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/export.h>
13 #include <linux/iio/timer/stm32-lptim-trigger.h>
14 #include <linux/mfd/stm32-lptimer.h>
15 #include <linux/mod_devicetable.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/property.h>
19
20 /* Maximum triggers + one trailing null entry to indicate the end of array */
21 #define MAX_TRIGGERS 3
22
23 struct stm32_lptim_cfg {
24 const char * const (*triggers)[MAX_TRIGGERS];
25 unsigned int nb_triggers;
26 };
27
28 /* List Low-Power Timer triggers for H7, MP13, MP15 */
29 static const char * const stm32_lptim_triggers[][MAX_TRIGGERS] = {
30 { LPTIM1_OUT,},
31 { LPTIM2_OUT,},
32 { LPTIM3_OUT,},
33 };
34
35 /* List Low-Power Timer triggers for STM32MP25 */
36 static const char * const stm32mp25_lptim_triggers[][MAX_TRIGGERS] = {
37 { LPTIM1_CH1, LPTIM1_CH2, },
38 { LPTIM2_CH1, LPTIM2_CH2, },
39 { LPTIM3_CH1,},
40 { LPTIM4_CH1,},
41 { LPTIM5_OUT,},
42 };
43
44 static const struct stm32_lptim_cfg stm32mp15_lptim_cfg = {
45 .triggers = stm32_lptim_triggers,
46 .nb_triggers = ARRAY_SIZE(stm32_lptim_triggers),
47 };
48
49 static const struct stm32_lptim_cfg stm32mp25_lptim_cfg = {
50 .triggers = stm32mp25_lptim_triggers,
51 .nb_triggers = ARRAY_SIZE(stm32mp25_lptim_triggers),
52 };
53
54 struct stm32_lptim_trigger {
55 struct device *dev;
56 const char * const *triggers;
57 };
58
stm32_lptim_validate_device(struct iio_trigger * trig,struct iio_dev * indio_dev)59 static int stm32_lptim_validate_device(struct iio_trigger *trig,
60 struct iio_dev *indio_dev)
61 {
62 if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
63 return 0;
64
65 return -EINVAL;
66 }
67
68 static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
69 .validate_device = stm32_lptim_validate_device,
70 };
71
72 /**
73 * is_stm32_lptim_trigger
74 * @trig: trigger to be checked
75 *
76 * return true if the trigger is a valid STM32 IIO Low-Power Timer Trigger
77 * either return false
78 */
is_stm32_lptim_trigger(struct iio_trigger * trig)79 bool is_stm32_lptim_trigger(struct iio_trigger *trig)
80 {
81 return (trig->ops == &stm32_lptim_trigger_ops);
82 }
83 EXPORT_SYMBOL(is_stm32_lptim_trigger);
84
stm32_lptim_setup_trig(struct stm32_lptim_trigger * priv)85 static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
86 {
87 const char * const *cur = priv->triggers;
88 int ret;
89
90 while (cur && *cur) {
91 struct iio_trigger *trig;
92
93 trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
94 if (!trig)
95 return -ENOMEM;
96
97 trig->dev.parent = priv->dev->parent;
98 trig->ops = &stm32_lptim_trigger_ops;
99 iio_trigger_set_drvdata(trig, priv);
100
101 ret = devm_iio_trigger_register(priv->dev, trig);
102 if (ret)
103 return ret;
104 cur++;
105 }
106
107 return 0;
108 }
109
stm32_lptim_trigger_probe(struct platform_device * pdev)110 static int stm32_lptim_trigger_probe(struct platform_device *pdev)
111 {
112 struct stm32_lptim_trigger *priv;
113 struct stm32_lptim_cfg const *lptim_cfg;
114 u32 index;
115
116 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
117 if (!priv)
118 return -ENOMEM;
119
120 if (device_property_read_u32(&pdev->dev, "reg", &index))
121 return -EINVAL;
122
123 lptim_cfg = device_get_match_data(&pdev->dev);
124
125 if (index >= lptim_cfg->nb_triggers)
126 return -EINVAL;
127
128 priv->dev = &pdev->dev;
129 priv->triggers = lptim_cfg->triggers[index];
130
131 return stm32_lptim_setup_trig(priv);
132 }
133
134 static const struct of_device_id stm32_lptim_trig_of_match[] = {
135 { .compatible = "st,stm32-lptimer-trigger", .data = &stm32mp15_lptim_cfg },
136 { .compatible = "st,stm32mp25-lptimer-trigger", .data = &stm32mp25_lptim_cfg},
137 { }
138 };
139 MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
140
141 static struct platform_driver stm32_lptim_trigger_driver = {
142 .probe = stm32_lptim_trigger_probe,
143 .driver = {
144 .name = "stm32-lptimer-trigger",
145 .of_match_table = stm32_lptim_trig_of_match,
146 },
147 };
148 module_platform_driver(stm32_lptim_trigger_driver);
149
150 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
151 MODULE_ALIAS("platform:stm32-lptimer-trigger");
152 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
153 MODULE_LICENSE("GPL v2");
154