On Thu, 5 Oct 2023 19:50:31 -0500 David Lechner <dlechner@xxxxxxxxxxxx> wrote: > The ad2s1210 driver shoe-horns the register and fault support into IIO > events. The mapping between the registers/faults and the events is not > obvious. To save users from having to read the entire driver to figure > out how to use it, add a summary of the register/fault support to the > top of the file. > > Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx> This is indeed useful to have. Applied. Thanks, Jonathan > --- > > v4 changes: New patch in v4. > > drivers/staging/iio/resolver/ad2s1210.c | 40 +++++++++++++++++++++++++++++++++ > 1 file changed, 40 insertions(+) > > diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c > index d9d51bbbade8..51490fea1647 100644 > --- a/drivers/staging/iio/resolver/ad2s1210.c > +++ b/drivers/staging/iio/resolver/ad2s1210.c > @@ -4,7 +4,47 @@ > * > * Copyright (c) 2010-2010 Analog Devices Inc. > * Copyright (c) 2023 BayLibre, SAS > + * > + * Device register to IIO ABI mapping: > + * > + * Register | Addr | IIO ABI (sysfs) > + * ----------------------------|------|------------------------------------------- > + * DOS Overrange Threshold | 0x89 | events/in_altvoltage0_thresh_rising_value > + * DOS Mismatch Threshold | 0x8A | events/in_altvoltage0_mag_rising_value > + * DOS Reset Maximum Threshold | 0x8B | events/in_altvoltage0_mag_rising_reset_max > + * DOS Reset Minimum Threshold | 0x8C | events/in_altvoltage0_mag_rising_reset_min > + * LOT High Threshold | 0x8D | events/in_angl1_thresh_rising_value > + * LOT Low Threshold [1] | 0x8E | events/in_angl1_thresh_rising_hysteresis > + * Excitation Frequency | 0x91 | out_altvoltage0_frequency > + * Control | 0x92 | *as bit fields* > + * Phase lock range | D5 | events/in_phase0_mag_rising_value > + * Hysteresis | D4 | in_angl0_hysteresis > + * Encoder resolution | D3:2 | *not implemented* > + * Resolution | D1:0 | *device tree: assigned-resolution-bits* > + * Soft Reset | 0xF0 | [2] > + * Fault | 0xFF | *not implemented* > + * > + * [1]: The value written to the LOT low register is high value minus the > + * hysteresis. > + * [2]: Soft reset is performed when `out_altvoltage0_frequency` is written. > + * > + * Fault to event mapping: > + * > + * Fault | | Channel | Type | Direction > + * ----------------------------------------|----|--------------------------------- > + * Sine/cosine inputs clipped [3] | D7 | altvoltage1 | mag | either > + * Sine/cosine inputs below LOS | D6 | altvoltage0 | thresh | falling > + * Sine/cosine inputs exceed DOS overrange | D5 | altvoltage0 | thresh | rising > + * Sine/cosine inputs exceed DOS mismatch | D4 | altvoltage0 | mag | rising > + * Tracking error exceeds LOT | D3 | angl1 | thresh | rising > + * Velocity exceeds maximum tracking rate | D2 | anglvel0 | mag | rising > + * Phase error exceeds phase lock range | D1 | phase0 | mag | rising > + * Configuration parity error | D0 | *writes to kernel log* > + * > + * [3]: The chip does not differentiate between fault on sine vs. cosine so > + * there will also be an event on the altvoltage2 channel. > */ > + > #include <linux/bitfield.h> > #include <linux/bits.h> > #include <linux/clk.h> >
