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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 | // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org> #include <linux/kernel.h> #include <linux/platform_device.h> #include <linux/leds.h> #include <linux/delay.h> #include <linux/gpio.h> #include <linux/gpio/consumer.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/of.h> #include <uapi/linux/uleds.h> struct lt3593_led_data { char name[LED_MAX_NAME_SIZE]; struct led_classdev cdev; struct gpio_desc *gpiod; }; static int lt3593_led_set(struct led_classdev *led_cdev, enum led_brightness value) { struct lt3593_led_data *led_dat = container_of(led_cdev, struct lt3593_led_data, cdev); int pulses; /* * The LT3593 resets its internal current level register to the maximum * level on the first falling edge on the control pin. Each following * falling edge decreases the current level by 625uA. Up to 32 pulses * can be sent, so the maximum power reduction is 20mA. * After a timeout of 128us, the value is taken from the register and * applied is to the output driver. */ if (value == 0) { gpiod_set_value_cansleep(led_dat->gpiod, 0); return 0; } pulses = 32 - (value * 32) / 255; if (pulses == 0) { gpiod_set_value_cansleep(led_dat->gpiod, 0); mdelay(1); gpiod_set_value_cansleep(led_dat->gpiod, 1); return 0; } gpiod_set_value_cansleep(led_dat->gpiod, 1); while (pulses--) { gpiod_set_value_cansleep(led_dat->gpiod, 0); udelay(1); gpiod_set_value_cansleep(led_dat->gpiod, 1); udelay(1); } return 0; } static int lt3593_led_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct lt3593_led_data *led_data; struct fwnode_handle *child; int ret, state = LEDS_GPIO_DEFSTATE_OFF; const char *tmp; if (!dev->of_node) return -ENODEV; led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL); if (!led_data) return -ENOMEM; if (device_get_child_node_count(dev) != 1) { dev_err(dev, "Device must have exactly one LED sub-node."); return -EINVAL; } led_data->gpiod = devm_gpiod_get(dev, "lltc,ctrl", 0); if (IS_ERR(led_data->gpiod)) return PTR_ERR(led_data->gpiod); child = device_get_next_child_node(dev, NULL); ret = fwnode_property_read_string(child, "label", &tmp); if (ret < 0) snprintf(led_data->name, sizeof(led_data->name), "lt3593::"); else snprintf(led_data->name, sizeof(led_data->name), "lt3593:%s", tmp); fwnode_property_read_string(child, "linux,default-trigger", &led_data->cdev.default_trigger); if (!fwnode_property_read_string(child, "default-state", &tmp)) { if (!strcmp(tmp, "on")) state = LEDS_GPIO_DEFSTATE_ON; } led_data->cdev.name = led_data->name; led_data->cdev.brightness_set_blocking = lt3593_led_set; led_data->cdev.brightness = state ? LED_FULL : LED_OFF; ret = devm_led_classdev_register(dev, &led_data->cdev); if (ret < 0) { fwnode_handle_put(child); return ret; } led_data->cdev.dev->of_node = dev->of_node; platform_set_drvdata(pdev, led_data); return 0; } static const struct of_device_id of_lt3593_leds_match[] = { { .compatible = "lltc,lt3593", }, {}, }; MODULE_DEVICE_TABLE(of, of_lt3593_leds_match); static struct platform_driver lt3593_led_driver = { .probe = lt3593_led_probe, .driver = { .name = "leds-lt3593", .of_match_table = of_match_ptr(of_lt3593_leds_match), }, }; module_platform_driver(lt3593_led_driver); MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>"); MODULE_DESCRIPTION("LED driver for LT3593 controllers"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:leds-lt3593"); |