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leds: qcom-lpg: Fix PWM period limits

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The introduction of high resolution PWM support changed the order of the
operations in the calculation of min and max period. The result in both
divisions is in most cases a truncation to 0, which limits the period to
the range of [0, 0].

Both numerators (and denominators) are within 64 bits, so the whole
expression can be put directly into the div64_u64, instead of doing it
partially.

Fixes: b00d2ed376 ("leds: rgb: leds-qcom-lpg: Add support for high resolution PWM")
Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org>
Tested-by: Steev Klimaszewski <steev@kali.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Acked-by: Lee Jones <lee@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
Link: https://lore.kernel.org/r/20230515162604.649203-1-quic_bjorande@quicinc.com
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Bjorn Andersson 2023-05-15 09:26:04 -07:00 committed by Johan Hovold
parent 7877cb91f1
commit b05d39466b
1 changed files with 4 additions and 4 deletions
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8
drivers/leds/rgb/leds-qcom-lpg.c
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@ -312,14 +312,14 @@ static int lpg_calc_freq(struct lpg_channel *chan, uint64_t period)
max_res = LPG_RESOLUTION_9BIT;
}
min_period = (u64)NSEC_PER_SEC *
div64_u64((1 << pwm_resolution_arr[0]), clk_rate_arr[clk_len - 1]);
min_period = div64_u64((u64)NSEC_PER_SEC * (1 << pwm_resolution_arr[0]),
clk_rate_arr[clk_len - 1]);
if (period <= min_period)
return -EINVAL;
/* Limit period to largest possible value, to avoid overflows */
max_period = (u64)NSEC_PER_SEC * max_res * LPG_MAX_PREDIV *
div64_u64((1 << LPG_MAX_M), 1024);
max_period = div64_u64((u64)NSEC_PER_SEC * max_res * LPG_MAX_PREDIV * (1 << LPG_MAX_M),
1024);
if (period > max_period)
period = max_period;