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"); 171