max517.c

  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/* Commands */
 19#define COMMAND_CHANNEL0	0x00
 20#define COMMAND_CHANNEL1	0x01 /* for MAX518 and MAX519 */
 21#define COMMAND_PD		0x08 /* Power Down */
 22
 23enum max517_device_ids {
 24	ID_MAX517,
 25	ID_MAX518,
 26	ID_MAX519,
 27	ID_MAX520,
 28	ID_MAX521,
 29};
 30
 31struct max517_data {
 32	struct i2c_client	*client;
 33	unsigned short		vref_mv[8];
 34};
 35
 36/*
 37 * channel: bit 0: channel 1
 38 *          bit 1: channel 2
 39 * (this way, it's possible to set both channels at once)
 40 */
 41static int max517_set_value(struct iio_dev *indio_dev,
 42	long val, int channel)
 43{
 44	struct max517_data *data = iio_priv(indio_dev);
 45	struct i2c_client *client = data->client;
 46	u8 outbuf[2];
 47	int res;
 48
 49	if (val < 0 || val > 255)
 50		return -EINVAL;
 51
 52	outbuf[0] = channel;
 53	outbuf[1] = val;
 54
 55	res = i2c_master_send(client, outbuf, 2);
 56	if (res < 0)
 57		return res;
 58	else if (res != 2)
 59		return -EIO;
 60	else
 61		return 0;
 62}
 63
 64static int max517_read_raw(struct iio_dev *indio_dev,
 65			   struct iio_chan_spec const *chan,
 66			   int *val,
 67			   int *val2,
 68			   long m)
 69{
 70	struct max517_data *data = iio_priv(indio_dev);
 71
 72	switch (m) {
 73	case IIO_CHAN_INFO_SCALE:
 74		/* Corresponds to Vref / 2^(bits) */
 75		*val = data->vref_mv[chan->channel];
 76		*val2 = 8;
 77		return IIO_VAL_FRACTIONAL_LOG2;
 78	default:
 79		break;
 80	}
 81	return -EINVAL;
 82}
 83
 84static int max517_write_raw(struct iio_dev *indio_dev,
 85	struct iio_chan_spec const *chan, int val, int val2, long mask)
 86{
 87	int ret;
 88
 89	switch (mask) {
 90	case IIO_CHAN_INFO_RAW:
 91		ret = max517_set_value(indio_dev, val, chan->channel);
 92		break;
 93	default:
 94		ret = -EINVAL;
 95		break;
 96	}
 97
 98	return ret;
 99}
100
101static int max517_suspend(struct device *dev)
102{
103	u8 outbuf = COMMAND_PD;
104
105	return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
106}
107
108static int max517_resume(struct device *dev)
109{
110	u8 outbuf = 0;
111
112	return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
113}
114
115static DEFINE_SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
116
117static const struct iio_info max517_info = {
118	.read_raw = max517_read_raw,
119	.write_raw = max517_write_raw,
120};
121
122#define MAX517_CHANNEL(chan) {				\
123	.type = IIO_VOLTAGE,				\
124	.indexed = 1,					\
125	.output = 1,					\
126	.channel = (chan),				\
127	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
128	BIT(IIO_CHAN_INFO_SCALE),			\
129}
130
131static const struct iio_chan_spec max517_channels[] = {
132	MAX517_CHANNEL(0),
133	MAX517_CHANNEL(1),
134	MAX517_CHANNEL(2),
135	MAX517_CHANNEL(3),
136	MAX517_CHANNEL(4),
137	MAX517_CHANNEL(5),
138	MAX517_CHANNEL(6),
139	MAX517_CHANNEL(7),
140};
141
142static int max517_probe(struct i2c_client *client)
143{
144	const struct max517_platform_data *platform_data = dev_get_platdata(&client->dev);
145	const struct i2c_device_id *id = i2c_client_get_device_id(client);
146	struct max517_data *data;
147	struct iio_dev *indio_dev;
148	int chan;
149
150	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
151	if (!indio_dev)
152		return -ENOMEM;
153	data = iio_priv(indio_dev);
154	data->client = client;
155
156	switch (id->driver_data) {
157	case ID_MAX521:
158		indio_dev->num_channels = 8;
159		break;
160	case ID_MAX520:
161		indio_dev->num_channels = 4;
162		break;
163	case ID_MAX519:
164	case ID_MAX518:
165		indio_dev->num_channels = 2;
166		break;
167	default:  /* single channel for MAX517 */
168		indio_dev->num_channels = 1;
169		break;
170	}
171	indio_dev->channels = max517_channels;
172	indio_dev->modes = INDIO_DIRECT_MODE;
173	indio_dev->info = &max517_info;
174
175	/*
176	 * Reference voltage on MAX518 and default is 5V, else take vref_mv
177	 * from platform_data
178	 */
179	for (chan = 0; chan < indio_dev->num_channels; chan++) {
180		if (id->driver_data == ID_MAX518 || !platform_data)
181			data->vref_mv[chan] = 5000; /* mV */
182		else
183			data->vref_mv[chan] = platform_data->vref_mv[chan];
184	}
185
186	return devm_iio_device_register(&client->dev, indio_dev);
187}
188
189static const struct i2c_device_id max517_id[] = {
190	{ "max517", ID_MAX517 },
191	{ "max518", ID_MAX518 },
192	{ "max519", ID_MAX519 },
193	{ "max520", ID_MAX520 },
194	{ "max521", ID_MAX521 },
195	{ }
196};
197MODULE_DEVICE_TABLE(i2c, max517_id);
198
199static struct i2c_driver max517_driver = {
200	.driver = {
201		.name	= "max517",
202		.pm	= pm_sleep_ptr(&max517_pm_ops),
203	},
204	.probe		= max517_probe,
205	.id_table	= max517_id,
206};
207module_i2c_driver(max517_driver);
208
209MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
210MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
211MODULE_LICENSE("GPL");