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/mod_devicetable.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/property.h>
  18
  19 /* List Low-Power Timer triggers */
  20 static const char * const stm32_lptim_triggers[] = {
  21         LPTIM1_OUT,
  22         LPTIM2_OUT,
  23         LPTIM3_OUT,
  24 };
  25
  26 struct stm32_lptim_trigger {
  27         struct device *dev;
  28         const char *trg;
  29 };
  30
  31 static int stm32_lptim_validate_device(struct iio_trigger *trig,
  32                                        struct iio_dev *indio_dev)
  33 {
  34         if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
  35                 return 0;
  36
  37         return -EINVAL;
  38 }
  39
  40 static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
  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
  77         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  78         if (!priv)
  79                 return -ENOMEM;
  80
  81         if (device_property_read_u32(&pdev->dev, "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         return stm32_lptim_setup_trig(priv);
  91 }
  92
  93 static const struct of_device_id stm32_lptim_trig_of_match[] = {
  94         { .compatible = "st,stm32-lptimer-trigger", },
  95         {},
  96 };
  97 MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);
  98
  99 static struct platform_driver stm32_lptim_trigger_driver = {
 100         .probe = stm32_lptim_trigger_probe,
 101         .driver = {
 102                 .name = "stm32-lptimer-trigger",
 103                 .of_match_table = stm32_lptim_trig_of_match,
 104         },
 105 };
 106 module_platform_driver(stm32_lptim_trigger_driver);
 107
 108 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
 109 MODULE_ALIAS("platform:stm32-lptimer-trigger");
 110 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
 111 MODULE_LICENSE("GPL v2");