drivers/leds/leds-max5970.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Device driver for leds in MAX5970 and MAX5978 IC
   4  *
   5  * Copyright (c) 2022 9elements GmbH
   6  *
   7  * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
   8  */
   9
  10 #include <linux/bits.h>
  11 #include <linux/container_of.h>
  12 #include <linux/device.h>
  13 #include <linux/leds.h>
  14 #include <linux/mfd/max5970.h>
  15 #include <linux/mod_devicetable.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/property.h>
  19 #include <linux/regmap.h>
  20
  21 #define ldev_to_maxled(c)       container_of(c, struct max5970_led, cdev)
  22
  23 struct max5970_led {
  24         struct device *dev;
  25         struct regmap *regmap;
  26         struct led_classdev cdev;
  27         unsigned int index;
  28 };
  29
  30 static int max5970_led_set_brightness(struct led_classdev *cdev,
  31                                       enum led_brightness brightness)
  32 {
  33         struct max5970_led *ddata = ldev_to_maxled(cdev);
  34         int ret, val;
  35
  36         /* Set/clear corresponding bit for given led index */
  37         val = !brightness ? BIT(ddata->index) : 0;
  38
  39         ret = regmap_update_bits(ddata->regmap, MAX5970_REG_LED_FLASH, BIT(ddata->index), val);
  40         if (ret < 0)
  41                 dev_err(cdev->dev, "failed to set brightness %d", ret);
  42
  43         return ret;
  44 }
  45
  46 static int max5970_led_probe(struct platform_device *pdev)
  47 {
  48         struct fwnode_handle *led_node, *child;
  49         struct device *dev = &pdev->dev;
  50         struct regmap *regmap;
  51         struct max5970_led *ddata;
  52         int ret = -ENODEV;
  53
  54         regmap = dev_get_regmap(dev->parent, NULL);
  55         if (!regmap)
  56                 return -ENODEV;
  57
  58         led_node = device_get_named_child_node(dev->parent, "leds");
  59         if (!led_node)
  60                 return -ENODEV;
  61
  62         fwnode_for_each_available_child_node(led_node, child) {
  63                 u32 reg;
  64
  65                 if (fwnode_property_read_u32(child, "reg", &reg))
  66                         continue;
  67
  68                 if (reg >= MAX5970_NUM_LEDS) {
  69                         dev_err_probe(dev, -EINVAL, "invalid LED (%u >= %d)\n", reg, MAX5970_NUM_LEDS);
  70                         continue;
  71                 }
  72
  73                 ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
  74                 if (!ddata) {
  75                         fwnode_handle_put(child);
  76                         return -ENOMEM;
  77                 }
  78
  79                 ddata->index = reg;
  80                 ddata->regmap = regmap;
  81                 ddata->dev = dev;
  82
  83                 if (fwnode_property_read_string(child, "label", &ddata->cdev.name))
  84                         ddata->cdev.name = fwnode_get_name(child);
  85
  86                 ddata->cdev.max_brightness = 1;
  87                 ddata->cdev.brightness_set_blocking = max5970_led_set_brightness;
  88                 ddata->cdev.default_trigger = "none";
  89
  90                 ret = devm_led_classdev_register(dev, &ddata->cdev);
  91                 if (ret < 0) {
  92                         fwnode_handle_put(child);
  93                         return dev_err_probe(dev, ret, "Failed to initialize LED %u\n", reg);
  94                 }
  95         }
  96
  97         return ret;
  98 }
  99
 100 static struct platform_driver max5970_led_driver = {
 101         .driver = {
 102                 .name = "max5970-led",
 103         },
 104         .probe = max5970_led_probe,
 105 };
 106 module_platform_driver(max5970_led_driver);
 107
 108 MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@9elements.com>");
 109 MODULE_AUTHOR("Naresh Solanki <Naresh.Solanki@9elements.com>");
 110 MODULE_DESCRIPTION("MAX5970_hot-swap controller LED driver");
 111 MODULE_LICENSE("GPL");