diff options
Diffstat (limited to 'drivers/hwmon/ads7828.c')
| -rw-r--r-- | drivers/hwmon/ads7828.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c new file mode 100644 index 000000000..7246198f0 --- /dev/null +++ b/drivers/hwmon/ads7828.c @@ -0,0 +1,218 @@ +// 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 <shardy@redhat.com> + * + * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com> + * + * 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_device.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 const struct i2c_device_id ads7828_device_ids[]; + +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; + } + } + + if (client->dev.of_node) + chip = (enum ads7828_chips) + of_device_get_match_data(&client->dev); + else + chip = i2c_match_id(ads7828_device_ids, client)->driver_data; + + /* 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_new = ads7828_probe, +}; + +module_i2c_driver(ads7828_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>"); +MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles"); |