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From:   Guru Das Srinagesh <gurus@codeaurora.org>
To:     linux-pwm@vger.kernel.org
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <uwe@kleine-koenig.org>,
        Subbaraman Narayanamurthy <subbaram@codeaurora.org>,
        linux-kernel@vger.kernel.org,
        Guru Das Srinagesh <gurus@codeaurora.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>
Subject: [PATCH v7 06/13] pwm: pwm-imx-tpm: Use 64-bit division macros for period and duty cycle
Date:   Mon,  9 Mar 2020 12:35:09 -0700
Message-Id: <e429fdb80dd6a77c57798a9c317c2206f37bc01f.1583782035.git.gurus@codeaurora.org>
In-Reply-To: <cover.1583782035.git.gurus@codeaurora.org>
References: <cover.1583782035.git.gurus@codeaurora.org>
In-Reply-To: <cover.1583782035.git.gurus@codeaurora.org>
References: <cover.1583782035.git.gurus@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>

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

diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c
index 9145f61..53bf364 100644
--- a/drivers/pwm/pwm-imx-tpm.c
+++ b/drivers/pwm/pwm-imx-tpm.c
@@ -126,7 +126,7 @@ static int pwm_imx_tpm_round_state(struct pwm_chip *chip,
 		real_state->duty_cycle = state->duty_cycle;
 
 	tmp = (u64)p->mod * real_state->duty_cycle;
-	p->val = DIV_ROUND_CLOSEST_ULL(tmp, real_state->period);
+	p->val = DIV64_U64_ROUND_CLOSEST(tmp, real_state->period);
 
 	real_state->polarity = state->polarity;
 	real_state->enabled = state->enabled;
-- 
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