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 */
 18static const char * const stm32_lptim_triggers[] = {
 19	LPTIM1_OUT,
 20	LPTIM2_OUT,
 21	LPTIM3_OUT,
 22};
 23
 24struct stm32_lptim_trigger {
 25	struct device *dev;
 26	const char *trg;
 27};
 28
 29static 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
 38static 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 */
 49bool is_stm32_lptim_trigger(struct iio_trigger *trig)
 50{
 51	return (trig->ops == &stm32_lptim_trigger_ops);
 52}
 53EXPORT_SYMBOL(is_stm32_lptim_trigger);
 54
 55static 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
 70static 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
 98static const struct of_device_id stm32_lptim_trig_of_match[] = {
 99	{ .compatible = "st,stm32-lptimer-trigger", },
100	{},
101};
102MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
103
104static 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};
111module_platform_driver(stm32_lptim_trigger_driver);
112
113MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
114MODULE_ALIAS("platform:stm32-lptimer-trigger");
115MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
116MODULE_LICENSE("GPL v2");