During device instantiation have the at24 driver add the new device to the eeprom_dev hardware class. The functionality is enabled by CONFIG_EEPROM_CLASS.
Signed-off-by: Curt Brune <[email protected]> --- drivers/misc/eeprom/at24.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c index d87f77f..07782ea 100644 --- a/drivers/misc/eeprom/at24.c +++ b/drivers/misc/eeprom/at24.c @@ -1,170 +1,177 @@ /* * at24.c - handle most I2C EEPROMs * * Copyright (C) 2005-2007 David Brownell * Copyright (C) 2008 Wolfram Sang, Pengutronix * * 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. */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/delay.h> #include <linux/mutex.h> #include <linux/sysfs.h> #include <linux/mod_devicetable.h> #include <linux/log2.h> #include <linux/bitops.h> #include <linux/jiffies.h> #include <linux/of.h> #include <linux/i2c.h> #include <linux/platform_data/at24.h> +#ifdef CONFIG_EEPROM_CLASS +#include <linux/eeprom_class.h> +#endif + /* * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable. * Differences between different vendor product lines (like Atmel AT24C or * MicroChip 24LC, etc) won't much matter for typical read/write access. * There are also I2C RAM chips, likewise interchangeable. One example * would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes). * * However, misconfiguration can lose data. "Set 16-bit memory address" * to a part with 8-bit addressing will overwrite data. Writing with too * big a page size also loses data. And it's not safe to assume that the * conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC * uses 0x51, for just one example. * * Accordingly, explicit board-specific configuration data should be used * in almost all cases. (One partial exception is an SMBus used to access * "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.) * * So this driver uses "new style" I2C driver binding, expecting to be * told what devices exist. That may be in arch/X/mach-Y/board-Z.c or * similar kernel-resident tables; or, configuration data coming from * a bootloader. * * Other than binding model, current differences from "eeprom" driver are * that this one handles write access and isn't restricted to 24c02 devices. * It also handles larger devices (32 kbit and up) with two-byte addresses, * which won't work on pure SMBus systems. */ struct at24_data { struct at24_platform_data chip; struct memory_accessor macc; int use_smbus; /* * Lock protects against activities from other Linux tasks, * but not from changes by other I2C masters. */ struct mutex lock; struct bin_attribute bin; u8 *writebuf; unsigned write_max; unsigned num_addresses; +#ifdef CONFIG_EEPROM_CLASS + struct device *eeprom_dev; +#endif /* * Some chips tie up multiple I2C addresses; dummy devices reserve * them for us, and we'll use them with SMBus calls. */ struct i2c_client *client[]; }; /* * This parameter is to help this driver avoid blocking other drivers out * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C * clock, one 256 byte read takes about 1/43 second which is excessive; * but the 1/170 second it takes at 400 kHz may be quite reasonable; and * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible. * * This value is forced to be a power of two so that writes align on pages. */ static unsigned io_limit = 128; module_param(io_limit, uint, 0); MODULE_PARM_DESC(io_limit, "Maximum bytes per I/O (default 128)"); /* * Specs often allow 5 msec for a page write, sometimes 20 msec; * it's important to recover from write timeouts. */ static unsigned write_timeout = 25; module_param(write_timeout, uint, 0); MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)"); #define AT24_SIZE_BYTELEN 5 #define AT24_SIZE_FLAGS 8 #define AT24_BITMASK(x) (BIT(x) - 1) /* create non-zero magic value for given eeprom parameters */ #define AT24_DEVICE_MAGIC(_len, _flags) \ ((1 << AT24_SIZE_FLAGS | (_flags)) \ << AT24_SIZE_BYTELEN | ilog2(_len)) static const struct i2c_device_id at24_ids[] = { /* needs 8 addresses as A0-A2 are ignored */ { "24c00", AT24_DEVICE_MAGIC(128 / 8, AT24_FLAG_TAKE8ADDR) }, /* old variants can't be handled with this generic entry! */ { "24c01", AT24_DEVICE_MAGIC(1024 / 8, 0) }, { "24c02", AT24_DEVICE_MAGIC(2048 / 8, 0) }, /* spd is a 24c02 in memory DIMMs */ { "spd", AT24_DEVICE_MAGIC(2048 / 8, AT24_FLAG_READONLY | AT24_FLAG_IRUGO) }, { "24c04", AT24_DEVICE_MAGIC(4096 / 8, 0) }, /* 24rf08 quirk is handled at i2c-core */ { "24c08", AT24_DEVICE_MAGIC(8192 / 8, 0) }, { "24c16", AT24_DEVICE_MAGIC(16384 / 8, 0) }, { "24c32", AT24_DEVICE_MAGIC(32768 / 8, AT24_FLAG_ADDR16) }, { "24c64", AT24_DEVICE_MAGIC(65536 / 8, AT24_FLAG_ADDR16) }, { "24c128", AT24_DEVICE_MAGIC(131072 / 8, AT24_FLAG_ADDR16) }, { "24c256", AT24_DEVICE_MAGIC(262144 / 8, AT24_FLAG_ADDR16) }, { "24c512", AT24_DEVICE_MAGIC(524288 / 8, AT24_FLAG_ADDR16) }, { "24c1024", AT24_DEVICE_MAGIC(1048576 / 8, AT24_FLAG_ADDR16) }, { "at24", 0 }, { /* END OF LIST */ } }; MODULE_DEVICE_TABLE(i2c, at24_ids); /*-------------------------------------------------------------------------*/ /* * This routine supports chips which consume multiple I2C addresses. It * computes the addressing information to be used for a given r/w request. * Assumes that sanity checks for offset happened at sysfs-layer. */ static struct i2c_client *at24_translate_offset(struct at24_data *at24, unsigned *offset) { unsigned i; if (at24->chip.flags & AT24_FLAG_ADDR16) { i = *offset >> 16; *offset &= 0xffff; } else { i = *offset >> 8; *offset &= 0xff; } return at24->client[i]; } static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf, unsigned offset, size_t count) { struct i2c_msg msg[2]; u8 msgbuf[2]; struct i2c_client *client; unsigned long timeout, read_time; int status, i; memset(msg, 0, sizeof(msg)); /* * REVISIT some multi-address chips don't rollover page reads to * the next slave address, so we may need to truncate the count. * Those chips might need another quirk flag. @@ -524,173 +531,186 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) return -EINVAL; } if (!is_power_of_2(chip.page_size)) dev_warn(&client->dev, "page_size looks suspicious (no power of 2)!\n"); /* Use I2C operations unless we're stuck with SMBus extensions. */ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { if (chip.flags & AT24_FLAG_ADDR16) return -EPFNOSUPPORT; if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { use_smbus = I2C_SMBUS_I2C_BLOCK_DATA; } else if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) { use_smbus = I2C_SMBUS_WORD_DATA; } else if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) { use_smbus = I2C_SMBUS_BYTE_DATA; } else { return -EPFNOSUPPORT; } } if (chip.flags & AT24_FLAG_TAKE8ADDR) num_addresses = 8; else num_addresses = DIV_ROUND_UP(chip.byte_len, (chip.flags & AT24_FLAG_ADDR16) ? 65536 : 256); at24 = devm_kzalloc(&client->dev, sizeof(struct at24_data) + num_addresses * sizeof(struct i2c_client *), GFP_KERNEL); if (!at24) return -ENOMEM; mutex_init(&at24->lock); at24->use_smbus = use_smbus; at24->chip = chip; at24->num_addresses = num_addresses; /* * Export the EEPROM bytes through sysfs, since that's convenient. * By default, only root should see the data (maybe passwords etc) */ sysfs_bin_attr_init(&at24->bin); at24->bin.attr.name = "eeprom"; at24->bin.attr.mode = chip.flags & AT24_FLAG_IRUGO ? S_IRUGO : S_IRUSR; at24->bin.read = at24_bin_read; at24->bin.size = chip.byte_len; at24->macc.read = at24_macc_read; writable = !(chip.flags & AT24_FLAG_READONLY); if (writable) { if (!use_smbus || i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) { unsigned write_max = chip.page_size; at24->macc.write = at24_macc_write; at24->bin.write = at24_bin_write; at24->bin.attr.mode |= S_IWUSR; if (write_max > io_limit) write_max = io_limit; if (use_smbus && write_max > I2C_SMBUS_BLOCK_MAX) write_max = I2C_SMBUS_BLOCK_MAX; at24->write_max = write_max; /* buffer (data + address at the beginning) */ at24->writebuf = devm_kzalloc(&client->dev, write_max + 2, GFP_KERNEL); if (!at24->writebuf) return -ENOMEM; } else { dev_warn(&client->dev, "cannot write due to controller restrictions."); } } at24->client[0] = client; /* use dummy devices for multiple-address chips */ for (i = 1; i < num_addresses; i++) { at24->client[i] = i2c_new_dummy(client->adapter, client->addr + i); if (!at24->client[i]) { dev_err(&client->dev, "address 0x%02x unavailable\n", client->addr + i); err = -EADDRINUSE; goto err_clients; } } err = sysfs_create_bin_file(&client->dev.kobj, &at24->bin); if (err) goto err_clients; +#ifdef CONFIG_EEPROM_CLASS + at24->eeprom_dev = eeprom_device_register(&client->dev); + if (IS_ERR(at24->eeprom_dev)) { + dev_err(&client->dev, "error registering eeprom device.\n"); + err = PTR_ERR(at24->eeprom_dev); + goto err_clients; + } +#endif + i2c_set_clientdata(client, at24); dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n", at24->bin.size, client->name, writable ? "writable" : "read-only", at24->write_max); if (use_smbus == I2C_SMBUS_WORD_DATA || use_smbus == I2C_SMBUS_BYTE_DATA) { dev_notice(&client->dev, "Falling back to %s reads, " "performance will suffer\n", use_smbus == I2C_SMBUS_WORD_DATA ? "word" : "byte"); } /* export data to kernel code */ if (chip.setup) chip.setup(&at24->macc, chip.context); return 0; err_clients: for (i = 1; i < num_addresses; i++) if (at24->client[i]) i2c_unregister_device(at24->client[i]); return err; } static int at24_remove(struct i2c_client *client) { struct at24_data *at24; int i; at24 = i2c_get_clientdata(client); sysfs_remove_bin_file(&client->dev.kobj, &at24->bin); for (i = 1; i < at24->num_addresses; i++) i2c_unregister_device(at24->client[i]); +#ifdef CONFIG_EEPROM_CLASS + eeprom_device_unregister(at24->eeprom_dev); +#endif + return 0; } /*-------------------------------------------------------------------------*/ static struct i2c_driver at24_driver = { .driver = { .name = "at24", .owner = THIS_MODULE, }, .probe = at24_probe, .remove = at24_remove, .id_table = at24_ids, }; static int __init at24_init(void) { if (!io_limit) { pr_err("at24: io_limit must not be 0!\n"); return -EINVAL; } io_limit = rounddown_pow_of_two(io_limit); return i2c_add_driver(&at24_driver); } module_init(at24_init); static void __exit at24_exit(void) { i2c_del_driver(&at24_driver); } module_exit(at24_exit); MODULE_DESCRIPTION("Driver for most I2C EEPROMs"); MODULE_AUTHOR("David Brownell and Wolfram Sang"); MODULE_LICENSE("GPL"); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
