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 - http://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 *led = container_of(led_cdev, struct lm36274, led_dev);
  47
  48         return ti_lmu_common_set_brightness(&led->lmu_data, brt_val);
  49 }
  50
  51 static int lm36274_init(struct lm36274 *lm36274_data)
  52 {
  53         int enable_val = 0;
  54         int i;
  55
  56         for (i = 0; i < lm36274_data->num_leds; i++)
  57                 enable_val |= (1 << lm36274_data->led_sources[i]);
  58
  59         if (!enable_val) {
  60                 dev_err(lm36274_data->dev, "No LEDs were enabled\n");
  61                 return -EINVAL;
  62         }
  63
  64         enable_val |= LM36274_BL_EN;
  65
  66         return regmap_write(lm36274_data->regmap, LM36274_REG_BL_EN,
  67                             enable_val);
  68 }
  69
  70 static int lm36274_parse_dt(struct lm36274 *lm36274_data)
  71 {
  72         struct fwnode_handle *child = NULL;
  73         char label[LED_MAX_NAME_SIZE];
  74         struct device *dev = &lm36274_data->pdev->dev;
  75         const char *name;
  76         int child_cnt;
  77         int ret = -EINVAL;
  78
  79         /* There should only be 1 node */
  80         child_cnt = device_get_child_node_count(dev);
  81         if (child_cnt != 1)
  82                 return -EINVAL;
  83
  84         device_for_each_child_node(dev, child) {
  85                 ret = fwnode_property_read_string(child, "label", &name);
  86                 if (ret)
  87                         snprintf(label, sizeof(label),
  88                                 "%s::", lm36274_data->pdev->name);
  89                 else
  90                         snprintf(label, sizeof(label),
  91                                  "%s:%s", lm36274_data->pdev->name, name);
  92
  93                 lm36274_data->num_leds = fwnode_property_count_u32(child, "led-sources");
  94                 if (lm36274_data->num_leds <= 0)
  95                         return -ENODEV;
  96
  97                 ret = fwnode_property_read_u32_array(child, "led-sources",
  98                                                      lm36274_data->led_sources,
  99                                                      lm36274_data->num_leds);
 100                 if (ret) {
 101                         dev_err(dev, "led-sources property missing\n");
 102                         return ret;
 103                 }
 104
 105                 fwnode_property_read_string(child, "linux,default-trigger",
 106                                         &lm36274_data->led_dev.default_trigger);
 107
 108         }
 109
 110         lm36274_data->lmu_data.regmap = lm36274_data->regmap;
 111         lm36274_data->lmu_data.max_brightness = MAX_BRIGHTNESS_11BIT;
 112         lm36274_data->lmu_data.msb_brightness_reg = LM36274_REG_BRT_MSB;
 113         lm36274_data->lmu_data.lsb_brightness_reg = LM36274_REG_BRT_LSB;
 114
 115         lm36274_data->led_dev.name = label;
 116         lm36274_data->led_dev.max_brightness = MAX_BRIGHTNESS_11BIT;
 117         lm36274_data->led_dev.brightness_set_blocking = lm36274_brightness_set;
 118
 119         return 0;
 120 }
 121
 122 static int lm36274_probe(struct platform_device *pdev)
 123 {
 124         struct ti_lmu *lmu = dev_get_drvdata(pdev->dev.parent);
 125         struct lm36274 *lm36274_data;
 126         int ret;
 127
 128         lm36274_data = devm_kzalloc(&pdev->dev, sizeof(*lm36274_data),
 129                                     GFP_KERNEL);
 130         if (!lm36274_data)
 131                 return -ENOMEM;
 132
 133         lm36274_data->pdev = pdev;
 134         lm36274_data->dev = lmu->dev;
 135         lm36274_data->regmap = lmu->regmap;
 136         dev_set_drvdata(&pdev->dev, lm36274_data);
 137
 138         ret = lm36274_parse_dt(lm36274_data);
 139         if (ret) {
 140                 dev_err(lm36274_data->dev, "Failed to parse DT node\n");
 141                 return ret;
 142         }
 143
 144         ret = lm36274_init(lm36274_data);
 145         if (ret) {
 146                 dev_err(lm36274_data->dev, "Failed to init the device\n");
 147                 return ret;
 148         }
 149
 150         return devm_led_classdev_register(lm36274_data->dev,
 151                                          &lm36274_data->led_dev);
 152 }
 153
 154 static const struct of_device_id of_lm36274_leds_match[] = {
 155         { .compatible = "ti,lm36274-backlight", },
 156         {},
 157 };
 158 MODULE_DEVICE_TABLE(of, of_lm36274_leds_match);
 159
 160 static struct platform_driver lm36274_driver = {
 161         .probe  = lm36274_probe,
 162         .driver = {
 163                 .name = "lm36274-leds",
 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");