1 // SPDX-License-Identifier: GPL-2.0-only
3 * MAX1117/MAX1118/MAX1119 8-bit, dual-channel ADCs driver
5 * Copyright (c) 2017 Akinobu Mita <akinobu.mita@gmail.com>
7 * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1117-MAX1119.pdf
9 * SPI interface connections
12 * Master Direction MAX1117/8/9
13 * ------ --------- -----------
17 * ------ --------- -----------
20 #include <linux/module.h>
21 #include <linux/spi/spi.h>
22 #include <linux/iio/iio.h>
23 #include <linux/iio/buffer.h>
24 #include <linux/iio/triggered_buffer.h>
25 #include <linux/iio/trigger_consumer.h>
26 #include <linux/regulator/consumer.h>
35 struct spi_device *spi;
37 struct regulator *reg;
39 u8 data ____cacheline_aligned;
42 #define MAX1118_CHANNEL(ch) \
44 .type = IIO_VOLTAGE, \
47 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
48 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
57 static const struct iio_chan_spec max1118_channels[] = {
60 IIO_CHAN_SOFT_TIMESTAMP(2),
63 static int max1118_read(struct spi_device *spi, int channel)
65 struct iio_dev *indio_dev = spi_get_drvdata(spi);
66 struct max1118 *adc = iio_priv(indio_dev);
67 struct spi_transfer xfers[] = {
69 * To select CH1 for conversion, CNVST pin must be brought high
70 * and low for a second time.
74 .delay_usecs = 1, /* > CNVST Low Time 100 ns */
78 * The acquisition interval begins with the falling edge of
79 * CNVST. The total acquisition and conversion process takes
94 ret = spi_sync_transfer(spi, xfers + 1, 2);
96 ret = spi_sync_transfer(spi, xfers, 3);
104 static int max1118_get_vref_mV(struct spi_device *spi)
106 struct iio_dev *indio_dev = spi_get_drvdata(spi);
107 struct max1118 *adc = iio_priv(indio_dev);
108 const struct spi_device_id *id = spi_get_device_id(spi);
111 switch (id->driver_data) {
117 vref_uV = regulator_get_voltage(adc->reg);
120 return vref_uV / 1000;
126 static int max1118_read_raw(struct iio_dev *indio_dev,
127 struct iio_chan_spec const *chan,
128 int *val, int *val2, long mask)
130 struct max1118 *adc = iio_priv(indio_dev);
133 case IIO_CHAN_INFO_RAW:
134 mutex_lock(&adc->lock);
135 *val = max1118_read(adc->spi, chan->channel);
136 mutex_unlock(&adc->lock);
141 case IIO_CHAN_INFO_SCALE:
142 *val = max1118_get_vref_mV(adc->spi);
147 return IIO_VAL_FRACTIONAL_LOG2;
153 static const struct iio_info max1118_info = {
154 .read_raw = max1118_read_raw,
157 static irqreturn_t max1118_trigger_handler(int irq, void *p)
159 struct iio_poll_func *pf = p;
160 struct iio_dev *indio_dev = pf->indio_dev;
161 struct max1118 *adc = iio_priv(indio_dev);
162 u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */
166 mutex_lock(&adc->lock);
168 for_each_set_bit(scan_index, indio_dev->active_scan_mask,
169 indio_dev->masklength) {
170 const struct iio_chan_spec *scan_chan =
171 &indio_dev->channels[scan_index];
172 int ret = max1118_read(adc->spi, scan_chan->channel);
175 dev_warn(&adc->spi->dev,
176 "failed to get conversion data\n");
183 iio_push_to_buffers_with_timestamp(indio_dev, data,
184 iio_get_time_ns(indio_dev));
186 mutex_unlock(&adc->lock);
188 iio_trigger_notify_done(indio_dev->trig);
193 static int max1118_probe(struct spi_device *spi)
195 struct iio_dev *indio_dev;
197 const struct spi_device_id *id = spi_get_device_id(spi);
200 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
204 adc = iio_priv(indio_dev);
206 mutex_init(&adc->lock);
208 if (id->driver_data == max1118) {
209 adc->reg = devm_regulator_get(&spi->dev, "vref");
210 if (IS_ERR(adc->reg)) {
211 dev_err(&spi->dev, "failed to get vref regulator\n");
212 return PTR_ERR(adc->reg);
214 ret = regulator_enable(adc->reg);
219 spi_set_drvdata(spi, indio_dev);
221 indio_dev->name = spi_get_device_id(spi)->name;
222 indio_dev->dev.parent = &spi->dev;
223 indio_dev->info = &max1118_info;
224 indio_dev->modes = INDIO_DIRECT_MODE;
225 indio_dev->channels = max1118_channels;
226 indio_dev->num_channels = ARRAY_SIZE(max1118_channels);
229 * To reinitiate a conversion on CH0, it is necessary to allow for a
230 * conversion to be complete and all of the data to be read out. Once
231 * a conversion has been completed, the MAX1117/MAX1118/MAX1119 will go
232 * into AutoShutdown mode until the next conversion is initiated.
234 max1118_read(spi, 0);
236 ret = iio_triggered_buffer_setup(indio_dev, NULL,
237 max1118_trigger_handler, NULL);
239 goto err_reg_disable;
241 ret = iio_device_register(indio_dev);
243 goto err_buffer_cleanup;
248 iio_triggered_buffer_cleanup(indio_dev);
250 if (id->driver_data == max1118)
251 regulator_disable(adc->reg);
256 static int max1118_remove(struct spi_device *spi)
258 struct iio_dev *indio_dev = spi_get_drvdata(spi);
259 struct max1118 *adc = iio_priv(indio_dev);
260 const struct spi_device_id *id = spi_get_device_id(spi);
262 iio_device_unregister(indio_dev);
263 iio_triggered_buffer_cleanup(indio_dev);
264 if (id->driver_data == max1118)
265 return regulator_disable(adc->reg);
270 static const struct spi_device_id max1118_id[] = {
271 { "max1117", max1117 },
272 { "max1118", max1118 },
273 { "max1119", max1119 },
276 MODULE_DEVICE_TABLE(spi, max1118_id);
280 static const struct of_device_id max1118_dt_ids[] = {
281 { .compatible = "maxim,max1117" },
282 { .compatible = "maxim,max1118" },
283 { .compatible = "maxim,max1119" },
286 MODULE_DEVICE_TABLE(of, max1118_dt_ids);
290 static struct spi_driver max1118_spi_driver = {
293 .of_match_table = of_match_ptr(max1118_dt_ids),
295 .probe = max1118_probe,
296 .remove = max1118_remove,
297 .id_table = max1118_id,
299 module_spi_driver(max1118_spi_driver);
301 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
302 MODULE_DESCRIPTION("MAXIM MAX1117/MAX1118/MAX1119 ADCs driver");
303 MODULE_LICENSE("GPL v2");