diff options
| author | Uwe Kleine-König <u.kleine-koenig@baylibre.com> | 2025-04-05 11:27:16 +0200 |
|---|---|---|
| committer | Uwe Kleine-König <ukleinek@kernel.org> | 2025-04-07 15:10:30 +0200 |
| commit | a85e08a05bf77d5d03b4ac0c59768a606a1b640b (patch) | |
| tree | b52784e1d7eaa072dc21a9c3603816bfc3554106 | |
| parent | fda6e0034e9da64e1cec31f4539b6c7abd9ed8be (diff) | |
pwm: axi-pwmgen: Let .round_waveform_tohw() signal when request was rounded up
The .round_waveform_tohw() is supposed to return 1 if the requested
waveform cannot be implemented by rounding down all parameters. Also
adapt the corresponding comment to better describe why the implemented
procedure is right.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/ba451573f0218d76645f068cec78bd97802cf010.1743844730.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
| -rw-r--r-- | drivers/pwm/pwm-axi-pwmgen.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/pwm/pwm-axi-pwmgen.c b/drivers/pwm/pwm-axi-pwmgen.c index 4259a0db9ff4..4337c8f5acf0 100644 --- a/drivers/pwm/pwm-axi-pwmgen.c +++ b/drivers/pwm/pwm-axi-pwmgen.c @@ -75,6 +75,7 @@ static int axi_pwmgen_round_waveform_tohw(struct pwm_chip *chip, { struct axi_pwmgen_waveform *wfhw = _wfhw; struct axi_pwmgen_ddata *ddata = axi_pwmgen_ddata_from_chip(chip); + int ret = 0; if (wf->period_length_ns == 0) { *wfhw = (struct axi_pwmgen_waveform){ @@ -91,12 +92,15 @@ static int axi_pwmgen_round_waveform_tohw(struct pwm_chip *chip, if (wfhw->period_cnt == 0) { /* * The specified period is too short for the hardware. - * Let's round .duty_cycle down to 0 to get a (somewhat) - * valid result. + * So round up .period_cnt to 1 (i.e. the smallest + * possible period). With .duty_cycle and .duty_offset + * being less than or equal to .period, their rounded + * value must be 0. */ wfhw->period_cnt = 1; wfhw->duty_cycle_cnt = 0; wfhw->duty_offset_cnt = 0; + ret = 1; } else { wfhw->duty_cycle_cnt = min_t(u64, mul_u64_u32_div(wf->duty_length_ns, ddata->clk_rate_hz, NSEC_PER_SEC), @@ -111,7 +115,7 @@ static int axi_pwmgen_round_waveform_tohw(struct pwm_chip *chip, pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns, ddata->clk_rate_hz, wfhw->period_cnt, wfhw->duty_cycle_cnt, wfhw->duty_offset_cnt); - return 0; + return ret; } static int axi_pwmgen_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm, |