drivers/adc/adc_mcux_lpadc.c

/*
 * Copyright 2023 NXP
 * Copyright (c) 2020 Toby Firth
 *
 * Based on adc_mcux_adc16.c and adc_mcux_adc12.c, which are:
 * Copyright (c) 2017-2018, NXP
 * Copyright (c) 2019 Vestas Wind Systems A/S
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT nxp_lpc_lpadc

#include <errno.h>
#include <zephyr/drivers/adc.h>
#include <fsl_lpadc.h>

#include <zephyr/drivers/pinctrl.h>

#define LOG_LEVEL CONFIG_ADC_LOG_LEVEL
#include <zephyr/logging/log.h>
#include <zephyr/irq.h>
LOG_MODULE_REGISTER(nxp_mcux_lpadc);

/*
 * Currently, no instance of the ADC IP has more than
 * 8 channels present. Therefore, we treat channels
 * with an index 8 or higher as a side b channel, with
 * the channel index given by channel_num % 8
 */
#define CHANNELS_PER_SIDE 0x8

#define ADC_CONTEXT_USES_KERNEL_TIMER
#include "adc_context.h"


struct mcux_lpadc_config {
	ADC_Type *base;
	lpadc_reference_voltage_source_t voltage_ref;
	uint8_t power_level;
	uint32_t calibration_average;
	uint32_t offset_a;
	uint32_t offset_b;
	void (*irq_config_func)(const struct device *dev);
	const struct pinctrl_dev_config *pincfg;
};

struct mcux_lpadc_data {
	const struct device *dev;
	struct adc_context ctx;
	uint16_t *buffer;
	uint16_t *repeat_buffer;
	uint32_t channels;
	lpadc_conv_command_config_t cmd_config[CONFIG_LPADC_CHANNEL_COUNT];
};



static int mcux_lpadc_channel_setup(const struct device *dev,
				const struct adc_channel_cfg *channel_cfg)
{


	struct mcux_lpadc_data *data = dev->data;
	lpadc_conv_command_config_t *cmd;
	uint8_t channel_side;
	uint8_t channel_num;

	/* User may configure maximum number of active channels */
	if (channel_cfg->channel_id >= CONFIG_LPADC_CHANNEL_COUNT) {
		LOG_ERR("Channel %d is not valid", channel_cfg->channel_id);
		return -EINVAL;
	}

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

	/* Select ADC CMD register to configure based off channel ID */
	cmd = &data->cmd_config[channel_cfg->channel_id];

	/* If bit 5 of input_positive is set, then channel side B is used */
	channel_side = 0x20 & channel_cfg->input_positive;
	/* Channel number is selected by lower 4 bits of input_positive */
	channel_num = ADC_CMDL_ADCH(channel_cfg->input_positive);

	LOG_DBG("Channel num: %u, channel side: %c", channel_num,
		channel_side == 0 ? 'A' : 'B');

	LPADC_GetDefaultConvCommandConfig(cmd);

	if (channel_cfg->differential) {
		/* Channel pairs must match in differential mode */
		if ((ADC_CMDL_ADCH(channel_cfg->input_positive)) !=
		   (ADC_CMDL_ADCH(channel_cfg->input_negative))) {
			return -ENOTSUP;
		}

#if defined(FSL_FEATURE_LPADC_HAS_CMDL_DIFF) && FSL_FEATURE_LPADC_HAS_CMDL_DIFF
		/* Check to see which channel is the positive input */
		if (channel_cfg->input_positive & 0x20) {
			/* Channel B is positive side */
			cmd->sampleChannelMode =
				kLPADC_SampleChannelDiffBothSideBA;
		} else {
			/* Channel A is positive side */
			cmd->sampleChannelMode =
				kLPADC_SampleChannelDiffBothSideAB;
		}
#else
		cmd->sampleChannelMode = kLPADC_SampleChannelDiffBothSide;
#endif
	} else if (channel_side != 0) {
		cmd->sampleChannelMode = kLPADC_SampleChannelSingleEndSideB;
	} else {
		/* Default value for sampleChannelMode is SideA */
	}
#if defined(FSL_FEATURE_LPADC_HAS_CMDL_CSCALE) && FSL_FEATURE_LPADC_HAS_CMDL_CSCALE
	/*
	 * The true scaling factor used by the LPADC is 30/64, instead of
	 * 1/2. Select 1/2 as this is the closest scaling factor available
	 * in Zephyr.
	 */
	if (channel_cfg->gain == ADC_GAIN_1_2) {
		LOG_INF("Channel gain of 30/64 selected");
		cmd->sampleScaleMode = kLPADC_SamplePartScale;
	} else if (channel_cfg->gain == ADC_GAIN_1) {
		cmd->sampleScaleMode = kLPADC_SampleFullScale;
	} else {
		LOG_ERR("Invalid channel gain");
		return -EINVAL;
	}
#else
	if (channel_cfg->gain != ADC_GAIN_1) {
		LOG_ERR("Invalid channel gain");
		return -EINVAL;
	}
#endif

	if (channel_cfg->reference != ADC_REF_EXTERNAL0) {
		LOG_ERR("Invalid channel reference");
		return -EINVAL;
	}

	cmd->channelNumber = channel_num;
	return 0;
}

static int mcux_lpadc_start_read(const struct device *dev,
		 const struct adc_sequence *sequence)
{
	const struct mcux_lpadc_config *config = dev->config;
	struct mcux_lpadc_data *data = dev->data;
	lpadc_hardware_average_mode_t hardware_average_mode;
	uint8_t channel, last_enabled;
#if defined(FSL_FEATURE_LPADC_HAS_CMDL_MODE) \
	&& FSL_FEATURE_LPADC_HAS_CMDL_MODE
	lpadc_conversion_resolution_mode_t resolution_mode;

	switch (sequence->resolution) {
	case 12:
	case 13:
		resolution_mode = kLPADC_ConversionResolutionStandard;
		break;
	case 16:
		resolution_mode = kLPADC_ConversionResolutionHigh;
		break;
	default:
		LOG_ERR("Unsupported resolution %d", sequence->resolution);
		return -ENOTSUP;
	}
#else
	/* If FSL_FEATURE_LPADC_HAS_CMDL_MODE is not defined
	   only 12/13 bit resolution is supported. */
	if (sequence->resolution != 12 && sequence->resolution != 13) {
		LOG_ERR("Unsupported resolution %d", sequence->resolution);
		return -ENOTSUP;
	}
#endif /* FSL_FEATURE_LPADC_HAS_CMDL_MODE */

	switch (sequence->oversampling) {
	case 0:
		hardware_average_mode = kLPADC_HardwareAverageCount1;
		break;
	case 1:
		hardware_average_mode = kLPADC_HardwareAverageCount2;
		break;
	case 2:
		hardware_average_mode = kLPADC_HardwareAverageCount4;
		break;
	case 3:
		hardware_average_mode = kLPADC_HardwareAverageCount8;
		break;
	case 4:
		hardware_average_mode = kLPADC_HardwareAverageCount16;
		break;
	case 5:
		hardware_average_mode = kLPADC_HardwareAverageCount32;
		break;
	case 6:
		hardware_average_mode = kLPADC_HardwareAverageCount64;
		break;
	case 7:
		hardware_average_mode = kLPADC_HardwareAverageCount128;
		break;
	default:
		LOG_ERR("Unsupported oversampling value %d",
			sequence->oversampling);
		return -ENOTSUP;
	}

	/*
	 * Now, look at the selected channels to determine which ADC channels
	 * we need to configure, and set those channels up.
	 *
	 * Since this ADC supports chaining channels in hardware, we will
	 * start with the highest channel ID and work downwards, chaining
	 * channels as we go.
	 */
	channel = CONFIG_LPADC_CHANNEL_COUNT;
	last_enabled = 0;
	while (channel-- > 0) {
		if (sequence->channels & BIT(channel)) {
			/* Setup this channel command */
#if defined(FSL_FEATURE_LPADC_HAS_CMDL_MODE) && FSL_FEATURE_LPADC_HAS_CMDL_MODE
			data->cmd_config[channel].conversionResolutionMode =
				resolution_mode;
#endif
			data->cmd_config[channel].hardwareAverageMode =
				hardware_average_mode;
			if (last_enabled) {
				/* Chain channel */
				data->cmd_config[channel].chainedNextCommandNumber =
					last_enabled + 1;
				LOG_DBG("Chaining channel %u to %u",
					channel, last_enabled);
			} else {
				/* End of chain */
				data->cmd_config[channel].chainedNextCommandNumber = 0;
			}
			last_enabled = channel;
			LPADC_SetConvCommandConfig(config->base,
				channel + 1, &data->cmd_config[channel]);
		}
	};

	data->buffer = sequence->buffer;

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

	return error;
}

static int mcux_lpadc_read_async(const struct device *dev,
			const struct adc_sequence *sequence,
			struct k_poll_signal *async)
{
	struct mcux_lpadc_data *data = dev->data;
	int error;

	adc_context_lock(&data->ctx, async ? true : false, async);
	error = mcux_lpadc_start_read(dev, sequence);
	adc_context_release(&data->ctx, error);

	return error;
}

static int mcux_lpadc_read(const struct device *dev,
		   const struct adc_sequence *sequence)
{
	return mcux_lpadc_read_async(dev, sequence, NULL);
}

static void mcux_lpadc_start_channel(const struct device *dev)
{
	const struct mcux_lpadc_config *config = dev->config;
	struct mcux_lpadc_data *data = dev->data;
	lpadc_conv_trigger_config_t trigger_config;
	uint8_t first_channel;

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

	LOG_DBG("Starting channel %d, input %d", first_channel,
		data->cmd_config[first_channel].channelNumber);

	LPADC_GetDefaultConvTriggerConfig(&trigger_config);

	trigger_config.targetCommandId = first_channel + 1;

	/* configures trigger0. */
	LPADC_SetConvTriggerConfig(config->base, 0, &trigger_config);

	/* 1 is trigger0 mask. */
	LPADC_DoSoftwareTrigger(config->base, 1);
}

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

	data->channels = ctx->sequence.channels;
	data->repeat_buffer = data->buffer;

	mcux_lpadc_start_channel(data->dev);
}

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

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

static void mcux_lpadc_isr(const struct device *dev)
{
	const struct mcux_lpadc_config *config = dev->config;
	struct mcux_lpadc_data *data = dev->data;
	ADC_Type *base = config->base;

	lpadc_conv_result_t conv_result;
	lpadc_sample_channel_mode_t conv_mode;
	int16_t result;
	uint16_t channel;

#if (defined(FSL_FEATURE_LPADC_FIFO_COUNT) \
	&& (FSL_FEATURE_LPADC_FIFO_COUNT == 2U))
	LPADC_GetConvResult(base, &conv_result, 0U);
#else
	LPADC_GetConvResult(base, &conv_result);
#endif /* FSL_FEATURE_LPADC_FIFO_COUNT */

	channel = conv_result.commandIdSource - 1;
	LOG_DBG("Finished channel %d. Raw result is 0x%04x",
		channel, conv_result.convValue);
	/*
	 * For 12 or 13 bit resolution the the LSBs will be 0, so a bit shift
	 * is needed. For differential modes, the ADC conversion to
	 * millivolts expects to use a shift one less than the resolution.
	 *
	 * For 16 bit modes, the adc value can be left untouched. ADC
	 * API should treat the value as signed if the channel is
	 * in differential mode
	 */
	conv_mode = data->cmd_config[channel].sampleChannelMode;
	if (data->ctx.sequence.resolution < 15) {
		result = ((conv_result.convValue >> 3) & 0xFFF);
#if defined(FSL_FEATURE_LPADC_HAS_CMDL_DIFF) && FSL_FEATURE_LPADC_HAS_CMDL_DIFF
		if (conv_mode == kLPADC_SampleChannelDiffBothSideAB ||
		    conv_mode == kLPADC_SampleChannelDiffBothSideBA) {
#else
		if (conv_mode == kLPADC_SampleChannelDiffBothSide) {
#endif
			if ((conv_result.convValue & 0x8000)) {
				/* 13 bit mode, MSB is sign bit. (2's complement) */
				result -= 0x1000;
			}
		}
		*data->buffer++ = result;
	} else {
		*data->buffer++ = conv_result.convValue;
	}


	data->channels &= ~BIT(channel);

	/*
	 * Hardware will automatically continue sampling, so no need
	 * to issue new trigger
	 */
	if (data->channels == 0) {
		adc_context_on_sampling_done(&data->ctx, dev);
	}
}

static int mcux_lpadc_init(const struct device *dev)
{
	const struct mcux_lpadc_config *config = dev->config;
	struct mcux_lpadc_data *data = dev->data;
	ADC_Type *base = config->base;
	lpadc_config_t adc_config;
	int err;

	err = pinctrl_apply_state(config->pincfg, PINCTRL_STATE_DEFAULT);
	if (err) {
		return err;
	}

	LPADC_GetDefaultConfig(&adc_config);

	adc_config.enableAnalogPreliminary = true;
	adc_config.referenceVoltageSource = config->voltage_ref;

#if defined(FSL_FEATURE_LPADC_HAS_CTRL_CAL_AVGS) \
	&& FSL_FEATURE_LPADC_HAS_CTRL_CAL_AVGS
	adc_config.conversionAverageMode = config->calibration_average;
#endif /* FSL_FEATURE_LPADC_HAS_CTRL_CAL_AVGS */

	adc_config.powerLevelMode = config->power_level;

	LPADC_Init(base, &adc_config);

	/* Do ADC calibration. */
#if defined(FSL_FEATURE_LPADC_HAS_CTRL_CALOFS) \
	&& FSL_FEATURE_LPADC_HAS_CTRL_CALOFS
#if defined(FSL_FEATURE_LPADC_HAS_OFSTRIM) \
	&& FSL_FEATURE_LPADC_HAS_OFSTRIM
	/* Request offset calibration. */
#if defined(CONFIG_LPADC_DO_OFFSET_CALIBRATION) \
	&& CONFIG_LPADC_DO_OFFSET_CALIBRATION
	LPADC_DoOffsetCalibration(base);
#else
	LPADC_SetOffsetValue(base,
			config->offset_a,
			config->offset_b);
#endif  /* DEMO_LPADC_DO_OFFSET_CALIBRATION */
#endif  /* FSL_FEATURE_LPADC_HAS_OFSTRIM */
	/* Request gain calibration. */
	LPADC_DoAutoCalibration(base);
#endif /* FSL_FEATURE_LPADC_HAS_CTRL_CALOFS */

#if (defined(FSL_FEATURE_LPADC_HAS_CFG_CALOFS) \
	&& FSL_FEATURE_LPADC_HAS_CFG_CALOFS)
	/* Do auto calibration. */
	LPADC_DoAutoCalibration(base);
#endif /* FSL_FEATURE_LPADC_HAS_CFG_CALOFS */

/* Enable the watermark interrupt. */
#if (defined(FSL_FEATURE_LPADC_FIFO_COUNT) \
	&& (FSL_FEATURE_LPADC_FIFO_COUNT == 2U))
	LPADC_EnableInterrupts(base, kLPADC_FIFO0WatermarkInterruptEnable);
#else
	LPADC_EnableInterrupts(base, kLPADC_FIFOWatermarkInterruptEnable);
#endif /* FSL_FEATURE_LPADC_FIFO_COUNT */

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

	adc_context_unlock_unconditionally(&data->ctx);

	return 0;
}

static const struct adc_driver_api mcux_lpadc_driver_api = {
	.channel_setup = mcux_lpadc_channel_setup,
	.read = mcux_lpadc_read,
#ifdef CONFIG_ADC_ASYNC
	.read_async = mcux_lpadc_read_async,
#endif
};


#define LPADC_MCUX_INIT(n)						\
	static void mcux_lpadc_config_func_##n(const struct device *dev);	\
									\
	PINCTRL_DT_INST_DEFINE(n);						\
	static const struct mcux_lpadc_config mcux_lpadc_config_##n = {	\
		.base = (ADC_Type *)DT_INST_REG_ADDR(n),	\
		.voltage_ref =	DT_INST_PROP(n, voltage_ref),	\
		.calibration_average = DT_INST_ENUM_IDX_OR(n, calibration_average, 0),	\
		.power_level = DT_INST_PROP(n, power_level),	\
		.offset_a = DT_INST_PROP(n, offset_value_a),	\
		.offset_b = DT_INST_PROP(n, offset_value_b),	\
		.irq_config_func = mcux_lpadc_config_func_##n,				\
		.pincfg = PINCTRL_DT_INST_DEV_CONFIG_GET(n),			\
	};									\
										\
	static struct mcux_lpadc_data mcux_lpadc_data_##n = {	\
		ADC_CONTEXT_INIT_TIMER(mcux_lpadc_data_##n, ctx),	\
		ADC_CONTEXT_INIT_LOCK(mcux_lpadc_data_##n, ctx),	\
		ADC_CONTEXT_INIT_SYNC(mcux_lpadc_data_##n, ctx),	\
	};														\
										\
	DEVICE_DT_INST_DEFINE(n,						\
		&mcux_lpadc_init, NULL, &mcux_lpadc_data_##n,			\
		&mcux_lpadc_config_##n, POST_KERNEL,				\
		CONFIG_ADC_INIT_PRIORITY,					\
		&mcux_lpadc_driver_api);							\
										\
	static void mcux_lpadc_config_func_##n(const struct device *dev)	\
	{									\
		IRQ_CONNECT(DT_INST_IRQN(n),					\
			DT_INST_IRQ(n, priority), mcux_lpadc_isr,	\
			DEVICE_DT_INST_GET(n), 0);				\
										\
		irq_enable(DT_INST_IRQN(n));					\
	}

DT_INST_FOREACH_STATUS_OKAY(LPADC_MCUX_INIT)