/* * 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 file. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #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/platform_data/ads7828.h> #include <linux/regmap.h> #include <linux/slab.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_show_in(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(in0_input, S_IRUGO, ads7828_show_in, NULL, 0); static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1); static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2); static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3); static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4); static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5); static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6); static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 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, const struct i2c_device_id *id) { 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; bool diff_input = false; bool ext_vref = false; 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; } /* 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 (id->driver_data == 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; 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 struct i2c_driver ads7828_driver = { .driver = { .name = "ads7828", }, .id_table = ads7828_device_ids, .probe = 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");