[PATCH v7 4/5] pwm: kona: Add debug info to config function

Jonathan Richardson
2015-05-12T23:28:15Z

Adds debugging info to config function where duty cycle and period
are calculated and verified.

Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
---
drivers/pwm/pwm-bcm-kona.c | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c
index 0654981..c6069c7 100644
--- a/drivers/pwm/pwm-bcm-kona.c
+++ b/drivers/pwm/pwm-bcm-kona.c
@@ -138,18 +138,39 @@ static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,
dc = div64_u64(val, div);

/* If duty_ns or period_ns are not achievable then return */
- if (pc < PERIOD_COUNT_MIN || dc < DUTY_CYCLE_HIGH_MIN)
+ if (pc < PERIOD_COUNT_MIN) {
+ dev_warn(chip->dev,
+ "%s: pwm[%d]: period=%d is not achievable, pc=%lu, prescale=%lu\n",
+ __func__, chan, period_ns, pc, prescale);
return -EINVAL;
+ }
+
+ if (dc < DUTY_CYCLE_HIGH_MIN) {
+ if (0 != duty_ns) {
+ dev_warn(chip->dev,
+ "%s: pwm[%d]: duty cycle=%d is not achievable, dc=%lu, prescale=%lu\n",
+ __func__, chan, duty_ns, dc, prescale);
+ }
+ return -EINVAL;
+ }

/* If pc and dc are in bounds, the calculation is done */
if (pc <= PERIOD_COUNT_MAX && dc <= DUTY_CYCLE_HIGH_MAX)
break;

/* Otherwise, increase prescale and recalculate pc and dc */
- if (++prescale > PRESCALE_MAX)
+ if (++prescale > PRESCALE_MAX) {
+ dev_warn(chip->dev,
+ "%s: pwm[%d]: Prescale (=%lu) within max (=%d) for period=%d and duty cycle=%d is not achievable\n",
+ __func__, chan, prescale, PRESCALE_MAX,
+ period_ns, duty_ns);
return -EINVAL;
+ }
}

+ dev_dbg(chip->dev, "pwm[%d]: period=%lu, duty_high=%lu, prescale=%lu\n",
+ chan, pc, dc, prescale);
+
/*
* Don't apply settings if disabled. The period and duty cycle are
* always calculated above to ensure the new values are
--
1.7.9.5