Currently the TIA gain settings are exported to userspace as sysfs
entries that do not clearly represent their internal relation to the
sampling stages. The gain settings are enabled on a per-stage basis,
this can be seen in figure 24 of the current AFE4404 datasheet.
These gain settings should therefore be tied to the channels that are
read during these stages. Make this change here.
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
These AFEs have 4 ADC mesuring stages (called LED2, ALED2, LED1, and
ALED1 in the datasheet), we map these as channels, these stages can serve
different purposes depending on the application. For instance the AFE4404
has an additional LED (LED3), this LED can be timed to be active during
stage 2 (or anystage, but the datasheet describes this case and the name
of the stage reflects this use). This ability is used further in upcoming
parts that tie the front-end gain and the LED timings together. For these
reasons we remove explicit naming the channels.
Without channel names it is best that the index numbers are in order to
match the stage number, reorder the channel numbers.
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Locking the two gain stages to the same setting adds no value for us,
so initialize them as unlocked and remove the sysfs for unlocking them.
This also allows us to greatly simplify showing and setting the gain
registers.
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Add driver for the TI AFE4404 heart rate monitor and pulse oximeter.
This device detects reflected LED light fluctuations and presents an ADC
value to the user space for further signal processing.
Datasheet: http://www.ti.com/product/AFE4404/datasheet
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Andrew F. Davis