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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300// SPDX-License-Identifier: GPL-2.0-only/* * Dallas Semiconductor DS1682 Elapsed Time Recorder device driver * * Written by: Grant Likely <grant.likely@secretlab.ca> * * Copyright (C) 2007 Secret Lab Technologies Ltd. */
/* * The DS1682 elapsed timer recorder is a simple device that implements * one elapsed time counter, one event counter, an alarm signal and 10 * bytes of general purpose EEPROM. * * This driver provides access to the DS1682 counters and user data via * the sysfs. The following attributes are added to the device node: * elapsed_time (u32): Total elapsed event time in ms resolution * alarm_time (u32): When elapsed time exceeds the value in alarm_time, * then the alarm pin is asserted. * event_count (u16): number of times the event pin has gone low. * eeprom (u8[10]): general purpose EEPROM * * Counter registers and user data are both read/write unless the device * has been write protected. This driver does not support turning off write * protection. Once write protection is turned on, it is impossible to * turn it off again, so I have left the feature out of this driver to avoid * accidental enabling, but it is trivial to add write protect support. * */
#include <linux/module.h>#include <linux/i2c.h>#include <linux/string.h>#include <linux/list.h>#include <linux/nvmem-provider.h>#include <linux/sysfs.h>#include <linux/ctype.h>#include <linux/hwmon-sysfs.h>
/* Device registers */#define DS1682_REG_CONFIG 0x00#define DS1682_REG_ALARM 0x01#define DS1682_REG_ELAPSED 0x05#define DS1682_REG_EVT_CNTR 0x09#define DS1682_REG_EEPROM 0x0b#define DS1682_REG_RESET 0x1d#define DS1682_REG_WRITE_DISABLE 0x1e#define DS1682_REG_WRITE_MEM_DISABLE 0x1f
#define DS1682_EEPROM_SIZE 10
/* * Generic counter attributes */static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr, char *buf){ struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr); struct i2c_client *client = to_i2c_client(dev); unsigned long long val, check; __le32 val_le = 0; int rc;
dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name);
/* Read the register */ rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr, (u8 *)&val_le); if (rc < 0) return -EIO;
val = le32_to_cpu(val_le);
if (sattr->index == DS1682_REG_ELAPSED) { int retries = 5;
/* Detect and retry when a tick occurs mid-read */ do { rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr, (u8 *)&val_le); if (rc < 0 || retries <= 0) return -EIO;
check = val; val = le32_to_cpu(val_le); retries--; } while (val != check && val != (check + 1)); }
/* Format the output string and return # of bytes * Special case: the 32 bit regs are time values with 1/4s * resolution, scale them up to milliseconds */ return sprintf(buf, "%llu\n", (sattr->nr == 4) ? (val * 250) : val);}
static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count){ struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr); struct i2c_client *client = to_i2c_client(dev); u64 val; __le32 val_le; int rc;
dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);
/* Decode input */ rc = kstrtoull(buf, 0, &val); if (rc < 0) { dev_dbg(dev, "input string not a number\n"); return -EINVAL; }
/* Special case: the 32 bit regs are time values with 1/4s * resolution, scale input down to quarter-seconds */ if (sattr->nr == 4) do_div(val, 250);
/* write out the value */ val_le = cpu_to_le32(val); rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr, (u8 *) & val_le); if (rc < 0) { dev_err(dev, "register write failed; reg=0x%x, size=%i\n", sattr->index, sattr->nr); return -EIO; }
return count;}
/* * Simple register attributes */static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show, ds1682_store, 4, DS1682_REG_ELAPSED);static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show, ds1682_store, 4, DS1682_REG_ALARM);static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show, ds1682_store, 2, DS1682_REG_EVT_CNTR);
static const struct attribute_group ds1682_group = { .attrs = (struct attribute *[]) { &sensor_dev_attr_elapsed_time.dev_attr.attr, &sensor_dev_attr_alarm_time.dev_attr.attr, &sensor_dev_attr_event_count.dev_attr.attr, NULL, },};
/* * User data attribute */static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj, const struct bin_attribute *attr, char *buf, loff_t off, size_t count){ struct i2c_client *client = kobj_to_i2c_client(kobj); int rc;
dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n", buf, off, count);
rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off, count, buf); if (rc < 0) return -EIO;
return count;}
static ssize_t ds1682_eeprom_write(struct file *filp, struct kobject *kobj, const struct bin_attribute *attr, char *buf, loff_t off, size_t count){ struct i2c_client *client = kobj_to_i2c_client(kobj);
dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n", buf, off, count);
/* Write out to the device */ if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off, count, buf) < 0) return -EIO;
return count;}
static const struct bin_attribute ds1682_eeprom_attr = { .attr = { .name = "eeprom", .mode = S_IRUGO | S_IWUSR, }, .size = DS1682_EEPROM_SIZE, .read = ds1682_eeprom_read, .write = ds1682_eeprom_write,};
static int ds1682_nvmem_read(void *priv, unsigned int offset, void *val, size_t bytes){ struct i2c_client *client = priv; int ret;
ret = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + offset, bytes, val); return ret < 0 ? ret : 0;}
static int ds1682_nvmem_write(void *priv, unsigned int offset, void *val, size_t bytes){ struct i2c_client *client = priv; int ret;
ret = i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + offset, bytes, val); return ret < 0 ? ret : 0;}
/* * Called when a ds1682 device is matched with this driver */static int ds1682_probe(struct i2c_client *client){ struct nvmem_config config = { .dev = &client->dev, .owner = THIS_MODULE, .type = NVMEM_TYPE_EEPROM, .reg_read = ds1682_nvmem_read, .reg_write = ds1682_nvmem_write, .size = DS1682_EEPROM_SIZE, .priv = client, }; struct nvmem_device *nvmem; int rc;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) { dev_err(&client->dev, "i2c bus does not support the ds1682\n"); rc = -ENODEV; goto exit; }
nvmem = devm_nvmem_register(&client->dev, &config); if (IS_ENABLED(CONFIG_NVMEM) && IS_ERR(nvmem)) return PTR_ERR(nvmem);
rc = sysfs_create_group(&client->dev.kobj, &ds1682_group); if (rc) goto exit;
rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); if (rc) goto exit_bin_attr;
return 0;
exit_bin_attr: sysfs_remove_group(&client->dev.kobj, &ds1682_group); exit: return rc;}
static void ds1682_remove(struct i2c_client *client){ sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); sysfs_remove_group(&client->dev.kobj, &ds1682_group);}
static const struct i2c_device_id ds1682_id[] = { { "ds1682" }, { }};MODULE_DEVICE_TABLE(i2c, ds1682_id);
static const struct of_device_id ds1682_of_match[] = { { .compatible = "dallas,ds1682", }, {}};MODULE_DEVICE_TABLE(of, ds1682_of_match);
static struct i2c_driver ds1682_driver = { .driver = { .name = "ds1682", .of_match_table = ds1682_of_match, }, .probe = ds1682_probe, .remove = ds1682_remove, .id_table = ds1682_id,};
module_i2c_driver(ds1682_driver);
MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");MODULE_LICENSE("GPL");