// SPDX-License-Identifier: GPL-2.0
/*
 * STM32 Low-Power Timer Trigger driver
 *
 * Copyright (C) STMicroelectronics 2017
 *
 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
 *
 * Inspired by Benjamin Gaignard's stm32-timer-trigger driver
 */

#include <linux/export.h>
#include <linux/iio/timer/stm32-lptim-trigger.h>
#include <linux/mfd/stm32-lptimer.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>

/* Maximum triggers + one trailing null entry to indicate the end of array */
#define MAX_TRIGGERS 3

struct stm32_lptim_cfg {
        const char * const (*triggers)[MAX_TRIGGERS];
        unsigned int nb_triggers;
};

/* List Low-Power Timer triggers for H7, MP13, MP15 */
static const char * const stm32_lptim_triggers[][MAX_TRIGGERS] = {
        { LPTIM1_OUT,},
        { LPTIM2_OUT,},
        { LPTIM3_OUT,},
};

/* List Low-Power Timer triggers for STM32MP25 */
static const char * const stm32mp25_lptim_triggers[][MAX_TRIGGERS] = {
        { LPTIM1_CH1, LPTIM1_CH2, },
        { LPTIM2_CH1, LPTIM2_CH2, },
        { LPTIM3_CH1,},
        { LPTIM4_CH1,},
        { LPTIM5_OUT,},
};

static const struct stm32_lptim_cfg stm32mp15_lptim_cfg = {
        .triggers = stm32_lptim_triggers,
        .nb_triggers = ARRAY_SIZE(stm32_lptim_triggers),
};

static const struct stm32_lptim_cfg stm32mp25_lptim_cfg = {
        .triggers = stm32mp25_lptim_triggers,
        .nb_triggers = ARRAY_SIZE(stm32mp25_lptim_triggers),
};

struct stm32_lptim_trigger {
        struct device *dev;
        const char * const *triggers;
};

static int stm32_lptim_validate_device(struct iio_trigger *trig,
                                       struct iio_dev *indio_dev)
{
        if (indio_dev->modes & INDIO_HARDWARE_TRIGGERED)
                return 0;

        return -EINVAL;
}

static const struct iio_trigger_ops stm32_lptim_trigger_ops = {
        .validate_device = stm32_lptim_validate_device,
};

/**
 * is_stm32_lptim_trigger
 * @trig: trigger to be checked
 *
 * return true if the trigger is a valid STM32 IIO Low-Power Timer Trigger
 * either return false
 */
bool is_stm32_lptim_trigger(struct iio_trigger *trig)
{
        return (trig->ops == &stm32_lptim_trigger_ops);
}
EXPORT_SYMBOL(is_stm32_lptim_trigger);

static int stm32_lptim_setup_trig(struct stm32_lptim_trigger *priv)
{
        const char * const *cur = priv->triggers;
        int ret;

        while (cur && *cur) {
                struct iio_trigger *trig;

                trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
                if  (!trig)
                        return -ENOMEM;

                trig->dev.parent = priv->dev->parent;
                trig->ops = &stm32_lptim_trigger_ops;
                iio_trigger_set_drvdata(trig, priv);

                ret = devm_iio_trigger_register(priv->dev, trig);
                if (ret)
                        return ret;
                cur++;
        }

        return 0;
}

static int stm32_lptim_trigger_probe(struct platform_device *pdev)
{
        struct stm32_lptim_trigger *priv;
        struct stm32_lptim_cfg const *lptim_cfg;
        u32 index;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        if (device_property_read_u32(&pdev->dev, "reg", &index))
                return -EINVAL;

        lptim_cfg = device_get_match_data(&pdev->dev);

        if (index >= lptim_cfg->nb_triggers)
                return -EINVAL;

        priv->dev = &pdev->dev;
        priv->triggers = lptim_cfg->triggers[index];

        return stm32_lptim_setup_trig(priv);
}

static const struct of_device_id stm32_lptim_trig_of_match[] = {
        { .compatible = "st,stm32-lptimer-trigger", .data = &stm32mp15_lptim_cfg },
        { .compatible = "st,stm32mp25-lptimer-trigger", .data = &stm32mp25_lptim_cfg},
        { }
};
MODULE_DEVICE_TABLE(of, stm32_lptim_trig_of_match);

static struct platform_driver stm32_lptim_trigger_driver = {
        .probe = stm32_lptim_trigger_probe,
        .driver = {
                .name = "stm32-lptimer-trigger",
                .of_match_table = stm32_lptim_trig_of_match,
        },
};
module_platform_driver(stm32_lptim_trigger_driver);

MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
MODULE_ALIAS("platform:stm32-lptimer-trigger");
MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM trigger driver");
MODULE_LICENSE("GPL v2");