6.14-stable review patch. If anyone has any objections, please let me know.
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From: Uwe Kleine-König u.kleine-koenig@baylibre.com
[ Upstream commit a85e08a05bf77d5d03b4ac0c59768a606a1b640b ]
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/ba451573f0218d76645f068cec78bd97802cf010.174384473... Signed-off-by: Uwe Kleine-König ukleinek@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pwm/pwm-axi-pwmgen.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/pwm/pwm-axi-pwmgen.c b/drivers/pwm/pwm-axi-pwmgen.c index 4259a0db9ff45..4337c8f5acf05 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,