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drivers/hwmon/ads7828.c
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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 * * This driver is based on the lm75 and other lm_sensors/hwmon drivers * * Written by Steve Hardy <shardy@redhat.com> * |
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* ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com> * |
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* For further information, see the Documentation/hwmon/ads7828 file. |
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* * 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. */ |
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#include <linux/err.h> |
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#include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> |
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#include <linux/i2c.h> #include <linux/init.h> #include <linux/jiffies.h> #include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/platform_data/ads7828.h> #include <linux/slab.h> |
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/* The ADS7828 registers */ |
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#define ADS7828_NCH 8 /* 8 channels supported */ #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 */ |
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/* List of supported devices */ enum ads7828_chips { ads7828, ads7830 }; |
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/* Client specific data */ |
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struct ads7828_data { |
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struct device *hwmon_dev; |
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struct mutex update_lock; /* Mutex protecting updates */ unsigned long last_updated; /* Last updated time (in jiffies) */ u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH samples */ bool valid; /* Validity flag */ bool diff_input; /* Differential input */ bool ext_vref; /* External voltage reference */ unsigned int vref_mv; /* voltage reference value */ u8 cmd_byte; /* Command byte without channel bits */ unsigned int lsb_resol; /* Resolution of the ADC sample LSB */ |
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s32 (*read_channel)(const struct i2c_client *client, u8 command); |
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}; |
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/* Command byte C2,C1,C0 - see datasheet */ 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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} /* Update data for the device (all 8 channels) */ static struct ads7828_data *ads7828_update_device(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); struct ads7828_data *data = i2c_get_clientdata(client); mutex_lock(&data->update_lock); if (time_after(jiffies, data->last_updated + HZ + HZ / 2) || !data->valid) { unsigned int ch; dev_dbg(&client->dev, "Starting ads7828 update "); for (ch = 0; ch < ADS7828_NCH; ch++) { |
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u8 cmd = ads7828_cmd_byte(data->cmd_byte, ch); |
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data->adc_input[ch] = data->read_channel(client, cmd); |
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} data->last_updated = jiffies; |
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data->valid = true; |
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} mutex_unlock(&data->update_lock); return data; } /* sysfs callback function */ |
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static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da, char *buf) |
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{ struct sensor_device_attribute *attr = to_sensor_dev_attr(da); struct ads7828_data *data = ads7828_update_device(dev); |
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unsigned int value = DIV_ROUND_CLOSEST(data->adc_input[attr->index] * data->lsb_resol, 1000); |
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return sprintf(buf, "%d ", value); } |
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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); |
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static struct attribute *ads7828_attributes[] = { &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 }; static const struct attribute_group ads7828_group = { .attrs = ads7828_attributes, }; |
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static int ads7828_remove(struct i2c_client *client) |
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{ struct ads7828_data *data = i2c_get_clientdata(client); |
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hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&client->dev.kobj, &ads7828_group); |
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return 0; } |
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static int ads7828_probe(struct i2c_client *client, const struct i2c_device_id *id) { |
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struct ads7828_platform_data *pdata = client->dev.platform_data; |
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struct ads7828_data *data; int err; |
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data = devm_kzalloc(&client->dev, sizeof(struct ads7828_data), GFP_KERNEL); if (!data) return -ENOMEM; |
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if (pdata) { data->diff_input = pdata->diff_input; data->ext_vref = pdata->ext_vref; if (data->ext_vref) data->vref_mv = pdata->vref_mv; } /* Bound Vref with min/max values if it was provided */ if (data->vref_mv) data->vref_mv = SENSORS_LIMIT(data->vref_mv, ADS7828_EXT_VREF_MV_MIN, ADS7828_EXT_VREF_MV_MAX); else data->vref_mv = ADS7828_INT_VREF_MV; |
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/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */ if (id->driver_data == ads7828) { data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096); data->read_channel = i2c_smbus_read_word_swapped; } else { data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 256); data->read_channel = i2c_smbus_read_byte_data; } |
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data->cmd_byte = data->ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3; if (!data->diff_input) data->cmd_byte |= ADS7828_CMD_SD_SE; |
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i2c_set_clientdata(client, data); |
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mutex_init(&data->update_lock); |
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err = sysfs_create_group(&client->dev.kobj, &ads7828_group); if (err) |
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return err; |
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data->hwmon_dev = hwmon_device_register(&client->dev); if (IS_ERR(data->hwmon_dev)) { err = PTR_ERR(data->hwmon_dev); |
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goto error; |
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} return 0; |
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error: |
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sysfs_remove_group(&client->dev.kobj, &ads7828_group); |
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return err; } |
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static const struct i2c_device_id ads7828_device_ids[] = { |
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{ "ads7828", ads7828 }, { "ads7830", ads7830 }, |
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{ } }; MODULE_DEVICE_TABLE(i2c, ads7828_device_ids); |
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static struct i2c_driver ads7828_driver = { .driver = { .name = "ads7828", }, |
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.id_table = ads7828_device_ids, .probe = ads7828_probe, .remove = ads7828_remove, }; |
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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"); |