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