Hello, On Thursday, 14 June 2018 18:33:58 EEST Wolfram Sang wrote: > On Wed, Jun 13, 2018 at 12:34:46AM +0900, Akinobu Mita wrote: > > (This is 2nd version of SCCB helpers patch. After 1st version was > > submitted, I sent alternative patch titled "i2c: add I2C_M_FORCE_STOP". > > But it wasn't accepted because it makes the I2C core code unreadable. > > I couldn't find out a way to untangle it, so I returned to the original > > approach.) > > > > This adds Serial Camera Control Bus (SCCB) helper functions > > (sccb_read_byte and sccb_write_byte) that are intended to be used by some > > of Omnivision sensor drivers. > > > > The ov772x driver is going to use these functions in order to make it work > > with most i2c controllers. > > > > As the ov772x device doesn't support repeated starts, this driver > > currently requires I2C_FUNC_PROTOCOL_MANGLING that is not supported by > > many i2c controller drivers. > > > > With the sccb_read_byte() that issues two separated requests in order to > > avoid repeated start, the driver doesn't require > > I2C_FUNC_PROTOCOL_MANGLING. > > From a first glance, this looks like my preferred solution so far. > Thanks for doing it! Let me sleep a bit over it for a thorough review... > > > --- /dev/null > > +++ b/drivers/media/i2c/sccb.h > > I'd prefer this file to be in the i2c realm. Maybe > 'include/linux/i2c-sccb.h" or something. I will come back to this. And while at it, I think we also need a .c file, the functions (and especially sccb_read_byte()) should not be static inline. -- Regards, Laurent Pinchart
