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_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
141				 RN5T618_ADCCNT3_GODONE,
142				 RN5T618_ADCCNT3_GODONE);
143	if (ret < 0)
144		return ret;
145
146	ret = wait_for_completion_timeout(&adc->conv_completion,
147					  RN5T618_ADC_CONVERSION_TIMEOUT);
148	if (ret == 0) {
149		dev_warn(adc->dev, "timeout waiting for adc result\n");
150		return -ETIMEDOUT;
151	}
152
153	ret = rn5t618_read_adc_reg(adc->rn5t618,
154				   RN5T618_ILIMDATAH + 2 * chan->channel,
155				   &raw);
156	if (ret < 0)
157		return ret;
158
159	*val = raw;
160
161	return IIO_VAL_INT;
162}
163
164static const struct iio_info rn5t618_adc_iio_info = {
165	.read_raw = &rn5t618_adc_read,
166};
167
168#define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
169	.type = _type, \
170	.channel = _channel, \
171	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
172			      BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
173			      BIT(IIO_CHAN_INFO_SCALE), \
174	.datasheet_name = _name, \
175	.indexed = 1. \
176}
177
178static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
179	RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
180	RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
181	RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
182	RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
183	RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
184	RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
185	RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
186	RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
187};
188
189static struct iio_map rn5t618_maps[] = {
190	IIO_MAP("VADP", "rn5t618-power", "vadp"),
191	IIO_MAP("VUSB", "rn5t618-power", "vusb"),
192	{ /* sentinel */ }
193};
194
195static int rn5t618_adc_probe(struct platform_device *pdev)
196{
197	int ret;
198	struct iio_dev *iio_dev;
199	struct rn5t618_adc_data *adc;
200	struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
201
202	iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
203	if (!iio_dev) {
204		dev_err(&pdev->dev, "failed allocating iio device\n");
205		return -ENOMEM;
206	}
207
208	adc = iio_priv(iio_dev);
209	adc->dev = &pdev->dev;
210	adc->rn5t618 = rn5t618;
211
212	if (rn5t618->irq_data)
213		adc->irq = regmap_irq_get_virq(rn5t618->irq_data,
214					       RN5T618_IRQ_ADC);
215
216	if (adc->irq <= 0) {
217		dev_err(&pdev->dev, "get virq failed\n");
218		return -EINVAL;
219	}
220
221	init_completion(&adc->conv_completion);
222
223	iio_dev->name = dev_name(&pdev->dev);
224	iio_dev->info = &rn5t618_adc_iio_info;
225	iio_dev->modes = INDIO_DIRECT_MODE;
226	iio_dev->channels = rn5t618_adc_iio_channels;
227	iio_dev->num_channels = ARRAY_SIZE(rn5t618_adc_iio_channels);
228
229	/* stop any auto-conversion */
230	ret = regmap_write(rn5t618->regmap, RN5T618_ADCCNT3, 0);
231	if (ret < 0)
232		return ret;
233
234	platform_set_drvdata(pdev, iio_dev);
235
236	ret = devm_request_threaded_irq(adc->dev, adc->irq, NULL,
237					rn5t618_adc_irq,
238					IRQF_ONESHOT, dev_name(adc->dev),
239					adc);
240	if (ret < 0) {
241		dev_err(adc->dev, "request irq %d failed: %d\n", adc->irq, ret);
242		return ret;
243	}
244
245	ret = devm_iio_map_array_register(adc->dev, iio_dev, rn5t618_maps);
246	if (ret < 0)
247		return ret;
248
249	return devm_iio_device_register(adc->dev, iio_dev);
250}
251
252static struct platform_driver rn5t618_adc_driver = {
253	.driver = {
254		.name   = "rn5t618-adc",
255	},
256	.probe = rn5t618_adc_probe,
257};
258
259module_platform_driver(rn5t618_adc_driver);
260MODULE_ALIAS("platform:rn5t618-adc");
261MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
262MODULE_LICENSE("GPL");
263