2008-07-14 16:38:35 -04:00
|
|
|
/*
|
|
|
|
* 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/i2c.h>
|
|
|
|
#include <linux/i2c/at24.h>
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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;
|
2009-04-02 19:56:57 -04:00
|
|
|
struct memory_accessor macc;
|
2008-07-14 16:38:35 -04:00
|
|
|
bool 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;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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;
|
2009-11-26 03:22:33 -05:00
|
|
|
unsigned long timeout, read_time;
|
2008-07-14 16:38:35 -04:00
|
|
|
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.
|
|
|
|
*
|
|
|
|
* If the real hardware used four adjacent 24c02 chips and that
|
|
|
|
* were misconfigured as one 24c08, that would be a similar effect:
|
|
|
|
* one "eeprom" file not four, but larger reads would fail when
|
|
|
|
* they crossed certain pages.
|
|
|
|
*/
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Slave address and byte offset derive from the offset. Always
|
|
|
|
* set the byte address; on a multi-master board, another master
|
|
|
|
* may have changed the chip's "current" address pointer.
|
|
|
|
*/
|
|
|
|
client = at24_translate_offset(at24, &offset);
|
|
|
|
|
|
|
|
if (count > io_limit)
|
|
|
|
count = io_limit;
|
|
|
|
|
|
|
|
if (at24->use_smbus) {
|
2009-11-26 03:22:33 -05:00
|
|
|
/* Smaller eeproms can work given some SMBus extension calls */
|
2008-07-14 16:38:35 -04:00
|
|
|
if (count > I2C_SMBUS_BLOCK_MAX)
|
|
|
|
count = I2C_SMBUS_BLOCK_MAX;
|
2009-11-26 03:22:33 -05:00
|
|
|
} else {
|
|
|
|
/*
|
|
|
|
* When we have a better choice than SMBus calls, use a
|
|
|
|
* combined I2C message. Write address; then read up to
|
|
|
|
* io_limit data bytes. Note that read page rollover helps us
|
|
|
|
* here (unlike writes). msgbuf is u8 and will cast to our
|
|
|
|
* needs.
|
|
|
|
*/
|
|
|
|
i = 0;
|
|
|
|
if (at24->chip.flags & AT24_FLAG_ADDR16)
|
|
|
|
msgbuf[i++] = offset >> 8;
|
|
|
|
msgbuf[i++] = offset;
|
|
|
|
|
|
|
|
msg[0].addr = client->addr;
|
|
|
|
msg[0].buf = msgbuf;
|
|
|
|
msg[0].len = i;
|
|
|
|
|
|
|
|
msg[1].addr = client->addr;
|
|
|
|
msg[1].flags = I2C_M_RD;
|
|
|
|
msg[1].buf = buf;
|
|
|
|
msg[1].len = count;
|
2008-07-14 16:38:35 -04:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
2009-11-26 03:22:33 -05:00
|
|
|
* Reads fail if the previous write didn't complete yet. We may
|
|
|
|
* loop a few times until this one succeeds, waiting at least
|
|
|
|
* long enough for one entire page write to work.
|
2008-07-14 16:38:35 -04:00
|
|
|
*/
|
2009-11-26 03:22:33 -05:00
|
|
|
timeout = jiffies + msecs_to_jiffies(write_timeout);
|
|
|
|
do {
|
|
|
|
read_time = jiffies;
|
|
|
|
if (at24->use_smbus) {
|
|
|
|
status = i2c_smbus_read_i2c_block_data(client, offset,
|
|
|
|
count, buf);
|
|
|
|
} else {
|
|
|
|
status = i2c_transfer(client->adapter, msg, 2);
|
|
|
|
if (status == 2)
|
|
|
|
status = count;
|
|
|
|
}
|
|
|
|
dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
|
|
|
|
count, offset, status, jiffies);
|
2008-07-14 16:38:35 -04:00
|
|
|
|
2009-11-26 03:22:33 -05:00
|
|
|
if (status == count)
|
|
|
|
return count;
|
2008-07-14 16:38:35 -04:00
|
|
|
|
2009-11-26 03:22:33 -05:00
|
|
|
/* REVISIT: at HZ=100, this is sloooow */
|
|
|
|
msleep(1);
|
|
|
|
} while (time_before(read_time, timeout));
|
2008-07-14 16:38:35 -04:00
|
|
|
|
2009-11-26 03:22:33 -05:00
|
|
|
return -ETIMEDOUT;
|
2008-07-14 16:38:35 -04:00
|
|
|
}
|
|
|
|
|
2009-04-02 19:56:57 -04:00
|
|
|
static ssize_t at24_read(struct at24_data *at24,
|
2008-07-14 16:38:35 -04:00
|
|
|
char *buf, loff_t off, size_t count)
|
|
|
|
{
|
|
|
|
ssize_t retval = 0;
|
|
|
|
|
|
|
|
if (unlikely(!count))
|
|
|
|
return count;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Read data from chip, protecting against concurrent updates
|
|
|
|
* from this host, but not from other I2C masters.
|
|
|
|
*/
|
|
|
|
mutex_lock(&at24->lock);
|
|
|
|
|
|
|
|
while (count) {
|
|
|
|
ssize_t status;
|
|
|
|
|
|
|
|
status = at24_eeprom_read(at24, buf, off, count);
|
|
|
|
if (status <= 0) {
|
|
|
|
if (retval == 0)
|
|
|
|
retval = status;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
buf += status;
|
|
|
|
off += status;
|
|
|
|
count -= status;
|
|
|
|
retval += status;
|
|
|
|
}
|
|
|
|
|
|
|
|
mutex_unlock(&at24->lock);
|
|
|
|
|
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
|
2009-04-02 19:56:57 -04:00
|
|
|
static ssize_t at24_bin_read(struct kobject *kobj, struct bin_attribute *attr,
|
|
|
|
char *buf, loff_t off, size_t count)
|
|
|
|
{
|
|
|
|
struct at24_data *at24;
|
2008-07-14 16:38:35 -04:00
|
|
|
|
2009-04-02 19:56:57 -04:00
|
|
|
at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
|
|
|
|
return at24_read(at24, buf, off, count);
|
|
|
|
}
|
2008-07-14 16:38:35 -04:00
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Note that if the hardware write-protect pin is pulled high, the whole
|
|
|
|
* chip is normally write protected. But there are plenty of product
|
|
|
|
* variants here, including OTP fuses and partial chip protect.
|
|
|
|
*
|
|
|
|
* We only use page mode writes; the alternative is sloooow. This routine
|
|
|
|
* writes at most one page.
|
|
|
|
*/
|
2009-04-13 17:40:06 -04:00
|
|
|
static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
|
2008-07-14 16:38:35 -04:00
|
|
|
unsigned offset, size_t count)
|
|
|
|
{
|
|
|
|
struct i2c_client *client;
|
|
|
|
struct i2c_msg msg;
|
|
|
|
ssize_t status;
|
|
|
|
unsigned long timeout, write_time;
|
|
|
|
unsigned next_page;
|
|
|
|
|
|
|
|
/* Get corresponding I2C address and adjust offset */
|
|
|
|
client = at24_translate_offset(at24, &offset);
|
|
|
|
|
|
|
|
/* write_max is at most a page */
|
|
|
|
if (count > at24->write_max)
|
|
|
|
count = at24->write_max;
|
|
|
|
|
|
|
|
/* Never roll over backwards, to the start of this page */
|
|
|
|
next_page = roundup(offset + 1, at24->chip.page_size);
|
|
|
|
if (offset + count > next_page)
|
|
|
|
count = next_page - offset;
|
|
|
|
|
|
|
|
/* If we'll use I2C calls for I/O, set up the message */
|
|
|
|
if (!at24->use_smbus) {
|
|
|
|
int i = 0;
|
|
|
|
|
|
|
|
msg.addr = client->addr;
|
|
|
|
msg.flags = 0;
|
|
|
|
|
|
|
|
/* msg.buf is u8 and casts will mask the values */
|
|
|
|
msg.buf = at24->writebuf;
|
|
|
|
if (at24->chip.flags & AT24_FLAG_ADDR16)
|
|
|
|
msg.buf[i++] = offset >> 8;
|
|
|
|
|
|
|
|
msg.buf[i++] = offset;
|
|
|
|
memcpy(&msg.buf[i], buf, count);
|
|
|
|
msg.len = i + count;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Writes fail if the previous one didn't complete yet. We may
|
|
|
|
* loop a few times until this one succeeds, waiting at least
|
|
|
|
* long enough for one entire page write to work.
|
|
|
|
*/
|
|
|
|
timeout = jiffies + msecs_to_jiffies(write_timeout);
|
|
|
|
do {
|
|
|
|
write_time = jiffies;
|
|
|
|
if (at24->use_smbus) {
|
|
|
|
status = i2c_smbus_write_i2c_block_data(client,
|
|
|
|
offset, count, buf);
|
|
|
|
if (status == 0)
|
|
|
|
status = count;
|
|
|
|
} else {
|
|
|
|
status = i2c_transfer(client->adapter, &msg, 1);
|
|
|
|
if (status == 1)
|
|
|
|
status = count;
|
|
|
|
}
|
2008-08-10 16:56:16 -04:00
|
|
|
dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",
|
2008-07-14 16:38:35 -04:00
|
|
|
count, offset, status, jiffies);
|
|
|
|
|
|
|
|
if (status == count)
|
|
|
|
return count;
|
|
|
|
|
|
|
|
/* REVISIT: at HZ=100, this is sloooow */
|
|
|
|
msleep(1);
|
|
|
|
} while (time_before(write_time, timeout));
|
|
|
|
|
|
|
|
return -ETIMEDOUT;
|
|
|
|
}
|
|
|
|
|
2009-04-13 17:40:06 -04:00
|
|
|
static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off,
|
|
|
|
size_t count)
|
2008-07-14 16:38:35 -04:00
|
|
|
{
|
|
|
|
ssize_t retval = 0;
|
|
|
|
|
|
|
|
if (unlikely(!count))
|
|
|
|
return count;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Write data to chip, protecting against concurrent updates
|
|
|
|
* from this host, but not from other I2C masters.
|
|
|
|
*/
|
|
|
|
mutex_lock(&at24->lock);
|
|
|
|
|
|
|
|
while (count) {
|
|
|
|
ssize_t status;
|
|
|
|
|
|
|
|
status = at24_eeprom_write(at24, buf, off, count);
|
|
|
|
if (status <= 0) {
|
|
|
|
if (retval == 0)
|
|
|
|
retval = status;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
buf += status;
|
|
|
|
off += status;
|
|
|
|
count -= status;
|
|
|
|
retval += status;
|
|
|
|
}
|
|
|
|
|
|
|
|
mutex_unlock(&at24->lock);
|
|
|
|
|
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
|
2009-04-02 19:56:57 -04:00
|
|
|
static ssize_t at24_bin_write(struct kobject *kobj, struct bin_attribute *attr,
|
|
|
|
char *buf, loff_t off, size_t count)
|
|
|
|
{
|
|
|
|
struct at24_data *at24;
|
|
|
|
|
|
|
|
at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
|
|
|
|
return at24_write(at24, buf, off, count);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*-------------------------------------------------------------------------*/
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This lets other kernel code access the eeprom data. For example, it
|
|
|
|
* might hold a board's Ethernet address, or board-specific calibration
|
|
|
|
* data generated on the manufacturing floor.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static ssize_t at24_macc_read(struct memory_accessor *macc, char *buf,
|
|
|
|
off_t offset, size_t count)
|
|
|
|
{
|
|
|
|
struct at24_data *at24 = container_of(macc, struct at24_data, macc);
|
|
|
|
|
|
|
|
return at24_read(at24, buf, offset, count);
|
|
|
|
}
|
|
|
|
|
2009-04-13 17:40:06 -04:00
|
|
|
static ssize_t at24_macc_write(struct memory_accessor *macc, const char *buf,
|
2009-04-02 19:56:57 -04:00
|
|
|
off_t offset, size_t count)
|
|
|
|
{
|
|
|
|
struct at24_data *at24 = container_of(macc, struct at24_data, macc);
|
|
|
|
|
|
|
|
return at24_write(at24, buf, offset, count);
|
|
|
|
}
|
|
|
|
|
2008-07-14 16:38:35 -04:00
|
|
|
/*-------------------------------------------------------------------------*/
|
|
|
|
|
|
|
|
static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
|
|
|
|
{
|
|
|
|
struct at24_platform_data chip;
|
|
|
|
bool writable;
|
|
|
|
bool use_smbus = false;
|
|
|
|
struct at24_data *at24;
|
|
|
|
int err;
|
|
|
|
unsigned i, num_addresses;
|
|
|
|
kernel_ulong_t magic;
|
|
|
|
|
|
|
|
if (client->dev.platform_data) {
|
|
|
|
chip = *(struct at24_platform_data *)client->dev.platform_data;
|
|
|
|
} else {
|
|
|
|
if (!id->driver_data) {
|
|
|
|
err = -ENODEV;
|
|
|
|
goto err_out;
|
|
|
|
}
|
|
|
|
magic = id->driver_data;
|
|
|
|
chip.byte_len = BIT(magic & AT24_BITMASK(AT24_SIZE_BYTELEN));
|
|
|
|
magic >>= AT24_SIZE_BYTELEN;
|
|
|
|
chip.flags = magic & AT24_BITMASK(AT24_SIZE_FLAGS);
|
|
|
|
/*
|
|
|
|
* This is slow, but we can't know all eeproms, so we better
|
|
|
|
* play safe. Specifying custom eeprom-types via platform_data
|
|
|
|
* is recommended anyhow.
|
|
|
|
*/
|
|
|
|
chip.page_size = 1;
|
2009-04-02 19:56:57 -04:00
|
|
|
|
|
|
|
chip.setup = NULL;
|
|
|
|
chip.context = NULL;
|
2008-07-14 16:38:35 -04:00
|
|
|
}
|
|
|
|
|
|
|
|
if (!is_power_of_2(chip.byte_len))
|
|
|
|
dev_warn(&client->dev,
|
|
|
|
"byte_len looks suspicious (no power of 2)!\n");
|
|
|
|
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) {
|
|
|
|
err = -EPFNOSUPPORT;
|
|
|
|
goto err_out;
|
|
|
|
}
|
|
|
|
if (!i2c_check_functionality(client->adapter,
|
|
|
|
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
|
|
|
|
err = -EPFNOSUPPORT;
|
|
|
|
goto err_out;
|
|
|
|
}
|
|
|
|
use_smbus = true;
|
|
|
|
}
|
|
|
|
|
|
|
|
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 = kzalloc(sizeof(struct at24_data) +
|
|
|
|
num_addresses * sizeof(struct i2c_client *), GFP_KERNEL);
|
|
|
|
if (!at24) {
|
|
|
|
err = -ENOMEM;
|
|
|
|
goto err_out;
|
|
|
|
}
|
|
|
|
|
|
|
|
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)
|
|
|
|
*/
|
2010-03-13 14:56:55 -05:00
|
|
|
sysfs_bin_attr_init(&at24->bin);
|
2008-07-14 16:38:35 -04:00
|
|
|
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;
|
|
|
|
|
2009-04-02 19:56:57 -04:00
|
|
|
at24->macc.read = at24_macc_read;
|
|
|
|
|
2008-07-14 16:38:35 -04:00
|
|
|
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;
|
|
|
|
|
2009-04-02 19:56:57 -04:00
|
|
|
at24->macc.write = at24_macc_write;
|
|
|
|
|
2008-07-14 16:38:35 -04:00
|
|
|
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 = kmalloc(write_max + 2, GFP_KERNEL);
|
|
|
|
if (!at24->writebuf) {
|
|
|
|
err = -ENOMEM;
|
|
|
|
goto err_struct;
|
|
|
|
}
|
|
|
|
} 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;
|
|
|
|
|
|
|
|
i2c_set_clientdata(client, at24);
|
|
|
|
|
2008-08-10 16:56:16 -04:00
|
|
|
dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
|
2008-07-14 16:38:35 -04:00
|
|
|
at24->bin.size, client->name,
|
|
|
|
writable ? "(writable)" : "(read-only)");
|
|
|
|
dev_dbg(&client->dev,
|
|
|
|
"page_size %d, num_addresses %d, write_max %d%s\n",
|
|
|
|
chip.page_size, num_addresses,
|
|
|
|
at24->write_max,
|
|
|
|
use_smbus ? ", use_smbus" : "");
|
|
|
|
|
2009-04-02 19:56:57 -04:00
|
|
|
/* export data to kernel code */
|
|
|
|
if (chip.setup)
|
|
|
|
chip.setup(&at24->macc, chip.context);
|
|
|
|
|
2008-07-14 16:38:35 -04:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
err_clients:
|
|
|
|
for (i = 1; i < num_addresses; i++)
|
|
|
|
if (at24->client[i])
|
|
|
|
i2c_unregister_device(at24->client[i]);
|
|
|
|
|
|
|
|
kfree(at24->writebuf);
|
|
|
|
err_struct:
|
|
|
|
kfree(at24);
|
|
|
|
err_out:
|
|
|
|
dev_dbg(&client->dev, "probe error %d\n", err);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int __devexit 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]);
|
|
|
|
|
|
|
|
kfree(at24->writebuf);
|
|
|
|
kfree(at24);
|
|
|
|
i2c_set_clientdata(client, NULL);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*-------------------------------------------------------------------------*/
|
|
|
|
|
|
|
|
static struct i2c_driver at24_driver = {
|
|
|
|
.driver = {
|
|
|
|
.name = "at24",
|
|
|
|
.owner = THIS_MODULE,
|
|
|
|
},
|
|
|
|
.probe = at24_probe,
|
|
|
|
.remove = __devexit_p(at24_remove),
|
|
|
|
.id_table = at24_ids,
|
|
|
|
};
|
|
|
|
|
|
|
|
static int __init at24_init(void)
|
|
|
|
{
|
|
|
|
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");
|