1/*
2 * TI LP8788 MFD - ADC driver
3 *
4 * Copyright 2012 Texas Instruments
5 *
6 * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/delay.h>
14#include <linux/iio/iio.h>
15#include <linux/iio/driver.h>
16#include <linux/iio/machine.h>
17#include <linux/mfd/lp8788.h>
18#include <linux/module.h>
19#include <linux/mutex.h>
20#include <linux/platform_device.h>
21#include <linux/slab.h>
22
23/* register address */
24#define LP8788_ADC_CONF			0x60
25#define LP8788_ADC_RAW			0x61
26#define LP8788_ADC_DONE			0x63
27
28#define ADC_CONV_START			1
29
30struct lp8788_adc {
31	struct lp8788 *lp;
32	struct iio_map *map;
33	struct mutex lock;
34};
35
36static const int lp8788_scale[LPADC_MAX] = {
37	[LPADC_VBATT_5P5] = 1343101,
38	[LPADC_VIN_CHG]   = 3052503,
39	[LPADC_IBATT]     = 610500,
40	[LPADC_IC_TEMP]   = 61050,
41	[LPADC_VBATT_6P0] = 1465201,
42	[LPADC_VBATT_5P0] = 1221001,
43	[LPADC_ADC1]      = 610500,
44	[LPADC_ADC2]      = 610500,
45	[LPADC_VDD]       = 1025641,
46	[LPADC_VCOIN]     = 757020,
47	[LPADC_ADC3]      = 610500,
48	[LPADC_ADC4]      = 610500,
49};
50
51static int lp8788_get_adc_result(struct lp8788_adc *adc, enum lp8788_adc_id id,
52				int *val)
53{
54	unsigned int msb;
55	unsigned int lsb;
56	unsigned int result;
57	u8 data;
58	u8 rawdata[2];
59	int size = ARRAY_SIZE(rawdata);
60	int retry = 5;
61	int ret;
62
63	data = (id << 1) | ADC_CONV_START;
64	ret = lp8788_write_byte(adc->lp, LP8788_ADC_CONF, data);
65	if (ret)
66		goto err_io;
67
68	/* retry until adc conversion is done */
69	data = 0;
70	while (retry--) {
71		usleep_range(100, 200);
72
73		ret = lp8788_read_byte(adc->lp, LP8788_ADC_DONE, &data);
74		if (ret)
75			goto err_io;
76
77		/* conversion done */
78		if (data)
79			break;
80	}
81
82	ret = lp8788_read_multi_bytes(adc->lp, LP8788_ADC_RAW, rawdata, size);
83	if (ret)
84		goto err_io;
85
86	msb = (rawdata[0] << 4) & 0x00000ff0;
87	lsb = (rawdata[1] >> 4) & 0x0000000f;
88	result = msb | lsb;
89	*val = result;
90
91	return 0;
92
93err_io:
94	return ret;
95}
96
97static int lp8788_adc_read_raw(struct iio_dev *indio_dev,
98			struct iio_chan_spec const *chan,
99			int *val, int *val2, long mask)
100{
101	struct lp8788_adc *adc = iio_priv(indio_dev);
102	enum lp8788_adc_id id = chan->channel;
103	int ret;
104
105	mutex_lock(&adc->lock);
106
107	switch (mask) {
108	case IIO_CHAN_INFO_RAW:
109		ret = lp8788_get_adc_result(adc, id, val) ? -EIO : IIO_VAL_INT;
110		break;
111	case IIO_CHAN_INFO_SCALE:
112		*val = lp8788_scale[id] / 1000000;
113		*val2 = lp8788_scale[id] % 1000000;
114		ret = IIO_VAL_INT_PLUS_MICRO;
115		break;
116	default:
117		ret = -EINVAL;
118		break;
119	}
120
121	mutex_unlock(&adc->lock);
122
123	return ret;
124}
125
126static const struct iio_info lp8788_adc_info = {
127	.read_raw = &lp8788_adc_read_raw,
128	.driver_module = THIS_MODULE,
129};
130
131#define LP8788_CHAN(_id, _type) {				\
132		.type = _type,					\
133		.indexed = 1,					\
134		.channel = LPADC_##_id,				\
135		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
136			BIT(IIO_CHAN_INFO_SCALE),		\
137		.datasheet_name = #_id,				\
138}
139
140static const struct iio_chan_spec lp8788_adc_channels[] = {
141	[LPADC_VBATT_5P5] = LP8788_CHAN(VBATT_5P5, IIO_VOLTAGE),
142	[LPADC_VIN_CHG]   = LP8788_CHAN(VIN_CHG, IIO_VOLTAGE),
143	[LPADC_IBATT]     = LP8788_CHAN(IBATT, IIO_CURRENT),
144	[LPADC_IC_TEMP]   = LP8788_CHAN(IC_TEMP, IIO_TEMP),
145	[LPADC_VBATT_6P0] = LP8788_CHAN(VBATT_6P0, IIO_VOLTAGE),
146	[LPADC_VBATT_5P0] = LP8788_CHAN(VBATT_5P0, IIO_VOLTAGE),
147	[LPADC_ADC1]      = LP8788_CHAN(ADC1, IIO_VOLTAGE),
148	[LPADC_ADC2]      = LP8788_CHAN(ADC2, IIO_VOLTAGE),
149	[LPADC_VDD]       = LP8788_CHAN(VDD, IIO_VOLTAGE),
150	[LPADC_VCOIN]     = LP8788_CHAN(VCOIN, IIO_VOLTAGE),
151	[LPADC_ADC3]      = LP8788_CHAN(ADC3, IIO_VOLTAGE),
152	[LPADC_ADC4]      = LP8788_CHAN(ADC4, IIO_VOLTAGE),
153};
154
155/* default maps used by iio consumer (lp8788-charger driver) */
156static struct iio_map lp8788_default_iio_maps[] = {
157	{
158		.consumer_dev_name = "lp8788-charger",
159		.consumer_channel = "lp8788_vbatt_5p0",
160		.adc_channel_label = "VBATT_5P0",
161	},
162	{
163		.consumer_dev_name = "lp8788-charger",
164		.consumer_channel = "lp8788_adc1",
165		.adc_channel_label = "ADC1",
166	},
167	{ }
168};
169
170static int lp8788_iio_map_register(struct iio_dev *indio_dev,
171				struct lp8788_platform_data *pdata,
172				struct lp8788_adc *adc)
173{
174	struct iio_map *map;
175	int ret;
176
177	map = (!pdata || !pdata->adc_pdata) ?
178		lp8788_default_iio_maps : pdata->adc_pdata;
179
180	ret = iio_map_array_register(indio_dev, map);
181	if (ret) {
182		dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
183		return ret;
184	}
185
186	adc->map = map;
187	return 0;
188}
189
190static int lp8788_adc_probe(struct platform_device *pdev)
191{
192	struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
193	struct iio_dev *indio_dev;
194	struct lp8788_adc *adc;
195	int ret;
196
197	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
198	if (!indio_dev)
199		return -ENOMEM;
200
201	adc = iio_priv(indio_dev);
202	adc->lp = lp;
203	platform_set_drvdata(pdev, indio_dev);
204
205	indio_dev->dev.of_node = pdev->dev.of_node;
206	ret = lp8788_iio_map_register(indio_dev, lp->pdata, adc);
207	if (ret)
208		return ret;
209
210	mutex_init(&adc->lock);
211
212	indio_dev->dev.parent = &pdev->dev;
213	indio_dev->name = pdev->name;
214	indio_dev->modes = INDIO_DIRECT_MODE;
215	indio_dev->info = &lp8788_adc_info;
216	indio_dev->channels = lp8788_adc_channels;
217	indio_dev->num_channels = ARRAY_SIZE(lp8788_adc_channels);
218
219	ret = iio_device_register(indio_dev);
220	if (ret) {
221		dev_err(&pdev->dev, "iio dev register err: %d\n", ret);
222		goto err_iio_device;
223	}
224
225	return 0;
226
227err_iio_device:
228	iio_map_array_unregister(indio_dev);
229	return ret;
230}
231
232static int lp8788_adc_remove(struct platform_device *pdev)
233{
234	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
235
236	iio_device_unregister(indio_dev);
237	iio_map_array_unregister(indio_dev);
238
239	return 0;
240}
241
242static struct platform_driver lp8788_adc_driver = {
243	.probe = lp8788_adc_probe,
244	.remove = lp8788_adc_remove,
245	.driver = {
246		.name = LP8788_DEV_ADC,
247	},
248};
249module_platform_driver(lp8788_adc_driver);
250
251MODULE_DESCRIPTION("Texas Instruments LP8788 ADC Driver");
252MODULE_AUTHOR("Milo Kim");
253MODULE_LICENSE("GPL");
254MODULE_ALIAS("platform:lp8788-adc");
255