Re: [PATCH v6 2/2] i2c: sunxi: add P2WI (Push/Pull 2 Wire Interface) controller support
From: Arnd Bergmann <hidden>
Date: 2014-06-11 08:49:06
Also in:
linux-arm-kernel, linux-i2c, lkml
On Wednesday 11 June 2014 10:39:40 Boris BREZILLON wrote:
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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> Acked-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
Acked-by: Arnd Bergmann <redacted>
quoted hunk ↗ jump to hunk
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index c94db1c..a6023fe 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig@@ -771,6 +771,18 @@ config I2C_STU300 This driver can also be built as a module. If so, the module will be called i2c-stu300. +config I2C_SUN6I_P2WI + tristate "Allwinner sun6i internal P2WI controller" + depends on MACH_SUN6I && RESET_CONTROLLER
One very minor comment: I wonder if we should make this depends on RESET_CONTROLLER depends on MACH_SUN6I || COMPILE_TEST instead so we have better build coverage. I haven't tested if building on other architectures works, or if there are additional dependencies. No need to change this if there are no other comments. Arnd