linux.git/drivers/counter, branch v6.10-rc2

counter: ti-ecap-capture: Utilize COUNTER_COMP_FREQUENCY macro

2024-04-02T17:15:03+00:00

Reduce boilerplate by leveraging the COUNTER_COMP_FREQUENCY() macro to
define the "frequency" extension.

Link: https://lore.kernel.org/r/ZfxhEKdSi1amfcJC@ishi
Signed-off-by: William Breathitt Gray

counter: ti-eqep: Convert to platform remove callback returning void

2024-04-02T17:10:35+00:00

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König 
Acked-by: David Lechner 
Link: https://lore.kernel.org/r/bf78595f6a49be0b6bb403b466c13177d72c02b7.1710057753.git.u.kleine-koenig@pengutronix.de
Signed-off-by: William Breathitt Gray

counter: ti-ecap-capture: Convert to platform remove callback returning void

2024-04-02T17:10:34+00:00

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/f70902b2aabecaa9295c28629cd7a8a0e6eb06d0.1710057753.git.u.kleine-koenig@pengutronix.de
Signed-off-by: William Breathitt Gray

counter: stm32-timer-cnt: add support for capture events

2024-04-02T17:10:34+00:00

Add support for capture events. Captured counter value for each channel
can be retrieved through CCRx register.
STM32 timers can have up to 4 capture channels (on input channel 1 to
channel 4), hence need to check the number of channels before reading
the capture data.
The capture configuration is hard-coded to capture signals on both edges
(non-inverted). Interrupts are used to report events independently for
each channel.

Reviewed-by: William Breathitt Gray 
Acked-by: Lee Jones 
Signed-off-by: Fabrice Gasnier 
Link: https://lore.kernel.org/r/20240307133306.383045-11-fabrice.gasnier@foss.st.com
Signed-off-by: William Breathitt Gray

counter: stm32-timer-cnt: add support for overflow events

2024-04-02T17:10:34+00:00

Add support overflow events. Also add the related validation and
configuration routine. Register and enable interrupts to push events.
STM32 Timers can have either 1 global interrupt, or 4 dedicated interrupt
lines. Request only the necessary interrupt, e.g. either global interrupt
that can report all event types, or update interrupt only for overflow
event.

Reviewed-by: William Breathitt Gray 
Signed-off-by: Fabrice Gasnier 
Link: https://lore.kernel.org/r/20240307133306.383045-10-fabrice.gasnier@foss.st.com
Signed-off-by: William Breathitt Gray

counter: stm32-timer-cnt: probe number of channels from registers

2024-04-02T17:10:34+00:00

Probe the number of capture compare channels, by writing CCER register bits
and read them back. Take care to restore the register original value.

This is a precursor patch to support capture channels.

Reviewed-by: William Breathitt Gray 
Signed-off-by: Fabrice Gasnier 
Link: https://lore.kernel.org/r/20240307133306.383045-9-fabrice.gasnier@foss.st.com
Signed-off-by: William Breathitt Gray

counter: stm32-timer-cnt: introduce channels

2024-04-02T17:10:34+00:00

Simply add channels 3 and 4 that can be used for capture. Statically
add them, despite some timers doesn't have them. Rather rely on
stm32_action_read that will report "none" action for these currently.

Reviewed-by: William Breathitt Gray 
Signed-off-by: Fabrice Gasnier 
Link: https://lore.kernel.org/r/20240307133306.383045-8-fabrice.gasnier@foss.st.com
Signed-off-by: William Breathitt Gray

counter: stm32-timer-cnt: add checks on quadrature encoder capability

2024-04-02T17:10:34+00:00

This is a precursor patch to support capture channels on all possible
channels and stm32 timer types. Original driver was intended to be used
only as quadrature encoder and simple counter on internal clock.

So, add a check on encoder capability, so the driver may be probed for
timer instances without encoder feature. This way, all timers may be used
as simple counter on internal clock, starting from here.

Encoder capability is retrieved by using the timer index (originally in
stm32-timer-trigger driver and dt-bindings). The need to keep backward
compatibility with existing device tree lead to parse aside trigger node.

Reviewed-by: William Breathitt Gray 
Signed-off-by: Fabrice Gasnier 
Link: https://lore.kernel.org/r/20240307133306.383045-7-fabrice.gasnier@foss.st.com
Signed-off-by: William Breathitt Gray

counter: stm32-timer-cnt: add counter prescaler extension

2024-04-02T17:10:34+00:00

There's a prescaler in between the selected input signal used for
counting (CK_PSC), and the counter input (CK_CNT).
So add the "prescaler" extension to the counter.

Reviewed-by: William Breathitt Gray 
Signed-off-by: Fabrice Gasnier 
Link: https://lore.kernel.org/r/20240307133306.383045-6-fabrice.gasnier@foss.st.com
Signed-off-by: William Breathitt Gray

counter: stm32-timer-cnt: introduce clock signal

2024-04-02T17:10:34+00:00

Introduce the internal clock signal, used to count when in simple rising
function. Also add the "frequency" extension to the clock signal.

With this patch, signal action reports a consistent state when "increase"
function is used, and the counting frequency:
    $ echo increase > function
    $ grep -H "" signal*_action
    signal0_action:none
    signal1_action:none
    signal2_action:rising edge
    $ echo 1 > enable
    $ cat count
    25425
    $ cat count
    44439
    $ cat ../signal2/frequency
    208877930

Signed-off-by: Fabrice Gasnier 
Link: https://lore.kernel.org/r/20240307133306.383045-5-fabrice.gasnier@foss.st.com
Signed-off-by: William Breathitt Gray