package/kernel/leds-gca230718/src/leds-gca230718.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * GCA230718 LED support (e.g. for D-Link M30) using I2C
   4  *
   5  * Copyright 2022 Roland Reinl <reinlroland+github@gmail.com>
   6  *
   7  * This driver can control RGBW LEDs which are connected to a GCA230718.
   8  */
   9
  10 #include <linux/delay.h>
  11 #include <linux/led-class-multicolor.h>
  12 #include <linux/leds.h>
  13 #include <linux/module.h>
  14 #include <linux/of_device.h>
  15 #include <linux/property.h>
  16 #include <linux/i2c.h>
  17 #include <linux/mutex.h>
  18 #include <linux/version.h>
  19
  20 #define GCA230718_MAX_LEDS                                      (4u)
  21
  22 #define GCA230718_OPMODE_DISABLED                               (0x00u)
  23 #define GCA230718_OPMODE_NO_TOGGLE                              (0x01u)
  24 #define GCA230718_OPMODE_TOGGLE_RAMP_CONTROL_DISABLED           (0x02u)
  25 #define GCA230718_OPMODE_TOGGLE_RAMP_CONTROL_ENSABLED           (0x03u)
  26
  27 #define GCA230718_1ST_SEQUENCE_BYTE_1                           (0x02u)
  28 #define GCA230718_2ND_SEQUENCE_BYTE_1                           (0x01u)
  29 #define GCA230718_3RD_SEQUENCE_BYTE_1                           (0x03u)
  30
  31 struct gca230718_led
  32 {
  33         enum led_brightness brightness;
  34         struct i2c_client *client;
  35         struct led_classdev ledClassDev;
  36 };
  37
  38 struct gca230718_private
  39 {
  40         struct mutex lock;
  41         struct gca230718_led leds[GCA230718_MAX_LEDS];
  42 };
  43
  44 static void gca230718_init_private_led_data(struct gca230718_private* data)
  45 {
  46         u8 ledIndex;
  47         for (ledIndex = 0; ledIndex < GCA230718_MAX_LEDS; ledIndex++)
  48         {
  49                 data->leds[ledIndex].client = NULL;
  50         }
  51 }
  52
  53 static void gca230718_send_sequence(struct i2c_client *client, u8 byte0, struct gca230718_private* gca230718_privateData)
  54 {
  55         int status = 0;
  56         u8 ledIndex;
  57         const u8 resetCommand[2] = { 0x81, 0xE4 };
  58         const u8 resetCommandRegister = 0x00;
  59
  60         u8 controlCommand[13];
  61         const u8 controlCommandRegister = 0x03;
  62
  63         controlCommand[0] = 0x0C; /* Unknown */
  64         controlCommand[1] = byte0;
  65         controlCommand[2] = GCA230718_OPMODE_NO_TOGGLE;
  66         /* Byte 3-6 are set below to the brighness value of the individual LEDs */
  67         controlCommand[7] = 0x01; /* Frequency, doesn't care as long as GCA230718_OPMODE_NO_TOGGLE is used above */
  68         /* Byte 8-11 are set below to the brighness value of the individual LEDs */
  69         controlCommand[12] = 0x87;
  70
  71         for (ledIndex = 0; ledIndex < GCA230718_MAX_LEDS; ledIndex++)
  72         {
  73                 controlCommand[3 + ledIndex] = gca230718_privateData->leds[ledIndex].brightness;
  74                 controlCommand[8 + ledIndex] = gca230718_privateData->leds[ledIndex].brightness;
  75         }
  76
  77         mutex_lock(&(gca230718_privateData->lock));
  78
  79         if ((status = i2c_smbus_write_i2c_block_data(client, resetCommandRegister, sizeof(resetCommand), resetCommand)) != 0)
  80         {
  81                 pr_info("Error %i during call of i2c_smbus_write_i2c_block_data for reset command\n", status);
  82         }
  83         else if ((status = i2c_smbus_write_i2c_block_data(client, controlCommandRegister, sizeof(controlCommand), controlCommand)) != 0)
  84         {
  85                 pr_info("Error %i during call of i2c_smbus_write_i2c_block_data for control command\n", status);
  86         }
  87
  88         mutex_unlock(&(gca230718_privateData->lock));
  89 }
  90
  91 static int gca230718_set_brightness(struct led_classdev *led_cdev, enum led_brightness value)
  92 {
  93         struct gca230718_led* led;
  94         struct i2c_client* client;
  95
  96         led = container_of(led_cdev, struct gca230718_led, ledClassDev);
  97         client = led->client;
  98
  99         if (client != NULL)
 100         {
 101                 struct gca230718_private* gca230718_privateData;
 102
 103                 led->brightness = value;
 104                 gca230718_privateData = i2c_get_clientdata(client);
 105
 106                 gca230718_send_sequence(client, GCA230718_2ND_SEQUENCE_BYTE_1, gca230718_privateData);
 107         }
 108
 109         return 0;
 110 }
 111
 112 static int gca230718_probe(struct i2c_client *client, const struct i2c_device_id *id)
 113 {
 114         int status = 0;
 115         struct gca230718_private* gca230718_privateData;
 116
 117         pr_info("Enter gca230718_probe for device address %u\n", client->addr);
 118         gca230718_privateData = devm_kzalloc(&(client->dev), sizeof(struct gca230718_private), GFP_KERNEL);
 119
 120         if (gca230718_privateData == NULL)
 121         {
 122                 pr_info("Error during allocating memory for private data\n");
 123                 status = -ENOMEM;
 124         }
 125         else
 126         {
 127                 struct device_node* ledNode;
 128                 mutex_init(&gca230718_privateData->lock);
 129                 gca230718_init_private_led_data(gca230718_privateData);
 130                 i2c_set_clientdata(client, gca230718_privateData);
 131
 132                 for_each_child_of_node(client->dev.of_node, ledNode)
 133                 {
 134                         u32 regValue = 0;
 135                         if (of_property_read_u32(ledNode, "reg", &regValue) != 0)
 136                         {
 137                                 pr_info("Missing entry \"reg\" in node %s\n", ledNode->name);
 138                         }
 139                         else if (regValue >= GCA230718_MAX_LEDS)
 140                         {
 141                                 pr_info("Invalid entry \"reg\" in node %s (%u)\n", ledNode->name, regValue);
 142                         }
 143                         else
 144                         {
 145                                 struct led_classdev* ledClassDev = &(gca230718_privateData->leds[regValue].ledClassDev);
 146                                 struct led_init_data init_data = {};
 147
 148                                 gca230718_privateData->leds[regValue].client = client;
 149                                 init_data.fwnode = of_fwnode_handle(ledNode);
 150
 151                                 pr_info("Creating LED for node %s: reg=%u\n", ledNode->name, regValue);
 152
 153                                 ledClassDev->name = of_get_property(ledNode, "label", NULL);
 154                                 if (ledClassDev->name == NULL)
 155                                 {
 156                                         ledClassDev->name = ledNode->name;
 157                                 }
 158
 159                                 ledClassDev->brightness = LED_OFF;
 160                                 ledClassDev->max_brightness = LED_FULL;
 161                                 ledClassDev->brightness_set_blocking = gca230718_set_brightness;
 162
 163                                 if (devm_led_classdev_register_ext(&(client->dev), ledClassDev, &init_data) != 0)
 164                                 {
 165                                         pr_info("Error during call of devm_led_classdev_register_ext");
 166                                 }
 167                         }
 168                 }
 169         }
 170
 171         if (status == 0)
 172         {
 173                 /*
 174                 Send full initialization sequence.
 175                 Afterwards only GCA230718_2ND_SEQUENCE_BYTE_1 must be send to upddate the brightness values.
 176                 */
 177                 gca230718_send_sequence(client, GCA230718_1ST_SEQUENCE_BYTE_1, gca230718_privateData);
 178                 gca230718_send_sequence(client, GCA230718_2ND_SEQUENCE_BYTE_1, gca230718_privateData);
 179                 gca230718_send_sequence(client, GCA230718_3RD_SEQUENCE_BYTE_1, gca230718_privateData);
 180         }
 181
 182         return status;
 183 }
 184
 185 #if LINUX_VERSION_CODE >= KERNEL_VERSION(5,18,0)
 186 static void gca230718_remove(struct i2c_client *client)
 187 #else
 188 static int gca230718_remove(struct i2c_client *client)
 189 #endif
 190 {
 191         struct gca230718_private* gca230718_privateData;
 192         gca230718_privateData = i2c_get_clientdata(client);
 193         mutex_destroy(&gca230718_privateData->lock);
 194         gca230718_init_private_led_data(gca230718_privateData);
 195
 196 #if LINUX_VERSION_CODE < KERNEL_VERSION(5,18,0)
 197         return 0;
 198 #endif
 199 }
 200
 201 static const struct i2c_device_id gca230718_i2c_ids[] = {
 202         { "gca230718", 0 },
 203         {},
 204 };
 205 MODULE_DEVICE_TABLE(i2c, gca230718_i2c_ids);
 206
 207 static const struct of_device_id gca230718_dt_ids[] = {
 208         { .compatible = "unknown,gca230718" },
 209         {},
 210 };
 211 MODULE_DEVICE_TABLE(of, gca230718_dt_ids);
 212
 213 static struct i2c_driver gca230718_driver = {
 214         .probe          = gca230718_probe,
 215         .remove         = gca230718_remove,
 216         .id_table       = gca230718_i2c_ids,
 217         .driver = {
 218                 .name           = KBUILD_MODNAME,
 219                 .of_match_table = gca230718_dt_ids,
 220         },
 221 };
 222
 223 module_i2c_driver(gca230718_driver);
 224
 225 MODULE_AUTHOR("Roland Reinl <reinlroland+github@gmail.com>");
 226 MODULE_DESCRIPTION("GCA230718 LED support (e.g. for D-Link M30) using I2C");
 227 MODULE_LICENSE("GPL");