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"); 171