rn5t618-adc.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * ADC driver for the RICOH RN5T618 power management chip family
  4 *
  5 * Copyright (C) 2019 Andreas Kemnade
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/device.h>
 10#include <linux/errno.h>
 11#include <linux/interrupt.h>
 12#include <linux/init.h>
 13#include <linux/module.h>
 14#include <linux/mfd/rn5t618.h>
 15#include <linux/platform_device.h>
 16#include <linux/completion.h>
 17#include <linux/regmap.h>
 18#include <linux/iio/iio.h>
 19#include <linux/iio/driver.h>
 20#include <linux/iio/machine.h>
 21#include <linux/slab.h>
 22
 23#define RN5T618_ADC_CONVERSION_TIMEOUT   (msecs_to_jiffies(500))
 24#define RN5T618_REFERENCE_VOLT 2500
 25
 26/* mask for selecting channels for single conversion */
 27#define RN5T618_ADCCNT3_CHANNEL_MASK 0x7
 28/* average 4-time conversion mode */
 29#define RN5T618_ADCCNT3_AVG BIT(3)
 30/* set for starting a single conversion, gets cleared by hw when done */
 31#define RN5T618_ADCCNT3_GODONE BIT(4)
 32/* automatic conversion, period is in ADCCNT2, selected channels are
 33 * in ADCCNT1
 34 */
 35#define RN5T618_ADCCNT3_AUTO BIT(5)
 36#define RN5T618_ADCEND_IRQ BIT(0)
 37
 38struct rn5t618_adc_data {
 39	struct device *dev;
 40	struct rn5t618 *rn5t618;
 41	struct completion conv_completion;
 42	int irq;
 43};
 44
 45enum rn5t618_channels {
 46	LIMMON = 0,
 47	VBAT,
 48	VADP,
 49	VUSB,
 50	VSYS,
 51	VTHM,
 52	AIN1,
 53	AIN0
 54};
 55
 56static const struct u16_fract rn5t618_ratios[8] = {
 57	[LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
 58	[VBAT] = {2, 1},
 59	[VADP] = {3, 1},
 60	[VUSB] = {3, 1},
 61	[VSYS] = {3, 1},
 62	[VTHM] = {1, 1},
 63	[AIN1] = {1, 1},
 64	[AIN0] = {1, 1},
 65};
 66
 67static int rn5t618_read_adc_reg(struct rn5t618 *rn5t618, int reg, u16 *val)
 68{
 69	u8 data[2];
 70	int ret;
 71
 72	ret = regmap_bulk_read(rn5t618->regmap, reg, data, sizeof(data));
 73	if (ret < 0)
 74		return ret;
 75
 76	*val = (data[0] << 4) | (data[1] & 0xF);
 77
 78	return 0;
 79}
 80
 81static irqreturn_t rn5t618_adc_irq(int irq, void *data)
 82{
 83	struct rn5t618_adc_data *adc = data;
 84	unsigned int r = 0;
 85	int ret;
 86
 87	/* clear low & high threshold irqs */
 88	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC1, 0);
 89	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC2, 0);
 90
 91	ret = regmap_read(adc->rn5t618->regmap, RN5T618_IR_ADC3, &r);
 92	if (ret < 0)
 93		dev_err(adc->dev, "failed to read IRQ status: %d\n", ret);
 94
 95	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC3, 0);
 96
 97	if (r & RN5T618_ADCEND_IRQ)
 98		complete(&adc->conv_completion);
 99
100	return IRQ_HANDLED;
101}
102
103static int rn5t618_adc_read(struct iio_dev *iio_dev,
104			    const struct iio_chan_spec *chan,
105			    int *val, int *val2, long mask)
106{
107	struct rn5t618_adc_data *adc = iio_priv(iio_dev);
108	u16 raw;
109	int ret;
110
111	if (mask == IIO_CHAN_INFO_SCALE) {
112		*val = RN5T618_REFERENCE_VOLT *
113		       rn5t618_ratios[chan->channel].numerator;
114		*val2 = rn5t618_ratios[chan->channel].denominator * 4095;
115
116		return IIO_VAL_FRACTIONAL;
117	}
118
119	/* select channel */
120	ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
121				 RN5T618_ADCCNT3_CHANNEL_MASK,
122				 chan->channel);
123	if (ret < 0)
124		return ret;
125
126	ret = regmap_write(adc->rn5t618->regmap, RN5T618_EN_ADCIR3,
127			   RN5T618_ADCEND_IRQ);
128	if (ret < 0)
129		return ret;
130
131	ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
132				 RN5T618_ADCCNT3_AVG,
133				 mask == IIO_CHAN_INFO_AVERAGE_RAW ?
134				 RN5T618_ADCCNT3_AVG : 0);
135	if (ret < 0)
136		return ret;
137
138	init_completion(&adc->conv_completion);
139	/* single conversion */
140	ret = regmap_set_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
141			      RN5T618_ADCCNT3_GODONE);
142	if (ret < 0)
143		return ret;
144
145	ret = wait_for_completion_timeout(&adc->conv_completion,
146					  RN5T618_ADC_CONVERSION_TIMEOUT);
147	if (ret == 0) {
148		dev_warn(adc->dev, "timeout waiting for adc result\n");
149		return -ETIMEDOUT;
150	}
151
152	ret = rn5t618_read_adc_reg(adc->rn5t618,
153				   RN5T618_ILIMDATAH + 2 * chan->channel,
154				   &raw);
155	if (ret < 0)
156		return ret;
157
158	*val = raw;
159
160	return IIO_VAL_INT;
161}
162
163static const struct iio_info rn5t618_adc_iio_info = {
164	.read_raw = &rn5t618_adc_read,
165};
166
167#define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
168	.type = _type, \
169	.channel = _channel, \
170	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
171			      BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
172			      BIT(IIO_CHAN_INFO_SCALE), \
173	.datasheet_name = _name, \
174	.indexed = 1. \
175}
176
177static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
178	RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
179	RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
180	RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
181	RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
182	RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
183	RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
184	RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
185	RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
186};
187
188static const struct iio_map rn5t618_maps[] = {
189	IIO_MAP("VADP", "rn5t618-power", "vadp"),
190	IIO_MAP("VUSB", "rn5t618-power", "vusb"),
191	{ }
192};
193
194static int rn5t618_adc_probe(struct platform_device *pdev)
195{
196	int ret;
197	struct iio_dev *iio_dev;
198	struct rn5t618_adc_data *adc;
199	struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
200
201	iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
202	if (!iio_dev)
203		return -ENOMEM;
204
205	adc = iio_priv(iio_dev);
206	adc->dev = &pdev->dev;
207	adc->rn5t618 = rn5t618;
208
209	if (rn5t618->irq_data)
210		adc->irq = regmap_irq_get_virq(rn5t618->irq_data,
211					       RN5T618_IRQ_ADC);
212
213	if (adc->irq <= 0) {
214		dev_err(&pdev->dev, "get virq failed\n");
215		return -EINVAL;
216	}
217
218	init_completion(&adc->conv_completion);
219
220	iio_dev->name = dev_name(&pdev->dev);
221	iio_dev->info = &rn5t618_adc_iio_info;
222	iio_dev->modes = INDIO_DIRECT_MODE;
223	iio_dev->channels = rn5t618_adc_iio_channels;
224	iio_dev->num_channels = ARRAY_SIZE(rn5t618_adc_iio_channels);
225
226	/* stop any auto-conversion */
227	ret = regmap_write(rn5t618->regmap, RN5T618_ADCCNT3, 0);
228	if (ret < 0)
229		return ret;
230
231	platform_set_drvdata(pdev, iio_dev);
232
233	ret = devm_request_threaded_irq(adc->dev, adc->irq, NULL,
234					rn5t618_adc_irq,
235					IRQF_ONESHOT, dev_name(adc->dev),
236					adc);
237	if (ret < 0) {
238		dev_err(adc->dev, "request irq %d failed: %d\n", adc->irq, ret);
239		return ret;
240	}
241
242	ret = devm_iio_map_array_register(adc->dev, iio_dev, rn5t618_maps);
243	if (ret < 0)
244		return ret;
245
246	return devm_iio_device_register(adc->dev, iio_dev);
247}
248
249static struct platform_driver rn5t618_adc_driver = {
250	.driver = {
251		.name   = "rn5t618-adc",
252	},
253	.probe = rn5t618_adc_probe,
254};
255
256module_platform_driver(rn5t618_adc_driver);
257MODULE_ALIAS("platform:rn5t618-adc");
258MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
259MODULE_LICENSE("GPL");