Hello Nick,
Nick Thompson wrote:
The omap24xx driver only seems to support devices that have a single subaddress byte. With these types of devices, the first access in a bus transaction is usually a write (writes the subaddress) followed by either a read or write to access the devices registers.
Many such devices will respond to a read as the first access, but there are at least some that will NACK such a read. (e.g. ADV7180.)
The probe function attempts to detect a devices ACK to a read access only and fails to find devices that NACK a read.
This commit modifies the probe function to start a write instead. This detects devices that respond to reads (since they must also respond to writes) as well as those that only respond to writes. The bus is immediately set to idle after a (N)ACK avoiding actually writing anything to the device.
Signed-off-by: Nick Thompson nick.thompson@ge.com
Tested on OMAP3530 with an ADV7180 video ADC.
Detection of a device takes the same time as failing to find a device, so the probe is slightly faster.
drivers/i2c/omap24xx_i2c.c | 42 +++++++++++------------------------------- 1 files changed, 11 insertions(+), 31 deletions(-)
Please check your patch with checkpatch, as it shows:
total: 2 errors, 8 warnings, 54 lines checked
NOTE: whitespace errors detected, you may wish to use scripts/cleanpatch or scripts/cleanfile
[PATCH] I2C: OMAP: detect more devices when probing an i2c bus.eml has style problems, please review. If any of these errors are false positives report them to the maintainer, see CHECKPATCH in MAINTAINERS.
Beside of this, your patch looks ok to me.
bye, Heiko