1 // SPDX-License-Identifier: GPL-2.0
2 /* ad7949.c - Analog Devices ADC driver 14/16 bits 4/8 channels
6  * https://www.analog.com/media/en/technical-documentation/data-sheets/AD7949.pdf
39  * struct ad7949_adc_chip - AD ADC chip
41  * @vref: regulator generating Vref
51 	struct regulator *vref;  member
64 	int bits_per_word = ad7949_adc->resolution;  in ad7949_spi_write_cfg()
65 	int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS;  in ad7949_spi_write_cfg()
69 			.tx_buf = &ad7949_adc->buffer,  in ad7949_spi_write_cfg()
75 	ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask);  in ad7949_spi_write_cfg()
76 	ad7949_adc->buffer = ad7949_adc->cfg << shift;  in ad7949_spi_write_cfg()
78 	ret = spi_sync(ad7949_adc->spi, &msg);  in ad7949_spi_write_cfg()
93 	int bits_per_word = ad7949_adc->resolution;  in ad7949_spi_read_channel()
94 	int mask = GENMASK(ad7949_adc->resolution - 1, 0);  in ad7949_spi_read_channel()
98 			.rx_buf = &ad7949_adc->buffer,  in ad7949_spi_read_channel()
105 	 * 1: write CFG for sample N and read old data (sample N-2)  in ad7949_spi_read_channel()
106 	 * 2: if CFG was not changed since sample N-1 then we'll get good data  in ad7949_spi_read_channel()
107 	 *    at the next xfer, so we bail out now, otherwise we write something  in ad7949_spi_read_channel()
108 	 *    and we read garbage (sample N-1 configuration).  in ad7949_spi_read_channel()
116 		if (channel == ad7949_adc->current_channel)  in ad7949_spi_read_channel()
121 	ad7949_adc->buffer = 0;  in ad7949_spi_read_channel()
123 	ret = spi_sync(ad7949_adc->spi, &msg);  in ad7949_spi_read_channel()
133 	ad7949_adc->current_channel = channel;  in ad7949_spi_read_channel()
135 	*val = ad7949_adc->buffer & mask;  in ad7949_spi_read_channel()
167 		return -EINVAL;  in ad7949_spi_read_raw()
171 		mutex_lock(&ad7949_adc->lock);  in ad7949_spi_read_raw()
172 		ret = ad7949_spi_read_channel(ad7949_adc, val, chan->channel);  in ad7949_spi_read_raw()
173 		mutex_unlock(&ad7949_adc->lock);  in ad7949_spi_read_raw()
181 		ret = regulator_get_voltage(ad7949_adc->vref);  in ad7949_spi_read_raw()
189 	return -EINVAL;  in ad7949_spi_read_raw()
200 		*readval = ad7949_adc->cfg;  in ad7949_spi_reg_access()
219 	ad7949_adc->current_channel = 0;  in ad7949_spi_init()
226 	ad7949_spi_read_channel(ad7949_adc, &val, ad7949_adc->current_channel);  in ad7949_spi_init()
227 	ad7949_spi_read_channel(ad7949_adc, &val, ad7949_adc->current_channel);  in ad7949_spi_init()
234 	struct device *dev = &spi->dev;  in ad7949_spi_probe()
243 		return -ENOMEM;  in ad7949_spi_probe()
246 	indio_dev->info = &ad7949_spi_info;  in ad7949_spi_probe()
247 	indio_dev->name = spi_get_device_id(spi)->name;  in ad7949_spi_probe()
248 	indio_dev->modes = INDIO_DIRECT_MODE;  in ad7949_spi_probe()
249 	indio_dev->channels = ad7949_adc_channels;  in ad7949_spi_probe()
253 	ad7949_adc->indio_dev = indio_dev;  in ad7949_spi_probe()
254 	ad7949_adc->spi = spi;  in ad7949_spi_probe()
256 	spec = &ad7949_adc_spec[spi_get_device_id(spi)->driver_data];  in ad7949_spi_probe()
257 	indio_dev->num_channels = spec->num_channels;  in ad7949_spi_probe()
258 	ad7949_adc->resolution = spec->resolution;  in ad7949_spi_probe()
260 	ad7949_adc->vref = devm_regulator_get(dev, "vref");  in ad7949_spi_probe()
261 	if (IS_ERR(ad7949_adc->vref)) {  in ad7949_spi_probe()
263 		return PTR_ERR(ad7949_adc->vref);  in ad7949_spi_probe()
266 	ret = regulator_enable(ad7949_adc->vref);  in ad7949_spi_probe()
272 	mutex_init(&ad7949_adc->lock);  in ad7949_spi_probe()
289 	mutex_destroy(&ad7949_adc->lock);  in ad7949_spi_probe()
290 	regulator_disable(ad7949_adc->vref);  in ad7949_spi_probe()
301 	mutex_destroy(&ad7949_adc->lock);  in ad7949_spi_remove()
302 	regulator_disable(ad7949_adc->vref);  in ad7949_spi_remove()
334 MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
335 MODULE_DESCRIPTION("Analog Devices 14/16-bit 8-channel ADC driver");