After a reset event, the device automatically triggers ATI at the
default core clock frequency (16 MHz). Soon afterward, the driver
loads firmware which may attempt to lower the frequency.
If this initial ATI cycle is still in progress when the frequency
is changed, however, the device incorrectly reports channels 0, 1
and 2 to be in a state of touch once ATI finally completes.
To solve this problem, wait until ATI is complete before lowering
the frequency. Because this particular ATI cycle occurs following
a reset event, its duration is predictable and a simple delay can
suffice.
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
After loading firmware, the driver triggers ATI (calibration) with
the newly loaded register configuration in place. Next, the driver
polls a register field to ensure ATI completed in a timely fashion
and that the device is ready to sense.
However, communicating with the device over I2C while ATI is under-
way may induce noise in the device and cause ATI to fail. As such,
the vendor recommends not to poll the device during ATI.
To solve this problem, let the device naturally signal to the host
that ATI is complete by way of an interrupt. A completion prevents
the sub-devices from being registered until this happens.
The former logic that scaled ATI timeout and filter settling delay
is not carried forward with the new implementation, as it produces
overly conservative delays at lower clock rates. Instead, a single
pair of delays that covers all cases is used.
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The time the device takes to deassert its RDY output following an
I2C stop condition scales with the core clock frequency.
To prevent level-triggered interrupts from being reasserted after
the interrupt handler returns, increase the time before returning
to account for the worst-case delay (~90 us) plus margin.
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The regmap member of the driver's private data is called 'regmap',
but the regmap_config struct is called 'iqs62x_map_config'. Rename
the latter to 'iqs62x_regmap_config' for consistency.
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The register write that performed a mandatory soft reset during
probe was removed during development of the driver, however the
IQS62X_SYS_SETTINGS_SOFT_RESET bit mask was left behind. Remove
it to keep stray macros out of the driver.
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Previously, all instances of the /* fall through */ comment were
preceded by a newline to improve readability.
Now that /* fall through */ comments have been replaced with the
fallthrough pseudo-keyword, the leftover whitespace looks out of
place and can simply be removed.
Fixes: df561f6688 ("treewide: Use fallthrough pseudo-keyword")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This patch adds core support for the Azoteq IQS620A, IQS621, IQS622,
IQS624 and IQS625 multi-function sensors.
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
