drivers/leds/leds-bd2606mvv.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2023 Andreas Kemnade
   4  *
   5  * Datasheet:
   6  * https://fscdn.rohm.com/en/products/databook/datasheet/ic/power/led_driver/bd2606mvv_1-e.pdf
   7  *
   8  * If LED brightness cannot be controlled independently due to shared
   9  * brightness registers, max_brightness is set to 1 and only on/off
  10  * is possible for the affected LED pair.
  11  */
  12
  13 #include <linux/i2c.h>
  14 #include <linux/leds.h>
  15 #include <linux/module.h>
  16 #include <linux/mod_devicetable.h>
  17 #include <linux/property.h>
  18 #include <linux/regmap.h>
  19 #include <linux/slab.h>
  20
  21 #define BD2606_MAX_LEDS 6
  22 #define BD2606_MAX_BRIGHTNESS 63
  23 #define BD2606_REG_PWRCNT 3
  24 #define ldev_to_led(c)  container_of(c, struct bd2606mvv_led, ldev)
  25
  26 struct bd2606mvv_led {
  27         unsigned int led_no;
  28         struct led_classdev ldev;
  29         struct bd2606mvv_priv *priv;
  30 };
  31
  32 struct bd2606mvv_priv {
  33         struct bd2606mvv_led leds[BD2606_MAX_LEDS];
  34         struct regmap *regmap;
  35 };
  36
  37 static int
  38 bd2606mvv_brightness_set(struct led_classdev *led_cdev,
  39                       enum led_brightness brightness)
  40 {
  41         struct bd2606mvv_led *led = ldev_to_led(led_cdev);
  42         struct bd2606mvv_priv *priv = led->priv;
  43         int err;
  44
  45         if (brightness == 0)
  46                 return regmap_update_bits(priv->regmap,
  47                                           BD2606_REG_PWRCNT,
  48                                           1 << led->led_no,
  49                                           0);
  50
  51         /* shared brightness register */
  52         err = regmap_write(priv->regmap, led->led_no / 2,
  53                            led_cdev->max_brightness == 1 ?
  54                            BD2606_MAX_BRIGHTNESS : brightness);
  55         if (err)
  56                 return err;
  57
  58         return regmap_update_bits(priv->regmap,
  59                                   BD2606_REG_PWRCNT,
  60                                   1 << led->led_no,
  61                                   1 << led->led_no);
  62 }
  63
  64 static const struct regmap_config bd2606mvv_regmap = {
  65         .reg_bits = 8,
  66         .val_bits = 8,
  67         .max_register = 0x3,
  68 };
  69
  70 static int bd2606mvv_probe(struct i2c_client *client)
  71 {
  72         struct fwnode_handle *np, *child;
  73         struct device *dev = &client->dev;
  74         struct bd2606mvv_priv *priv;
  75         struct fwnode_handle *led_fwnodes[BD2606_MAX_LEDS] = { 0 };
  76         int active_pairs[BD2606_MAX_LEDS / 2] = { 0 };
  77         int err, reg;
  78         int i;
  79
  80         np = dev_fwnode(dev);
  81         if (!np)
  82                 return -ENODEV;
  83
  84         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  85         if (!priv)
  86                 return -ENOMEM;
  87
  88         priv->regmap = devm_regmap_init_i2c(client, &bd2606mvv_regmap);
  89         if (IS_ERR(priv->regmap)) {
  90                 err = PTR_ERR(priv->regmap);
  91                 dev_err(dev, "Failed to allocate register map: %d\n", err);
  92                 return err;
  93         }
  94
  95         i2c_set_clientdata(client, priv);
  96
  97         fwnode_for_each_available_child_node(np, child) {
  98                 struct bd2606mvv_led *led;
  99
 100                 err = fwnode_property_read_u32(child, "reg", &reg);
 101                 if (err) {
 102                         fwnode_handle_put(child);
 103                         return err;
 104                 }
 105                 if (reg < 0 || reg >= BD2606_MAX_LEDS || led_fwnodes[reg]) {
 106                         fwnode_handle_put(child);
 107                         return -EINVAL;
 108                 }
 109                 led = &priv->leds[reg];
 110                 led_fwnodes[reg] = child;
 111                 active_pairs[reg / 2]++;
 112                 led->priv = priv;
 113                 led->led_no = reg;
 114                 led->ldev.brightness_set_blocking = bd2606mvv_brightness_set;
 115                 led->ldev.max_brightness = BD2606_MAX_BRIGHTNESS;
 116         }
 117
 118         for (i = 0; i < BD2606_MAX_LEDS; i++) {
 119                 struct led_init_data init_data = {};
 120
 121                 if (!led_fwnodes[i])
 122                         continue;
 123
 124                 init_data.fwnode = led_fwnodes[i];
 125                 /* Check whether brightness can be independently adjusted. */
 126                 if (active_pairs[i / 2] == 2)
 127                         priv->leds[i].ldev.max_brightness = 1;
 128
 129                 err = devm_led_classdev_register_ext(dev,
 130                                                      &priv->leds[i].ldev,
 131                                                      &init_data);
 132                 if (err < 0) {
 133                         fwnode_handle_put(child);
 134                         return dev_err_probe(dev, err,
 135                                              "couldn't register LED %s\n",
 136                                              priv->leds[i].ldev.name);
 137                 }
 138         }
 139         return 0;
 140 }
 141
 142 static const struct of_device_id __maybe_unused of_bd2606mvv_leds_match[] = {
 143         { .compatible = "rohm,bd2606mvv", },
 144         {},
 145 };
 146 MODULE_DEVICE_TABLE(of, of_bd2606mvv_leds_match);
 147
 148 static struct i2c_driver bd2606mvv_driver = {
 149         .driver   = {
 150                 .name    = "leds-bd2606mvv",
 151                 .of_match_table = of_match_ptr(of_bd2606mvv_leds_match),
 152         },
 153         .probe = bd2606mvv_probe,
 154 };
 155
 156 module_i2c_driver(bd2606mvv_driver);
 157
 158 MODULE_AUTHOR("Andreas Kemnade <andreas@kemnade.info>");
 159 MODULE_DESCRIPTION("BD2606 LED driver");
 160 MODULE_LICENSE("GPL");