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         .validate_device = stm32_lptim_validate_device,
  41 };
  42
  43 /**
  44  * is_stm32_lptim_trigger
  45  * @trig: trigger to be checked
  46  *
  47  * return true if the trigger is a valid STM32 IIO Low-Power Timer Trigger
  48  * either return false
  49  */
  50 bool is_stm32_lptim_trigger(struct iio_trigger *trig)
  51 {
  52         return (trig->ops == &stm32_lptim_trigger_ops);
  53 }
  54 EXPORT_SYMBOL(is_stm32_lptim_trigger);
  55
  56 static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
  57 {
  58         struct iio_trigger *trig;
  59
  60         trig = devm_iio_trigger_alloc(priv->dev, "%s", priv->trg);
  61         if  (!trig)
  62                 return -ENOMEM;
  63
  64         trig->dev.parent = priv->dev->parent;
  65         trig->ops = &stm32_lptim_trigger_ops;
  66         iio_trigger_set_drvdata(trig, priv);
  67
  68         return devm_iio_trigger_register(priv->dev, trig);
  69 }
  70
  71 static int stm32_lptim_trigger_probe(struct platform_device *pdev)
  72 {
  73         struct stm32_lptim_trigger *priv;
  74         u32 index;
  75         int ret;
  76
  77         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  78         if (!priv)
  79                 return -ENOMEM;
  80
  81         if (of_property_read_u32(pdev->dev.of_node, "reg", &index))
  82                 return -EINVAL;
  83
  84         if (index >= ARRAY_SIZE(stm32_lptim_triggers))
  85                 return -EINVAL;
  86
  87         priv->dev = &pdev->dev;
  88         priv->trg = stm32_lptim_triggers[index];
  89
  90         ret = stm32_lptim_setup_trig(priv);
  91         if (ret)
  92                 return ret;
  93
  94         platform_set_drvdata(pdev, priv);
  95
  96         return 0;
  97 }
  98
  99 static const struct of_device_id stm32_lptim_trig_of_match[] = {
 100         { .compatible = "st,stm32-lptimer-trigger", },
 101         {},
 102 };
 103 MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
 104
 105 static struct platform_driver stm32_lptim_trigger_driver = {
 106         .probe = stm32_lptim_trigger_probe,
 107         .driver = {
 108                 .name = "stm32-lptimer-trigger",
 109                 .of_match_table = stm32_lptim_trig_of_match,
 110         },
 111 };
 112 module_platform_driver(stm32_lptim_trigger_driver);
 113
 114 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
 115 MODULE_ALIAS("platform:stm32-lptimer-trigger");
 116 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
 117 MODULE_LICENSE("GPL v2");