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(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
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(&priv->work, 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, 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
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(&priv->work);
89	linedisp_unregister(&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