1 /*
2  * STM32 Low-Power Timer Trigger driver
3  *
4  * Copyright (C) STMicroelectronics 2017
5  *
6  * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
7  *
8  * License terms:  GNU General Public License (GPL), version 2
9  *
10  * Inspired by Benjamin Gaignard's stm32-timer-trigger driver
11  */
12 
13 #include <linux/iio/timer/stm32-lptim-trigger.h>
14 #include <linux/mfd/stm32-lptimer.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 
18 /* List Low-Power Timer triggers */
19 static const char * const stm32_lptim_triggers[] = {
20 	LPTIM1_OUT,
21 	LPTIM2_OUT,
22 	LPTIM3_OUT,
23 };
24 
25 struct stm32_lptim_trigger {
26 	struct device *dev;
27 	const char *trg;
28 };
29 
30 static int stm32_lptim_validate_device(struct iio_trigger *trig,
31 				       struct iio_dev *indio_dev)
32 {
33 	if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
34 		return 0;
35 
36 	return -EINVAL;
37 }
38 
39 static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
40 	.owner = THIS_MODULE,
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  */
51 bool is_stm32_lptim_trigger(struct iio_trigger *trig)
52 {
53 	return (trig->ops == &stm32_lptim_trigger_ops);
54 }
55 EXPORT_SYMBOL(is_stm32_lptim_trigger);
56 
57 static 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 
72 static int stm32_lptim_trigger_probe(struct platform_device *pdev)
73 {
74 	struct stm32_lptim_trigger *priv;
75 	u32 index;
76 	int ret;
77 
78 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
79 	if (!priv)
80 		return -ENOMEM;
81 
82 	if (of_property_read_u32(pdev->dev.of_node, "reg", &index))
83 		return -EINVAL;
84 
85 	if (index >= ARRAY_SIZE(stm32_lptim_triggers))
86 		return -EINVAL;
87 
88 	priv->dev = &pdev->dev;
89 	priv->trg = stm32_lptim_triggers[index];
90 
91 	ret = stm32_lptim_setup_trig(priv);
92 	if (ret)
93 		return ret;
94 
95 	platform_set_drvdata(pdev, priv);
96 
97 	return 0;
98 }
99 
100 static const struct of_device_id stm32_lptim_trig_of_match[] = {
101 	{ .compatible = "st,stm32-lptimer-trigger", },
102 	{},
103 };
104 MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
105 
106 static struct platform_driver stm32_lptim_trigger_driver = {
107 	.probe = stm32_lptim_trigger_probe,
108 	.driver = {
109 		.name = "stm32-lptimer-trigger",
110 		.of_match_table = stm32_lptim_trig_of_match,
111 	},
112 };
113 module_platform_driver(stm32_lptim_trigger_driver);
114 
115 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
116 MODULE_ALIAS("platform:stm32-lptimer-trigger");
117 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
118 MODULE_LICENSE("GPL v2");
119