drivers/leds/leds-el15203000.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2019 Crane Merchandising Systems. All rights reserved.
   3 // Copyright (C) 2019 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
  11 /*
  12  * EL15203000 SPI protocol description:
  13  * +-----+---------+
  14  * | LED | COMMAND |
  15  * +-----+---------+
  16  * |  1  |    1    |
  17  * +-----+---------+
  18  * (*) LEDs MCU board expects 20 msec delay per byte.
  19  *
  20  * LEDs:
  21  * +----------+--------------+-------------------------------------------+
  22  * |    ID    |     NAME     |         DESCRIPTION                       |
  23  * +----------+--------------+-------------------------------------------+
  24  * | 'P' 0x50 |     Pipe     | Consists from 5 LEDs, controlled by board |
  25  * +----------+--------------+-------------------------------------------+
  26  * | 'S' 0x53 | Screen frame | Light tube around the screen              |
  27  * +----------+--------------+-------------------------------------------+
  28  * | 'V' 0x56 | Vending area | Highlights a cup of coffee                |
  29  * +----------+--------------+-------------------------------------------+
  30  *
  31  * COMMAND:
  32  * +----------+-----------------+--------------+--------------+
  33  * |  VALUES  |       PIPE      | SCREEN FRAME | VENDING AREA |
  34  * +----------+-----------------+--------------+--------------+
  35  * | '0' 0x30 |                      Off                      |
  36  * +----------+-----------------------------------------------+
  37  * | '1' 0x31 |                      On                       |
  38  * +----------+-----------------+--------------+--------------+
  39  * | '2' 0x32 |     Cascade     |   Breathing  |
  40  * +----------+-----------------+--------------+
  41  * | '3' 0x33 | Inverse cascade |
  42  * +----------+-----------------+
  43  * | '4' 0x34 |     Bounce      |
  44  * +----------+-----------------+
  45  * | '5' 0x35 | Inverse bounce  |
  46  * +----------+-----------------+
  47  */
  48
  49 /* EL15203000 default settings */
  50 #define EL_FW_DELAY_USEC        20000ul
  51 #define EL_PATTERN_DELAY_MSEC   800u
  52 #define EL_PATTERN_LEN          10u
  53 #define EL_PATTERN_HALF_LEN     (EL_PATTERN_LEN / 2)
  54
  55 enum el15203000_command {
  56         /* for all LEDs */
  57         EL_OFF                  = '0',
  58         EL_ON                   = '1',
  59
  60         /* for Screen LED */
  61         EL_SCREEN_BREATHING     = '2',
  62
  63         /* for Pipe LED */
  64         EL_PIPE_CASCADE         = '2',
  65         EL_PIPE_INV_CASCADE     = '3',
  66         EL_PIPE_BOUNCE          = '4',
  67         EL_PIPE_INV_BOUNCE      = '5',
  68 };
  69
  70 struct el15203000_led {
  71         struct el15203000       *priv;
  72         struct led_classdev     ldev;
  73         u32                     reg;
  74 };
  75
  76 struct el15203000 {
  77         struct device           *dev;
  78         struct mutex            lock;
  79         struct spi_device       *spi;
  80         unsigned long           delay;
  81         size_t                  count;
  82         struct el15203000_led   leds[];
  83 };
  84
  85 static int el15203000_cmd(struct el15203000_led *led, u8 brightness)
  86 {
  87         int             ret;
  88         u8              cmd[2];
  89         size_t          i;
  90
  91         mutex_lock(&led->priv->lock);
  92
  93         dev_dbg(led->priv->dev, "Set brightness of 0x%02x(%c) to 0x%02x(%c)",
  94                 led->reg, led->reg, brightness, brightness);
  95
  96         /* to avoid SPI mistiming with firmware we should wait some time */
  97         if (time_after(led->priv->delay, jiffies)) {
  98                 dev_dbg(led->priv->dev, "Wait %luus to sync",
  99                         EL_FW_DELAY_USEC);
 100
 101                 usleep_range(EL_FW_DELAY_USEC,
 102                              EL_FW_DELAY_USEC + 1);
 103         }
 104
 105         cmd[0] = led->reg;
 106         cmd[1] = brightness;
 107
 108         for (i = 0; i < ARRAY_SIZE(cmd); i++) {
 109                 if (i)
 110                         usleep_range(EL_FW_DELAY_USEC,
 111                                      EL_FW_DELAY_USEC + 1);
 112
 113                 ret = spi_write(led->priv->spi, &cmd[i], sizeof(cmd[i]));
 114                 if (ret) {
 115                         dev_err(led->priv->dev,
 116                                 "spi_write() error %d", ret);
 117                         break;
 118                 }
 119         }
 120
 121         led->priv->delay = jiffies + usecs_to_jiffies(EL_FW_DELAY_USEC);
 122
 123         mutex_unlock(&led->priv->lock);
 124
 125         return ret;
 126 }
 127
 128 static int el15203000_set_blocking(struct led_classdev *ldev,
 129                                    enum led_brightness brightness)
 130 {
 131         struct el15203000_led *led = container_of(ldev,
 132                                                   struct el15203000_led,
 133                                                   ldev);
 134
 135         return el15203000_cmd(led, brightness == LED_OFF ? EL_OFF : EL_ON);
 136 }
 137
 138 static int el15203000_pattern_set_S(struct led_classdev *ldev,
 139                                     struct led_pattern *pattern,
 140                                     u32 len, int repeat)
 141 {
 142         struct el15203000_led *led = container_of(ldev,
 143                                                   struct el15203000_led,
 144                                                   ldev);
 145
 146         if (repeat > 0 || len != 2 ||
 147             pattern[0].delta_t != 4000 || pattern[0].brightness != 0 ||
 148             pattern[1].delta_t != 4000 || pattern[1].brightness != 1)
 149                 return -EINVAL;
 150
 151         dev_dbg(led->priv->dev, "Breathing mode for 0x%02x(%c)",
 152                 led->reg, led->reg);
 153
 154         return el15203000_cmd(led, EL_SCREEN_BREATHING);
 155 }
 156
 157 static bool is_cascade(const struct led_pattern *pattern, u32 len,
 158                        bool inv, bool right)
 159 {
 160         int val, t;
 161         u32 i;
 162
 163         if (len != EL_PATTERN_HALF_LEN)
 164                 return false;
 165
 166         val = right ? BIT(4) : BIT(0);
 167
 168         for (i = 0; i < len; i++) {
 169                 t = inv ? ~val & GENMASK(4, 0) : val;
 170
 171                 if (pattern[i].delta_t != EL_PATTERN_DELAY_MSEC ||
 172                     pattern[i].brightness != t)
 173                         return false;
 174
 175                 val = right ? val >> 1 : val << 1;
 176         }
 177
 178         return true;
 179 }
 180
 181 static bool is_bounce(const struct led_pattern *pattern, u32 len, bool inv)
 182 {
 183         if (len != EL_PATTERN_LEN)
 184                 return false;
 185
 186         return is_cascade(pattern, EL_PATTERN_HALF_LEN, inv, false) &&
 187                is_cascade(pattern + EL_PATTERN_HALF_LEN,
 188                           EL_PATTERN_HALF_LEN, inv, true);
 189 }
 190
 191 static int el15203000_pattern_set_P(struct led_classdev *ldev,
 192                                     struct led_pattern *pattern,
 193                                     u32 len, int repeat)
 194 {
 195         u8                      cmd;
 196         struct el15203000_led   *led = container_of(ldev,
 197                                                     struct el15203000_led,
 198                                                     ldev);
 199
 200         if (repeat > 0)
 201                 return -EINVAL;
 202
 203         if (is_cascade(pattern, len, false, false)) {
 204                 dev_dbg(led->priv->dev, "Cascade mode for 0x%02x(%c)",
 205                         led->reg, led->reg);
 206
 207                 cmd = EL_PIPE_CASCADE;
 208         } else if (is_cascade(pattern, len, true, false)) {
 209                 dev_dbg(led->priv->dev, "Inverse cascade mode for 0x%02x(%c)",
 210                         led->reg, led->reg);
 211
 212                 cmd = EL_PIPE_INV_CASCADE;
 213         } else if (is_bounce(pattern, len, false)) {
 214                 dev_dbg(led->priv->dev, "Bounce mode for 0x%02x(%c)",
 215                         led->reg, led->reg);
 216
 217                 cmd = EL_PIPE_BOUNCE;
 218         } else if (is_bounce(pattern, len, true)) {
 219                 dev_dbg(led->priv->dev, "Inverse bounce mode for 0x%02x(%c)",
 220                         led->reg, led->reg);
 221
 222                 cmd = EL_PIPE_INV_BOUNCE;
 223         } else {
 224                 dev_err(led->priv->dev, "Invalid hw_pattern for 0x%02x(%c)!",
 225                         led->reg, led->reg);
 226
 227                 return -EINVAL;
 228         }
 229
 230         return el15203000_cmd(led, cmd);
 231 }
 232
 233 static int el15203000_pattern_clear(struct led_classdev *ldev)
 234 {
 235         struct el15203000_led   *led = container_of(ldev,
 236                                                     struct el15203000_led,
 237                                                     ldev);
 238
 239         return el15203000_cmd(led, EL_OFF);
 240 }
 241
 242 static int el15203000_probe_dt(struct el15203000 *priv)
 243 {
 244         struct el15203000_led   *led = priv->leds;
 245         struct fwnode_handle    *child;
 246         int                     ret;
 247
 248         device_for_each_child_node(priv->dev, child) {
 249                 struct led_init_data init_data = {};
 250
 251                 ret = fwnode_property_read_u32(child, "reg", &led->reg);
 252                 if (ret) {
 253                         dev_err(priv->dev, "LED without ID number");
 254                         fwnode_handle_put(child);
 255
 256                         break;
 257                 }
 258
 259                 if (led->reg > U8_MAX) {
 260                         dev_err(priv->dev, "LED value %d is invalid", led->reg);
 261                         fwnode_handle_put(child);
 262
 263                         return -EINVAL;
 264                 }
 265
 266                 led->priv                         = priv;
 267                 led->ldev.max_brightness          = LED_ON;
 268                 led->ldev.brightness_set_blocking = el15203000_set_blocking;
 269
 270                 if (led->reg == 'S') {
 271                         led->ldev.pattern_set   = el15203000_pattern_set_S;
 272                         led->ldev.pattern_clear = el15203000_pattern_clear;
 273                 } else if (led->reg == 'P') {
 274                         led->ldev.pattern_set   = el15203000_pattern_set_P;
 275                         led->ldev.pattern_clear = el15203000_pattern_clear;
 276                 }
 277
 278                 init_data.fwnode = child;
 279                 ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,
 280                                                      &init_data);
 281                 if (ret) {
 282                         dev_err(priv->dev,
 283                                 "failed to register LED device %s, err %d",
 284                                 led->ldev.name, ret);
 285                         fwnode_handle_put(child);
 286
 287                         break;
 288                 }
 289
 290                 led++;
 291         }
 292
 293         return ret;
 294 }
 295
 296 static int el15203000_probe(struct spi_device *spi)
 297 {
 298         struct el15203000       *priv;
 299         size_t                  count;
 300
 301         count = device_get_child_node_count(&spi->dev);
 302         if (!count) {
 303                 dev_err(&spi->dev, "LEDs are not defined in device tree!");
 304                 return -ENODEV;
 305         }
 306
 307         priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
 308                             GFP_KERNEL);
 309         if (!priv)
 310                 return -ENOMEM;
 311
 312         mutex_init(&priv->lock);
 313         priv->count     = count;
 314         priv->dev       = &spi->dev;
 315         priv->spi       = spi;
 316         priv->delay     = jiffies -
 317                           usecs_to_jiffies(EL_FW_DELAY_USEC);
 318
 319         spi_set_drvdata(spi, priv);
 320
 321         return el15203000_probe_dt(priv);
 322 }
 323
 324 static int el15203000_remove(struct spi_device *spi)
 325 {
 326         struct el15203000 *priv = spi_get_drvdata(spi);
 327
 328         mutex_destroy(&priv->lock);
 329
 330         return 0;
 331 }
 332
 333 static const struct of_device_id el15203000_dt_ids[] = {
 334         { .compatible = "crane,el15203000", },
 335         {},
 336 };
 337
 338 MODULE_DEVICE_TABLE(of, el15203000_dt_ids);
 339
 340 static struct spi_driver el15203000_driver = {
 341         .probe          = el15203000_probe,
 342         .remove         = el15203000_remove,
 343         .driver = {
 344                 .name           = KBUILD_MODNAME,
 345                 .of_match_table = el15203000_dt_ids,
 346         },
 347 };
 348
 349 module_spi_driver(el15203000_driver);
 350
 351 MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
 352 MODULE_DESCRIPTION("el15203000 LED driver");
 353 MODULE_LICENSE("GPL v2");
 354 MODULE_ALIAS("spi:el15203000");