Messages in this thread | | | Date | Tue, 8 May 2012 22:50:09 -0700 | From | Dmitry Torokhov <> | Subject | Re: [PATCH 03/14 v3] Input: atmel_mxt_ts - refactor mxt_read/write_reg to take a length |
| |
Hi Henrik,
On Tue, Apr 24, 2012 at 01:23:19PM +0200, Henrik Rydberg wrote: > Hi Daniel, > > > The i2c bus requires 5 bytes to do a 1 byte read (1-byte i2c address + 2 > > byte offset + 1-byte i2c address + 1 byte data), or 4 bytes to do a > > 1-byte write (1 byte i2c address + 2 byte offset + 1 byte data). > > > > By taking a length with reads and writes, the driver can amortize > > transaction overhead by performing larger transactions where appropriate. > > > > This patch just sets up the new API. Later patches refactor reads/writes > > to take advantage of the larger transactions. > > > > These functions are also now return any errors reported by the i2c layer. > > > > Signed-off-by: Daniel Kurtz <djkurtz@chromium.org> > > --- > > In the cyttsp a dedicate tx buffer is used, which is a bit easier on > the eyes.
Cyttsp needs a cacheline aligned buffer because it can be wired over SPI, that is why it has a dedicate buffer.
-- Dmitry
| |