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"); 173