Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.
As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.
Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64
Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64
Cc: Lee Jones <lee.jo...@linaro.org>
Cc: Daniel Thompson <daniel.thomp...@linaro.org>
Cc: Jingoo Han <jingooh...@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnier...@samsung.com>
Cc: linux-...@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fb...@vger.kernel.org
Signed-off-by: Guru Das Srinagesh <gu...@codeaurora.org>
---
drivers/video/backlight/pwm_bl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index efb4efc..3e5dbcf 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -625,7 +625,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
pb->scale = data->max_brightness;
}
- pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
+ pb->lth_brightness = data->lth_brightness * (div_u64(state.period,
+ pb->scale));
props.type = BACKLIGHT_RAW;
props.max_brightness = data->max_brightness;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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