lp8788_adc.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * TI LP8788 MFD - ADC driver
  4 *
  5 * Copyright 2012 Texas Instruments
  6 *
  7 * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
  8 */
  9
 10#include <linux/delay.h>
 11#include <linux/iio/iio.h>
 12#include <linux/iio/driver.h>
 13#include <linux/iio/machine.h>
 14#include <linux/mfd/lp8788.h>
 15#include <linux/module.h>
 16#include <linux/mutex.h>
 17#include <linux/platform_device.h>
 18#include <linux/slab.h>
 19
 20/* register address */
 21#define LP8788_ADC_CONF			0x60
 22#define LP8788_ADC_RAW			0x61
 23#define LP8788_ADC_DONE			0x63
 24
 25#define ADC_CONV_START			1
 26
 27struct lp8788_adc {
 28	struct lp8788 *lp;
 29	const struct iio_map *map;
 30	struct mutex lock;
 31};
 32
 33static const int lp8788_scale[LPADC_MAX] = {
 34	[LPADC_VBATT_5P5] = 1343101,
 35	[LPADC_VIN_CHG]   = 3052503,
 36	[LPADC_IBATT]     = 610500,
 37	[LPADC_IC_TEMP]   = 61050,
 38	[LPADC_VBATT_6P0] = 1465201,
 39	[LPADC_VBATT_5P0] = 1221001,
 40	[LPADC_ADC1]      = 610500,
 41	[LPADC_ADC2]      = 610500,
 42	[LPADC_VDD]       = 1025641,
 43	[LPADC_VCOIN]     = 757020,
 44	[LPADC_ADC3]      = 610500,
 45	[LPADC_ADC4]      = 610500,
 46};
 47
 48static int lp8788_get_adc_result(struct lp8788_adc *adc, enum lp8788_adc_id id,
 49				int *val)
 50{
 51	unsigned int msb;
 52	unsigned int lsb;
 53	unsigned int result;
 54	u8 data;
 55	u8 rawdata[2];
 56	int size = ARRAY_SIZE(rawdata);
 57	int retry = 5;
 58	int ret;
 59
 60	data = (id << 1) | ADC_CONV_START;
 61	ret = lp8788_write_byte(adc->lp, LP8788_ADC_CONF, data);
 62	if (ret)
 63		goto err_io;
 64
 65	/* retry until adc conversion is done */
 66	data = 0;
 67	while (retry--) {
 68		usleep_range(100, 200);
 69
 70		ret = lp8788_read_byte(adc->lp, LP8788_ADC_DONE, &data);
 71		if (ret)
 72			goto err_io;
 73
 74		/* conversion done */
 75		if (data)
 76			break;
 77	}
 78
 79	ret = lp8788_read_multi_bytes(adc->lp, LP8788_ADC_RAW, rawdata, size);
 80	if (ret)
 81		goto err_io;
 82
 83	msb = (rawdata[0] << 4) & 0x00000ff0;
 84	lsb = (rawdata[1] >> 4) & 0x0000000f;
 85	result = msb | lsb;
 86	*val = result;
 87
 88	return 0;
 89
 90err_io:
 91	return ret;
 92}
 93
 94static int lp8788_adc_read_raw(struct iio_dev *indio_dev,
 95			struct iio_chan_spec const *chan,
 96			int *val, int *val2, long mask)
 97{
 98	struct lp8788_adc *adc = iio_priv(indio_dev);
 99	enum lp8788_adc_id id = chan->channel;
100	int ret;
101
102	mutex_lock(&adc->lock);
103
104	switch (mask) {
105	case IIO_CHAN_INFO_RAW:
106		ret = lp8788_get_adc_result(adc, id, val) ? -EIO : IIO_VAL_INT;
107		break;
108	case IIO_CHAN_INFO_SCALE:
109		*val = lp8788_scale[id] / 1000000;
110		*val2 = lp8788_scale[id] % 1000000;
111		ret = IIO_VAL_INT_PLUS_MICRO;
112		break;
113	default:
114		ret = -EINVAL;
115		break;
116	}
117
118	mutex_unlock(&adc->lock);
119
120	return ret;
121}
122
123static const struct iio_info lp8788_adc_info = {
124	.read_raw = &lp8788_adc_read_raw,
125};
126
127#define LP8788_CHAN(_id, _type) {				\
128		.type = _type,					\
129		.indexed = 1,					\
130		.channel = LPADC_##_id,				\
131		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
132			BIT(IIO_CHAN_INFO_SCALE),		\
133		.datasheet_name = #_id,				\
134}
135
136static const struct iio_chan_spec lp8788_adc_channels[] = {
137	[LPADC_VBATT_5P5] = LP8788_CHAN(VBATT_5P5, IIO_VOLTAGE),
138	[LPADC_VIN_CHG]   = LP8788_CHAN(VIN_CHG, IIO_VOLTAGE),
139	[LPADC_IBATT]     = LP8788_CHAN(IBATT, IIO_CURRENT),
140	[LPADC_IC_TEMP]   = LP8788_CHAN(IC_TEMP, IIO_TEMP),
141	[LPADC_VBATT_6P0] = LP8788_CHAN(VBATT_6P0, IIO_VOLTAGE),
142	[LPADC_VBATT_5P0] = LP8788_CHAN(VBATT_5P0, IIO_VOLTAGE),
143	[LPADC_ADC1]      = LP8788_CHAN(ADC1, IIO_VOLTAGE),
144	[LPADC_ADC2]      = LP8788_CHAN(ADC2, IIO_VOLTAGE),
145	[LPADC_VDD]       = LP8788_CHAN(VDD, IIO_VOLTAGE),
146	[LPADC_VCOIN]     = LP8788_CHAN(VCOIN, IIO_VOLTAGE),
147	[LPADC_ADC3]      = LP8788_CHAN(ADC3, IIO_VOLTAGE),
148	[LPADC_ADC4]      = LP8788_CHAN(ADC4, IIO_VOLTAGE),
149};
150
151/* default maps used by iio consumer (lp8788-charger driver) */
152static const struct iio_map lp8788_default_iio_maps[] = {
153	IIO_MAP("VBATT_5P0", "lp8788-charger", "lp8788_vbatt_5p0"),
154	IIO_MAP("ADC1", "lp8788-charger", "lp8788_adc1"),
155	{ }
156};
157
158static int lp8788_iio_map_register(struct device *dev,
159				struct iio_dev *indio_dev,
160				struct lp8788_platform_data *pdata,
161				struct lp8788_adc *adc)
162{
163	const struct iio_map *map;
164	int ret;
165
166	map = (!pdata || !pdata->adc_pdata) ?
167		lp8788_default_iio_maps : pdata->adc_pdata;
168
169	ret = devm_iio_map_array_register(dev, indio_dev, map);
170	if (ret) {
171		dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
172		return ret;
173	}
174
175	adc->map = map;
176	return 0;
177}
178
179static int lp8788_adc_probe(struct platform_device *pdev)
180{
181	struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
182	struct iio_dev *indio_dev;
183	struct lp8788_adc *adc;
184	int ret;
185
186	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
187	if (!indio_dev)
188		return -ENOMEM;
189
190	adc = iio_priv(indio_dev);
191	adc->lp = lp;
192
193	ret = lp8788_iio_map_register(&pdev->dev, indio_dev, lp->pdata, adc);
194	if (ret)
195		return ret;
196
197	mutex_init(&adc->lock);
198
199	indio_dev->name = pdev->name;
200	indio_dev->modes = INDIO_DIRECT_MODE;
201	indio_dev->info = &lp8788_adc_info;
202	indio_dev->channels = lp8788_adc_channels;
203	indio_dev->num_channels = ARRAY_SIZE(lp8788_adc_channels);
204
205	return devm_iio_device_register(&pdev->dev, indio_dev);
206}
207
208static struct platform_driver lp8788_adc_driver = {
209	.probe = lp8788_adc_probe,
210	.driver = {
211		.name = LP8788_DEV_ADC,
212	},
213};
214module_platform_driver(lp8788_adc_driver);
215
216MODULE_DESCRIPTION("Texas Instruments LP8788 ADC Driver");
217MODULE_AUTHOR("Milo Kim");
218MODULE_LICENSE("GPL");
219MODULE_ALIAS("platform:lp8788-adc");