1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Driver for a 7-segment LED display 4 * 5 * The decimal point LED present on some devices is currently not 6 * supported. 7 * 8 * Copyright (C) Allied Telesis Labs 9 */ 10 11 #include <linux/bitmap.h> 12 #include <linux/container_of.h> 13 #include <linux/errno.h> 14 #include <linux/gpio/consumer.h> 15 #include <linux/map_to_7segment.h> 16 #include <linux/module.h> 17 #include <linux/platform_device.h> 18 #include <linux/types.h> 19 #include <linux/workqueue.h> 20 21 #include "line-display.h" 22 23 struct seg_led_priv { 24 struct linedisp linedisp; 25 struct delayed_work work; 26 struct gpio_descs *segment_gpios; 27 }; 28 29 static void seg_led_update(struct work_struct *work) 30 { 31 struct seg_led_priv *priv = container_of(work, struct seg_led_priv, work.work); 32 struct linedisp *linedisp = &priv->linedisp; 33 struct linedisp_map *map = linedisp->map; 34 DECLARE_BITMAP(values, 8) = { }; 35 36 bitmap_set_value8(values, map_to_seg7(&map->map.seg7, linedisp->buf[0]), 0); 37 38 gpiod_multi_set_value_cansleep(priv->segment_gpios, values); 39 } 40 41 static int seg_led_linedisp_get_map_type(struct linedisp *linedisp) 42 { 43 struct seg_led_priv *priv = container_of(linedisp, struct seg_led_priv, linedisp); 44 45 INIT_DELAYED_WORK(&priv->work, seg_led_update); 46 return LINEDISP_MAP_SEG7; 47 } 48 49 static void seg_led_linedisp_update(struct linedisp *linedisp) 50 { 51 struct seg_led_priv *priv = container_of(linedisp, struct seg_led_priv, linedisp); 52 53 schedule_delayed_work(&priv->work, 0); 54 } 55 56 static const struct linedisp_ops seg_led_linedisp_ops = { 57 .get_map_type = seg_led_linedisp_get_map_type, 58 .update = seg_led_linedisp_update, 59 }; 60 61 static int seg_led_probe(struct platform_device *pdev) 62 { 63 struct seg_led_priv *priv; 64 struct device *dev = &pdev->dev; 65 66 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 67 if (!priv) 68 return -ENOMEM; 69 70 platform_set_drvdata(pdev, priv); 71 72 priv->segment_gpios = devm_gpiod_get_array(dev, "segment", GPIOD_OUT_LOW); 73 if (IS_ERR(priv->segment_gpios)) 74 return PTR_ERR(priv->segment_gpios); 75 76 if (priv->segment_gpios->ndescs < 7 || priv->segment_gpios->ndescs > 8) 77 return -EINVAL; 78 79 return linedisp_register(&priv->linedisp, dev, 1, &seg_led_linedisp_ops); 80 } 81 82 static void seg_led_remove(struct platform_device *pdev) 83 { 84 struct seg_led_priv *priv = platform_get_drvdata(pdev); 85 86 cancel_delayed_work_sync(&priv->work); 87 linedisp_unregister(&priv->linedisp); 88 } 89 90 static const struct of_device_id seg_led_of_match[] = { 91 { .compatible = "gpio-7-segment"}, 92 {} 93 }; 94 MODULE_DEVICE_TABLE(of, seg_led_of_match); 95 96 static struct platform_driver seg_led_driver = { 97 .probe = seg_led_probe, 98 .remove = seg_led_remove, 99 .driver = { 100 .name = "seg-led-gpio", 101 .of_match_table = seg_led_of_match, 102 }, 103 }; 104 module_platform_driver(seg_led_driver); 105 106 MODULE_AUTHOR("Chris Packham <chris.packham@alliedtelesis.co.nz>"); 107 MODULE_DESCRIPTION("7 segment LED driver"); 108 MODULE_LICENSE("GPL"); 109 MODULE_IMPORT_NS("LINEDISP"); 110