tree fe0e93f7eeaca9ba6b06bd74bf6758b8a1986b94
parent 48c06d5e2d63c1d6282c0f7fe67741a39d6c1852
author Mauro Carvalho Chehab <mchehab@infradead.org> 1157580268 -0300
committer Mauro Carvalho Chehab <mchehab@infradead.org> 1159284635 -0300

V4L/DVB (4609): Improved i2c performance on software bitbang algoritm

Software I2C were using a very conservative value of udelay=16, meaning about
20Kbps. According with Philips I2C datasheet, the i2c should answer well for
times at the order of 4.7 us. So, using udelay=5 should work for all devices.
After this patch, the speed should be close to 66,67 Kbps, with the current
kernel software bitbang, with 30/60 duty cycle.
Anyway, added a new parameter (i2c_udelay) that would allow using conservative
values, if eventually a hardware doesn't support the datasheet values.
Thanks to Jean Delvare <khali@linux-fr.org> for pointing this improvement.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>