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 /* Maximum triggers + one trailing null entry to indicate the end of array */
20 #define MAX_TRIGGERS 3
21 
22 struct stm32_lptim_cfg {
23 	const char * const (*triggers)[MAX_TRIGGERS];
24 	unsigned int nb_triggers;
25 };
26 
27 /* List Low-Power Timer triggers for H7, MP13, MP15 */
28 static const char * const stm32_lptim_triggers[][MAX_TRIGGERS] = {
29 	{ LPTIM1_OUT,},
30 	{ LPTIM2_OUT,},
31 	{ LPTIM3_OUT,},
32 };
33 
34 /* List Low-Power Timer triggers for STM32MP25 */
35 static const char * const stm32mp25_lptim_triggers[][MAX_TRIGGERS] = {
36 	{ LPTIM1_CH1, LPTIM1_CH2, },
37 	{ LPTIM2_CH1, LPTIM2_CH2, },
38 	{ LPTIM3_CH1,},
39 	{ LPTIM4_CH1,},
40 	{ LPTIM5_OUT,},
41 };
42 
43 static const struct stm32_lptim_cfg stm32mp15_lptim_cfg = {
44 	.triggers = stm32_lptim_triggers,
45 	.nb_triggers = ARRAY_SIZE(stm32_lptim_triggers),
46 };
47 
48 static const struct stm32_lptim_cfg stm32mp25_lptim_cfg = {
49 	.triggers = stm32mp25_lptim_triggers,
50 	.nb_triggers = ARRAY_SIZE(stm32mp25_lptim_triggers),
51 };
52 
53 struct stm32_lptim_trigger {
54 	struct device *dev;
55 	const char * const *triggers;
56 };
57 
58 static int stm32_lptim_validate_device(struct iio_trigger *trig,
59 				       struct iio_dev *indio_dev)
60 {
61 	if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
62 		return 0;
63 
64 	return -EINVAL;
65 }
66 
67 static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
68 	.validate_device = stm32_lptim_validate_device,
69 };
70 
71 /**
72  * is_stm32_lptim_trigger
73  * @trig: trigger to be checked
74  *
75  * return true if the trigger is a valid STM32 IIO Low-Power Timer Trigger
76  * either return false
77  */
78 bool is_stm32_lptim_trigger(struct iio_trigger *trig)
79 {
80 	return (trig->ops == &stm32_lptim_trigger_ops);
81 }
82 EXPORT_SYMBOL(is_stm32_lptim_trigger);
83 
84 static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
85 {
86 	const char * const *cur = priv->triggers;
87 	int ret;
88 
89 	while (cur && *cur) {
90 		struct iio_trigger *trig;
91 
92 		trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
93 		if  (!trig)
94 			return -ENOMEM;
95 
96 		trig->dev.parent = priv->dev->parent;
97 		trig->ops = &stm32_lptim_trigger_ops;
98 		iio_trigger_set_drvdata(trig, priv);
99 
100 		ret = devm_iio_trigger_register(priv->dev, trig);
101 		if (ret)
102 			return ret;
103 		cur++;
104 	}
105 
106 	return 0;
107 }
108 
109 static int stm32_lptim_trigger_probe(struct platform_device *pdev)
110 {
111 	struct stm32_lptim_trigger *priv;
112 	struct stm32_lptim_cfg const *lptim_cfg;
113 	u32 index;
114 
115 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
116 	if (!priv)
117 		return -ENOMEM;
118 
119 	if (device_property_read_u32(&pdev->dev, "reg", &index))
120 		return -EINVAL;
121 
122 	lptim_cfg = device_get_match_data(&pdev->dev);
123 
124 	if (index >= lptim_cfg->nb_triggers)
125 		return -EINVAL;
126 
127 	priv->dev = &pdev->dev;
128 	priv->triggers = lptim_cfg->triggers[index];
129 
130 	return stm32_lptim_setup_trig(priv);
131 }
132 
133 static const struct of_device_id stm32_lptim_trig_of_match[] = {
134 	{ .compatible = "st,stm32-lptimer-trigger", .data = &stm32mp15_lptim_cfg },
135 	{ .compatible = "st,stm32mp25-lptimer-trigger", .data = &stm32mp25_lptim_cfg},
136 	{ }
137 };
138 MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
139 
140 static struct platform_driver stm32_lptim_trigger_driver = {
141 	.probe = stm32_lptim_trigger_probe,
142 	.driver = {
143 		.name = "stm32-lptimer-trigger",
144 		.of_match_table = stm32_lptim_trig_of_match,
145 	},
146 };
147 module_platform_driver(stm32_lptim_trigger_driver);
148 
149 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
150 MODULE_ALIAS("platform:stm32-lptimer-trigger");
151 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
152 MODULE_LICENSE("GPL v2");
153