Commit Graph

4 Commits

Author SHA1 Message Date
Sachin Kamat 098aebc302 i2c: sun6i-p2wi: Remove duplicate inclusion of module.h
module.h was included twice.

Signed-off-by: Sachin Kamat <sachin.kamat@samsung.com>
Acked-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-06-27 14:39:36 +02:00
Boris BREZILLON 4632a93f01 i2c: sun6-p2wi: fix call to snprintf
Fixes possible issue in case pdev name contains formatting characters.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-06-17 14:28:04 +02:00
Wolfram Sang c155ba884f i2c: sun6i-p2wi: use proper return value in probe
Fixes:
>> drivers/i2c/busses/i2c-sun6i-p2wi.c:243:10: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-06-12 22:22:25 +02:00
Boris BREZILLON 3e833490fa i2c: sunxi: add P2WI (Push/Pull 2 Wire Interface) controller support
The P2WI controller looks like an SMBus controller which only supports byte
data transfers. But, it differs from standard SMBus protocol on several
aspects:
- it supports only one slave device, and thus drop the address field
- it adds a parity bit every 8bits of data
- only one read access is required to read a byte (instead of a write
  followed by a read access in standard SMBus protocol)
- there's no Ack bit after each byte transfer

This means this bus cannot be used to interface with standard SMBus
devices (the only known device to support this interface is the AXP221
PMIC).
However the P2WI protocol is close enough to SMBus to be integrated in
the I2C subsystem (see this thread [1] for detailed reasons that led to
integrating this driver in the I2C subsystem).

[1] http://www.spinics.net/lists/linux-i2c/msg15066.html

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-06-12 00:24:06 +02:00