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/mod_devicetable.h>
   8 #include <linux/module.h>
   9 #include <linux/spi/spi.h>
  10 #include <linux/workqueue.h>
  11
  12 /*
  13  *  CR0014114 SPI protocol descrtiption:
  14  *  +----+-----------------------------------+----+
  15  *  | CMD|             BRIGHTNESS            |CRC |
  16  *  +----+-----------------------------------+----+
  17  *  |    | LED0| LED1| LED2| LED3| LED4| LED5|    |
  18  *  |    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+    |
  19  *  |    |R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|    |
  20  *  | 1  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1  |
  21  *  |    |1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|    |
  22  *  |    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+    |
  23  *  |    |               18                  |    |
  24  *  +----+-----------------------------------+----+
  25  *  |                    20                       |
  26  *  +---------------------------------------------+
  27  *
  28  *  PS: Boards can be connected to the chain:
  29  *      SPI -> board0 -> board1 -> board2 ..
  30  */
  31
  32 /* CR0014114 SPI commands */
  33 #define CR_SET_BRIGHTNESS       0x80
  34 #define CR_INIT_REENUMERATE     0x81
  35 #define CR_NEXT_REENUMERATE     0x82
  36
  37 /* CR0014114 default settings */
  38 #define CR_MAX_BRIGHTNESS       GENMASK(6, 0)
  39 #define CR_FW_DELAY_MSEC        10
  40 #define CR_RECOUNT_DELAY        (HZ * 3600)
  41
  42 #define CR_DEV_NAME             "cr0014114"
  43
  44 struct cr0014114_led {
  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[] __counted_by(count);
  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 to %d\n", brightness);
 171
 172         mutex_lock(&led->priv->lock);
 173         led->brightness = (u8)brightness;
 174         ret = cr0014114_sync(led->priv);
 175         mutex_unlock(&led->priv->lock);
 176
 177         return ret;
 178 }
 179
 180 static int cr0014114_probe_dt(struct cr0014114 *priv)
 181 {
 182         size_t                  i = 0;
 183         struct cr0014114_led    *led;
 184         struct led_init_data    init_data = {};
 185         int                     ret;
 186
 187         device_for_each_child_node_scoped(priv->dev, child) {
 188                 led = &priv->leds[i];
 189
 190                 led->priv                         = priv;
 191                 led->ldev.max_brightness          = CR_MAX_BRIGHTNESS;
 192                 led->ldev.brightness_set_blocking = cr0014114_set_sync;
 193
 194                 init_data.fwnode = child;
 195                 init_data.devicename = CR_DEV_NAME;
 196                 init_data.default_label = ":";
 197
 198                 ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,
 199                                                      &init_data);
 200                 if (ret) {
 201                         dev_err(priv->dev,
 202                                 "failed to register LED device, err %d", ret);
 203                         return ret;
 204                 }
 205
 206                 i++;
 207         }
 208
 209         return 0;
 210 }
 211
 212 static int cr0014114_probe(struct spi_device *spi)
 213 {
 214         struct cr0014114        *priv;
 215         size_t                  count;
 216         int                     ret;
 217
 218         count = device_get_child_node_count(&spi->dev);
 219         if (!count) {
 220                 dev_err(&spi->dev, "LEDs are not defined in device tree!");
 221                 return -ENODEV;
 222         }
 223
 224         priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
 225                             GFP_KERNEL);
 226         if (!priv)
 227                 return -ENOMEM;
 228
 229         priv->buf = devm_kzalloc(&spi->dev, count + 2, GFP_KERNEL);
 230         if (!priv->buf)
 231                 return -ENOMEM;
 232
 233         mutex_init(&priv->lock);
 234         INIT_DELAYED_WORK(&priv->work, cr0014114_recount_work);
 235         priv->count     = count;
 236         priv->dev       = &spi->dev;
 237         priv->spi       = spi;
 238         priv->delay     = jiffies -
 239                           msecs_to_jiffies(CR_FW_DELAY_MSEC);
 240
 241         priv->do_recount = true;
 242         ret = cr0014114_sync(priv);
 243         if (ret) {
 244                 dev_err(priv->dev, "first recount failed %d\n", ret);
 245                 return ret;
 246         }
 247
 248         priv->do_recount = true;
 249         ret = cr0014114_sync(priv);
 250         if (ret) {
 251                 dev_err(priv->dev, "second recount failed %d\n", ret);
 252                 return ret;
 253         }
 254
 255         ret = cr0014114_probe_dt(priv);
 256         if (ret)
 257                 return ret;
 258
 259         /* setup recount work to workaround buggy firmware */
 260         schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);
 261
 262         spi_set_drvdata(spi, priv);
 263
 264         return 0;
 265 }
 266
 267 static void cr0014114_remove(struct spi_device *spi)
 268 {
 269         struct cr0014114 *priv = spi_get_drvdata(spi);
 270
 271         cancel_delayed_work_sync(&priv->work);
 272         mutex_destroy(&priv->lock);
 273 }
 274
 275 static const struct of_device_id cr0014114_dt_ids[] = {
 276         { .compatible = "crane,cr0014114", },
 277         {},
 278 };
 279
 280 MODULE_DEVICE_TABLE(of, cr0014114_dt_ids);
 281
 282 static struct spi_driver cr0014114_driver = {
 283         .probe          = cr0014114_probe,
 284         .remove         = cr0014114_remove,
 285         .driver = {
 286                 .name           = KBUILD_MODNAME,
 287                 .of_match_table = cr0014114_dt_ids,
 288         },
 289 };
 290
 291 module_spi_driver(cr0014114_driver);
 292
 293 MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
 294 MODULE_DESCRIPTION("cr0014114 LED driver");
 295 MODULE_LICENSE("GPL v2");
 296 MODULE_ALIAS("spi:cr0014114");