1 // SPDX-License-Identifier: GPL-2.0
3  * Driver for Microchip MCP3911, Two-channel Analog Front End
41 /* Internal voltage reference in mV */
52 	struct regulator *vref;  member
61 	reg = MCP3911_REG_READ(reg, adc->dev_addr);  in mcp3911_read()
62 	ret = spi_write_then_read(adc->spi, &reg, 1, val, len);  in mcp3911_read()
67 	*val >>= ((4 - len) * 8);  in mcp3911_read()
68 	dev_dbg(&adc->spi->dev, "reading 0x%x from register 0x%x\n", *val,  in mcp3911_read()
75 	dev_dbg(&adc->spi->dev, "writing 0x%x to register 0x%x\n", val, reg);  in mcp3911_write()
77 	val <<= (3 - len) * 8;  in mcp3911_write()
79 	val |= MCP3911_REG_WRITE(reg, adc->dev_addr);  in mcp3911_write()
81 	return spi_write(adc->spi, &val, len + 1);  in mcp3911_write()
104 	int ret = -EINVAL;  in mcp3911_read_raw()
106 	mutex_lock(&adc->lock);  in mcp3911_read_raw()
110 				   MCP3911_CHANNEL(channel->channel), val, 3);  in mcp3911_read_raw()
121 				   MCP3911_OFFCAL(channel->channel), val, 3);  in mcp3911_read_raw()
129 		if (adc->vref) {  in mcp3911_read_raw()
130 			ret = regulator_get_voltage(adc->vref);  in mcp3911_read_raw()
132 				dev_err(indio_dev->dev.parent,  in mcp3911_read_raw()
133 					"failed to get vref voltage: %d\n",  in mcp3911_read_raw()
145 		 * Raw = ((Voltage)/(Vref) * 2^23 * Gain * 1.5  in mcp3911_read_raw()
146 		 * Voltage = Raw * (Vref)/(2^23 * Gain * 1.5)  in mcp3911_read_raw()
156 	mutex_unlock(&adc->lock);  in mcp3911_read_raw()
165 	int ret = -EINVAL;  in mcp3911_write_raw()
167 	mutex_lock(&adc->lock);  in mcp3911_write_raw()
171 			ret = -EINVAL;  in mcp3911_write_raw()
176 		ret = mcp3911_write(adc, MCP3911_OFFCAL(channel->channel), val,  in mcp3911_write_raw()
189 	mutex_unlock(&adc->lock);  in mcp3911_write_raw()
217 	of_property_read_u32(of_node, "device-addr", &adc->dev_addr);  in mcp3911_config()
218 	if (adc->dev_addr > 3) {  in mcp3911_config()
219 		dev_err(&adc->spi->dev,  in mcp3911_config()
220 			"invalid device address (%i). Must be in range 0-3.\n",  in mcp3911_config()
221 			adc->dev_addr);  in mcp3911_config()
222 		return -EINVAL;  in mcp3911_config()
224 	dev_dbg(&adc->spi->dev, "use device address %i\n", adc->dev_addr);  in mcp3911_config()
230 	if (adc->vref) {  in mcp3911_config()
231 		dev_dbg(&adc->spi->dev, "use external voltage reference\n");  in mcp3911_config()
234 		dev_dbg(&adc->spi->dev,  in mcp3911_config()
235 			"use internal voltage reference (1.2V)\n");  in mcp3911_config()
239 	if (adc->clki) {  in mcp3911_config()
240 		dev_dbg(&adc->spi->dev, "use external clock as clocksource\n");  in mcp3911_config()
243 		dev_dbg(&adc->spi->dev,  in mcp3911_config()
257 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));  in mcp3911_probe()
259 		return -ENOMEM;  in mcp3911_probe()
262 	adc->spi = spi;  in mcp3911_probe()
264 	adc->vref = devm_regulator_get_optional(&adc->spi->dev, "vref");  in mcp3911_probe()
265 	if (IS_ERR(adc->vref)) {  in mcp3911_probe()
266 		if (PTR_ERR(adc->vref) == -ENODEV) {  in mcp3911_probe()
267 			adc->vref = NULL;  in mcp3911_probe()
269 			dev_err(&adc->spi->dev,  in mcp3911_probe()
271 				PTR_ERR(adc->vref));  in mcp3911_probe()
272 			return PTR_ERR(adc->vref);  in mcp3911_probe()
276 		ret = regulator_enable(adc->vref);  in mcp3911_probe()
281 	adc->clki = devm_clk_get(&adc->spi->dev, NULL);  in mcp3911_probe()
282 	if (IS_ERR(adc->clki)) {  in mcp3911_probe()
283 		if (PTR_ERR(adc->clki) == -ENOENT) {  in mcp3911_probe()
284 			adc->clki = NULL;  in mcp3911_probe()
286 			dev_err(&adc->spi->dev,  in mcp3911_probe()
288 				PTR_ERR(adc->clki));  in mcp3911_probe()
289 			ret = PTR_ERR(adc->clki);  in mcp3911_probe()
293 		ret = clk_prepare_enable(adc->clki);  in mcp3911_probe()
295 			dev_err(&adc->spi->dev,  in mcp3911_probe()
301 	ret = mcp3911_config(adc, spi->dev.of_node);  in mcp3911_probe()
305 	indio_dev->name = spi_get_device_id(spi)->name;  in mcp3911_probe()
306 	indio_dev->modes = INDIO_DIRECT_MODE;  in mcp3911_probe()
307 	indio_dev->info = &mcp3911_info;  in mcp3911_probe()
310 	indio_dev->channels = mcp3911_channels;  in mcp3911_probe()
311 	indio_dev->num_channels = ARRAY_SIZE(mcp3911_channels);  in mcp3911_probe()
313 	mutex_init(&adc->lock);  in mcp3911_probe()
322 	clk_disable_unprepare(adc->clki);  in mcp3911_probe()
324 	if (adc->vref)  in mcp3911_probe()
325 		regulator_disable(adc->vref);  in mcp3911_probe()
337 	clk_disable_unprepare(adc->clki);  in mcp3911_remove()
338 	if (adc->vref)  in mcp3911_remove()
339 		regulator_disable(adc->vref);  in mcp3911_remove()