linux-stable/drivers/i2c
Felipe Balbi 540a4790f7 i2c: omap: simplify omap_i2c_ack_stat()
stat & BIT(1) is the same as BIT(1), so let's
simplify things a bit by removing "stat &" from
all omap_i2c_ack_stat() calls.

Code snippet (extremely simplified):

if (stat & NACK) {
        ...
        omap_i2c_ack_stat(dev, stat & NACK);
}

if (stat & RDR) {
        ...
        omap_i2c_ack_stat(dev, stat & RDR);
}

and so on. The tricky place is only WRT errata handling, for example:

if (*stat & (NACK | AL)) {
        omap_i2c_ack_stat(dev, *stat & (XRDY | XDR));
        ...
}

but in this case, the errata says we must clear XRDY and XDR if that
errata triggers, so if they just got enabled or not, it doesn't matter.

Another tricky place is RDR | RRDY (likewise for XDR | XRDY):

if (stat & (RDR | RRDY)) {
        ...
        omap_i2c_ack_stat(dev, stat & (RDR | RRDY));
}

again here there will be no issues because those IRQs never fire
simultaneously and one will only after after we have handled the
previous, that's because the same FIFO is used anyway and we won't shift
data into FIFO until we tell the IP "hey, I'm done with the FIFO, you
can shift more data"

Signed-off-by: Felipe Balbi <balbi@ti.com>
Reviewed-by : Santosh Shilimkar <santosh.shilimkar@ti.com>
[Added the explaination from the discurssion to the commit logs]
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-09-12 15:02:14 +02:00
..
algos i2c: Split I2C_M_NOSTART support out of I2C_FUNC_PROTOCOL_MANGLING 2012-05-30 10:55:34 +02:00
busses i2c: omap: simplify omap_i2c_ack_stat() 2012-09-12 15:02:14 +02:00
muxes i2c: Update Guenter Roeck's e-mail address 2012-07-24 14:13:56 +02:00
i2c-boardinfo.c i2c: Update the FSF address 2012-03-26 21:47:19 +02:00
i2c-core.c Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2012-07-30 19:03:41 -07:00
i2c-core.h i2c: Update the FSF address 2012-03-26 21:47:19 +02:00
i2c-dev.c i2c-dev: Add support for I2C_M_RECV_LEN 2012-05-30 10:55:34 +02:00
i2c-mux.c i2c/of: Automatically populate i2c mux busses from device tree data. 2012-05-12 14:28:16 +02:00
i2c-smbus.c i2c-smbus: Use module_i2c_driver() 2012-07-24 14:13:57 +02:00
Kconfig i2c: muxes are not EXPERIMENTAL anymore 2012-05-12 14:28:16 +02:00
Makefile i2c: Deprecate i2c_driver.attach_adapter and .detach_adapter 2011-03-20 14:50:53 +01:00