1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
17 #include <linux/hwmon-sysfs.h>
29 #define ADS7828_CMD_PD1		0x04	/* Internal vref OFF && A/D ON */
30 #define ADS7828_CMD_PD3		0x0C	/* Internal vref ON && A/D ON */
31 #define ADS7828_INT_VREF_MV	2500	/* Internal vref is 2.5V, 2500mV */
32 #define ADS7828_EXT_VREF_MV_MIN	50	/* External vref min value 0.05V */
33 #define ADS7828_EXT_VREF_MV_MAX	5250	/* External vref max value 5.25V */
45 /* Command byte C2,C1,C0 - see datasheet */
57 	u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);  in ads7828_in_show()
61 	err = regmap_read(data->regmap, cmd, &regval);  in ads7828_in_show()
66 		       DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));  in ads7828_in_show()
106 	struct device *dev = &client->dev;  in ads7828_probe()
120 		return -ENOMEM;  in ads7828_probe()
123 		diff_input = pdata->diff_input;  in ads7828_probe()
124 		ext_vref = pdata->ext_vref;  in ads7828_probe()
125 		if (ext_vref && pdata->vref_mv)  in ads7828_probe()
126 			vref_mv = pdata->vref_mv;  in ads7828_probe()
127 	} else if (dev->of_node) {  in ads7828_probe()
128 		diff_input = of_property_read_bool(dev->of_node,  in ads7828_probe()
129 						   "ti,differential-input");  in ads7828_probe()
130 		reg = devm_regulator_get_optional(dev, "vref");  in ads7828_probe()
136 				return -EINVAL;  in ads7828_probe()
141 	if (client->dev.of_node)  in ads7828_probe()
142 		chip = (uintptr_t)of_device_get_match_data(&client->dev);  in ads7828_probe()
144 		chip = i2c_match_id(ads7828_device_ids, client)->driver_data;  in ads7828_probe()
146 	/* Bound Vref with min/max values */  in ads7828_probe()
150 	/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */  in ads7828_probe()
152 		data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);  in ads7828_probe()
153 		data->regmap = devm_regmap_init_i2c(client,  in ads7828_probe()
156 		data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);  in ads7828_probe()
157 		data->regmap = devm_regmap_init_i2c(client,  in ads7828_probe()
161 	if (IS_ERR(data->regmap))  in ads7828_probe()
162 		return PTR_ERR(data->regmap);  in ads7828_probe()
164 	data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;  in ads7828_probe()
166 		data->cmd_byte |= ADS7828_CMD_SD_SE;  in ads7828_probe()
169 	 * Datasheet specifies internal reference voltage is disabled by  in ads7828_probe()
170 	 * default. The internal reference voltage needs to be enabled and  in ads7828_probe()
172 	 * dummy read to enable the internal reference voltage.  in ads7828_probe()
175 		regmap_read(data->regmap, data->cmd_byte, &regval);  in ads7828_probe()
177 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,  in ads7828_probe()