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

   1 /*
   2  * STM32 Low-Power Timer Trigger driver
   3  *
   4  * Copyright (C) STMicroelectronics 2017
   5  *
   6  * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
   7  *
   8  * License terms:  GNU General Public License (GPL), version 2
   9  *
  10  * Inspired by Benjamin Gaignard's stm32-timer-trigger driver
  11  */
  12
  13 #include <linux/iio/timer/stm32-lptim-trigger.h>
  14 #include <linux/mfd/stm32-lptimer.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17
  18 /* List Low-Power Timer triggers */
  19 static const char * const stm32_lptim_triggers[] = {
  20         LPTIM1_OUT,
  21         LPTIM2_OUT,
  22         LPTIM3_OUT,
  23 };
  24
  25 struct stm32_lptim_trigger {
  26         struct device *dev;
  27         const char *trg;
  28 };
  29
  30 static int stm32_lptim_validate_device(struct iio_trigger *trig,
  31                                        struct iio_dev *indio_dev)
  32 {
  33         if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
  34                 return 0;
  35
  36         return -EINVAL;
  37 }
  38
  39 static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
  40         .owner = THIS_MODULE,
  41         .validate_device = stm32_lptim_validate_device,
  42 };
  43
  44 /**
  45  * is_stm32_lptim_trigger
  46  * @trig: trigger to be checked
  47  *
  48  * return true if the trigger is a valid STM32 IIO Low-Power Timer Trigger
  49  * either return false
  50  */
  51 bool is_stm32_lptim_trigger(struct iio_trigger *trig)
  52 {
  53         return (trig->ops == &stm32_lptim_trigger_ops);
  54 }
  55 EXPORT_SYMBOL(is_stm32_lptim_trigger);
  56
  57 static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
  58 {
  59         struct iio_trigger *trig;
  60
  61         trig = devm_iio_trigger_alloc(priv->dev, "%s", priv->trg);
  62         if  (!trig)
  63                 return -ENOMEM;
  64
  65         trig->dev.parent = priv->dev->parent;
  66         trig->ops = &stm32_lptim_trigger_ops;
  67         iio_trigger_set_drvdata(trig, priv);
  68
  69         return devm_iio_trigger_register(priv->dev, trig);
  70 }
  71
  72 static int stm32_lptim_trigger_probe(struct platform_device *pdev)
  73 {
  74         struct stm32_lptim_trigger *priv;
  75         u32 index;
  76         int ret;
  77
  78         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  79         if (!priv)
  80                 return -ENOMEM;
  81
  82         if (of_property_read_u32(pdev->dev.of_node, "reg", &index))
  83                 return -EINVAL;
  84
  85         if (index >= ARRAY_SIZE(stm32_lptim_triggers))
  86                 return -EINVAL;
  87
  88         priv->dev = &pdev->dev;
  89         priv->trg = stm32_lptim_triggers[index];
  90
  91         ret = stm32_lptim_setup_trig(priv);
  92         if (ret)
  93                 return ret;
  94
  95         platform_set_drvdata(pdev, priv);
  96
  97         return 0;
  98 }
  99
 100 static const struct of_device_id stm32_lptim_trig_of_match[] = {
 101         { .compatible = "st,stm32-lptimer-trigger", },
 102         {},
 103 };
 104 MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
 105
 106 static struct platform_driver stm32_lptim_trigger_driver = {
 107         .probe = stm32_lptim_trigger_probe,
 108         .driver = {
 109                 .name = "stm32-lptimer-trigger",
 110                 .of_match_table = stm32_lptim_trig_of_match,
 111         },
 112 };
 113 module_platform_driver(stm32_lptim_trigger_driver);
 114
 115 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
 116 MODULE_ALIAS("platform:stm32-lptimer-trigger");
 117 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
 118 MODULE_LICENSE("GPL v2");