drivers/iio/trigger/stm32-lptimer-trigger.c

   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
  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  */
  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
  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
  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");