drivers/hwmon/qpnp-adc-common.c

/* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#define pr_fmt(fmt) "%s: " fmt, __func__

#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/types.h>
#include <linux/hwmon.h>
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/spmi.h>
#include <linux/of_irq.h>
#include <linux/interrupt.h>
#include <linux/qpnp/qpnp-adc.h>
#include <linux/platform_device.h>

/* Min ADC code represets 0V */
#define QPNP_VADC_MIN_ADC_CODE			0x6000
/* Max ADC code represents full-scale range of 1.8V */
#define QPNP_VADC_MAX_ADC_CODE			0xA800

int32_t qpnp_adc_scale_default(int32_t adc_code,
		const struct qpnp_adc_properties *adc_properties,
		const struct qpnp_vadc_chan_properties *chan_properties,
		struct qpnp_vadc_result *adc_chan_result)
{
	bool negative_rawfromoffset = 0, negative_offset = 0;
	int64_t scale_voltage = 0;

	if (!chan_properties || !chan_properties->offset_gain_numerator ||
		!chan_properties->offset_gain_denominator || !adc_properties
		|| !adc_chan_result)
		return -EINVAL;

	scale_voltage = (adc_code -
		chan_properties->adc_graph[CALIB_ABSOLUTE].adc_gnd)
		* chan_properties->adc_graph[CALIB_ABSOLUTE].dx;
	if (scale_voltage < 0) {
		negative_offset = 1;
		scale_voltage = -scale_voltage;
	}
	do_div(scale_voltage,
		chan_properties->adc_graph[CALIB_ABSOLUTE].dy);
	if (negative_offset)
		scale_voltage = -scale_voltage;
	scale_voltage += chan_properties->adc_graph[CALIB_ABSOLUTE].dx;

	if (scale_voltage < 0) {
		if (adc_properties->bipolar) {
			scale_voltage = -scale_voltage;
			negative_rawfromoffset = 1;
		} else {
			scale_voltage = 0;
		}
	}

	adc_chan_result->measurement = scale_voltage *
				chan_properties->offset_gain_denominator;

	/* do_div only perform positive integer division! */
	do_div(adc_chan_result->measurement,
				chan_properties->offset_gain_numerator);

	if (negative_rawfromoffset)
		adc_chan_result->measurement = -adc_chan_result->measurement;

	/*
	 * Note: adc_chan_result->measurement is in the unit of
	 * adc_properties.adc_reference. For generic channel processing,
	 * channel measurement is a scale/ratio relative to the adc
	 * reference input
	 */
	adc_chan_result->physical = adc_chan_result->measurement;

	return 0;
}
EXPORT_SYMBOL_GPL(qpnp_adc_scale_default);

int32_t qpnp_vadc_check_result(int32_t *data)
{
	if (*data < QPNP_VADC_MIN_ADC_CODE)
		*data = QPNP_VADC_MIN_ADC_CODE;
	else if (*data > QPNP_VADC_MAX_ADC_CODE)
		*data = QPNP_VADC_MAX_ADC_CODE;

	return 0;
}
EXPORT_SYMBOL_GPL(qpnp_vadc_check_result);

int32_t qpnp_adc_get_devicetree_data(struct spmi_device *spmi,
			struct qpnp_adc_drv *adc_qpnp)
{
	struct device_node *node = spmi->dev.of_node;
	struct resource *res;
	struct device_node *child;
	struct qpnp_vadc_amux *adc_channel_list;
	struct qpnp_adc_properties *adc_prop;
	struct qpnp_adc_amux_properties *amux_prop;
	int count_adc_channel_list = 0, decimation, rc = 0;

	if (!node)
		return -EINVAL;

	for_each_child_of_node(node, child)
		count_adc_channel_list++;

	if (!count_adc_channel_list) {
		pr_err("No channel listing\n");
		return -EINVAL;
	}

	adc_qpnp->spmi = spmi;

	adc_prop = devm_kzalloc(&spmi->dev, sizeof(struct qpnp_adc_properties),
					GFP_KERNEL);
	if (!adc_prop) {
		dev_err(&spmi->dev, "Unable to allocate memory\n");
		return -ENOMEM;
	}
	adc_channel_list = devm_kzalloc(&spmi->dev,
		(sizeof(struct qpnp_vadc_amux) * count_adc_channel_list),
				GFP_KERNEL);
	if (!adc_channel_list) {
		dev_err(&spmi->dev, "Unable to allocate memory\n");
		return -ENOMEM;
	}

	amux_prop = devm_kzalloc(&spmi->dev,
		sizeof(struct qpnp_adc_amux_properties) +
		sizeof(struct qpnp_vadc_chan_properties), GFP_KERNEL);
	if (!amux_prop) {
		dev_err(&spmi->dev, "Unable to allocate memory\n");
		return -ENOMEM;
	}

	for_each_child_of_node(node, child) {
		int channel_num, scaling, post_scaling, hw_settle_time;
		int fast_avg_setup, calib_type, i = 0, rc;
		const char *calibration_param, *channel_name;

		channel_name = of_get_property(child,
				"label", NULL) ? : child->name;
		if (!channel_name) {
			pr_err("Invalid channel name\n");
			return -EINVAL;
		}

		rc = of_property_read_u32(child, "qcom,channel-num",
								&channel_num);
		if (rc) {
			pr_err("Invalid channel num\n");
			return -EINVAL;
		}
		rc = of_property_read_u32(child, "qcom,decimation",
								&decimation);
		if (rc) {
			pr_err("Invalid channel decimation property\n");
			return -EINVAL;
		}
		rc = of_property_read_u32(child,
				"qcom,pre-div-channel-scaling", &scaling);
		if (rc) {
			pr_err("Invalid channel scaling property\n");
			return -EINVAL;
		}
		rc = of_property_read_u32(child,
				"qcom,scale-function", &post_scaling);
		if (rc) {
			pr_err("Invalid channel post scaling property\n");
			return -EINVAL;
		}
		rc = of_property_read_u32(child,
				"qcom,hw-settle-time", &hw_settle_time);
		if (rc) {
			pr_err("Invalid channel hw settle time property\n");
			return -EINVAL;
		}
		rc = of_property_read_u32(child,
				"qcom,fast-avg-setup", &fast_avg_setup);
		if (rc) {
			pr_err("Invalid channel fast average setup\n");
			return -EINVAL;
		}
		calibration_param = of_get_property(child,
				"qcom,calibration-type", NULL);
		if (!strncmp(calibration_param, "absolute", 8))
			calib_type = CALIB_ABSOLUTE;
		else if (!strncmp(calibration_param, "historical", 9))
			calib_type = CALIB_RATIOMETRIC;
		else {
			pr_err("%s: Invalid calibration property\n", __func__);
			return -EINVAL;
		}
		/* Individual channel properties */
		adc_channel_list[i].name = (char *)channel_name;
		adc_channel_list[i].channel_num = channel_num;
		adc_channel_list[i].chan_path_prescaling = scaling;
		adc_channel_list[i].adc_decimation = decimation;
		adc_channel_list[i].adc_scale_fn = post_scaling;
		adc_channel_list[i].hw_settle_time = hw_settle_time;
		adc_channel_list[i].fast_avg_setup = fast_avg_setup;
		i++;
	}
	adc_qpnp->adc_channels = adc_channel_list;
	adc_qpnp->amux_prop = amux_prop;

	/* Get the ADC VDD reference voltage and ADC bit resolution */
	rc = of_property_read_u32(node, "qcom,adc-vdd-reference",
			&adc_prop->adc_vdd_reference);
	if (rc) {
		pr_err("Invalid adc vdd reference property\n");
		return -EINVAL;
	}
	rc = of_property_read_u32(node, "qcom,adc-bit-resolution",
			&adc_prop->bitresolution);
	if (rc) {
		pr_err("Invalid adc bit resolution property\n");
		return -EINVAL;
	}
	adc_qpnp->adc_prop = adc_prop;

	/* Get the peripheral address */
	res = spmi_get_resource(spmi, 0, IORESOURCE_MEM, 0);
	if (!res) {
		pr_err("No base address definition\n");
		return -EINVAL;
	}

	adc_qpnp->slave = spmi->sid;
	adc_qpnp->offset = res->start;

	/* Register the ADC peripheral interrupt */
	adc_qpnp->adc_irq = spmi_get_irq(spmi, 0, 0);
	if (adc_qpnp->adc_irq < 0) {
		pr_err("Invalid irq\n");
		return -ENXIO;
	}

	mutex_init(&adc_qpnp->adc_lock);

	return 0;
}
EXPORT_SYMBOL(qpnp_adc_get_devicetree_data);