spi: offload: Add offset parameter

Add an offset parameter that can be passed in the periodic trigger.
This is useful for example when ADC drivers implement a separate periodic
signal to trigger conversion and need offload to read the result with
some delay. While at it, add some documentation to offload periodic trigger
parameters.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Axel Haslam <ahaslam@baylibre.com>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
Link: https://patch.msgid.link/cd315e95c0bd8523f00e91c400abcd6a418e5924.1759760519.git.marcelo.schmitt@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-offload-trigger-pwm.c b/drivers/spi/spi-offload-trigger-pwm.c
index 805ed41560df090d85a8547b59f122cf2e3941a2..3e8c19227edb1921d637a09e4e197ec1bebdaead 100644 (file)
--- a/drivers/spi/spi-offload-trigger-pwm.c
+++ b/drivers/spi/spi-offload-trigger-pwm.c
@@ -51,12 +51,14 @@ static int spi_offload_trigger_pwm_validate(struct spi_offload_trigger *trigger,
        wf.period_length_ns = DIV_ROUND_UP_ULL(NSEC_PER_SEC, periodic->frequency_hz);
        /* REVISIT: 50% duty-cycle for now - may add config parameter later */
        wf.duty_length_ns = wf.period_length_ns / 2;
+       wf.duty_offset_ns = periodic->offset_ns;
 
        ret = pwm_round_waveform_might_sleep(st->pwm, &wf);
        if (ret < 0)
                return ret;
 
        periodic->frequency_hz = DIV_ROUND_UP_ULL(NSEC_PER_SEC, wf.period_length_ns);
+       periodic->offset_ns = wf.duty_offset_ns;
 
        return 0;
 }
@@ -77,6 +79,7 @@ static int spi_offload_trigger_pwm_enable(struct spi_offload_trigger *trigger,
        wf.period_length_ns = DIV_ROUND_UP_ULL(NSEC_PER_SEC, periodic->frequency_hz);
        /* REVISIT: 50% duty-cycle for now - may add config parameter later */
        wf.duty_length_ns = wf.period_length_ns / 2;
+       wf.duty_offset_ns = periodic->offset_ns;
 
        return pwm_set_waveform_might_sleep(st->pwm, &wf, false);
 }

diff --git a/include/linux/spi/offload/types.h b/include/linux/spi/offload/types.h
index 6f78923478713aa3c4fc03d7d47b768ed1d52682..cd61f8adb7a5b3c582c1571521dda61e62e86afc 100644 (file)
--- a/include/linux/spi/offload/types.h
+++ b/include/linux/spi/offload/types.h
@@ -57,8 +57,17 @@ enum spi_offload_trigger_type {
        SPI_OFFLOAD_TRIGGER_PERIODIC,
 };
 
+/**
+ * spi_offload_trigger_periodic - configuration parameters for periodic triggers
+ * @frequency_hz: The rate that the trigger should fire in Hz.
+ * @offset_ns: A delay in nanoseconds between when this trigger fires
+ *            compared to another trigger. This requires specialized hardware
+ *            that supports such synchronization with a delay between two or
+ *            more triggers. Set to 0 when not needed.
+ */
 struct spi_offload_trigger_periodic {
        u64 frequency_hz;
+       u64 offset_ns;
 };
 
 struct spi_offload_trigger_config {