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/mod_devicetable.h>
   8 #include <linux/module.h>
   9 #include <linux/property.h>
  10 #include <linux/spi/spi.h>
  11
  12 /*
  13  * EL15203000 SPI protocol description:
  14  * +-----+---------+
  15  * | LED | COMMAND |
  16  * +-----+---------+
  17  * |  1  |    1    |
  18  * +-----+---------+
  19  * (*) LEDs MCU board expects 20 msec delay per byte.
  20  *
  21  * LEDs:
  22  * +----------+--------------+-------------------------------------------+
  23  * |    ID    |     NAME     |         DESCRIPTION                       |
  24  * +----------+--------------+-------------------------------------------+
  25  * | 'P' 0x50 |     Pipe     | Consists from 5 LEDs, controlled by board |
  26  * +----------+--------------+-------------------------------------------+
  27  * | 'S' 0x53 | Screen frame | Light tube around the screen              |
  28  * +----------+--------------+-------------------------------------------+
  29  * | 'V' 0x56 | Vending area | Highlights a cup of coffee                |
  30  * +----------+--------------+-------------------------------------------+
  31  *
  32  * COMMAND:
  33  * +----------+-----------------+--------------+--------------+
  34  * |  VALUES  |       PIPE      | SCREEN FRAME | VENDING AREA |
  35  * +----------+-----------------+--------------+--------------+
  36  * | '0' 0x30 |                      Off                      |
  37  * +----------+-----------------------------------------------+
  38  * | '1' 0x31 |                      On                       |
  39  * +----------+-----------------+--------------+--------------+
  40  * | '2' 0x32 |     Cascade     |   Breathing  |
  41  * +----------+-----------------+--------------+
  42  * | '3' 0x33 | Inverse cascade |
  43  * +----------+-----------------+
  44  * | '4' 0x34 |     Bounce      |
  45  * +----------+-----------------+
  46  * | '5' 0x35 | Inverse bounce  |
  47  * +----------+-----------------+
  48  */
  49
  50 /* EL15203000 default settings */
  51 #define EL_FW_DELAY_USEC        20000ul
  52 #define EL_PATTERN_DELAY_MSEC   800u
  53 #define EL_PATTERN_LEN          10u
  54 #define EL_PATTERN_HALF_LEN     (EL_PATTERN_LEN / 2)
  55
  56 enum el15203000_command {
  57         /* for all LEDs */
  58         EL_OFF                  = '0',
  59         EL_ON                   = '1',
  60
  61         /* for Screen LED */
  62         EL_SCREEN_BREATHING     = '2',
  63
  64         /* for Pipe LED */
  65         EL_PIPE_CASCADE         = '2',
  66         EL_PIPE_INV_CASCADE     = '3',
  67         EL_PIPE_BOUNCE          = '4',
  68         EL_PIPE_INV_BOUNCE      = '5',
  69 };
  70
  71 struct el15203000_led {
  72         struct led_classdev     ldev;
  73         struct el15203000       *priv;
  74         u32                     reg;
  75 };
  76
  77 struct el15203000 {
  78         struct device           *dev;
  79         struct mutex            lock;
  80         struct spi_device       *spi;
  81         unsigned long           delay;
  82         size_t                  count;
  83         struct el15203000_led   leds[] __counted_by(count);
  84 };
  85
  86 #define to_el15203000_led(d)    container_of(d, struct el15203000_led, ldev)
  87
  88 static int el15203000_cmd(struct el15203000_led *led, u8 brightness)
  89 {
  90         int             ret;
  91         u8              cmd[2];
  92         size_t          i;
  93
  94         mutex_lock(&led->priv->lock);
  95
  96         dev_dbg(led->priv->dev, "Set brightness of 0x%02x(%c) to 0x%02x(%c)",
  97                 led->reg, led->reg, brightness, brightness);
  98
  99         /* to avoid SPI mistiming with firmware we should wait some time */
 100         if (time_after(led->priv->delay, jiffies)) {
 101                 dev_dbg(led->priv->dev, "Wait %luus to sync",
 102                         EL_FW_DELAY_USEC);
 103
 104                 usleep_range(EL_FW_DELAY_USEC,
 105                              EL_FW_DELAY_USEC + 1);
 106         }
 107
 108         cmd[0] = led->reg;
 109         cmd[1] = brightness;
 110
 111         for (i = 0; i < ARRAY_SIZE(cmd); i++) {
 112                 if (i)
 113                         usleep_range(EL_FW_DELAY_USEC,
 114                                      EL_FW_DELAY_USEC + 1);
 115
 116                 ret = spi_write(led->priv->spi, &cmd[i], sizeof(cmd[i]));
 117                 if (ret) {
 118                         dev_err(led->priv->dev,
 119                                 "spi_write() error %d", ret);
 120                         break;
 121                 }
 122         }
 123
 124         led->priv->delay = jiffies + usecs_to_jiffies(EL_FW_DELAY_USEC);
 125
 126         mutex_unlock(&led->priv->lock);
 127
 128         return ret;
 129 }
 130
 131 static int el15203000_set_blocking(struct led_classdev *ldev,
 132                                    enum led_brightness brightness)
 133 {
 134         struct el15203000_led *led = to_el15203000_led(ldev);
 135
 136         return el15203000_cmd(led, brightness == LED_OFF ? EL_OFF : EL_ON);
 137 }
 138
 139 static int el15203000_pattern_set_S(struct led_classdev *ldev,
 140                                     struct led_pattern *pattern,
 141                                     u32 len, int repeat)
 142 {
 143         struct el15203000_led *led = to_el15203000_led(ldev);
 144
 145         if (repeat > 0 || len != 2 ||
 146             pattern[0].delta_t != 4000 || pattern[0].brightness != 0 ||
 147             pattern[1].delta_t != 4000 || pattern[1].brightness != 1)
 148                 return -EINVAL;
 149
 150         dev_dbg(led->priv->dev, "Breathing mode for 0x%02x(%c)",
 151                 led->reg, led->reg);
 152
 153         return el15203000_cmd(led, EL_SCREEN_BREATHING);
 154 }
 155
 156 static bool is_cascade(const struct led_pattern *pattern, u32 len,
 157                        bool inv, bool right)
 158 {
 159         int val, t;
 160         u32 i;
 161
 162         if (len != EL_PATTERN_HALF_LEN)
 163                 return false;
 164
 165         val = right ? BIT(4) : BIT(0);
 166
 167         for (i = 0; i < len; i++) {
 168                 t = inv ? ~val & GENMASK(4, 0) : val;
 169
 170                 if (pattern[i].delta_t != EL_PATTERN_DELAY_MSEC ||
 171                     pattern[i].brightness != t)
 172                         return false;
 173
 174                 val = right ? val >> 1 : val << 1;
 175         }
 176
 177         return true;
 178 }
 179
 180 static bool is_bounce(const struct led_pattern *pattern, u32 len, bool inv)
 181 {
 182         if (len != EL_PATTERN_LEN)
 183                 return false;
 184
 185         return is_cascade(pattern, EL_PATTERN_HALF_LEN, inv, false) &&
 186                is_cascade(pattern + EL_PATTERN_HALF_LEN,
 187                           EL_PATTERN_HALF_LEN, inv, true);
 188 }
 189
 190 static int el15203000_pattern_set_P(struct led_classdev *ldev,
 191                                     struct led_pattern *pattern,
 192                                     u32 len, int repeat)
 193 {
 194         struct el15203000_led   *led = to_el15203000_led(ldev);
 195         u8                      cmd;
 196
 197         if (repeat > 0)
 198                 return -EINVAL;
 199
 200         if (is_cascade(pattern, len, false, false)) {
 201                 dev_dbg(led->priv->dev, "Cascade mode for 0x%02x(%c)",
 202                         led->reg, led->reg);
 203
 204                 cmd = EL_PIPE_CASCADE;
 205         } else if (is_cascade(pattern, len, true, false)) {
 206                 dev_dbg(led->priv->dev, "Inverse cascade mode for 0x%02x(%c)",
 207                         led->reg, led->reg);
 208
 209                 cmd = EL_PIPE_INV_CASCADE;
 210         } else if (is_bounce(pattern, len, false)) {
 211                 dev_dbg(led->priv->dev, "Bounce mode for 0x%02x(%c)",
 212                         led->reg, led->reg);
 213
 214                 cmd = EL_PIPE_BOUNCE;
 215         } else if (is_bounce(pattern, len, true)) {
 216                 dev_dbg(led->priv->dev, "Inverse bounce mode for 0x%02x(%c)",
 217                         led->reg, led->reg);
 218
 219                 cmd = EL_PIPE_INV_BOUNCE;
 220         } else {
 221                 dev_err(led->priv->dev, "Invalid hw_pattern for 0x%02x(%c)!",
 222                         led->reg, led->reg);
 223
 224                 return -EINVAL;
 225         }
 226
 227         return el15203000_cmd(led, cmd);
 228 }
 229
 230 static int el15203000_pattern_clear(struct led_classdev *ldev)
 231 {
 232         struct el15203000_led *led = to_el15203000_led(ldev);
 233
 234         return el15203000_cmd(led, EL_OFF);
 235 }
 236
 237 static int el15203000_probe_dt(struct el15203000 *priv)
 238 {
 239         struct el15203000_led   *led = priv->leds;
 240         struct fwnode_handle    *child;
 241         int                     ret;
 242
 243         device_for_each_child_node(priv->dev, child) {
 244                 struct led_init_data init_data = {};
 245
 246                 ret = fwnode_property_read_u32(child, "reg", &led->reg);
 247                 if (ret) {
 248                         dev_err(priv->dev, "LED without ID number");
 249                         goto err_child_out;
 250                 }
 251
 252                 if (led->reg > U8_MAX) {
 253                         dev_err(priv->dev, "LED value %d is invalid", led->reg);
 254                         ret = -EINVAL;
 255                         goto err_child_out;
 256                 }
 257
 258                 led->priv                         = priv;
 259                 led->ldev.max_brightness          = LED_ON;
 260                 led->ldev.brightness_set_blocking = el15203000_set_blocking;
 261
 262                 if (led->reg == 'S') {
 263                         led->ldev.pattern_set   = el15203000_pattern_set_S;
 264                         led->ldev.pattern_clear = el15203000_pattern_clear;
 265                 } else if (led->reg == 'P') {
 266                         led->ldev.pattern_set   = el15203000_pattern_set_P;
 267                         led->ldev.pattern_clear = el15203000_pattern_clear;
 268                 }
 269
 270                 init_data.fwnode = child;
 271                 ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,
 272                                                      &init_data);
 273                 if (ret) {
 274                         dev_err(priv->dev,
 275                                 "failed to register LED device %s, err %d",
 276                                 led->ldev.name, ret);
 277                         goto err_child_out;
 278                 }
 279
 280                 led++;
 281         }
 282
 283         return 0;
 284
 285 err_child_out:
 286         fwnode_handle_put(child);
 287         return ret;
 288 }
 289
 290 static int el15203000_probe(struct spi_device *spi)
 291 {
 292         struct el15203000       *priv;
 293         size_t                  count;
 294
 295         count = device_get_child_node_count(&spi->dev);
 296         if (!count) {
 297                 dev_err(&spi->dev, "LEDs are not defined in device tree!");
 298                 return -ENODEV;
 299         }
 300
 301         priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
 302                             GFP_KERNEL);
 303         if (!priv)
 304                 return -ENOMEM;
 305
 306         mutex_init(&priv->lock);
 307         priv->count     = count;
 308         priv->dev       = &spi->dev;
 309         priv->spi       = spi;
 310         priv->delay     = jiffies -
 311                           usecs_to_jiffies(EL_FW_DELAY_USEC);
 312
 313         spi_set_drvdata(spi, priv);
 314
 315         return el15203000_probe_dt(priv);
 316 }
 317
 318 static void el15203000_remove(struct spi_device *spi)
 319 {
 320         struct el15203000 *priv = spi_get_drvdata(spi);
 321
 322         mutex_destroy(&priv->lock);
 323 }
 324
 325 static const struct of_device_id el15203000_dt_ids[] = {
 326         { .compatible = "crane,el15203000", },
 327         {},
 328 };
 329
 330 MODULE_DEVICE_TABLE(of, el15203000_dt_ids);
 331
 332 static struct spi_driver el15203000_driver = {
 333         .probe          = el15203000_probe,
 334         .remove         = el15203000_remove,
 335         .driver = {
 336                 .name           = KBUILD_MODNAME,
 337                 .of_match_table = el15203000_dt_ids,
 338         },
 339 };
 340
 341 module_spi_driver(el15203000_driver);
 342
 343 MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
 344 MODULE_DESCRIPTION("el15203000 LED driver");
 345 MODULE_LICENSE("GPL v2");
 346 MODULE_ALIAS("spi:el15203000");