[PATCH v7 04/13] ir-rx51: Use 64-bit division macros for period and duty cycle

From: Guru Das Srinagesh
Date: Mon Mar 09 2020 - 15:35:30 EST


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: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: Richard Fontana <rfontana@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Kate Stewart <kstewart@xxxxxxxxxxxxxxxxxxx>
Cc: Allison Randal <allison@xxxxxxxxxxx>
Cc: linux-media@xxxxxxxxxxxxxxx

Signed-off-by: Guru Das Srinagesh <gurus@xxxxxxxxxxxxxx>
---
drivers/media/rc/ir-rx51.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/rc/ir-rx51.c b/drivers/media/rc/ir-rx51.c
index 8574eda..9a5dfd7 100644
--- a/drivers/media/rc/ir-rx51.c
+++ b/drivers/media/rc/ir-rx51.c
@@ -241,7 +241,8 @@ static int ir_rx51_probe(struct platform_device *dev)
}

/* Use default, in case userspace does not set the carrier */
- ir_rx51.freq = DIV_ROUND_CLOSEST(pwm_get_period(pwm), NSEC_PER_SEC);
+ ir_rx51.freq = DIV_ROUND_CLOSEST_ULL(pwm_get_period(pwm),
+ NSEC_PER_SEC);
pwm_put(pwm);

hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
--
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