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/module.h>
15#include <linux/platform_device.h>
16
17/* List Low-Power Timer triggers */
18static const char * const stm32_lptim_triggers[] = {
19	LPTIM1_OUT,
20	LPTIM2_OUT,
21	LPTIM3_OUT,
22};
23
24struct stm32_lptim_trigger {
25	struct device *dev;
26	const char *trg;
27};
28
29static int stm32_lptim_validate_device(struct iio_trigger *trig,
30				       struct iio_dev *indio_dev)
31{
32	if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
33		return 0;
34
35	return -EINVAL;
36}
37
38static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
39	.validate_device = stm32_lptim_validate_device,
40};
41
42/**
43 * is_stm32_lptim_trigger
44 * @trig: trigger to be checked
45 *
46 * return true if the trigger is a valid STM32 IIO Low-Power Timer Trigger
47 * either return false
48 */
49bool is_stm32_lptim_trigger(struct iio_trigger *trig)
50{
51	return (trig->ops == &stm32_lptim_trigger_ops);
52}
53EXPORT_SYMBOL(is_stm32_lptim_trigger);
54
55static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
56{
57	struct iio_trigger *trig;
58
59	trig = devm_iio_trigger_alloc(priv->dev, "%s", priv->trg);
60	if  (!trig)
61		return -ENOMEM;
62
63	trig->dev.parent = priv->dev->parent;
64	trig->ops = &stm32_lptim_trigger_ops;
65	iio_trigger_set_drvdata(trig, priv);
66
67	return devm_iio_trigger_register(priv->dev, trig);
68}
69
70static int stm32_lptim_trigger_probe(struct platform_device *pdev)
71{
72	struct stm32_lptim_trigger *priv;
73	u32 index;
74	int ret;
75
76	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
77	if (!priv)
78		return -ENOMEM;
79
80	if (of_property_read_u32(pdev->dev.of_node, "reg", &index))
81		return -EINVAL;
82
83	if (index >= ARRAY_SIZE(stm32_lptim_triggers))
84		return -EINVAL;
85
86	priv->dev = &pdev->dev;
87	priv->trg = stm32_lptim_triggers[index];
88
89	ret = stm32_lptim_setup_trig(priv);
90	if (ret)
91		return ret;
92
93	platform_set_drvdata(pdev, priv);
94
95	return 0;
96}
97
98static const struct of_device_id stm32_lptim_trig_of_match[] = {
99	{ .compatible = "st,stm32-lptimer-trigger", },
100	{},
101};
102MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
103
104static struct platform_driver stm32_lptim_trigger_driver = {
105	.probe = stm32_lptim_trigger_probe,
106	.driver = {
107		.name = "stm32-lptimer-trigger",
108		.of_match_table = stm32_lptim_trig_of_match,
109	},
110};
111module_platform_driver(stm32_lptim_trigger_driver);
112
113MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
114MODULE_ALIAS("platform:stm32-lptimer-trigger");
115MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
116MODULE_LICENSE("GPL v2");
117