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leds: qcom-lpg: Fix PWM period limits

Message ID 20230512165524.3367443-1-quic_bjorande@quicinc.com
State New
Headers show
Series leds: qcom-lpg: Fix PWM period limits | expand

Commit Message

Bjorn Andersson May 12, 2023, 4:55 p.m. UTC 
The introduction of high resolution PWM support moved the parenthesis of
the divisions in the calculation of min and max period. The result in
both divisions is in most cases 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: b00d2ed37617 ("leds: rgb: leds-qcom-lpg: Add support for high resolution PWM")
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---

This fixes the regression in v6.4-rc1.

 drivers/leds/rgb/leds-qcom-lpg.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c
index c9cea797a697..7287fadc00df 100644
--- a/drivers/leds/rgb/leds-qcom-lpg.c
+++ b/drivers/leds/rgb/leds-qcom-lpg.c
@@ -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;