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