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218 lines
6.3 KiB
218 lines
6.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles |
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* (C) 2007 EADS Astrium |
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* |
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* This driver is based on the lm75 and other lm_sensors/hwmon drivers |
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* |
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* Written by Steve Hardy <[email protected]> |
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* |
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* ADS7830 support, by Guillaume Roguez <[email protected]> |
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* |
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* For further information, see the Documentation/hwmon/ads7828.rst file. |
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*/ |
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#include <linux/err.h> |
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#include <linux/hwmon.h> |
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#include <linux/hwmon-sysfs.h> |
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#include <linux/i2c.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/of_device.h> |
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#include <linux/platform_data/ads7828.h> |
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#include <linux/regmap.h> |
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#include <linux/slab.h> |
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#include <linux/regulator/consumer.h> |
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/* The ADS7828 registers */ |
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#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */ |
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#define ADS7828_CMD_PD1 0x04 /* Internal vref OFF && A/D ON */ |
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#define ADS7828_CMD_PD3 0x0C /* Internal vref ON && A/D ON */ |
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#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */ |
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#define ADS7828_EXT_VREF_MV_MIN 50 /* External vref min value 0.05V */ |
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#define ADS7828_EXT_VREF_MV_MAX 5250 /* External vref max value 5.25V */ |
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/* List of supported devices */ |
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enum ads7828_chips { ads7828, ads7830 }; |
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/* Client specific data */ |
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struct ads7828_data { |
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struct regmap *regmap; |
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u8 cmd_byte; /* Command byte without channel bits */ |
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unsigned int lsb_resol; /* Resolution of the ADC sample LSB */ |
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}; |
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/* Command byte C2,C1,C0 - see datasheet */ |
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static inline u8 ads7828_cmd_byte(u8 cmd, int ch) |
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{ |
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return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4); |
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} |
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/* sysfs callback function */ |
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static ssize_t ads7828_in_show(struct device *dev, |
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struct device_attribute *da, char *buf) |
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{ |
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
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struct ads7828_data *data = dev_get_drvdata(dev); |
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u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index); |
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unsigned int regval; |
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int err; |
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err = regmap_read(data->regmap, cmd, ®val); |
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if (err < 0) |
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return err; |
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return sprintf(buf, "%d\n", |
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DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000)); |
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} |
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static SENSOR_DEVICE_ATTR_RO(in0_input, ads7828_in, 0); |
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static SENSOR_DEVICE_ATTR_RO(in1_input, ads7828_in, 1); |
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static SENSOR_DEVICE_ATTR_RO(in2_input, ads7828_in, 2); |
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static SENSOR_DEVICE_ATTR_RO(in3_input, ads7828_in, 3); |
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static SENSOR_DEVICE_ATTR_RO(in4_input, ads7828_in, 4); |
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static SENSOR_DEVICE_ATTR_RO(in5_input, ads7828_in, 5); |
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static SENSOR_DEVICE_ATTR_RO(in6_input, ads7828_in, 6); |
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static SENSOR_DEVICE_ATTR_RO(in7_input, ads7828_in, 7); |
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static struct attribute *ads7828_attrs[] = { |
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&sensor_dev_attr_in0_input.dev_attr.attr, |
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&sensor_dev_attr_in1_input.dev_attr.attr, |
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&sensor_dev_attr_in2_input.dev_attr.attr, |
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&sensor_dev_attr_in3_input.dev_attr.attr, |
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&sensor_dev_attr_in4_input.dev_attr.attr, |
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&sensor_dev_attr_in5_input.dev_attr.attr, |
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&sensor_dev_attr_in6_input.dev_attr.attr, |
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&sensor_dev_attr_in7_input.dev_attr.attr, |
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NULL |
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}; |
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ATTRIBUTE_GROUPS(ads7828); |
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static const struct regmap_config ads2828_regmap_config = { |
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.reg_bits = 8, |
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.val_bits = 16, |
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}; |
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static const struct regmap_config ads2830_regmap_config = { |
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.reg_bits = 8, |
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.val_bits = 8, |
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}; |
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static const struct i2c_device_id ads7828_device_ids[]; |
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static int ads7828_probe(struct i2c_client *client) |
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{ |
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struct device *dev = &client->dev; |
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struct ads7828_platform_data *pdata = dev_get_platdata(dev); |
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struct ads7828_data *data; |
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struct device *hwmon_dev; |
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unsigned int vref_mv = ADS7828_INT_VREF_MV; |
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unsigned int vref_uv; |
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bool diff_input = false; |
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bool ext_vref = false; |
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unsigned int regval; |
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enum ads7828_chips chip; |
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struct regulator *reg; |
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data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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if (pdata) { |
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diff_input = pdata->diff_input; |
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ext_vref = pdata->ext_vref; |
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if (ext_vref && pdata->vref_mv) |
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vref_mv = pdata->vref_mv; |
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} else if (dev->of_node) { |
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diff_input = of_property_read_bool(dev->of_node, |
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"ti,differential-input"); |
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reg = devm_regulator_get_optional(dev, "vref"); |
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if (!IS_ERR(reg)) { |
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vref_uv = regulator_get_voltage(reg); |
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vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000); |
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if (vref_mv < ADS7828_EXT_VREF_MV_MIN || |
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vref_mv > ADS7828_EXT_VREF_MV_MAX) |
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return -EINVAL; |
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ext_vref = true; |
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} |
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} |
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if (client->dev.of_node) |
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chip = (enum ads7828_chips) |
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of_device_get_match_data(&client->dev); |
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else |
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chip = i2c_match_id(ads7828_device_ids, client)->driver_data; |
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/* Bound Vref with min/max values */ |
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vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN, |
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ADS7828_EXT_VREF_MV_MAX); |
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/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */ |
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if (chip == ads7828) { |
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data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096); |
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data->regmap = devm_regmap_init_i2c(client, |
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&ads2828_regmap_config); |
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} else { |
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data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256); |
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data->regmap = devm_regmap_init_i2c(client, |
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&ads2830_regmap_config); |
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} |
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if (IS_ERR(data->regmap)) |
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return PTR_ERR(data->regmap); |
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data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3; |
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if (!diff_input) |
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data->cmd_byte |= ADS7828_CMD_SD_SE; |
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/* |
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* Datasheet specifies internal reference voltage is disabled by |
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* default. The internal reference voltage needs to be enabled and |
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* voltage needs to settle before getting valid ADC data. So perform a |
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* dummy read to enable the internal reference voltage. |
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*/ |
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if (!ext_vref) |
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regmap_read(data->regmap, data->cmd_byte, ®val); |
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
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data, |
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ads7828_groups); |
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return PTR_ERR_OR_ZERO(hwmon_dev); |
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} |
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static const struct i2c_device_id ads7828_device_ids[] = { |
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{ "ads7828", ads7828 }, |
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{ "ads7830", ads7830 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, ads7828_device_ids); |
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static const struct of_device_id __maybe_unused ads7828_of_match[] = { |
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{ |
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.compatible = "ti,ads7828", |
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.data = (void *)ads7828 |
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}, |
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{ |
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.compatible = "ti,ads7830", |
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.data = (void *)ads7830 |
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}, |
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{ }, |
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}; |
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MODULE_DEVICE_TABLE(of, ads7828_of_match); |
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static struct i2c_driver ads7828_driver = { |
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.driver = { |
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.name = "ads7828", |
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.of_match_table = of_match_ptr(ads7828_of_match), |
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}, |
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.id_table = ads7828_device_ids, |
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.probe_new = ads7828_probe, |
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}; |
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module_i2c_driver(ads7828_driver); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Steve Hardy <[email protected]>"); |
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MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
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