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The function i2c_match_id() is used to fetch the matching ID from the i2c_device_id table. This is often used to then retrieve the matching driver_data. This can be done in one step with the helper i2c_get_match_data(). This helper has a couple other benefits: * It doesn't need the i2c_device_id passed in so we do not need to have that forward declared, allowing us to remove those or move the i2c_device_id table down to its more natural spot with the other module info. * It also checks for device match data, which allows for OF and ACPI based probing. That means we do not have to manually check those first and can remove those checks. Signed-off-by: Andrew Davis <afd@ti.com> Link: https://lore.kernel.org/r/20240403203633.914389-5-afd@ti.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
213 lines
6.1 KiB
C
213 lines
6.1 KiB
C
// 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 <shardy@redhat.com>
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*
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* ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
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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.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 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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chip = (uintptr_t)i2c_get_match_data(client);
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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 = 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 <shardy@redhat.com>");
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MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
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