drivers/leds/leds-cr0014114.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2018 Crane Merchandising Systems. All rights reserved.
   3 // Copyright (C) 2018 Oleh Kravchenko <oleg@kaa.org.ua>
   4
   5 #include <linux/delay.h>
   6 #include <linux/leds.h>
   7 #include <linux/module.h>
   8 #include <linux/of_device.h>
   9 #include <linux/spi/spi.h>
  10 #include <linux/workqueue.h>
  11 #include <uapi/linux/uleds.h>
  12
  13 /*
  14  *  CR0014114 SPI protocol descrtiption:
  15  *  +----+-----------------------------------+----+
  16  *  | CMD|             BRIGHTNESS            |CRC |
  17  *  +----+-----------------------------------+----+
  18  *  |    | LED0| LED1| LED2| LED3| LED4| LED5|    |
  19  *  |    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+    |
  20  *  |    |R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|    |
  21  *  | 1  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1  |
  22  *  |    |1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|    |
  23  *  |    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+    |
  24  *  |    |               18                  |    |
  25  *  +----+-----------------------------------+----+
  26  *  |                    20                       |
  27  *  +---------------------------------------------+
  28  *
  29  *  PS: Boards can be connected to the chain:
  30  *      SPI -> board0 -> board1 -> board2 ..
  31  */
  32
  33 /* CR0014114 SPI commands */
  34 #define CR_SET_BRIGHTNESS       0x80
  35 #define CR_INIT_REENUMERATE     0x81
  36 #define CR_NEXT_REENUMERATE     0x82
  37
  38 /* CR0014114 default settings */
  39 #define CR_MAX_BRIGHTNESS       GENMASK(6, 0)
  40 #define CR_FW_DELAY_MSEC        10
  41 #define CR_RECOUNT_DELAY        (HZ * 3600)
  42
  43 struct cr0014114_led {
  44         char                    name[LED_MAX_NAME_SIZE];
  45         struct cr0014114        *priv;
  46         struct led_classdev     ldev;
  47         u8                      brightness;
  48 };
  49
  50 struct cr0014114 {
  51         bool                    do_recount;
  52         size_t                  count;
  53         struct delayed_work     work;
  54         struct device           *dev;
  55         struct mutex            lock;
  56         struct spi_device       *spi;
  57         u8                      *buf;
  58         unsigned long           delay;
  59         struct cr0014114_led    leds[];
  60 };
  61
  62 static void cr0014114_calc_crc(u8 *buf, const size_t len)
  63 {
  64         size_t  i;
  65         u8      crc;
  66
  67         for (i = 1, crc = 1; i < len - 1; i++)
  68                 crc += buf[i];
  69         crc |= BIT(7);
  70
  71         /* special case when CRC matches the SPI commands */
  72         if (crc == CR_SET_BRIGHTNESS ||
  73             crc == CR_INIT_REENUMERATE ||
  74             crc == CR_NEXT_REENUMERATE)
  75                 crc = 0xfe;
  76
  77         buf[len - 1] = crc;
  78 }
  79
  80 static int cr0014114_recount(struct cr0014114 *priv)
  81 {
  82         int     ret;
  83         size_t  i;
  84         u8      cmd;
  85
  86         dev_dbg(priv->dev, "LEDs recount is started\n");
  87
  88         cmd = CR_INIT_REENUMERATE;
  89         ret = spi_write(priv->spi, &cmd, sizeof(cmd));
  90         if (ret)
  91                 goto err;
  92
  93         cmd = CR_NEXT_REENUMERATE;
  94         for (i = 0; i < priv->count; i++) {
  95                 msleep(CR_FW_DELAY_MSEC);
  96
  97                 ret = spi_write(priv->spi, &cmd, sizeof(cmd));
  98                 if (ret)
  99                         goto err;
 100         }
 101
 102 err:
 103         dev_dbg(priv->dev, "LEDs recount is finished\n");
 104
 105         if (ret)
 106                 dev_err(priv->dev, "with error %d", ret);
 107
 108         return ret;
 109 }
 110
 111 static int cr0014114_sync(struct cr0014114 *priv)
 112 {
 113         int             ret;
 114         size_t          i;
 115         unsigned long   udelay, now = jiffies;
 116
 117         /* to avoid SPI mistiming with firmware we should wait some time */
 118         if (time_after(priv->delay, now)) {
 119                 udelay = jiffies_to_usecs(priv->delay - now);
 120                 usleep_range(udelay, udelay + 1);
 121         }
 122
 123         if (unlikely(priv->do_recount)) {
 124                 ret = cr0014114_recount(priv);
 125                 if (ret)
 126                         goto err;
 127
 128                 priv->do_recount = false;
 129                 msleep(CR_FW_DELAY_MSEC);
 130         }
 131
 132         priv->buf[0] = CR_SET_BRIGHTNESS;
 133         for (i = 0; i < priv->count; i++)
 134                 priv->buf[i + 1] = priv->leds[i].brightness;
 135         cr0014114_calc_crc(priv->buf, priv->count + 2);
 136         ret = spi_write(priv->spi, priv->buf, priv->count + 2);
 137
 138 err:
 139         priv->delay = jiffies + msecs_to_jiffies(CR_FW_DELAY_MSEC);
 140
 141         return ret;
 142 }
 143
 144 static void cr0014114_recount_work(struct work_struct *work)
 145 {
 146         int                     ret;
 147         struct cr0014114        *priv = container_of(work,
 148                                                      struct cr0014114,
 149                                                      work.work);
 150
 151         mutex_lock(&priv->lock);
 152         priv->do_recount = true;
 153         ret = cr0014114_sync(priv);
 154         mutex_unlock(&priv->lock);
 155
 156         if (ret)
 157                 dev_warn(priv->dev, "sync of LEDs failed %d\n", ret);
 158
 159         schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);
 160 }
 161
 162 static int cr0014114_set_sync(struct led_classdev *ldev,
 163                               enum led_brightness brightness)
 164 {
 165         int                     ret;
 166         struct cr0014114_led    *led = container_of(ldev,
 167                                                     struct cr0014114_led,
 168                                                     ldev);
 169
 170         dev_dbg(led->priv->dev, "Set brightness of %s to %d\n",
 171                 led->name, brightness);
 172
 173         mutex_lock(&led->priv->lock);
 174         led->brightness = (u8)brightness;
 175         ret = cr0014114_sync(led->priv);
 176         mutex_unlock(&led->priv->lock);
 177
 178         return ret;
 179 }
 180
 181 static int cr0014114_probe_dt(struct cr0014114 *priv)
 182 {
 183         size_t                  i = 0;
 184         struct cr0014114_led    *led;
 185         struct fwnode_handle    *child;
 186         struct device_node      *np;
 187         int                     ret;
 188         const char              *str;
 189
 190         device_for_each_child_node(priv->dev, child) {
 191                 np = to_of_node(child);
 192                 led = &priv->leds[i];
 193
 194                 ret = fwnode_property_read_string(child, "label", &str);
 195                 if (ret)
 196                         snprintf(led->name, sizeof(led->name),
 197                                  "cr0014114::");
 198                 else
 199                         snprintf(led->name, sizeof(led->name),
 200                                  "cr0014114:%s", str);
 201
 202                 fwnode_property_read_string(child, "linux,default-trigger",
 203                                             &led->ldev.default_trigger);
 204
 205                 led->priv                         = priv;
 206                 led->ldev.name                    = led->name;
 207                 led->ldev.max_brightness          = CR_MAX_BRIGHTNESS;
 208                 led->ldev.brightness_set_blocking = cr0014114_set_sync;
 209
 210                 ret = devm_of_led_classdev_register(priv->dev, np,
 211                                                     &led->ldev);
 212                 if (ret) {
 213                         dev_err(priv->dev,
 214                                 "failed to register LED device %s, err %d",
 215                                 led->name, ret);
 216                         fwnode_handle_put(child);
 217                         return ret;
 218                 }
 219
 220                 led->ldev.dev->of_node = np;
 221
 222                 i++;
 223         }
 224
 225         return 0;
 226 }
 227
 228 static int cr0014114_probe(struct spi_device *spi)
 229 {
 230         struct cr0014114        *priv;
 231         size_t                  count;
 232         int                     ret;
 233
 234         count = device_get_child_node_count(&spi->dev);
 235         if (!count) {
 236                 dev_err(&spi->dev, "LEDs are not defined in device tree!");
 237                 return -ENODEV;
 238         }
 239
 240         priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
 241                             GFP_KERNEL);
 242         if (!priv)
 243                 return -ENOMEM;
 244
 245         priv->buf = devm_kzalloc(&spi->dev, count + 2, GFP_KERNEL);
 246         if (!priv->buf)
 247                 return -ENOMEM;
 248
 249         mutex_init(&priv->lock);
 250         INIT_DELAYED_WORK(&priv->work, cr0014114_recount_work);
 251         priv->count     = count;
 252         priv->dev       = &spi->dev;
 253         priv->spi       = spi;
 254         priv->delay     = jiffies -
 255                           msecs_to_jiffies(CR_FW_DELAY_MSEC);
 256
 257         priv->do_recount = true;
 258         ret = cr0014114_sync(priv);
 259         if (ret) {
 260                 dev_err(priv->dev, "first recount failed %d\n", ret);
 261                 return ret;
 262         }
 263
 264         priv->do_recount = true;
 265         ret = cr0014114_sync(priv);
 266         if (ret) {
 267                 dev_err(priv->dev, "second recount failed %d\n", ret);
 268                 return ret;
 269         }
 270
 271         ret = cr0014114_probe_dt(priv);
 272         if (ret)
 273                 return ret;
 274
 275         /* setup recount work to workaround buggy firmware */
 276         schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);
 277
 278         spi_set_drvdata(spi, priv);
 279
 280         return 0;
 281 }
 282
 283 static int cr0014114_remove(struct spi_device *spi)
 284 {
 285         struct cr0014114 *priv = spi_get_drvdata(spi);
 286
 287         cancel_delayed_work_sync(&priv->work);
 288         mutex_destroy(&priv->lock);
 289
 290         return 0;
 291 }
 292
 293 static const struct of_device_id cr0014114_dt_ids[] = {
 294         { .compatible = "crane,cr0014114", },
 295         {},
 296 };
 297
 298 MODULE_DEVICE_TABLE(of, cr0014114_dt_ids);
 299
 300 static struct spi_driver cr0014114_driver = {
 301         .probe          = cr0014114_probe,
 302         .remove         = cr0014114_remove,
 303         .driver = {
 304                 .name           = KBUILD_MODNAME,
 305                 .of_match_table = cr0014114_dt_ids,
 306         },
 307 };
 308
 309 module_spi_driver(cr0014114_driver);
 310
 311 MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
 312 MODULE_DESCRIPTION("cr0014114 LED driver");
 313 MODULE_LICENSE("GPL v2");
 314 MODULE_ALIAS("spi:cr0014114");