On Tue, Jan 24, 2023 at 12:21:50PM +0100, Hans de Goede wrote: > On 1/23/23 19:09, Andy Shevchenko wrote: > > On Mon, Jan 23, 2023 at 01:51:36PM +0100, Hans de Goede wrote: > >> The following drivers under drivers/media/i2c: ov08x40.c, ov13858.c, > >> ov13b10.c, ov2680.c, ov2685.c, ov2740.c, ov4689.c, ov5670.c, > >> ov5675.c, ov5695.c, ov8856.c, ov9282.c and ov9734.c, > >> > >> as well as various "atomisp" sensor drivers in drivers/staging, *all* > >> use register access helpers with the following function prototypes: > >> > >> int ovxxxx_read_reg(struct ovxxxx_dev *sensor, u16 reg, > >> unsigned int len, u32 *val); > >> > >> int ovxxxx_write_reg(struct ovxxxx_dev *sensor, u16 reg, > >> unsigned int len, u32 val); > >> > >> To read/write registers on Omnivision OVxxxx image sensors wich expect > >> a 16 bit register address in big-endian format and which have 1-3 byte > >> wide registers, in big-endian format (for the higher width registers). > >> > >> Add a new ovxxxx_16bit_addr_reg_helpers.h header file with static inline > >> versions of these register access helpers, so that this code duplication > >> can be removed. ... > >> + msgs[1].buf = &data_buf[4 - len]; > > > > This trick I don't like. Can we have like other driver have it, i.e. switch > > case for the possible length and explicit usage of the endian conversion > > calls? > > This new header (which is intended to eventually be used in many other > ovXXXX drivers too) is modeled after the reg access helpers > in drivers/media/i2c/ov*.c > > And those do use be16 for the addr_buf in some cases, so I'm fine > with changing that. But non of them do a switch-case on len, > instead they all use similar tricks as this code (which was > copied from drivers/media/i2c/ov2680.c) does. > > So I would prefer to keep this as is, so that the new > ovxxxx_16bit_addr_reg_helpers.h code is more like the code which > it intends to replace. Yes, this is rather for the followup improvements when we have all drivers use these helpers. But under "other drivers" I meant more or less IIO ones where similar (to what I suggest) approach is being used. -- With Best Regards, Andy Shevchenko
