drivers/auxdisplay/seg-led-gpio.c

   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/mod_devicetable.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/types.h>
  20 #include <linux/workqueue.h>
  21
  22 #include "line-display.h"
  23
  24 struct seg_led_priv {
  25         struct linedisp linedisp;
  26         struct delayed_work work;
  27         struct gpio_descs *segment_gpios;
  28 };
  29
  30 static void seg_led_update(struct work_struct *work)
  31 {
  32         struct seg_led_priv *priv = container_of(work, struct seg_led_priv, work.work);
  33         struct linedisp *linedisp = &priv->linedisp;
  34         struct linedisp_map *map = linedisp->map;
  35         DECLARE_BITMAP(values, 8) = { };
  36
  37         bitmap_set_value8(values, map_to_seg7(&map->map.seg7, linedisp->buf[0]), 0);
  38
  39         gpiod_set_array_value_cansleep(priv->segment_gpios->ndescs, priv->segment_gpios->desc,
  40                                        priv->segment_gpios->info, values);
  41 }
  42
  43 static int seg_led_linedisp_get_map_type(struct linedisp *linedisp)
  44 {
  45         struct seg_led_priv *priv = container_of(linedisp, struct seg_led_priv, linedisp);
  46
  47         INIT_DELAYED_WORK(&priv->work, seg_led_update);
  48         return LINEDISP_MAP_SEG7;
  49 }
  50
  51 static void seg_led_linedisp_update(struct linedisp *linedisp)
  52 {
  53         struct seg_led_priv *priv = container_of(linedisp, struct seg_led_priv, linedisp);
  54
  55         schedule_delayed_work(&priv->work, 0);
  56 }
  57
  58 static const struct linedisp_ops seg_led_linedisp_ops = {
  59         .get_map_type = seg_led_linedisp_get_map_type,
  60         .update = seg_led_linedisp_update,
  61 };
  62
  63 static int seg_led_probe(struct platform_device *pdev)
  64 {
  65         struct seg_led_priv *priv;
  66         struct device *dev = &pdev->dev;
  67
  68         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  69         if (!priv)
  70                 return -ENOMEM;
  71
  72         platform_set_drvdata(pdev, priv);
  73
  74         priv->segment_gpios = devm_gpiod_get_array(dev, "segment", GPIOD_OUT_LOW);
  75         if (IS_ERR(priv->segment_gpios))
  76                 return PTR_ERR(priv->segment_gpios);
  77
  78         if (priv->segment_gpios->ndescs < 7 || priv->segment_gpios->ndescs > 8)
  79                 return -EINVAL;
  80
  81         return linedisp_register(&priv->linedisp, dev, 1, &seg_led_linedisp_ops);
  82 }
  83
  84 static void seg_led_remove(struct platform_device *pdev)
  85 {
  86         struct seg_led_priv *priv = platform_get_drvdata(pdev);
  87
  88         cancel_delayed_work_sync(&priv->work);
  89         linedisp_unregister(&priv->linedisp);
  90 }
  91
  92 static const struct of_device_id seg_led_of_match[] = {
  93         { .compatible = "gpio-7-segment"},
  94         {}
  95 };
  96 MODULE_DEVICE_TABLE(of, seg_led_of_match);
  97
  98 static struct platform_driver seg_led_driver = {
  99         .probe = seg_led_probe,
 100         .remove_new = seg_led_remove,
 101         .driver = {
 102                 .name = "seg-led-gpio",
 103                 .of_match_table = seg_led_of_match,
 104         },
 105 };
 106 module_platform_driver(seg_led_driver);
 107
 108 MODULE_AUTHOR("Chris Packham <chris.packham@alliedtelesis.co.nz>");
 109 MODULE_DESCRIPTION("7 segment LED driver");
 110 MODULE_LICENSE("GPL");
 111 MODULE_IMPORT_NS(LINEDISP);