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264 lines
7.0 KiB
264 lines
7.0 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Dallas Semiconductor DS1682 Elapsed Time Recorder device driver |
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* |
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* Written by: Grant Likely <[email protected]> |
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* |
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* Copyright (C) 2007 Secret Lab Technologies Ltd. |
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*/ |
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|
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/* |
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* The DS1682 elapsed timer recorder is a simple device that implements |
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* one elapsed time counter, one event counter, an alarm signal and 10 |
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* bytes of general purpose EEPROM. |
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* |
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* This driver provides access to the DS1682 counters and user data via |
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* the sysfs. The following attributes are added to the device node: |
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* elapsed_time (u32): Total elapsed event time in ms resolution |
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* alarm_time (u32): When elapsed time exceeds the value in alarm_time, |
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* then the alarm pin is asserted. |
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* event_count (u16): number of times the event pin has gone low. |
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* eeprom (u8[10]): general purpose EEPROM |
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* |
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* Counter registers and user data are both read/write unless the device |
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* has been write protected. This driver does not support turning off write |
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* protection. Once write protection is turned on, it is impossible to |
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* turn it off again, so I have left the feature out of this driver to avoid |
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* accidental enabling, but it is trivial to add write protect support. |
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* |
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*/ |
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#include <linux/module.h> |
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#include <linux/i2c.h> |
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#include <linux/string.h> |
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#include <linux/list.h> |
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#include <linux/sysfs.h> |
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#include <linux/ctype.h> |
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#include <linux/hwmon-sysfs.h> |
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/* Device registers */ |
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#define DS1682_REG_CONFIG 0x00 |
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#define DS1682_REG_ALARM 0x01 |
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#define DS1682_REG_ELAPSED 0x05 |
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#define DS1682_REG_EVT_CNTR 0x09 |
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#define DS1682_REG_EEPROM 0x0b |
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#define DS1682_REG_RESET 0x1d |
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#define DS1682_REG_WRITE_DISABLE 0x1e |
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#define DS1682_REG_WRITE_MEM_DISABLE 0x1f |
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#define DS1682_EEPROM_SIZE 10 |
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/* |
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* Generic counter attributes |
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*/ |
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static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr); |
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struct i2c_client *client = to_i2c_client(dev); |
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unsigned long long val, check; |
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__le32 val_le = 0; |
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int rc; |
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dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name); |
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/* Read the register */ |
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rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr, |
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(u8 *)&val_le); |
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if (rc < 0) |
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return -EIO; |
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val = le32_to_cpu(val_le); |
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if (sattr->index == DS1682_REG_ELAPSED) { |
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int retries = 5; |
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/* Detect and retry when a tick occurs mid-read */ |
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do { |
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rc = i2c_smbus_read_i2c_block_data(client, sattr->index, |
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sattr->nr, |
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(u8 *)&val_le); |
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if (rc < 0 || retries <= 0) |
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return -EIO; |
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check = val; |
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val = le32_to_cpu(val_le); |
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retries--; |
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} while (val != check && val != (check + 1)); |
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} |
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/* Format the output string and return # of bytes |
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* Special case: the 32 bit regs are time values with 1/4s |
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* resolution, scale them up to milliseconds |
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*/ |
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return sprintf(buf, "%llu\n", (sattr->nr == 4) ? (val * 250) : val); |
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} |
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static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr); |
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struct i2c_client *client = to_i2c_client(dev); |
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u64 val; |
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__le32 val_le; |
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int rc; |
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dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name); |
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/* Decode input */ |
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rc = kstrtoull(buf, 0, &val); |
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if (rc < 0) { |
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dev_dbg(dev, "input string not a number\n"); |
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return -EINVAL; |
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} |
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/* Special case: the 32 bit regs are time values with 1/4s |
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* resolution, scale input down to quarter-seconds */ |
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if (sattr->nr == 4) |
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do_div(val, 250); |
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/* write out the value */ |
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val_le = cpu_to_le32(val); |
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rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr, |
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(u8 *) & val_le); |
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if (rc < 0) { |
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dev_err(dev, "register write failed; reg=0x%x, size=%i\n", |
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sattr->index, sattr->nr); |
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return -EIO; |
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} |
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return count; |
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} |
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/* |
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* Simple register attributes |
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*/ |
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static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show, |
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ds1682_store, 4, DS1682_REG_ELAPSED); |
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static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show, |
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ds1682_store, 4, DS1682_REG_ALARM); |
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static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show, |
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ds1682_store, 2, DS1682_REG_EVT_CNTR); |
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static const struct attribute_group ds1682_group = { |
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.attrs = (struct attribute *[]) { |
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&sensor_dev_attr_elapsed_time.dev_attr.attr, |
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&sensor_dev_attr_alarm_time.dev_attr.attr, |
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&sensor_dev_attr_event_count.dev_attr.attr, |
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NULL, |
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}, |
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}; |
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/* |
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* User data attribute |
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*/ |
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static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj, |
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struct bin_attribute *attr, |
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char *buf, loff_t off, size_t count) |
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{ |
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struct i2c_client *client = kobj_to_i2c_client(kobj); |
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int rc; |
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dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n", |
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buf, off, count); |
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rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off, |
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count, buf); |
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if (rc < 0) |
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return -EIO; |
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return count; |
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} |
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static ssize_t ds1682_eeprom_write(struct file *filp, struct kobject *kobj, |
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struct bin_attribute *attr, |
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char *buf, loff_t off, size_t count) |
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{ |
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struct i2c_client *client = kobj_to_i2c_client(kobj); |
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dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n", |
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buf, off, count); |
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/* Write out to the device */ |
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if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off, |
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count, buf) < 0) |
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return -EIO; |
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return count; |
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} |
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static const struct bin_attribute ds1682_eeprom_attr = { |
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.attr = { |
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.name = "eeprom", |
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.mode = S_IRUGO | S_IWUSR, |
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}, |
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.size = DS1682_EEPROM_SIZE, |
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.read = ds1682_eeprom_read, |
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.write = ds1682_eeprom_write, |
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}; |
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/* |
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* Called when a ds1682 device is matched with this driver |
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*/ |
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static int ds1682_probe(struct i2c_client *client, |
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const struct i2c_device_id *id) |
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{ |
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int rc; |
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if (!i2c_check_functionality(client->adapter, |
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I2C_FUNC_SMBUS_I2C_BLOCK)) { |
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dev_err(&client->dev, "i2c bus does not support the ds1682\n"); |
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rc = -ENODEV; |
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goto exit; |
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} |
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rc = sysfs_create_group(&client->dev.kobj, &ds1682_group); |
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if (rc) |
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goto exit; |
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rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); |
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if (rc) |
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goto exit_bin_attr; |
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return 0; |
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exit_bin_attr: |
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sysfs_remove_group(&client->dev.kobj, &ds1682_group); |
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exit: |
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return rc; |
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} |
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static int ds1682_remove(struct i2c_client *client) |
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{ |
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sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); |
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sysfs_remove_group(&client->dev.kobj, &ds1682_group); |
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return 0; |
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} |
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static const struct i2c_device_id ds1682_id[] = { |
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{ "ds1682", 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, ds1682_id); |
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static const struct of_device_id ds1682_of_match[] = { |
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{ .compatible = "dallas,ds1682", }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, ds1682_of_match); |
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static struct i2c_driver ds1682_driver = { |
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.driver = { |
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.name = "ds1682", |
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.of_match_table = ds1682_of_match, |
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}, |
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.probe = ds1682_probe, |
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.remove = ds1682_remove, |
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.id_table = ds1682_id, |
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}; |
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module_i2c_driver(ds1682_driver); |
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MODULE_AUTHOR("Grant Likely <[email protected]>"); |
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MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver"); |
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MODULE_LICENSE("GPL");
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