RFC add generic helper function for I2C register write

This adds helper function for most typical I2C register write. Main reason was the fact I2C messages are are needed to split smaller parts as I2C-adapters cannot send all long messages used.

Basically there is three different kind of I2C register access used:
* register write (I2C write)
* register read (I2C write + I2C read)
* register read (I2C read)

Register read is usually done using write+read combination (with REPEATED START) and almost all I2C-adapters we have can handle it. Some rare situations simple read is used. That means for example reading small amount of registers starting from register 0 and thus register write for setting desired register is not needed. Other used rarely used combination for register read is simple register write (for set desired reg) and then perform simple register read. It looks like write+read but there is no REPEATED START, both messages are own transactions. I hope this story gives better understanding :)

At that point, I just implemented simple register write as a example. It does not have even any configuration for "register map", like register address length nor register value length. It just assumes register is one byte wide for both address and value. Lets add those later when needed.

And here is the list of drivers I have been working and this kind of splitting have been one problematic issue;
* RTL2832U & RTL2832
* RTL2831U & RTL2830
* AF9015 & TDA18212
* AF9015 & TDA18271
* EM28xx & TDA10071
* Anysee & CX24116
* <demod driver not released yet>

So, as you can see, there is a lot of drivers need splitting!

Any comments?

Antti Palosaari (2):
dvb-core: add generic helper function for I2C register write
tda18218: use generic dvb_wr_regs()

 drivers/media/common/tuners/tda18218.c      |   69 
+++++---------------------
 drivers/media/common/tuners/tda18218_priv.h |    3 +
 drivers/media/dvb/dvb-core/Makefile         |    2 +-
 drivers/media/dvb/dvb-core/dvb_generic.c    |   48 ++++++++++++++++++
 drivers/media/dvb/dvb-core/dvb_generic.h    |   21 ++++++++
 5 files changed, 87 insertions(+), 56 deletions(-)
 create mode 100644 drivers/media/dvb/dvb-core/dvb_generic.c
 create mode 100644 drivers/media/dvb/dvb-core/dvb_generic.h

1.7.4.4
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