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 */
18 static const char * const stm32_lptim_triggers[] = {
19 	LPTIM1_OUT,
20 	LPTIM2_OUT,
21 	LPTIM3_OUT,
22 };
23 
24 struct stm32_lptim_trigger {
25 	struct device *dev;
26 	const char *trg;
27 };
28 
29 static 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 
38 static 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  */
49 bool is_stm32_lptim_trigger(struct iio_trigger *trig)
50 {
51 	return (trig->ops == &stm32_lptim_trigger_ops);
52 }
53 EXPORT_SYMBOL(is_stm32_lptim_trigger);
54 
55 static 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 
70 static 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 
98 static const struct of_device_id stm32_lptim_trig_of_match[] = {
99 	{ .compatible = "st,stm32-lptimer-trigger", },
100 	{},
101 };
102 MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
103 
104 static 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 };
111 module_platform_driver(stm32_lptim_trigger_driver);
112 
113 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
114 MODULE_ALIAS("platform:stm32-lptimer-trigger");
115 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
116 MODULE_LICENSE("GPL v2");
117