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/slab.h>
 20
 21#define RN5T618_ADC_CONVERSION_TIMEOUT   (msecs_to_jiffies(500))
 22#define RN5T618_REFERENCE_VOLT 2500
 23
 24/* mask for selecting channels for single conversion */
 25#define RN5T618_ADCCNT3_CHANNEL_MASK 0x7
 26/* average 4-time conversion mode */
 27#define RN5T618_ADCCNT3_AVG BIT(3)
 28/* set for starting a single conversion, gets cleared by hw when done */
 29#define RN5T618_ADCCNT3_GODONE BIT(4)
 30/* automatic conversion, period is in ADCCNT2, selected channels are
 31 * in ADCCNT1
 32 */
 33#define RN5T618_ADCCNT3_AUTO BIT(5)
 34#define RN5T618_ADCEND_IRQ BIT(0)
 35
 36struct rn5t618_adc_data {
 37	struct device *dev;
 38	struct rn5t618 *rn5t618;
 39	struct completion conv_completion;
 40	int irq;
 41};
 42
 43struct rn5t618_channel_ratios {
 44	u16 numerator;
 45	u16 denominator;
 46};
 47
 48enum rn5t618_channels {
 49	LIMMON = 0,
 50	VBAT,
 51	VADP,
 52	VUSB,
 53	VSYS,
 54	VTHM,
 55	AIN1,
 56	AIN0
 57};
 58
 59static const struct rn5t618_channel_ratios rn5t618_ratios[8] = {
 60	[LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
 61	[VBAT] = {2, 1},
 62	[VADP] = {3, 1},
 63	[VUSB] = {3, 1},
 64	[VSYS] = {3, 1},
 65	[VTHM] = {1, 1},
 66	[AIN1] = {1, 1},
 67	[AIN0] = {1, 1},
 68};
 69
 70static int rn5t618_read_adc_reg(struct rn5t618 *rn5t618, int reg, u16 *val)
 71{
 72	u8 data[2];
 73	int ret;
 74
 75	ret = regmap_bulk_read(rn5t618->regmap, reg, data, sizeof(data));
 76	if (ret < 0)
 77		return ret;
 78
 79	*val = (data[0] << 4) | (data[1] & 0xF);
 80
 81	return 0;
 82}
 83
 84static irqreturn_t rn5t618_adc_irq(int irq, void *data)
 85{
 86	struct rn5t618_adc_data *adc = data;
 87	unsigned int r = 0;
 88	int ret;
 89
 90	/* clear low & high threshold irqs */
 91	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC1, 0);
 92	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC2, 0);
 93
 94	ret = regmap_read(adc->rn5t618->regmap, RN5T618_IR_ADC3, &r);
 95	if (ret < 0)
 96		dev_err(adc->dev, "failed to read IRQ status: %d\n", ret);
 97
 98	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC3, 0);
 99
100	if (r & RN5T618_ADCEND_IRQ)
101		complete(&adc->conv_completion);
102
103	return IRQ_HANDLED;
104}
105
106static int rn5t618_adc_read(struct iio_dev *iio_dev,
107			    const struct iio_chan_spec *chan,
108			    int *val, int *val2, long mask)
109{
110	struct rn5t618_adc_data *adc = iio_priv(iio_dev);
111	u16 raw;
112	int ret;
113
114	if (mask == IIO_CHAN_INFO_SCALE) {
115		*val = RN5T618_REFERENCE_VOLT *
116		       rn5t618_ratios[chan->channel].numerator;
117		*val2 = rn5t618_ratios[chan->channel].denominator * 4095;
118
119		return IIO_VAL_FRACTIONAL;
120	}
121
122	/* select channel */
123	ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
124				 RN5T618_ADCCNT3_CHANNEL_MASK,
125				 chan->channel);
126	if (ret < 0)
127		return ret;
128
129	ret = regmap_write(adc->rn5t618->regmap, RN5T618_EN_ADCIR3,
130			   RN5T618_ADCEND_IRQ);
131	if (ret < 0)
132		return ret;
133
134	ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
135				 RN5T618_ADCCNT3_AVG,
136				 mask == IIO_CHAN_INFO_AVERAGE_RAW ?
137				 RN5T618_ADCCNT3_AVG : 0);
138	if (ret < 0)
139		return ret;
140
141	init_completion(&adc->conv_completion);
142	/* single conversion */
143	ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
144				 RN5T618_ADCCNT3_GODONE,
145				 RN5T618_ADCCNT3_GODONE);
146	if (ret < 0)
147		return ret;
148
149	ret = wait_for_completion_timeout(&adc->conv_completion,
150					  RN5T618_ADC_CONVERSION_TIMEOUT);
151	if (ret == 0) {
152		dev_warn(adc->dev, "timeout waiting for adc result\n");
153		return -ETIMEDOUT;
154	}
155
156	ret = rn5t618_read_adc_reg(adc->rn5t618,
157				   RN5T618_ILIMDATAH + 2 * chan->channel,
158				   &raw);
159	if (ret < 0)
160		return ret;
161
162	*val = raw;
163
164	return IIO_VAL_INT;
165}
166
167static const struct iio_info rn5t618_adc_iio_info = {
168	.read_raw = &rn5t618_adc_read,
169};
170
171#define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
172	.type = _type, \
173	.channel = _channel, \
174	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
175			      BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
176			      BIT(IIO_CHAN_INFO_SCALE), \
177	.datasheet_name = _name, \
178	.indexed = 1. \
179}
180
181static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
182	RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
183	RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
184	RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
185	RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
186	RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
187	RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
188	RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
189	RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
190};
191
192static int rn5t618_adc_probe(struct platform_device *pdev)
193{
194	int ret;
195	struct iio_dev *iio_dev;
196	struct rn5t618_adc_data *adc;
197	struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
198
199	iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
200	if (!iio_dev) {
201		dev_err(&pdev->dev, "failed allocating iio device\n");
202		return -ENOMEM;
203	}
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	return devm_iio_device_register(adc->dev, iio_dev);
243}
244
245static struct platform_driver rn5t618_adc_driver = {
246	.driver = {
247		.name   = "rn5t618-adc",
248	},
249	.probe = rn5t618_adc_probe,
250};
251
252module_platform_driver(rn5t618_adc_driver);
253MODULE_ALIAS("platform:rn5t618-adc");
254MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
255MODULE_LICENSE("GPL");