linux-sg2042/drivers/i2c
Javier Martinez Canillas a841178445 mfd: cros_ec: Use a zero-length array for command data
Commit 1b84f2a4cd ("mfd: cros_ec: Use fixed size arrays to transfer
data with the EC") modified the struct cros_ec_command fields to not
use pointers for the input and output buffers and use fixed length
arrays instead.

This change was made because the cros_ec ioctl API uses that struct
cros_ec_command to allow user-space to send commands to the EC and
to get data from the EC. So using pointers made the API not 64-bit
safe. Unfortunately this approach was not flexible enough for all
the use-cases since there may be a need to send larger commands
on newer versions of the EC command protocol.

So to avoid to choose a constant length that it may be too big for
most commands and thus wasting memory and CPU cycles on copy from
and to user-space or having a size that is too small for some big
commands, use a zero-length array that is both 64-bit safe and
flexible. The same buffer is used for both output and input data
so the maximum of these values should be used to allocate it.

Suggested-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2015-06-15 13:18:19 +01:00
..
algos i2c: remove FSF address 2014-11-07 18:35:33 +01:00
busses mfd: cros_ec: Use a zero-length array for command data 2015-06-15 13:18:19 +01:00
muxes i2c: i2c-mux-gpio: remove error messages for probe deferrals 2015-04-03 22:00:14 +02:00
Kconfig kconfig: use bool instead of boolean for type definition attributes 2015-01-07 13:08:04 +01:00
Makefile i2c: slave-eeprom: add eeprom simulator driver 2014-12-11 22:25:54 +01:00
i2c-boardinfo.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-core.c i2c: Mark adapter devices with pm_runtime_no_callbacks 2015-04-23 19:35:31 +02:00
i2c-core.h i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-dev.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-mux.c i2c: mux: use proper dev when removing "channel-X" symlinks 2015-04-23 19:35:33 +02:00
i2c-slave-eeprom.c i2c: slave-eeprom: add more info when to increase the pointer 2015-03-27 16:53:40 +01:00
i2c-smbus.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00
i2c-stub.c i2c: remove FSF address 2014-11-07 18:35:33 +01:00