1// SPDX-License-Identifier: GPL-2.0
2/*
3 * STM32 Low-Power Timer Trigger driver
4 *
5 * Copyright (C) STMicroelectronics 2017
6 *
7 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
8 *
9 * Inspired by Benjamin Gaignard's stm32-timer-trigger driver
10 */
11
12#include <linux/iio/timer/stm32-lptim-trigger.h>
13#include <linux/mfd/stm32-lptimer.h>
14#include <linux/mod_devicetable.h>
15#include <linux/module.h>
16#include <linux/platform_device.h>
17#include <linux/property.h>
18
19/* List Low-Power Timer triggers */
20static const char * const stm32_lptim_triggers[] = {
21	LPTIM1_OUT,
22	LPTIM2_OUT,
23	LPTIM3_OUT,
24};
25
26struct stm32_lptim_trigger {
27	struct device *dev;
28	const char *trg;
29};
30
31static int stm32_lptim_validate_device(struct iio_trigger *trig,
32				       struct iio_dev *indio_dev)
33{
34	if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
35		return 0;
36
37	return -EINVAL;
38}
39
40static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
41	.validate_device = stm32_lptim_validate_device,
42};
43
44/**
45 * is_stm32_lptim_trigger
46 * @trig: trigger to be checked
47 *
48 * return true if the trigger is a valid STM32 IIO Low-Power Timer Trigger
49 * either return false
50 */
51bool is_stm32_lptim_trigger(struct iio_trigger *trig)
52{
53	return (trig->ops == &stm32_lptim_trigger_ops);
54}
55EXPORT_SYMBOL(is_stm32_lptim_trigger);
56
57static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
58{
59	struct iio_trigger *trig;
60
61	trig = devm_iio_trigger_alloc(priv->dev, "%s", priv->trg);
62	if  (!trig)
63		return -ENOMEM;
64
65	trig->dev.parent = priv->dev->parent;
66	trig->ops = &stm32_lptim_trigger_ops;
67	iio_trigger_set_drvdata(trig, priv);
68
69	return devm_iio_trigger_register(priv->dev, trig);
70}
71
72static int stm32_lptim_trigger_probe(struct platform_device *pdev)
73{
74	struct stm32_lptim_trigger *priv;
75	u32 index;
76
77	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
78	if (!priv)
79		return -ENOMEM;
80
81	if (device_property_read_u32(&pdev->dev, "reg", &index))
82		return -EINVAL;
83
84	if (index >= ARRAY_SIZE(stm32_lptim_triggers))
85		return -EINVAL;
86
87	priv->dev = &pdev->dev;
88	priv->trg = stm32_lptim_triggers[index];
89
90	return stm32_lptim_setup_trig(priv);
91}
92
93static const struct of_device_id stm32_lptim_trig_of_match[] = {
94	{ .compatible = "st,stm32-lptimer-trigger", },
95	{},
96};
97MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
98
99static struct platform_driver stm32_lptim_trigger_driver = {
100	.probe = stm32_lptim_trigger_probe,
101	.driver = {
102		.name = "stm32-lptimer-trigger",
103		.of_match_table = stm32_lptim_trig_of_match,
104	},
105};
106module_platform_driver(stm32_lptim_trigger_driver);
107
108MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
109MODULE_ALIAS("platform:stm32-lptimer-trigger");
110MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
111MODULE_LICENSE("GPL v2");
112