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
24struct seg_led_priv {
25 struct linedisp linedisp;
26 struct delayed_work work;
27 struct gpio_descs *segment_gpios;
28};
29
30static 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(map: values, value: map_to_seg7(map: &map->map.seg7, c: linedisp->buf[0]), start: 0);
38
39 gpiod_set_array_value_cansleep(array_size: priv->segment_gpios->ndescs, desc_array: priv->segment_gpios->desc,
40 array_info: priv->segment_gpios->info, value_bitmap: values);
41}
42
43static 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
51static 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(dwork: &priv->work, delay: 0);
56}
57
58static 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
63static 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, size: sizeof(*priv), GFP_KERNEL);
69 if (!priv)
70 return -ENOMEM;
71
72 platform_set_drvdata(pdev, data: priv);
73
74 priv->segment_gpios = devm_gpiod_get_array(dev, con_id: "segment", flags: GPIOD_OUT_LOW);
75 if (IS_ERR(ptr: priv->segment_gpios))
76 return PTR_ERR(ptr: priv->segment_gpios);
77
78 if (priv->segment_gpios->ndescs < 7 || priv->segment_gpios->ndescs > 8)
79 return -EINVAL;
80
81 return linedisp_register(linedisp: &priv->linedisp, parent: dev, num_chars: 1, ops: &seg_led_linedisp_ops);
82}
83
84static int seg_led_remove(struct platform_device *pdev)
85{
86 struct seg_led_priv *priv = platform_get_drvdata(pdev);
87
88 cancel_delayed_work_sync(dwork: &priv->work);
89 linedisp_unregister(linedisp: &priv->linedisp);
90
91 return 0;
92}
93
94static const struct of_device_id seg_led_of_match[] = {
95 { .compatible = "gpio-7-segment"},
96 {}
97};
98MODULE_DEVICE_TABLE(of, seg_led_of_match);
99
100static struct platform_driver seg_led_driver = {
101 .probe = seg_led_probe,
102 .remove = seg_led_remove,
103 .driver = {
104 .name = "seg-led-gpio",
105 .of_match_table = seg_led_of_match,
106 },
107};
108module_platform_driver(seg_led_driver);
109
110MODULE_AUTHOR("Chris Packham <chris.packham@alliedtelesis.co.nz>");
111MODULE_DESCRIPTION("7 segment LED driver");
112MODULE_LICENSE("GPL");
113MODULE_IMPORT_NS(LINEDISP);
114

source code of linux/drivers/auxdisplay/seg-led-gpio.c