1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *  max517.c - Support for Maxim MAX517, MAX518 and MAX519
  4 *
  5 *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
  6 */
  7
  8#include <linux/module.h>
  9#include <linux/slab.h>
 10#include <linux/jiffies.h>
 11#include <linux/i2c.h>
 12#include <linux/err.h>
 13
 14#include <linux/iio/iio.h>
 15#include <linux/iio/sysfs.h>
 16#include <linux/iio/dac/max517.h>
 17
 18#define MAX517_DRV_NAME	"max517"
 19
 20/* Commands */
 21#define COMMAND_CHANNEL0	0x00
 22#define COMMAND_CHANNEL1	0x01 /* for MAX518 and MAX519 */
 23#define COMMAND_PD		0x08 /* Power Down */
 24
 25enum max517_device_ids {
 26	ID_MAX517,
 27	ID_MAX518,
 28	ID_MAX519,
 29	ID_MAX520,
 30	ID_MAX521,
 31};
 32
 33struct max517_data {
 34	struct i2c_client	*client;
 35	unsigned short		vref_mv[8];
 36};
 37
 38/*
 39 * channel: bit 0: channel 1
 40 *          bit 1: channel 2
 41 * (this way, it's possible to set both channels at once)
 42 */
 43static int max517_set_value(struct iio_dev *indio_dev,
 44	long val, int channel)
 45{
 46	struct max517_data *data = iio_priv(indio_dev);
 47	struct i2c_client *client = data->client;
 48	u8 outbuf[2];
 49	int res;
 50
 51	if (val < 0 || val > 255)
 52		return -EINVAL;
 53
 54	outbuf[0] = channel;
 55	outbuf[1] = val;
 56
 57	res = i2c_master_send(client, outbuf, 2);
 58	if (res < 0)
 59		return res;
 60	else if (res != 2)
 61		return -EIO;
 62	else
 63		return 0;
 64}
 65
 66static int max517_read_raw(struct iio_dev *indio_dev,
 67			   struct iio_chan_spec const *chan,
 68			   int *val,
 69			   int *val2,
 70			   long m)
 71{
 72	struct max517_data *data = iio_priv(indio_dev);
 73
 74	switch (m) {
 75	case IIO_CHAN_INFO_SCALE:
 76		/* Corresponds to Vref / 2^(bits) */
 77		*val = data->vref_mv[chan->channel];
 78		*val2 = 8;
 79		return IIO_VAL_FRACTIONAL_LOG2;
 80	default:
 81		break;
 82	}
 83	return -EINVAL;
 84}
 85
 86static int max517_write_raw(struct iio_dev *indio_dev,
 87	struct iio_chan_spec const *chan, int val, int val2, long mask)
 88{
 89	int ret;
 90
 91	switch (mask) {
 92	case IIO_CHAN_INFO_RAW:
 93		ret = max517_set_value(indio_dev, val, chan->channel);
 94		break;
 95	default:
 96		ret = -EINVAL;
 97		break;
 98	}
 99
100	return ret;
101}
102
103static int __maybe_unused max517_suspend(struct device *dev)
104{
105	u8 outbuf = COMMAND_PD;
106
107	return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
108}
109
110static int __maybe_unused max517_resume(struct device *dev)
111{
112	u8 outbuf = 0;
113
114	return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
115}
116
117static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
118
119static const struct iio_info max517_info = {
120	.read_raw = max517_read_raw,
121	.write_raw = max517_write_raw,
122};
123
124#define MAX517_CHANNEL(chan) {				\
125	.type = IIO_VOLTAGE,				\
126	.indexed = 1,					\
127	.output = 1,					\
128	.channel = (chan),				\
129	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
130	BIT(IIO_CHAN_INFO_SCALE),			\
131}
132
133static const struct iio_chan_spec max517_channels[] = {
134	MAX517_CHANNEL(0),
135	MAX517_CHANNEL(1),
136	MAX517_CHANNEL(2),
137	MAX517_CHANNEL(3),
138	MAX517_CHANNEL(4),
139	MAX517_CHANNEL(5),
140	MAX517_CHANNEL(6),
141	MAX517_CHANNEL(7),
142};
143
144static int max517_probe(struct i2c_client *client,
145			const struct i2c_device_id *id)
146{
147	struct max517_data *data;
148	struct iio_dev *indio_dev;
149	struct max517_platform_data *platform_data = client->dev.platform_data;
150	int chan;
151
152	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
153	if (!indio_dev)
154		return -ENOMEM;
155	data = iio_priv(indio_dev);
156	i2c_set_clientdata(client, indio_dev);
157	data->client = client;
158
159	switch (id->driver_data) {
160	case ID_MAX521:
161		indio_dev->num_channels = 8;
162		break;
163	case ID_MAX520:
164		indio_dev->num_channels = 4;
165		break;
166	case ID_MAX519:
167	case ID_MAX518:
168		indio_dev->num_channels = 2;
169		break;
170	default:  /* single channel for MAX517 */
171		indio_dev->num_channels = 1;
172		break;
173	}
174	indio_dev->channels = max517_channels;
175	indio_dev->modes = INDIO_DIRECT_MODE;
176	indio_dev->info = &max517_info;
177
178	/*
179	 * Reference voltage on MAX518 and default is 5V, else take vref_mv
180	 * from platform_data
181	 */
182	for (chan = 0; chan < indio_dev->num_channels; chan++) {
183		if (id->driver_data == ID_MAX518 || !platform_data)
184			data->vref_mv[chan] = 5000; /* mV */
185		else
186			data->vref_mv[chan] = platform_data->vref_mv[chan];
187	}
188
189	return iio_device_register(indio_dev);
190}
191
192static int max517_remove(struct i2c_client *client)
193{
194	iio_device_unregister(i2c_get_clientdata(client));
195	return 0;
196}
197
198static const struct i2c_device_id max517_id[] = {
199	{ "max517", ID_MAX517 },
200	{ "max518", ID_MAX518 },
201	{ "max519", ID_MAX519 },
202	{ "max520", ID_MAX520 },
203	{ "max521", ID_MAX521 },
204	{ }
205};
206MODULE_DEVICE_TABLE(i2c, max517_id);
207
208static struct i2c_driver max517_driver = {
209	.driver = {
210		.name	= MAX517_DRV_NAME,
211		.pm	= &max517_pm_ops,
212	},
213	.probe		= max517_probe,
214	.remove		= max517_remove,
215	.id_table	= max517_id,
216};
217module_i2c_driver(max517_driver);
218
219MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
220MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
221MODULE_LICENSE("GPL");