i2c: Move at24 to drivers/misc/eeprom

As drivers/i2c/chips is going to go away, move the driver to
drivers/misc/eeprom. Other eeprom drivers may be moved here later, too.
Update Kconfig text to specify this driver as I2C.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

3 files changed, 0 insertions, 609 deletions

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index b9bef04..b58e770 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -16,32 +16,6 @@ config DS1682
 	  This driver can also be built as a module.  If so, the module
 	  will be called ds1682.
 
-config AT24
-	tristate "EEPROMs from most vendors"
-	depends on SYSFS && EXPERIMENTAL
-	help
-	  Enable this driver to get read/write support to most I2C EEPROMs,
-	  after you configure the driver to know about each EEPROM on
-	  your target board.  Use these generic chip names, instead of
-	  vendor-specific ones like at24c64 or 24lc02:
-
-	     24c00, 24c01, 24c02, spd (readonly 24c02), 24c04, 24c08,
-	     24c16, 24c32, 24c64, 24c128, 24c256, 24c512, 24c1024
-
-	  Unless you like data loss puzzles, always be sure that any chip
-	  you configure as a 24c32 (32 kbit) or larger is NOT really a
-	  24c16 (16 kbit) or smaller, and vice versa. Marking the chip
-	  as read-only won't help recover from this. Also, if your chip
-	  has any software write-protect mechanism you may want to review the
-	  code to make sure this driver won't turn it on by accident.
-
-	  If you use this with an SMBus adapter instead of an I2C adapter,
-	  full functionality is not available.  Only smaller devices are
-	  supported (24c16 and below, max 4 kByte).
-
-	  This driver can also be built as a module.  If so, the module
-	  will be called at24.
-
 config SENSORS_EEPROM
 	tristate "EEPROM reader"
 	depends on EXPERIMENTAL
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index 00fcb51..5c14776 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -11,7 +11,6 @@
 #
 
 obj-$(CONFIG_DS1682)		+= ds1682.o
-obj-$(CONFIG_AT24)		+= at24.o
 obj-$(CONFIG_SENSORS_EEPROM)	+= eeprom.o
 obj-$(CONFIG_SENSORS_MAX6875)	+= max6875.o
 obj-$(CONFIG_SENSORS_PCA9539)	+= pca9539.o
diff --git a/drivers/i2c/chips/at24.c b/drivers/i2c/chips/at24.c
deleted file mode 100644
index d477552..0000000
--- a/drivers/i2c/chips/at24.c
+++ /dev/null
@@ -1,582 +0,0 @@
-/*
- * 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;
-	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;
-	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;
-
-	/* Smaller eeproms can work given some SMBus extension calls */
-	if (at24->use_smbus) {
-		if (count > I2C_SMBUS_BLOCK_MAX)
-			count = I2C_SMBUS_BLOCK_MAX;
-		status = i2c_smbus_read_i2c_block_data(client, offset,
-				count, buf);
-		dev_dbg(&client->dev, "smbus read %zu@%d --> %d\n",
-				count, offset, status);
-		return (status < 0) ? -EIO : status;
-	}
-
-	/*
-	 * 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;
-
-	status = i2c_transfer(client->adapter, msg, 2);
-	dev_dbg(&client->dev, "i2c read %zu@%d --> %d\n",
-			count, offset, status);
-
-	if (status == 2)
-		return count;
-	else if (status >= 0)
-		return -EIO;
-	else
-		return status;
-}
-
-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;
-	ssize_t retval = 0;
-
-	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
-
-	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;
-}
-
-
-/*
- * REVISIT: export at24_bin{read,write}() to let other kernel code use
- * eeprom data. For example, it might hold a board's Ethernet address, or
- * board-specific calibration data generated on the manufacturing floor.
- */
-
-
-/*
- * 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.
- */
-static ssize_t at24_eeprom_write(struct at24_data *at24, char *buf,
-		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;
-		}
-		dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",
-				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;
-}
-
-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;
-	ssize_t retval = 0;
-
-	at24 = dev_get_drvdata(container_of(kobj, struct device, kobj));
-
-	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;
-}
-
-/*-------------------------------------------------------------------------*/
-
-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;
-	}
-
-	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)
-	 */
-	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;
-
-	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->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);
-
-	dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
-		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" : "");
-
-	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");