// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
* (C) 2007 EADS Astrium
*
* This driver is based on the lm75 and other lm_sensors/hwmon drivers
*
* Written by Steve Hardy <[email protected]>
*
* ADS7830 support, by Guillaume Roguez <[email protected]>
*
* For further information, see the Documentation/hwmon/ads7828.rst file.
*/
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_data/ads7828.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
/* The ADS7828 registers */
#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
#define ADS7828_CMD_PD1 0x04 /* Internal vref OFF && A/D ON */
#define ADS7828_CMD_PD3 0x0C /* Internal vref ON && A/D ON */
#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
#define ADS7828_EXT_VREF_MV_MIN 50 /* External vref min value 0.05V */
#define ADS7828_EXT_VREF_MV_MAX 5250 /* External vref max value 5.25V */
/* List of supported devices */
enum ads7828_chips { ads7828, ads7830 };
/* Client specific data */
struct ads7828_data {
struct regmap *regmap;
u8 cmd_byte; /* Command byte without channel bits */
unsigned int lsb_resol; /* Resolution of the ADC sample LSB */
};
/* Command byte C2,C1,C0 - see datasheet */
static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
{
return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);
}
/* sysfs callback function */
static ssize_t ads7828_in_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ads7828_data *data = dev_get_drvdata(dev);
u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);
unsigned int regval;
int err;
err = regmap_read(data->regmap, cmd, ®val);
if (err < 0)
return err;
return sprintf(buf, "%d\n",
DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));
}
static SENSOR_DEVICE_ATTR_RO(in0_input, ads7828_in, 0);
static SENSOR_DEVICE_ATTR_RO(in1_input, ads7828_in, 1);
static SENSOR_DEVICE_ATTR_RO(in2_input, ads7828_in, 2);
static SENSOR_DEVICE_ATTR_RO(in3_input, ads7828_in, 3);
static SENSOR_DEVICE_ATTR_RO(in4_input, ads7828_in, 4);
static SENSOR_DEVICE_ATTR_RO(in5_input, ads7828_in, 5);
static SENSOR_DEVICE_ATTR_RO(in6_input, ads7828_in, 6);
static SENSOR_DEVICE_ATTR_RO(in7_input, ads7828_in, 7);
static struct attribute *ads7828_attrs[] = {
&sensor_dev_attr_in0_input.dev_attr.attr,
&sensor_dev_attr_in1_input.dev_attr.attr,
&sensor_dev_attr_in2_input.dev_attr.attr,
&sensor_dev_attr_in3_input.dev_attr.attr,
&sensor_dev_attr_in4_input.dev_attr.attr,
&sensor_dev_attr_in5_input.dev_attr.attr,
&sensor_dev_attr_in6_input.dev_attr.attr,
&sensor_dev_attr_in7_input.dev_attr.attr,
NULL
};
ATTRIBUTE_GROUPS(ads7828);
static const struct regmap_config ads2828_regmap_config = {
.reg_bits = 8,
.val_bits = 16,
};
static const struct regmap_config ads2830_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
};
static int ads7828_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct ads7828_platform_data *pdata = dev_get_platdata(dev);
struct ads7828_data *data;
struct device *hwmon_dev;
unsigned int vref_mv = ADS7828_INT_VREF_MV;
unsigned int vref_uv;
bool diff_input = false;
bool ext_vref = false;
unsigned int regval;
enum ads7828_chips chip;
struct regulator *reg;
data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
if (pdata) {
diff_input = pdata->diff_input;
ext_vref = pdata->ext_vref;
if (ext_vref && pdata->vref_mv)
vref_mv = pdata->vref_mv;
} else if (dev->of_node) {
diff_input = of_property_read_bool(dev->of_node,
"ti,differential-input");
reg = devm_regulator_get_optional(dev, "vref");
if (!IS_ERR(reg)) {
vref_uv = regulator_get_voltage(reg);
vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
if (vref_mv < ADS7828_EXT_VREF_MV_MIN ||
vref_mv > ADS7828_EXT_VREF_MV_MAX)
return -EINVAL;
ext_vref = true;
}
}
chip = (uintptr_t)i2c_get_match_data(client);
/* Bound Vref with min/max values */
vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
ADS7828_EXT_VREF_MV_MAX);
/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
if (chip == ads7828) {
data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
data->regmap = devm_regmap_init_i2c(client,
&ads2828_regmap_config);
} else {
data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
data->regmap = devm_regmap_init_i2c(client,
&ads2830_regmap_config);
}
if (IS_ERR(data->regmap))
return PTR_ERR(data->regmap);
data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
if (!diff_input)
data->cmd_byte |= ADS7828_CMD_SD_SE;
/*
* Datasheet specifies internal reference voltage is disabled by
* default. The internal reference voltage needs to be enabled and
* voltage needs to settle before getting valid ADC data. So perform a
* dummy read to enable the internal reference voltage.
*/
if (!ext_vref)
regmap_read(data->regmap, data->cmd_byte, ®val);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data,
ads7828_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ads7828_device_ids[] = {
{ "ads7828", ads7828 },
{ "ads7830", ads7830 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
static const struct of_device_id __maybe_unused ads7828_of_match[] = {
{
.compatible = "ti,ads7828",
.data = (void *)ads7828
},
{
.compatible = "ti,ads7830",
.data = (void *)ads7830
},
{ },
};
MODULE_DEVICE_TABLE(of, ads7828_of_match);
static struct i2c_driver ads7828_driver = {
.driver = {
.name = "ads7828",
.of_match_table = of_match_ptr(ads7828_of_match),
},
.id_table = ads7828_device_ids,
.probe = ads7828_probe,
};
module_i2c_driver(ads7828_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steve Hardy <[email protected]>");
MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
Codebase Browser
linux