
  45 #define BCM63138_FLASH_S_LED_OUT_STATUS                 0xd8
  46
  47 struct bcm63138_leds {
  48         struct device *dev;
  49         void __iomem *base;
  50         spinlock_t lock;
  51 };
  52
  53 struct bcm63138_led {
  54         struct bcm63138_leds *leds;
  55         struct led_classdev cdev;
  56         u32 pin;
  57         bool active_low;
  58 };
  59
  60 /*
  61  * I/O access
  62  */
  63
  64 static void bcm63138_leds_write(struct bcm63138_leds *leds, unsigned int reg,
  65                                 u32 data)
  66 {
  67         writel(data, leds->base + reg);
  68 }
  69
  70 static unsigned long bcm63138_leds_read(struct bcm63138_leds *leds,
  71                                         unsigned int reg)
  72 {
  73         return readl(leds->base + reg);
  74 }
  75
  76 static void bcm63138_leds_update_bits(struct bcm63138_leds *leds,
  77                                       unsigned int reg, u32 mask, u32 val)
  78 {
  79         WARN_ON(val & ~mask);
  80
  81         bcm63138_leds_write(leds, reg, (bcm63138_leds_read(leds, reg) & ~mask) | (val & mask));
  82 }
  83
  84 /*
  85  * Helpers
  86  */
  87
  88 static void bcm63138_leds_set_flash_rate(struct bcm63138_leds *leds,
  89                                          struct bcm63138_led *led,
  90                                          u8 value)
  91 {
  92         int reg_offset = (led->pin >> fls((BCM63138_LEDS_PER_REG - 1))) * 4;
  93         int shift = (led->pin & (BCM63138_LEDS_PER_REG - 1)) * BCM63138_LED_BITS;
  94
  95         bcm63138_leds_update_bits(leds, BCM63138_FLASH_RATE_CTRL1 + reg_offset,
  96                                   BCM63138_LED_MASK << shift, value << shift);
  97 }
  98
  99 static void bcm63138_leds_set_bright(struct bcm63138_leds *leds,
 100                                      struct bcm63138_led *led,
 101                                      u8 value)
 102 {
 103         int reg_offset = (led->pin >> fls((BCM63138_LEDS_PER_REG - 1))) * 4;
 104         int shift = (led->pin & (BCM63138_LEDS_PER_REG - 1)) * BCM63138_LED_BITS;
 105
 106         bcm63138_leds_update_bits(leds, BCM63138_BRIGHT_CTRL1 + reg_offset,
 107                                   BCM63138_LED_MASK << shift, value << shift);
 108 }
 109
 110 static void bcm63138_leds_enable_led(struct bcm63138_leds *leds,
 111                                      struct bcm63138_led *led,
 112                                      enum led_brightness value)
 113 {
 114         u32 bit = BIT(led->pin);
 115
 116         bcm63138_leds_update_bits(leds, BCM63138_SW_DATA, bit, value ? bit : 0);
 117 }
 118
 119 /*
 120  * API callbacks
 121  */
 122
 123 static void bcm63138_leds_brightness_set(struct led_classdev *led_cdev,
 124                                          enum led_brightness value)
 125 {
 126         struct bcm63138_led *led = container_of(led_cdev, struct bcm63138_led, cdev);
 127         struct bcm63138_leds *leds = led->leds;
 128         unsigned long flags;
 129
 130         spin_lock_irqsave(&leds->lock, flags);
 131
 132         bcm63138_leds_enable_led(leds, led, value);
 133         if (!value)
 134                 bcm63138_leds_set_flash_rate(leds, led, 0);
 135         else
 136                 bcm63138_leds_set_bright(leds, led, value);
 137
 138         spin_unlock_irqrestore(&leds->lock, flags);
 139 }
 140
 141 static int bcm63138_leds_blink_set(struct led_classdev *led_cdev,
 142                                    unsigned long *delay_on,
 143                                    unsigned long *delay_off)
 144 {
 145         struct bcm63138_led *led = container_of(led_cdev, struct bcm63138_led, cdev);
 146         struct bcm63138_leds *leds = led->leds;
 147         unsigned long flags;
 148         u8 value;
 149
 150         if (!*delay_on && !*delay_off) {
 151                 *delay_on = 640;
 152                 *delay_off = 640;
 153         }
 154
 155         if (*delay_on != *delay_off) {
 156                 dev_dbg(led_cdev->dev, "Blinking at unequal delays is not supported\n");
 157                 return -EINVAL;
 158         }
 159
 160         switch (*delay_on) {
 161         case 1152 ... 1408: /* 1280 ms ± 10% */
 162                 value = 0x7;
 163                 break;
 164         case 576 ... 704: /* 640 ms ± 10% */
 165                 value = 0x6;
 166                 break;
 167         case 288 ... 352: /* 320 ms ± 10% */
 168                 value = 0x5;
 169                 break;
 170         case 126 ... 154: /* 140 ms ± 10% */
 171                 value = 0x4;
 172                 break;
 173         case 59 ... 72: /* 65 ms ± 10% */
 174                 value = 0x3;
 175                 break;
 176         default:
 177                 dev_dbg(led_cdev->dev, "Blinking delay value %lu is unsupported\n",
 178                         *delay_on);
 179                 return -EINVAL;
 180         }
 181
 182         spin_lock_irqsave(&leds->lock, flags);
 183
 184         bcm63138_leds_enable_led(leds, led, BCM63138_MAX_BRIGHTNESS);
 185         bcm63138_leds_set_flash_rate(leds, led, value);
 186
 187         spin_unlock_irqrestore(&leds->lock, flags);
 188
 189         return 0;
 190 }
 191
 192 /*
 193  * LED driver
 194  */
 195
 196 static void bcm63138_leds_create_led(struct bcm63138_leds *leds,
 197                                      struct device_node *np)
 198 {
 199         struct led_init_data init_data = {
 200                 .fwnode = of_fwnode_handle(np),
 201         };
 202         struct device *dev = leds->dev;
 203         struct bcm63138_led *led;
 204         struct pinctrl *pinctrl;
 205         u32 bit;
 206         int err;
 207
 208         led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
 209         if (!led) {
 210                 dev_err(dev, "Failed to alloc LED\n");
 211                 return;
 212         }
 213
 214         led->leds = leds;
 215
 216         if (of_property_read_u32(np, "reg", &led->pin)) {
 217                 dev_err(dev, "Missing \"reg\" property in %pOF\n", np);
 218                 goto err_free;
 219         }
 220
 221         if (led->pin >= BCM63138_MAX_LEDS) {
 222                 dev_err(dev, "Invalid \"reg\" value %d\n", led->pin);
 223                 goto err_free;
 224         }
 225
 226         led->active_low = of_property_read_bool(np, "active-low");
 227
 228         led->cdev.max_brightness = BCM63138_MAX_BRIGHTNESS;
 229         led->cdev.brightness_set = bcm63138_leds_brightness_set;
 230         led->cdev.blink_set = bcm63138_leds_blink_set;
 231
 232         err = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
 233         if (err) {
 234                 dev_err(dev, "Failed to register LED %pOF: %d\n", np, err);
 235                 goto err_free;
 236         }
 237
 238         pinctrl = devm_pinctrl_get_select_default(led->cdev.dev);
 239         if (IS_ERR(pinctrl) && PTR_ERR(pinctrl) != -ENODEV) {
 240                 dev_warn(led->cdev.dev, "Failed to select %pOF pinctrl: %ld\n",
 241                          np, PTR_ERR(pinctrl));
 242         }
 243
 244         bit = BIT(led->pin);
 245         bcm63138_leds_update_bits(leds, BCM63138_PARALLEL_LED_POLARITY, bit,
 246                                   led->active_low ? 0 : bit);
 247         bcm63138_leds_update_bits(leds, BCM63138_HW_LED_EN, bit, 0);
 248         bcm63138_leds_set_flash_rate(leds, led, 0);
 249         bcm63138_leds_enable_led(leds, led, led->cdev.brightness);
 250
 251         return;
 252
 253 err_free:
 254         devm_kfree(dev, led);
 255 }
 256
 257 static int bcm63138_leds_probe(struct platform_device *pdev)
 258 {
 259         struct device_node *np = dev_of_node(&pdev->dev);
 260         struct device *dev = &pdev->dev;
 261         struct bcm63138_leds *leds;
 262         struct device_node *child;
 263
 264         leds = devm_kzalloc(dev, sizeof(*leds), GFP_KERNEL);
 265         if (!leds)
 266                 return -ENOMEM;
 267
 268         leds->dev = dev;
 269
 270         leds->base = devm_platform_ioremap_resource(pdev, 0);
 271         if (IS_ERR(leds->base))
 272                 return PTR_ERR(leds->base);
 273
 274         spin_lock_init(&leds->lock);
 275
 276         bcm63138_leds_write(leds, BCM63138_GLB_CTRL,
 277                             BCM63138_GLB_CTRL_SERIAL_LED_DATA_PPOL |
 278                             BCM63138_GLB_CTRL_SERIAL_LED_EN_POL);
 279         bcm63138_leds_write(leds, BCM63138_HW_LED_EN, 0);
 280         bcm63138_leds_write(leds, BCM63138_SERIAL_LED_POLARITY, 0);
 281         bcm63138_leds_write(leds, BCM63138_PARALLEL_LED_POLARITY, 0);
 282
 283         for_each_available_child_of_node(np, child) {
 284                 bcm63138_leds_create_led(leds, child);
 285         }
 286
 287         return 0;
 288 }
 289
 290 static const struct of_device_id bcm63138_leds_of_match_table[] = {
 291         { .compatible = "brcm,bcm63138-leds", },
 292         { },
 293 };
 294
 295 static struct platform_driver bcm63138_leds_driver = {
 296         .probe = bcm63138_leds_probe,
 297         .driver = {
 298                 .name = "leds-bcm63xxx",
 299                 .of_match_table = bcm63138_leds_of_match_table,
 300         },
 301 };
 302
 303 module_platform_driver(bcm63138_leds_driver);
 304
 305 MODULE_AUTHOR("Rafał Miłecki");
 306 MODULE_LICENSE("GPL");
 307 MODULE_DEVICE_TABLE(of, bcm63138_leds_of_match_table);