Commit Graph

104 Commits

Author SHA1 Message Date
David Barksdale
8db08de4f6 [PATCH] m41t00: fix bitmasks when writing to chip
Fix the bitmasks used when writing to the M41T00 registers.

The original code used a mask of 0x7f when writing to each register,
this is incorrect and probably the result of a copy-paste error.  As a
result years from 1980 to 1999 will be read back as 2000 to 2019.

Signed-off-by: David Barksdale <amatus@ocgnet.org>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-19 09:13:49 -07:00
Mark A. Greer
8c750c0bd2 [PATCH] i2c: convert m41t00 to use a workqueue
The m41t00 i2c/rtc driver currently uses a tasklet to schedule
interrupt-level writes to the rtc.  This patch causes the driver
to use a workqueue instead.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-04-14 11:18:33 -07:00
Jean Delvare
524465df2a [PATCH] i2c: convert ds1374 to use a workqueue
A tasklet is not suitable for what the ds1374 driver does: neither sleeping
nor mutex operations are allowed in tasklets, and ds1374_set_tlet may do
both.

We can use a workqueue instead, where both sleeping and mutex operations
are allowed.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Randy Vinson <rvinson@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-04-14 11:18:33 -07:00
Alessandro Zummo
6fc7f10cee [PATCH] RTC subsystem: I2C cleanup
This patch, completely optional, removes from drivers/i2c/chips all the
drivers that are implemented in the new RTC subsystem.

It should be noted that none of the current driver is actually integrated,
i.e.  usable without further patches.

Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:44:51 -08:00
Alexey Dobriyan
53b3531bbb [PATCH] s/;;/;/g
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-24 07:33:24 -08:00
Jean Delvare
c006705e0f [PATCH] i2c: Cleanup isp1301_omap
Drop unused rogue i2c driver ID and nonsensical i2c class.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 14:21:54 -08:00
Ingo Molnar
5c085d369c [PATCH] i2c: Semaphore to mutex conversions, part 2
semaphore to mutex conversion.

the conversion was generated via scripts, and the result was validated
automatically via a script as well.

build tested.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 14:21:51 -08:00
Arjan van de Ven
b3585e4f5b [PATCH] I2C: Convert i2c to mutexes
The patch below converts a few i2c semaphores to mutexes

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 14:21:49 -08:00
Russell King
9ded96f24c [PATCH] IRQ type flags
Some ARM platforms have the ability to program the interrupt controller to
detect various interrupt edges and/or levels.  For some platforms, this is
critical to setup correctly, particularly those which the setting is dependent
on the device.

Currently, ARM drivers do (eg) the following:

	err = request_irq(irq, ...);

	set_irq_type(irq, IRQT_RISING);

However, if the interrupt has previously been programmed to be level sensitive
(for whatever reason) then this will cause an interrupt storm.

Hence, if we combine set_irq_type() with request_irq(), we can then safely set
the type prior to unmasking the interrupt.  The unfortunate problem is that in
order to support this, these flags need to be visible outside of the ARM
architecture - drivers such as smc91x need these flags and they're
cross-architecture.

Finally, the SA_TRIGGER_* flag passed to request_irq() should reflect the
property that the device would like.  The IRQ controller code should do its
best to select the most appropriate supported mode.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:46 -08:00
Greg Kroah-Hartman
2b48716d1d [PATCH] I2C: Remove .owner setting from i2c_driver as it's no longer needed
Now that i2c_add_driver() doesn't need the module owner to be set by
hand, we can delete it from the drivers.  This patch catches all of the
drivers that I found in the current tree (if a driver sets the .owner by
hand, it's not a problem, just not needed.)

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jean Delvare <khali@linux-fr.org>
2006-01-05 22:16:25 -08:00
Laurent Riffard
a9718b0c11 [PATCH] i2c: Drop i2c_driver.{owner,name}, 2 of 11
We should use the i2c_driver.driver's .name and .owner fields
instead of the i2c_driver's ones.

This patch updates the miscellaneaous i2c chip drivers.

Signed-off-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:23 -08:00
Jean Delvare
cde7859bda [PATCH] i2c: Rework client usage count, 2 of 3
Make I2C_CLIENT_ALLOW_USE the default for all i2c clients. It doesn't
hurt if the usage count is actually never used for any given driver,
and allows for nice code simplifications in i2c-core.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:22 -08:00
Jean Delvare
8a9947552d [PATCH] i2c: Drop i2c_driver.flags, 2 of 3
Just about every i2c chip driver sets the I2C_DF_NOTIFY flag, so we
can simply make it the default and drop the flag. If any driver really
doesn't want to be notified when i2c adapters are added, that driver
can simply omit to set .attach_adapter. This approach is also more
robust as it prevents accidental NULL pointer dereferences.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:21 -08:00
Nicolas Kaiser
7e94436942 [PATCH] i2c: Remove duplicate rtc8564 BCD macros
Remove duplicate of BCD macros.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:21 -08:00
Michael Burian
f9e8957937 [PATCH] i2c: Extend ds1337 initialization
Add code to handle case where board firmware does not start the
RTC.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
CC: James Chapman <jchapman@katalix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:20 -08:00
Linus Torvalds
5643f000c1 Merge master.kernel.org:/home/rmk/linux-2.6-drvmodel 2005-11-11 09:24:26 -08:00
Russell King
3ae5eaec1d [DRIVER MODEL] Convert platform drivers to use struct platform_driver
This allows us to eliminate the casts in the drivers, and eventually
remove the use of the device_driver function pointer methods for
platform device drivers.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-11-09 22:32:44 +00:00
James Chapman
ef96274644 [PATCH] i2c: ds1337 BCD conversion fix
Fix BCD value errors when month=9, moving the increment inside the
BIN2BCD macro.
Fix similar code for the weekday value, just for consistency.

This bug was reported by Michael Burian <dynmail1@gassner-waagen.at>.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-11-07 21:46:37 -08:00
Russell King
d052d1beff Create platform_device.h to contain all the platform device details.
Convert everyone who uses platform_bus_type to include
linux/platform_device.h.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-29 19:07:23 +01:00
Ben Dooks
6344a8ece0 [PATCH] i2c: Static function fixes, 4 of 4
Fix functions declared static and then implemented
without the static in drivers/i2c/chips.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:13 -07:00
Ben Dooks
6536c49a1e [PATCH] i2c: Static function fixes, 1 of 4
eeprom_detect is first declared static and then when
the function is actually implemented, there is no static.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:12 -07:00
Deepak Saxena
5263ebb51e [PATCH] i2c: kzalloc conversion, other drivers
Use kzalloc instead of kmalloc+memset in all remaining i2c bus and
chip drivers.

Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:12 -07:00
Alessandro Zummo
4d4e5ce864 [PATCH] i2c: New Xicor X1205 RTC driver
New driver for the Xicor X1205 RTC chip.

Signed-off-by: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:12 -07:00
Laurent Riffard
0cf3628181 [PATCH] Owner field additions to many i2c drivers, 2 of 5
This patch updates the .owner field for various struct xxxx_driver variables,
other than pci_driver.

Signed-off-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Jean Delvare <khali@linux-fr>
Acked-by: Mark A. Greer <mgreer@mvista.com>
Acked-by: Ben Dooks <ben-linux@fluff.org>
Acked-by: Deepak Saxena <dsaxena@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:11 -07:00
Jean Delvare
00bffb6e29 [PATCH] i2c: Drop meaningless use of I2C_DF_NOTIFY in i2c_client structures
I2C_DF_NOTIFY is an i2c_driver flag, using it as an i2c_client flag
doesn't make any sense.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Mark A. Greer <mgreer@mvista.com>
Acked-by: Randy Vinson <rvinson@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:10 -07:00
Jean Delvare
30dac74697 [PATCH] i2c: Drop I2C_SMBUS_I2C_BLOCK_MAX
Drop I2C_SMBUS_I2C_BLOCK_MAX, use I2C_SMBUS_BLOCK_MAX instead.

I2C_SMBUS_I2C_BLOCK_MAX has always been defined to the same value as
I2C_SMBUS_BLOCK_MAX, and this will never change: setting it to a lower
value would make no sense, setting it to a higher value would break
i2c_smbus_data compatibility. There is no point in changing
i2c_smbus_data to support larger block transactions in SMBus mode, as
no SMBus hardware supports more than 32 byte blocks. Thus, for larger
transactions, direct I2C transfers are the way to go.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:10 -07:00
Pekka Enberg
82ca76b6b1 [PATCH] drivers: convert kcalloc to kzalloc
This patch converts kcalloc(1, ...) calls to use the new kzalloc() function.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:46 -07:00
Mark A. Greer
8e14d6c173 [PATCH] i2c: chips/ds1374.c fixup
The 'new_time' variable should be static.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:26:53 -07:00
Mark A. Greer
a44e40b4d8 [PATCH] i2c: chips/m41t00.c fixup
The 'new_time' variable should be static.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:26:53 -07:00
Jean Delvare
4c9337da37 [PATCH] I2C: Centralize 24RF08 corruption prevention
The 24RF08 corruption would better be prevented at i2c-core level than
at chip driver level, for several reasons:
* The second quick write should happen as soon as possible after the
  first one, so as to limit the risk that another command is issued on
  the bus inbetween, causing the corruption.
* As a matter of fact, the protection code at driver level was reworked
  at least three times already, which proves how hard it is to get it
  right there, while it's straightforward at i2c-core level.
* It's easy to add a new driver that would need the protection, and
  forget to add it. This did happen already.
* As additional probing addresses can be passed to most i2c chip drivers
  as module parameters, virtually every i2c chip driver would need the
  protection if we want to be really safe.
* Why duplicate code when we can easily avoid it?

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:25 -07:00
Jean Delvare
303760b44a [PATCH] hwmon: hwmon vs i2c, second round (07/11)
The only part left in i2c-sensor is the VRM/VRD/VID handling code.
This is in no way related to i2c, so it doesn't belong there. Move
the code to hwmon, where it belongs.

Note that not all hardware monitoring drivers do VRM/VRD/VID
operations, so less drivers depend on hwmon-vid than there were
depending on i2c-sensor.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:22 -07:00
Jean Delvare
f4b5026120 [PATCH] hwmon: hwmon vs i2c, second round (06/11)
The only thing left in i2c-sensor.h are module parameter definition
macros. It's only an extension of what i2c.h offers, and this extension
is not sensors-specific. As a matter of fact, a few non-sensors drivers
use them. So we better merge them in i2c.h, and get rid of i2c-sensor.h
altogether.

Signed-off-by: Jean Delvare <khali@linux-fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:21 -07:00
Jean Delvare
2ed2dc3c11 [PATCH] hwmon: hwmon vs i2c, second round (04/11)
i2c_probe and i2c_detect now do the exact same thing and operate on
the same data structure, so we can have everyone call i2c_probe.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:20 -07:00
Jean Delvare
9fc6adfa9a [PATCH] hwmon: hwmon vs i2c, second round (01/11)
Add support for kind-forced addresses to i2c_probe, like i2c_detect
has for (essentially) hardware monitoring drivers.

Note that this change will slightly increase the size of the drivers
using I2C_CLIENT_INSMOD, with no immediate benefit. This is a
requirement if we want to merge i2c_probe and i2c_detect though, and
seems a reasonable price to pay in comparison with the previous
cleanups which saved much more than that (such as the i2c-isa cleanup
or the i2c address ranges removal.)

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:18 -07:00
Jean Delvare
7bef559455 [PATCH] I2C: refactor message in i2c_detach_client
We could refactor the error message 34 different i2c drivers print if
i2c_detach_client() fails in this function itself. Saves quite a few
lines of code. Documentation is updated to reflect that change.

Note that this patch should be applied after Rudolf Marek's w83792d
patches.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:14 -07:00
Jean Delvare
5071860aba [PATCH] I2C: Separate non-i2c hwmon drivers from i2c-core (7/9)
Kill normal_isa in header files, documentation and all chip drivers, as
it is no more used.

normal_i2c could be renamed to normal, but I decided not to do so at the
moment, so as to limit the number of changes. This might be done later
as part of the i2c_probe/i2c_detect merge.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:12 -07:00
bgardner@wabtec.com
17f990c87a [PATCH] I2C: max6875 code cleanup
Remove an unused local variable and change the subclient name.

Signed-off-by: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:06 -07:00
bgardner@wabtec.com
a61fc683ae [PATCH] I2C: add kobj_to_i2c_client
Move the inline function kobj_to_i2c_client() from max6875.c to i2c.h.

Signed-off-by: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:05 -07:00
Greg Kroah-Hartman
a8decc658a [PATCH] I2C: fix max6875 build error
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:04 -07:00
bgardner@wabtec.com
bc769ff8f5 [PATCH] I2C: simplify max6875 driver
This is an update to the max6875 driver.
It no longer does any detection, so the address must be forced on module load.
It only makes available the user EEPROM (read-only).

This patch is based off 2.6.13-rc2-mm2.

Signed-off-by: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-09-05 09:14:03 -07:00
Jean Delvare
0d73adc14e [PATCH] I2C: 24RF08 corruption prevention (again)
The 24RF08 corruption prevention in the eeprom and max6875 drivers wasn't
complete. For one thing, the additional quick write should happen as soon
as possible and unconditionally, while both drivers had error paths before.
For another, when a given chip is forced, the core does not emit a quick
write, so a second quick write would cause the corruption rather than
prevent it.

I plan to move the corruption prevention in the core in the long run, so
that individual drivers don't have to care anymore. But I need to merge
i2c_probe and i2c_detect before I do (work in progress).

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-29 13:12:51 -07:00
Ladislav Michl
d91e16943f [PATCH] I2C: ds1337 - fix 12/24 hour mode bug
DS1339 manual, page 6, chapter Date and time operation:
  The DS1339 can be run in either 12-hour or 24-hour mode. Bit 6 of the
  hours register is defined as the 12-hour or 24-hour mode-select bit.
  When high, the 12-hour mode is selected.

Patch below makes ds1337 driver work as documented in manual.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-29 13:12:50 -07:00
Jean Delvare
8d5d45fb14 [PATCH] I2C: Move hwmon drivers (2/3)
Part 2: Move the driver files themselves.

Note that the patch "adds trailing whitespace", because it does move the
files as-is, and some files happen to have trailing whitespace.

From: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:42:50 -07:00
Jean Delvare
ad2f931dcb [PATCH] I2C: Move hwmon drivers (1/3)
Part 1: Configuration files and Makefiles.

From: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:14:31 -07:00
Adrian Bunk
80efa8c720 [PATCH] I2C: SENSORS_ATXP1 must select I2C_SENSOR
On Thu, Jun 30, 2005 at 11:47:09PM +0200, Sebastian Pigulak wrote:
> I've tried patching linux-2.6.13-RC1 with patch-2.6.13-rc1-git2 and
> building atxp1(it allows Vcore voltage changing) into the kernel.
> Unfortunately, the kernel compilation stops with:
>
> LD      init/built-in.o
> LD      vmlinux
> drivers/built-in.o(.text+0x92298): In function `atxp1_detect':
> : undefined reference to `i2c_which_vrm'
> drivers/built-in.o(.text+0x921ae): In function `atxp1_attach_adapter':
> : undefined reference to `i2c_detect'
> make: *** [vmlinux] B??d 1
> ==> ERROR: Build Failed.  Aborting...
>
> Could someone have a look at the module and possibly fix it up?

SENSORS_ATXP1 must select I2C_SENSOR.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:10:37 -07:00
Jean Delvare
2db3276787 [PATCH] I2C: drop bogus eeprom comment
This simple patch drops an out-of-date comment in the eeprom i2c chip
driver.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:10:36 -07:00
Jean Delvare
5da69ba42a [PATCH] I2C: m41t00: fix incorrect kfree
Here is a simple path fixing an incorrect kfree in the m41t00 i2c chip
driver. The current code happens to work by accident, but the freed
pointer isn't the one which was allocated in the first place, which
could cause problems later.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:10:36 -07:00
Jean Delvare
2146fec20c [PATCH] I2C: max6875 Kconfig update
Here is a proposed Kconfig update for the new max6875 i2c chip driver.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:10:36 -07:00
Jean Delvare
9ab1ee2ab7 [PATCH] I2C: New max6875 driver may corrupt EEPROMs
After a careful code analysis on the new max6875 driver
(drivers/i2c/chips/max6875.c), I have come to the conclusion that this
driver may cause EEPROM corruptions if used on random systems.

The EEPROM part of the MAX6875 chip is accessed using rather uncommon
I2C sequences. What is seen by the MAX6875 as reads can be seen by a
standard EEPROM (24C02) as writes. If you check the detection method
used by the driver, you'll find that the first SMBus command it will
send on the bus is i2c_smbus_write_byte_data(client, 0x80, 0x40). For
the MAX6875 it makes an internal pointer point to a specific offset of
the EEPROM waiting for a subsequent read command, so it's not an actual
data write operation, but for a standard EEPROM, this instead means
writing value 0x40 to offset 0x80. Blame Philips and Intel for the
obscure protocol.

Since the MAX6875 and the standard, common 24C02 EEPROMs share two I2C
addresses (0x50 and 0x52), loading the max6875 driver on a system with
standard EEPROMs at either address will trigger a write on these
EEPROMs, which will lead to their corruption if they happen not to be
write protected. This kind of EEPROMs can be found on memory modules
(SPD), ethernet adapters (MAC address), laptops (proprietary data) and
displays (EDID/DDC). Most of these are hopefully write-protected, but
not all of them.

For this reason, I would recommend that the max6875 driver be
neutralized, in a way that nobody can corrupt his/her EEPROMs by just
loading the driver. This means either deleting the driver completely, or
not listing any default address for it. I'd like this to be done before
2.6.13-rc1 is released.

Additionally, the max6875 driver lacks the 24RF08 corruption preventer
present in the eeprom driver, which means that loading this driver in a
system with such a chip would corrupt it as well.

Here is a proposed quick patch addressing the issue, although I wouldn't
mind a complete removal if it makes everyone feel safer. I think Ben
has plans to replace this driver by a much simplified one anyway.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:10:36 -07:00
david-b@pacbell.net
65fc50e50f [PATCH] I2C: minor TPS6501x cleanups
This includes various small cleanups and fixes to the TPS 6501x driver that
came mostly from review feedback by Jean Delvare; thanks Jean!  Also some
goofy whitespace gets fixed.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-07-11 14:10:36 -07:00