linux-kernel - [PATCH AUTOSEL 4.19 350/671] pwm: meson: Consider 128 a valid pre-divider

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Message-Id: <20200116170509.12787-87-sashal@kernel.org>
Date:   Thu, 16 Jan 2020 11:59:48 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Neil Armstrong <narmstrong@...libre.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Sasha Levin <sashal@...nel.org>, linux-pwm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org
Subject: [PATCH AUTOSEL 4.19 350/671] pwm: meson: Consider 128 a valid pre-divider

From: Martin Blumenstingl <martin.blumenstingl@...glemail.com>

[ Upstream commit 51496e4446875726d50a5617a6e0e0dabbc2e6da ]

The pre-divider allows configuring longer PWM periods compared to using
the input clock directly. The pre-divider is 7 bit wide, meaning it's
maximum value is 128 (the register value is off-by-one: 0x7f or 127).

Change the loop to also allow for the maximum possible value to be
considered valid.

Fixes: 211ed630753d2f ("pwm: Add support for Meson PWM Controller")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Reviewed-by: Neil Armstrong <narmstrong@...libre.com>
Signed-off-by: Thierry Reding <thierry.reding@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pwm/pwm-meson.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
index f6e738ad7bd9..4b708c1fcb1d 100644
--- a/drivers/pwm/pwm-meson.c
+++ b/drivers/pwm/pwm-meson.c
@@ -188,7 +188,7 @@ static int meson_pwm_calc(struct meson_pwm *meson,
 	do_div(fin_ps, fin_freq);
 
 	/* Calc pre_div with the period */
-	for (pre_div = 0; pre_div < MISC_CLK_DIV_MASK; pre_div++) {
+	for (pre_div = 0; pre_div <= MISC_CLK_DIV_MASK; pre_div++) {
 		cnt = DIV_ROUND_CLOSEST_ULL((u64)period * 1000,
 					    fin_ps * (pre_div + 1));
 		dev_dbg(meson->chip.dev, "fin_ps=%llu pre_div=%u cnt=%u\n",
@@ -197,7 +197,7 @@ static int meson_pwm_calc(struct meson_pwm *meson,
 			break;
 	}
 
-	if (pre_div == MISC_CLK_DIV_MASK) {
+	if (pre_div > MISC_CLK_DIV_MASK) {
 		dev_err(meson->chip.dev, "unable to get period pre_div\n");
 		return -EINVAL;
 	}
-- 
2.20.1