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
stm32_lptim_validate_device(struct iio_trigger * trig,struct iio_dev * indio_dev)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 */
is_stm32_lptim_trigger(struct iio_trigger * trig)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
stm32_lptim_setup_trig(struct stm32_lptim_trigger * priv)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
stm32_lptim_trigger_probe(struct platform_device * pdev)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