Hello Marek,
On Thu, Sep 04, 2025 at 11:05:28PM +0200, Marek Vasut wrote:
> Convert the driver from legacy PWM apply ops to modern waveform ops.
> There is no functional change.
>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxxxx>
> ---
> Cc: "Uwe Kleine-König" <ukleinek@xxxxxxxxxx>
> Cc: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: linux-pwm@xxxxxxxxxxxxxxx
> Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
> ---
> V2: - Safeguard against wf->duty_length_ns > wf->period_length_ns
> ---
> drivers/regulator/rpi-panel-v2-regulator.c | 53 +++++++++++++++++-----
> 1 file changed, 42 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/regulator/rpi-panel-v2-regulator.c b/drivers/regulator/rpi-panel-v2-regulator.c
> index 30b78aa75ee38..eb4c4e3ead364 100644
> --- a/drivers/regulator/rpi-panel-v2-regulator.c
> +++ b/drivers/regulator/rpi-panel-v2-regulator.c
> @@ -35,24 +35,55 @@ static const struct regmap_config rpi_panel_regmap_config = {
> .can_sleep = true,
> };
>
> -static int rpi_panel_v2_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> - const struct pwm_state *state)
> +static int rpi_panel_v2_pwm_round_waveform_tohw(struct pwm_chip *chip,
> + struct pwm_device *pwm,
> + const struct pwm_waveform *wf,
> + void *_wfhw)
> {
> - struct regmap *regmap = pwmchip_get_drvdata(chip);
> - unsigned int duty;
> + u8 *wfhw = _wfhw;
> +
> + if (wf->duty_length_ns > wf->period_length_ns)
> + *wfhw = 100;
> + else
> + *wfhw = mul_u64_u64_div_u64(wf->duty_length_ns, 100, wf->period_length_ns);
If I understand correctly the device has a fixed period length but the
actual length is unknown and so assumed to be 100 ms, right?
In this case the right incarnation for .round_waveform_tohw() is:
/*
* The device has a fixed but unknown period length. To have something
* to work with, we're assuming this fixed length is 100 ms.
*/
#define RPI_PANEL_V2_PERIOD_NS 100000
static int rpi_panel_v2_pwm_round_waveform_tohw(...)
{
u8 *wfhw = _wfhw;
if (wf->period_length_ns == 0) {
*wfhw = 0;
return 0;
}
if (wf->duty_length_ns >= RPI_PANEL_V2_PERIOD_NS)
*wfhw = 100;
else
*wfhw = mul_u64_u64_div_u64(wf->duty_length_ns, 100, RPI_PANEL_V2_PERIOD_NS);
if (wf->period_length_ns < RPI_PANEL_V2_PERIOD_NS)
return 1;
else
return 0;
}
Extra points are awarded if you come up with a nice name for the plain
100 in here, maybe RPI_PANEL_V2_DUTY_STEPS?
Best regards
Uwe
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