[PATCH v7 05/13] pwm: clps711x: Use 64-bit division macros for period and duty cycle

From: Guru Das Srinagesh
Date: Mon Mar 09 2020 - 15:36:07 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: Alexander Shiyan <shc_work@xxxxxxx>

Signed-off-by: Guru Das Srinagesh <gurus@xxxxxxxxxxxxxx>
---
drivers/pwm/pwm-clps711x.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index 924d39a..ba9500a 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c
@@ -43,7 +43,7 @@ static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
{
/* Duty cycle 0..15 max */
- return DIV_ROUND_CLOSEST(v * 0xf, pwm->args.period);
+ return DIV64_U64_ROUND_CLOSEST(v * 0xf, pwm->args.period);
}

static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
--
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