/*
 * Copyright (c) 2017-2018, NXP
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <errno.h>
#include <adc.h>
#include <fsl_adc16.h>

#define SYS_LOG_LEVEL CONFIG_SYS_LOG_ADC_LEVEL
#include <logging/sys_log.h>

#define ADC_CONTEXT_USES_KERNEL_TIMER
#include "adc_context.h"

struct mcux_adc16_config {
	ADC_Type *base;
	void (*irq_config_func)(struct device *dev);
};

struct mcux_adc16_data {
	struct device *dev;
	struct adc_context ctx;
	u16_t *buffer;
	u16_t *repeat_buffer;
	u32_t channels;
	u8_t channel_id;
};

static int mcux_adc16_channel_setup(struct device *dev,
				    const struct adc_channel_cfg *channel_cfg)
{
	u8_t channel_id = channel_cfg->channel_id;

	if (channel_id > (ADC_SC1_ADCH_MASK >> ADC_SC1_ADCH_SHIFT)) {
		SYS_LOG_ERR("Channel %d is not valid", channel_id);
		return -EINVAL;
	}

	if (channel_cfg->acquisition_time != ADC_ACQ_TIME_DEFAULT) {
		SYS_LOG_ERR("Invalid channel acquisition time");
		return -EINVAL;
	}

	if (channel_cfg->differential) {
		SYS_LOG_ERR("Differential channels are not supported");
		return -EINVAL;
	}

	if (channel_cfg->gain != ADC_GAIN_1) {
		SYS_LOG_ERR("Invalid channel gain");
		return -EINVAL;
	}

	if (channel_cfg->reference != ADC_REF_INTERNAL) {
		SYS_LOG_ERR("Invalid channel reference");
		return -EINVAL;
	}

	return 0;
}

static int start_read(struct device *dev, const struct adc_sequence *sequence)
{
	const struct mcux_adc16_config *config = dev->config->config_info;
	struct mcux_adc16_data *data = dev->driver_data;
	adc16_hardware_average_mode_t mode;
	int error;

	if (sequence->resolution != 12) {
		SYS_LOG_ERR("Invalid resolution");
		return -EINVAL;
	}

	switch (sequence->oversampling) {
	case 0:
		mode = kADC16_HardwareAverageDisabled;
		break;
	case 2:
		mode = kADC16_HardwareAverageCount4;
		break;
	case 3:
		mode = kADC16_HardwareAverageCount8;
		break;
	case 4:
		mode = kADC16_HardwareAverageCount16;
		break;
	case 5:
		mode = kADC16_HardwareAverageCount32;
		break;
	default:
		SYS_LOG_ERR("Invalid oversampling");
		return -EINVAL;
	}
	ADC16_SetHardwareAverage(config->base, mode);

	data->buffer = sequence->buffer;
	data->repeat_buffer = sequence->buffer;

	adc_context_start_read(&data->ctx, sequence);
	error = adc_context_wait_for_completion(&data->ctx);
	adc_context_release(&data->ctx, error);

	return error;
}

static int mcux_adc16_read(struct device *dev,
			   const struct adc_sequence *sequence)
{
	struct mcux_adc16_data *data = dev->driver_data;

	adc_context_lock(&data->ctx, false, NULL);
	return start_read(dev, sequence);
}

#ifdef CONFIG_ADC_ASYNC
static int mcux_adc16_read_async(struct device *dev,
				 const struct adc_sequence *sequence,
				 struct k_poll_signal *async)
{
	struct mcux_adc16_data *data = dev->driver_data;

	adc_context_lock(&data->ctx, true, async);
	return start_read(dev, sequence);
}
#endif

static void mcux_adc16_start_channel(struct device *dev)
{
	const struct mcux_adc16_config *config = dev->config->config_info;
	struct mcux_adc16_data *data = dev->driver_data;

	adc16_channel_config_t channel_config;
	u32_t channel_group = 0;

	data->channel_id = find_lsb_set(data->channels) - 1;

	SYS_LOG_DBG("Starting channel %d", data->channel_id);

#if defined(FSL_FEATURE_ADC16_HAS_DIFF_MODE) && FSL_FEATURE_ADC16_HAS_DIFF_MODE
	channel_config.enableDifferentialConversion = false;
#endif
	channel_config.enableInterruptOnConversionCompleted = true;
	channel_config.channelNumber = data->channel_id;
	ADC16_SetChannelConfig(config->base, channel_group, &channel_config);
}

static void adc_context_start_sampling(struct adc_context *ctx)
{
	struct mcux_adc16_data *data =
		CONTAINER_OF(ctx, struct mcux_adc16_data, ctx);

	data->channels = ctx->sequence->channels;

	mcux_adc16_start_channel(data->dev);
}

static void adc_context_update_buffer_pointer(struct adc_context *ctx,
					      bool repeat_sampling)
{
	struct mcux_adc16_data *data =
		CONTAINER_OF(ctx, struct mcux_adc16_data, ctx);

	if (repeat_sampling) {
		data->buffer = data->repeat_buffer;
	}
}

static void mcux_adc16_isr(void *arg)
{
	struct device *dev = (struct device *)arg;
	const struct mcux_adc16_config *config = dev->config->config_info;
	struct mcux_adc16_data *data = dev->driver_data;
	ADC_Type *base = config->base;
	u32_t channel_group = 0;
	u16_t result;

	result = ADC16_GetChannelConversionValue(base, channel_group);
	SYS_LOG_DBG("Finished channel %d. Result is 0x%04x",
		    data->channel_id, result);

	*data->buffer++ = result;
	data->channels &= ~BIT(data->channel_id);

	if (data->channels) {
		mcux_adc16_start_channel(dev);
	} else {
		adc_context_on_sampling_done(&data->ctx, dev);
	}
}

static int mcux_adc16_init(struct device *dev)
{
	const struct mcux_adc16_config *config = dev->config->config_info;
	struct mcux_adc16_data *data = dev->driver_data;
	ADC_Type *base = config->base;
	adc16_config_t adc_config;

	ADC16_GetDefaultConfig(&adc_config);
	ADC16_Init(base, &adc_config);

	ADC16_EnableHardwareTrigger(base, false);

	config->irq_config_func(dev);
	data->dev = dev;

	adc_context_unlock_unconditionally(&data->ctx);

	return 0;
}

static const struct adc_driver_api mcux_adc16_driver_api = {
	.channel_setup = mcux_adc16_channel_setup,
	.read = mcux_adc16_read,
#ifdef CONFIG_ADC_ASYNC
	.read_async = mcux_adc16_read_async,
#endif
};

#if CONFIG_ADC_0
static void mcux_adc16_config_func_0(struct device *dev);

static const struct mcux_adc16_config mcux_adc16_config_0 = {
	.base = (ADC_Type *)CONFIG_ADC_0_BASE_ADDRESS,
	.irq_config_func = mcux_adc16_config_func_0,
};

static struct mcux_adc16_data mcux_adc16_data_0 = {
	ADC_CONTEXT_INIT_TIMER(mcux_adc16_data_0, ctx),
	ADC_CONTEXT_INIT_LOCK(mcux_adc16_data_0, ctx),
	ADC_CONTEXT_INIT_SYNC(mcux_adc16_data_0, ctx),
};

DEVICE_AND_API_INIT(mcux_adc16_0, CONFIG_ADC_0_NAME, &mcux_adc16_init,
		    &mcux_adc16_data_0, &mcux_adc16_config_0,
		    POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
		    &mcux_adc16_driver_api);

static void mcux_adc16_config_func_0(struct device *dev)
{
	IRQ_CONNECT(CONFIG_ADC_0_IRQ, CONFIG_ADC_0_IRQ_PRI,
		    mcux_adc16_isr, DEVICE_GET(mcux_adc16_0), 0);

	irq_enable(CONFIG_ADC_0_IRQ);
}
#endif /* CONFIG_ADC_0 */

#if CONFIG_ADC_1
static void mcux_adc16_config_func_1(struct device *dev);

static const struct mcux_adc16_config mcux_adc16_config_1 = {
	.base = (ADC_Type *)CONFIG_ADC_1_BASE_ADDRESS,
	.irq_config_func = mcux_adc16_config_func_1,
};

static struct mcux_adc16_data mcux_adc16_data_1 = {
	ADC_CONTEXT_INIT_TIMER(mcux_adc16_data_1, ctx),
	ADC_CONTEXT_INIT_LOCK(mcux_adc16_data_1, ctx),
	ADC_CONTEXT_INIT_SYNC(mcux_adc16_data_1, ctx),
};

DEVICE_AND_API_INIT(mcux_adc16_1, CONFIG_ADC_1_NAME, &mcux_adc16_init,
		    &mcux_adc16_data_1, &mcux_adc16_config_1,
		    POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
		    &mcux_adc16_driver_api);

static void mcux_adc16_config_func_1(struct device *dev)
{
	IRQ_CONNECT(CONFIG_ADC_1_IRQ, CONFIG_ADC_1_IRQ_PRI,
		    mcux_adc16_isr, DEVICE_GET(mcux_adc16_1), 0);

	irq_enable(CONFIG_ADC_1_IRQ);
}
#endif /* CONFIG_ADC_1 */