From: Jean Delvare Date: Fri, 18 Sep 2009 20:45:44 +0000 (+0200) Subject: i2c/tsl2550: Use combined SMBus transactions X-Git-Tag: v2.6.32-rc1~172^2~13 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ac7809414fb1e3e49b88ad6016e57598594aa4e2;p=pandora-kernel.git i2c/tsl2550: Use combined SMBus transactions Make the I/O faster, mainly by using combined SMBus transactions when possible. While the TSL2550 datasheet doesn't say the device supports them, they seem to work just fine in practice, and a combined transaction is faster than two simple transactions in many cases and always more reliable. A side effect is to suppress the delays between SMBus writes and reads. The datasheet doesn't say they are needed and things work just fine for me without them. I also couldn't see any reason for the delay between reading the two channels. Nor for the loop to get a reading in the first place. The 400 ms delay between samples only matters at chip power-up, after that the chip always hold the previously sampled value so we never get to wait. All these changes make reading the lux value much faster and cheaper. Signed-off-by: Jean Delvare Tested-by: Michele De Candia Cc: Rodolfo Giometti --- Reading git-diff-tree failed