1 // SPDX-License-Identifier: GPL-2.0+
15  * MAX127 Control Byte. Refer to MAX127 datasheet, Table 1 "Control-Byte
29  * MAX127 channel input ranges. Refer to MAX127 datasheet, Table 3 "Range
37  *   - the first byte contains data[11:4].
38  *   - the second byte contains data[3:0] (MSB) and 4 dummy 0s (LSB).
57 		.addr = client->addr,  in max127_select_channel()
63 	status = i2c_transfer(client->adapter, &msg, 1);  in max127_select_channel()
67 		return -EIO;  in max127_select_channel()
77 		.addr = client->addr,  in max127_read_channel()
83 	status = i2c_transfer(client->adapter, &msg, 1);  in max127_read_channel()
87 		return -EIO;  in max127_read_channel()
99 	 * MAX127's data coding is binary in unipolar mode with 1 LSB =  in max127_process_raw()
100 	 * (Full-Scale/4096) and two’s complement binary in bipolar mode  in max127_process_raw()
110 		raw -= weight;  in max127_process_raw()
117 static int max127_read_input(struct max127_data *data, int channel, long *val)  in max127_read_input()  argument
121 	struct i2c_client *client = data->client;  in max127_read_input()
122 	u8 ctrl_byte = data->ctrl_byte[channel];  in max127_read_input()
124 	mutex_lock(&data->lock);  in max127_read_input()
137 	mutex_unlock(&data->lock);  in max127_read_input()
141 static int max127_read_min(struct max127_data *data, int channel, long *val)  in max127_read_min()  argument
143 	u8 rng_bip = (data->ctrl_byte[channel] >> 2) & 3;  in max127_read_min()
146 		-MAX127_HALF_RANGE,	/* RNG=0, BIP=1 */  in max127_read_min()
148 		-MAX127_FULL_RANGE,	/* RNG=1, BIP=1 */  in max127_read_min()
155 static int max127_read_max(struct max127_data *data, int channel, long *val)  in max127_read_max()  argument
157 	u8 rng_bip = (data->ctrl_byte[channel] >> 2) & 3;  in max127_read_max()
169 static int max127_write_min(struct max127_data *data, int channel, long val)  in max127_write_min()  argument
173 	mutex_lock(&data->lock);  in max127_write_min()
175 	ctrl = data->ctrl_byte[channel];  in max127_write_min()
176 	if (val <= -MAX127_FULL_RANGE) {  in max127_write_min()
184 	data->ctrl_byte[channel] = ctrl;  in max127_write_min()
186 	mutex_unlock(&data->lock);  in max127_write_min()
191 static int max127_write_max(struct max127_data *data, int channel, long val)  in max127_write_max()  argument
193 	mutex_lock(&data->lock);  in max127_write_max()
196 		data->ctrl_byte[channel] |= MAX127_CTRL_RNG;  in max127_write_max()
198 		data->ctrl_byte[channel] &= ~MAX127_CTRL_RNG;  in max127_write_max()
200 	mutex_unlock(&data->lock);  in max127_write_max()
207 				 u32 attr, int channel)  in max127_is_visible()  argument
227 			u32 attr, int channel, long *val)  in max127_read()  argument
230 	struct max127_data *data = dev_get_drvdata(dev);  in max127_read()  local
233 		return -EOPNOTSUPP;  in max127_read()
237 		status = max127_read_input(data, channel, val);  in max127_read()
241 		status = max127_read_min(data, channel, val);  in max127_read()
245 		status = max127_read_max(data, channel, val);  in max127_read()
249 		status = -EOPNOTSUPP;  in max127_read()
257 			u32 attr, int channel, long val)  in max127_write()  argument
260 	struct max127_data *data = dev_get_drvdata(dev);  in max127_write()  local
263 		return -EOPNOTSUPP;  in max127_write()
267 		status = max127_write_min(data, channel, val);  in max127_write()
271 		status = max127_write_max(data, channel, val);  in max127_write()
275 		status = -EOPNOTSUPP;  in max127_write()
310 	struct max127_data *data;  in max127_probe()  local
311 	struct device *dev = &client->dev;  in max127_probe()
313 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);  in max127_probe()
314 	if (!data)  in max127_probe()
315 		return -ENOMEM;  in max127_probe()
317 	data->client = client;  in max127_probe()
318 	mutex_init(&data->lock);  in max127_probe()
319 	for (i = 0; i < ARRAY_SIZE(data->ctrl_byte); i++)  in max127_probe()
320 		data->ctrl_byte[i] = (MAX127_CTRL_START |  in max127_probe()
323 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,  in max127_probe()
324 							 data,  in max127_probe()