linux-kernel - [PATCH v2 1/2] pwm: bcm-iproc: handle clk_get

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Date:   Mon, 23 Mar 2020 14:54:23 +0530
From:   Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        bcm-kernel-feedback-list@...adcom.com,
        Yendapally Reddy Dhananjaya Reddy 
        <yendapally.reddy@...adcom.com>, linux-pwm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
Subject: [PATCH v2 1/2] pwm: bcm-iproc: handle clk_get_rate() return

Handle clk_get_rate() returning <= 0 condition to avoid
possible division by zero.

Fixes: daa5abc41c80 ("pwm: Add support for Broadcom iProc PWM controller")
Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
---
 drivers/pwm/pwm-bcm-iproc.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c
index 1f829edd8ee7..8bbd2a04fead 100644
--- a/drivers/pwm/pwm-bcm-iproc.c
+++ b/drivers/pwm/pwm-bcm-iproc.c
@@ -99,19 +99,25 @@ static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 	else
 		state->polarity = PWM_POLARITY_INVERSED;
 
-	value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
-	prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
-	prescale &= IPROC_PWM_PRESCALE_MAX;
-
-	multi = NSEC_PER_SEC * (prescale + 1);
-
-	value = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
-	tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
-	state->period = div64_u64(tmp, rate);
-
-	value = readl(ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
-	tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
-	state->duty_cycle = div64_u64(tmp, rate);
+	if (rate == 0) {
+		state->period = 0;
+		state->duty_cycle = 0;
+	} else {
+		value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
+		prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
+		prescale &= IPROC_PWM_PRESCALE_MAX;
+
+		multi = NSEC_PER_SEC * (prescale + 1);
+
+		value = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
+		tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
+		state->period = div64_u64(tmp, rate);
+
+		value = readl(ip->base +
+			      IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
+		tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
+		state->duty_cycle = div64_u64(tmp, rate);
+	}
 }
 
 static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
-- 
2.17.1