1 // SPDX-License-Identifier: GPL-2.0
3 * DAC7612 Dual, 12-Bit Serial input Digital-to-Analog Converter
5 * Copyright 2019 Qtechnology A/S
6 * 2019 Ricardo Ribalda <ribalda@kernel.org>
8 * Licensed under the GPL-2.
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/spi/spi.h>
13 #include <linux/gpio/consumer.h>
14 #include <linux/iio/iio.h>
16 #define DAC7612_RESOLUTION 12
17 #define DAC7612_ADDRESS 4
18 #define DAC7612_START 5
21 struct spi_device *spi;
22 struct gpio_desc *loaddacs;
26 * DMA (thus cache coherency maintenance) requires the
27 * transfer buffers to live in their own cache lines.
29 uint8_t data[2] ____cacheline_aligned;
32 static int dac7612_cmd_single(struct dac7612 *priv, int channel, u16 val)
36 priv->data[0] = BIT(DAC7612_START) | (channel << DAC7612_ADDRESS);
37 priv->data[0] |= val >> 8;
38 priv->data[1] = val & 0xff;
40 priv->cache[channel] = val;
42 ret = spi_write(priv->spi, priv->data, sizeof(priv->data));
46 gpiod_set_value(priv->loaddacs, 1);
47 gpiod_set_value(priv->loaddacs, 0);
52 #define dac7612_CHANNEL(chan, name) { \
53 .type = IIO_VOLTAGE, \
57 .datasheet_name = name, \
58 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
59 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
62 static const struct iio_chan_spec dac7612_channels[] = {
63 dac7612_CHANNEL(0, "OUTA"),
64 dac7612_CHANNEL(1, "OUTB"),
67 static int dac7612_read_raw(struct iio_dev *iio_dev,
68 const struct iio_chan_spec *chan,
69 int *val, int *val2, long mask)
74 case IIO_CHAN_INFO_RAW:
75 priv = iio_priv(iio_dev);
76 *val = priv->cache[chan->channel];
79 case IIO_CHAN_INFO_SCALE:
88 static int dac7612_write_raw(struct iio_dev *iio_dev,
89 const struct iio_chan_spec *chan,
90 int val, int val2, long mask)
92 struct dac7612 *priv = iio_priv(iio_dev);
95 if (mask != IIO_CHAN_INFO_RAW)
98 if ((val >= BIT(DAC7612_RESOLUTION)) || val < 0 || val2)
101 if (val == priv->cache[chan->channel])
104 mutex_lock(&iio_dev->mlock);
105 ret = dac7612_cmd_single(priv, chan->channel, val);
106 mutex_unlock(&iio_dev->mlock);
111 static const struct iio_info dac7612_info = {
112 .read_raw = dac7612_read_raw,
113 .write_raw = dac7612_write_raw,
116 static int dac7612_probe(struct spi_device *spi)
118 struct iio_dev *iio_dev;
119 struct dac7612 *priv;
123 iio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
127 priv = iio_priv(iio_dev);
129 * LOADDACS pin can be controlled by the driver or externally.
130 * When controlled by the driver, the DAC value is updated after
132 * When the driver does not control the PIN, the user or an external
133 * event can change the value of all DACs by pulsing down the LOADDACs
136 priv->loaddacs = devm_gpiod_get_optional(&spi->dev, "ti,loaddacs",
138 if (IS_ERR(priv->loaddacs))
139 return PTR_ERR(priv->loaddacs);
141 spi_set_drvdata(spi, iio_dev);
142 iio_dev->info = &dac7612_info;
143 iio_dev->modes = INDIO_DIRECT_MODE;
144 iio_dev->channels = dac7612_channels;
145 iio_dev->num_channels = ARRAY_SIZE(priv->cache);
146 iio_dev->name = spi_get_device_id(spi)->name;
148 for (i = 0; i < ARRAY_SIZE(priv->cache); i++) {
149 ret = dac7612_cmd_single(priv, i, 0);
154 return devm_iio_device_register(&spi->dev, iio_dev);
157 static const struct spi_device_id dac7612_id[] = {
161 MODULE_DEVICE_TABLE(spi, dac7612_id);
163 static const struct of_device_id dac7612_of_match[] = {
164 { .compatible = "ti,dac7612" },
165 { .compatible = "ti,dac7612u" },
166 { .compatible = "ti,dac7612ub" },
169 MODULE_DEVICE_TABLE(of, dac7612_of_match);
171 static struct spi_driver dac7612_driver = {
173 .name = "ti-dac7612",
174 .of_match_table = dac7612_of_match,
176 .probe = dac7612_probe,
177 .id_table = dac7612_id,
179 module_spi_driver(dac7612_driver);
181 MODULE_AUTHOR("Ricardo Ribalda <ribalda@kernel.org>");
182 MODULE_DESCRIPTION("Texas Instruments DAC7612 DAC driver");
183 MODULE_LICENSE("GPL v2");