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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles4 * (C) 2007 EADS Astrium5 *6 * This driver is based on the lm75 and other lm_sensors/hwmon drivers7 *8 * Written by Steve Hardy <shardy@redhat.com>9 *10 * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>11 *12 * For further information, see the Documentation/hwmon/ads7828.rst file.13 */14 15#include <linux/err.h>16#include <linux/hwmon.h>17#include <linux/hwmon-sysfs.h>18#include <linux/i2c.h>19#include <linux/init.h>20#include <linux/module.h>21#include <linux/of.h>22#include <linux/platform_data/ads7828.h>23#include <linux/regmap.h>24#include <linux/slab.h>25#include <linux/regulator/consumer.h>26 27/* The ADS7828 registers */28#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */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 */34 35/* List of supported devices */36enum ads7828_chips { ads7828, ads7830 };37 38/* Client specific data */39struct ads7828_data {40 struct regmap *regmap;41 u8 cmd_byte; /* Command byte without channel bits */42 unsigned int lsb_resol; /* Resolution of the ADC sample LSB */43};44 45/* Command byte C2,C1,C0 - see datasheet */46static inline u8 ads7828_cmd_byte(u8 cmd, int ch)47{48 return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);49}50 51/* sysfs callback function */52static ssize_t ads7828_in_show(struct device *dev,53 struct device_attribute *da, char *buf)54{55 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);56 struct ads7828_data *data = dev_get_drvdata(dev);57 u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);58 unsigned int regval;59 int err;60 61 err = regmap_read(data->regmap, cmd, ®val);62 if (err < 0)63 return err;64 65 return sprintf(buf, "%d\n",66 DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));67}68 69static SENSOR_DEVICE_ATTR_RO(in0_input, ads7828_in, 0);70static SENSOR_DEVICE_ATTR_RO(in1_input, ads7828_in, 1);71static SENSOR_DEVICE_ATTR_RO(in2_input, ads7828_in, 2);72static SENSOR_DEVICE_ATTR_RO(in3_input, ads7828_in, 3);73static SENSOR_DEVICE_ATTR_RO(in4_input, ads7828_in, 4);74static SENSOR_DEVICE_ATTR_RO(in5_input, ads7828_in, 5);75static SENSOR_DEVICE_ATTR_RO(in6_input, ads7828_in, 6);76static SENSOR_DEVICE_ATTR_RO(in7_input, ads7828_in, 7);77 78static struct attribute *ads7828_attrs[] = {79 &sensor_dev_attr_in0_input.dev_attr.attr,80 &sensor_dev_attr_in1_input.dev_attr.attr,81 &sensor_dev_attr_in2_input.dev_attr.attr,82 &sensor_dev_attr_in3_input.dev_attr.attr,83 &sensor_dev_attr_in4_input.dev_attr.attr,84 &sensor_dev_attr_in5_input.dev_attr.attr,85 &sensor_dev_attr_in6_input.dev_attr.attr,86 &sensor_dev_attr_in7_input.dev_attr.attr,87 NULL88};89 90ATTRIBUTE_GROUPS(ads7828);91 92static const struct regmap_config ads2828_regmap_config = {93 .reg_bits = 8,94 .val_bits = 16,95};96 97static const struct regmap_config ads2830_regmap_config = {98 .reg_bits = 8,99 .val_bits = 8,100};101 102static int ads7828_probe(struct i2c_client *client)103{104 struct device *dev = &client->dev;105 struct ads7828_platform_data *pdata = dev_get_platdata(dev);106 struct ads7828_data *data;107 struct device *hwmon_dev;108 unsigned int vref_mv = ADS7828_INT_VREF_MV;109 unsigned int vref_uv;110 bool diff_input = false;111 bool ext_vref = false;112 unsigned int regval;113 enum ads7828_chips chip;114 struct regulator *reg;115 116 data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);117 if (!data)118 return -ENOMEM;119 120 if (pdata) {121 diff_input = pdata->diff_input;122 ext_vref = pdata->ext_vref;123 if (ext_vref && pdata->vref_mv)124 vref_mv = pdata->vref_mv;125 } else if (dev->of_node) {126 diff_input = of_property_read_bool(dev->of_node,127 "ti,differential-input");128 reg = devm_regulator_get_optional(dev, "vref");129 if (!IS_ERR(reg)) {130 vref_uv = regulator_get_voltage(reg);131 vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);132 if (vref_mv < ADS7828_EXT_VREF_MV_MIN ||133 vref_mv > ADS7828_EXT_VREF_MV_MAX)134 return -EINVAL;135 ext_vref = true;136 }137 }138 139 chip = (uintptr_t)i2c_get_match_data(client);140 141 /* Bound Vref with min/max values */142 vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,143 ADS7828_EXT_VREF_MV_MAX);144 145 /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */146 if (chip == ads7828) {147 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);148 data->regmap = devm_regmap_init_i2c(client,149 &ads2828_regmap_config);150 } else {151 data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);152 data->regmap = devm_regmap_init_i2c(client,153 &ads2830_regmap_config);154 }155 156 if (IS_ERR(data->regmap))157 return PTR_ERR(data->regmap);158 159 data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;160 if (!diff_input)161 data->cmd_byte |= ADS7828_CMD_SD_SE;162 163 /*164 * Datasheet specifies internal reference voltage is disabled by165 * default. The internal reference voltage needs to be enabled and166 * voltage needs to settle before getting valid ADC data. So perform a167 * dummy read to enable the internal reference voltage.168 */169 if (!ext_vref)170 regmap_read(data->regmap, data->cmd_byte, ®val);171 172 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,173 data,174 ads7828_groups);175 return PTR_ERR_OR_ZERO(hwmon_dev);176}177 178static const struct i2c_device_id ads7828_device_ids[] = {179 { "ads7828", ads7828 },180 { "ads7830", ads7830 },181 { }182};183MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);184 185static const struct of_device_id __maybe_unused ads7828_of_match[] = {186 {187 .compatible = "ti,ads7828",188 .data = (void *)ads7828189 },190 {191 .compatible = "ti,ads7830",192 .data = (void *)ads7830193 },194 { },195};196MODULE_DEVICE_TABLE(of, ads7828_of_match);197 198static struct i2c_driver ads7828_driver = {199 .driver = {200 .name = "ads7828",201 .of_match_table = of_match_ptr(ads7828_of_match),202 },203 204 .id_table = ads7828_device_ids,205 .probe = ads7828_probe,206};207 208module_i2c_driver(ads7828_driver);209 210MODULE_LICENSE("GPL");211MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");212MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");213