drivers/leds/leds-lm36274.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // TI LM36274 LED chip family driver
   3 // Copyright (C) 2019 Texas Instruments Incorporated - https://www.ti.com/
   4
   5 #include <linux/bitops.h>
   6 #include <linux/device.h>
   7 #include <linux/err.h>
   8 #include <linux/leds.h>
   9 #include <linux/leds-ti-lmu-common.h>
  10 #include <linux/mod_devicetable.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/property.h>
  14
  15 #include <linux/mfd/ti-lmu.h>
  16 #include <linux/mfd/ti-lmu-register.h>
  17
  18 #include <uapi/linux/uleds.h>
  19
  20 #define LM36274_MAX_STRINGS     4
  21 #define LM36274_BL_EN           BIT(4)
  22
  23 /**
  24  * struct lm36274
  25  * @pdev: platform device
  26  * @led_dev: led class device
  27  * @lmu_data: Register and setting values for common code
  28  * @regmap: Devices register map
  29  * @dev: Pointer to the devices device struct
  30  * @led_sources: The LED strings supported in this array
  31  * @num_leds: Number of LED strings are supported in this array
  32  */
  33 struct lm36274 {
  34         struct platform_device *pdev;
  35         struct led_classdev led_dev;
  36         struct ti_lmu_bank lmu_data;
  37         struct regmap *regmap;
  38         struct device *dev;
  39
  40         u32 led_sources[LM36274_MAX_STRINGS];
  41         int num_leds;
  42 };
  43
  44 static int lm36274_brightness_set(struct led_classdev *led_cdev,
  45                                   enum led_brightness brt_val)
  46 {
  47         struct lm36274 *chip = container_of(led_cdev, struct lm36274, led_dev);
  48
  49         return ti_lmu_common_set_brightness(&chip->lmu_data, brt_val);
  50 }
  51
  52 static int lm36274_init(struct lm36274 *chip)
  53 {
  54         int enable_val = 0;
  55         int i;
  56
  57         for (i = 0; i < chip->num_leds; i++)
  58                 enable_val |= (1 << chip->led_sources[i]);
  59
  60         if (!enable_val) {
  61                 dev_err(chip->dev, "No LEDs were enabled\n");
  62                 return -EINVAL;
  63         }
  64
  65         enable_val |= LM36274_BL_EN;
  66
  67         return regmap_write(chip->regmap, LM36274_REG_BL_EN, enable_val);
  68 }
  69
  70 static int lm36274_parse_dt(struct lm36274 *chip,
  71                             struct led_init_data *init_data)
  72 {
  73         struct device *dev = chip->dev;
  74         struct fwnode_handle *child;
  75         int ret;
  76
  77         /* There should only be 1 node */
  78         if (device_get_child_node_count(dev) != 1)
  79                 return -EINVAL;
  80
  81         child = device_get_next_child_node(dev, NULL);
  82
  83         init_data->fwnode = child;
  84         init_data->devicename = chip->pdev->name;
  85         /* for backwards compatibility when `label` property is not present */
  86         init_data->default_label = ":";
  87
  88         chip->num_leds = fwnode_property_count_u32(child, "led-sources");
  89         if (chip->num_leds <= 0) {
  90                 ret = -ENODEV;
  91                 goto err;
  92         }
  93
  94         ret = fwnode_property_read_u32_array(child, "led-sources",
  95                                              chip->led_sources, chip->num_leds);
  96         if (ret) {
  97                 dev_err(dev, "led-sources property missing\n");
  98                 goto err;
  99         }
 100
 101         return 0;
 102 err:
 103         fwnode_handle_put(child);
 104         return ret;
 105 }
 106
 107 static int lm36274_probe(struct platform_device *pdev)
 108 {
 109         struct ti_lmu *lmu = dev_get_drvdata(pdev->dev.parent);
 110         struct led_init_data init_data = {};
 111         struct lm36274 *chip;
 112         int ret;
 113
 114         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 115         if (!chip)
 116                 return -ENOMEM;
 117
 118         chip->pdev = pdev;
 119         chip->dev = &pdev->dev;
 120         chip->regmap = lmu->regmap;
 121         platform_set_drvdata(pdev, chip);
 122
 123         ret = lm36274_parse_dt(chip, &init_data);
 124         if (ret) {
 125                 dev_err(chip->dev, "Failed to parse DT node\n");
 126                 return ret;
 127         }
 128
 129         ret = lm36274_init(chip);
 130         if (ret) {
 131                 fwnode_handle_put(init_data.fwnode);
 132                 dev_err(chip->dev, "Failed to init the device\n");
 133                 return ret;
 134         }
 135
 136         chip->lmu_data.regmap = chip->regmap;
 137         chip->lmu_data.max_brightness = MAX_BRIGHTNESS_11BIT;
 138         chip->lmu_data.msb_brightness_reg = LM36274_REG_BRT_MSB;
 139         chip->lmu_data.lsb_brightness_reg = LM36274_REG_BRT_LSB;
 140
 141         chip->led_dev.max_brightness = MAX_BRIGHTNESS_11BIT;
 142         chip->led_dev.brightness_set_blocking = lm36274_brightness_set;
 143
 144         ret = devm_led_classdev_register_ext(chip->dev, &chip->led_dev,
 145                                              &init_data);
 146         if (ret)
 147                 dev_err(chip->dev, "Failed to register LED for node %pfw\n",
 148                         init_data.fwnode);
 149
 150         fwnode_handle_put(init_data.fwnode);
 151
 152         return ret;
 153 }
 154
 155 static const struct of_device_id of_lm36274_leds_match[] = {
 156         { .compatible = "ti,lm36274-backlight", },
 157         {},
 158 };
 159 MODULE_DEVICE_TABLE(of, of_lm36274_leds_match);
 160
 161 static struct platform_driver lm36274_driver = {
 162         .probe  = lm36274_probe,
 163         .driver = {
 164                 .name = "lm36274-leds",
 165                 .of_match_table = of_lm36274_leds_match,
 166         },
 167 };
 168 module_platform_driver(lm36274_driver)
 169
 170 MODULE_DESCRIPTION("Texas Instruments LM36274 LED driver");
 171 MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
 172 MODULE_LICENSE("GPL v2");