drivers/leds/leds-turris-omnia.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * CZ.NIC's Turris Omnia LEDs driver
   4  *
   5  * 2020 by Marek Behún <kabel@kernel.org>
   6  */
   7
   8 #include <linux/i2c.h>
   9 #include <linux/led-class-multicolor.h>
  10 #include <linux/module.h>
  11 #include <linux/mutex.h>
  12 #include <linux/of.h>
  13 #include "leds.h"
  14
  15 #define OMNIA_BOARD_LEDS        12
  16 #define OMNIA_LED_NUM_CHANNELS  3
  17
  18 #define CMD_LED_MODE            3
  19 #define CMD_LED_MODE_LED(l)     ((l) & 0x0f)
  20 #define CMD_LED_MODE_USER       0x10
  21
  22 #define CMD_LED_STATE           4
  23 #define CMD_LED_STATE_LED(l)    ((l) & 0x0f)
  24 #define CMD_LED_STATE_ON        0x10
  25
  26 #define CMD_LED_COLOR           5
  27 #define CMD_LED_SET_BRIGHTNESS  7
  28 #define CMD_LED_GET_BRIGHTNESS  8
  29
  30 struct omnia_led {
  31         struct led_classdev_mc mc_cdev;
  32         struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
  33         int reg;
  34 };
  35
  36 #define to_omnia_led(l)         container_of(l, struct omnia_led, mc_cdev)
  37
  38 struct omnia_leds {
  39         struct i2c_client *client;
  40         struct mutex lock;
  41         struct omnia_led leds[];
  42 };
  43
  44 static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
  45                                              enum led_brightness brightness)
  46 {
  47         struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
  48         struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
  49         struct omnia_led *led = to_omnia_led(mc_cdev);
  50         u8 buf[5], state;
  51         int ret;
  52
  53         mutex_lock(&leds->lock);
  54
  55         led_mc_calc_color_components(&led->mc_cdev, brightness);
  56
  57         buf[0] = CMD_LED_COLOR;
  58         buf[1] = led->reg;
  59         buf[2] = mc_cdev->subled_info[0].brightness;
  60         buf[3] = mc_cdev->subled_info[1].brightness;
  61         buf[4] = mc_cdev->subled_info[2].brightness;
  62
  63         state = CMD_LED_STATE_LED(led->reg);
  64         if (buf[2] || buf[3] || buf[4])
  65                 state |= CMD_LED_STATE_ON;
  66
  67         ret = i2c_smbus_write_byte_data(leds->client, CMD_LED_STATE, state);
  68         if (ret >= 0 && (state & CMD_LED_STATE_ON))
  69                 ret = i2c_master_send(leds->client, buf, 5);
  70
  71         mutex_unlock(&leds->lock);
  72
  73         return ret;
  74 }
  75
  76 static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
  77                               struct device_node *np)
  78 {
  79         struct led_init_data init_data = {};
  80         struct device *dev = &client->dev;
  81         struct led_classdev *cdev;
  82         int ret, color;
  83
  84         ret = of_property_read_u32(np, "reg", &led->reg);
  85         if (ret || led->reg >= OMNIA_BOARD_LEDS) {
  86                 dev_warn(dev,
  87                          "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
  88                          np, OMNIA_BOARD_LEDS - 1);
  89                 return 0;
  90         }
  91
  92         ret = of_property_read_u32(np, "color", &color);
  93         if (ret || color != LED_COLOR_ID_RGB) {
  94                 dev_warn(dev,
  95                          "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
  96                          np);
  97                 return 0;
  98         }
  99
 100         led->subled_info[0].color_index = LED_COLOR_ID_RED;
 101         led->subled_info[0].channel = 0;
 102         led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
 103         led->subled_info[1].channel = 1;
 104         led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
 105         led->subled_info[2].channel = 2;
 106
 107         led->mc_cdev.subled_info = led->subled_info;
 108         led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
 109
 110         init_data.fwnode = &np->fwnode;
 111
 112         cdev = &led->mc_cdev.led_cdev;
 113         cdev->max_brightness = 255;
 114         cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
 115
 116         /* put the LED into software mode */
 117         ret = i2c_smbus_write_byte_data(client, CMD_LED_MODE,
 118                                         CMD_LED_MODE_LED(led->reg) |
 119                                         CMD_LED_MODE_USER);
 120         if (ret < 0) {
 121                 dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np,
 122                         ret);
 123                 return ret;
 124         }
 125
 126         /* disable the LED */
 127         ret = i2c_smbus_write_byte_data(client, CMD_LED_STATE,
 128                                         CMD_LED_STATE_LED(led->reg));
 129         if (ret < 0) {
 130                 dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
 131                 return ret;
 132         }
 133
 134         ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
 135                                                         &init_data);
 136         if (ret < 0) {
 137                 dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
 138                 return ret;
 139         }
 140
 141         return 1;
 142 }
 143
 144 /*
 145  * On the front panel of the Turris Omnia router there is also a button which
 146  * can be used to control the intensity of all the LEDs at once, so that if they
 147  * are too bright, user can dim them.
 148  * The microcontroller cycles between 8 levels of this global brightness (from
 149  * 100% to 0%), but this setting can have any integer value between 0 and 100.
 150  * It is therefore convenient to be able to change this setting from software.
 151  * We expose this setting via a sysfs attribute file called "brightness". This
 152  * file lives in the device directory of the LED controller, not an individual
 153  * LED, so it should not confuse users.
 154  */
 155 static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
 156                                char *buf)
 157 {
 158         struct i2c_client *client = to_i2c_client(dev);
 159         int ret;
 160
 161         ret = i2c_smbus_read_byte_data(client, CMD_LED_GET_BRIGHTNESS);
 162
 163         if (ret < 0)
 164                 return ret;
 165
 166         return sysfs_emit(buf, "%d\n", ret);
 167 }
 168
 169 static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
 170                                 const char *buf, size_t count)
 171 {
 172         struct i2c_client *client = to_i2c_client(dev);
 173         unsigned long brightness;
 174         int ret;
 175
 176         if (kstrtoul(buf, 10, &brightness))
 177                 return -EINVAL;
 178
 179         if (brightness > 100)
 180                 return -EINVAL;
 181
 182         ret = i2c_smbus_write_byte_data(client, CMD_LED_SET_BRIGHTNESS,
 183                                         (u8)brightness);
 184
 185         return ret < 0 ? ret : count;
 186 }
 187 static DEVICE_ATTR_RW(brightness);
 188
 189 static struct attribute *omnia_led_controller_attrs[] = {
 190         &dev_attr_brightness.attr,
 191         NULL,
 192 };
 193 ATTRIBUTE_GROUPS(omnia_led_controller);
 194
 195 static int omnia_leds_probe(struct i2c_client *client)
 196 {
 197         struct device *dev = &client->dev;
 198         struct device_node *np = dev_of_node(dev), *child;
 199         struct omnia_leds *leds;
 200         struct omnia_led *led;
 201         int ret, count;
 202
 203         count = of_get_available_child_count(np);
 204         if (!count) {
 205                 dev_err(dev, "LEDs are not defined in device tree!\n");
 206                 return -ENODEV;
 207         } else if (count > OMNIA_BOARD_LEDS) {
 208                 dev_err(dev, "Too many LEDs defined in device tree!\n");
 209                 return -EINVAL;
 210         }
 211
 212         leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
 213         if (!leds)
 214                 return -ENOMEM;
 215
 216         leds->client = client;
 217         i2c_set_clientdata(client, leds);
 218
 219         mutex_init(&leds->lock);
 220
 221         led = &leds->leds[0];
 222         for_each_available_child_of_node(np, child) {
 223                 ret = omnia_led_register(client, led, child);
 224                 if (ret < 0) {
 225                         of_node_put(child);
 226                         return ret;
 227                 }
 228
 229                 led += ret;
 230         }
 231
 232         return 0;
 233 }
 234
 235 static void omnia_leds_remove(struct i2c_client *client)
 236 {
 237         u8 buf[5];
 238
 239         /* put all LEDs into default (HW triggered) mode */
 240         i2c_smbus_write_byte_data(client, CMD_LED_MODE,
 241                                   CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
 242
 243         /* set all LEDs color to [255, 255, 255] */
 244         buf[0] = CMD_LED_COLOR;
 245         buf[1] = OMNIA_BOARD_LEDS;
 246         buf[2] = 255;
 247         buf[3] = 255;
 248         buf[4] = 255;
 249
 250         i2c_master_send(client, buf, 5);
 251 }
 252
 253 static const struct of_device_id of_omnia_leds_match[] = {
 254         { .compatible = "cznic,turris-omnia-leds", },
 255         {},
 256 };
 257
 258 static const struct i2c_device_id omnia_id[] = {
 259         { "omnia", 0 },
 260         { }
 261 };
 262 MODULE_DEVICE_TABLE(i2c, omnia_id);
 263
 264 static struct i2c_driver omnia_leds_driver = {
 265         .probe          = omnia_leds_probe,
 266         .remove         = omnia_leds_remove,
 267         .id_table       = omnia_id,
 268         .driver         = {
 269                 .name   = "leds-turris-omnia",
 270                 .of_match_table = of_omnia_leds_match,
 271                 .dev_groups = omnia_led_controller_groups,
 272         },
 273 };
 274
 275 module_i2c_driver(omnia_leds_driver);
 276
 277 MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
 278 MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
 279 MODULE_LICENSE("GPL v2");