linux-kernel - [tip: timers/core] clocksource/drivers/npcm: Fix GENMASK and timer operation

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Date:   Mon, 26 Aug 2019 22:52:15 -0000
From:   tip-bot2 for Avi Fishman <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Avi Fishman <avifishman70@...il.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Ingo Molnar <mingo@...nel.org>, linux-kernel@...r.kernel.org
Subject: [tip: timers/core] clocksource/drivers/npcm: Fix GENMASK and timer operation

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     a2b58537b4a1cc08fd254fb8d1c24191ce286ae1
Gitweb:        https://git.kernel.org/tip/a2b58537b4a1cc08fd254fb8d1c24191ce286ae1
Author:        Avi Fishman <avifishman70@...il.com>
AuthorDate:    Mon, 29 Jul 2019 20:03:54 +03:00
Committer:     Daniel Lezcano <daniel.lezcano@...aro.org>
CommitterDate: Tue, 27 Aug 2019 00:31:39 +02:00

clocksource/drivers/npcm: Fix GENMASK and timer operation

NPCM7XX_Tx_OPER GENMASK bits are wrong, fix them.

Hopefully the NPCM7XX_REG_TICR0 register reset value of those bits was 0,
so it did not cause an issue.

The function npcm7xx_timer_oneshot() reads the register
NPCM7XX_REG_TCSR0, modifies it and then reads it again overwriting the
previous changes. Remove the extra read which is pointless.

The function npcm7xx_timer_periodic() is correct but the code writes
to the NPCM7XX_REG_TICR0 register while it is dealing with the
NPCM7XX_REG_TCSR0 register, that is confusing. Separate the write to
the registers in the code for the sake of clarity.

Fixes: 1c00289ecd12 ("clocksource/drivers/npcm: Add NPCM7xx timer driver")
Signed-off-by: Avi Fishman <avifishman70@...il.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
---
 drivers/clocksource/timer-npcm7xx.c |  9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/clocksource/timer-npcm7xx.c b/drivers/clocksource/timer-npcm7xx.c
index 8a30da7..9780ffd 100644
--- a/drivers/clocksource/timer-npcm7xx.c
+++ b/drivers/clocksource/timer-npcm7xx.c
@@ -32,7 +32,7 @@
 #define NPCM7XX_Tx_INTEN		BIT(29)
 #define NPCM7XX_Tx_COUNTEN		BIT(30)
 #define NPCM7XX_Tx_ONESHOT		0x0
-#define NPCM7XX_Tx_OPER			GENMASK(27, 3)
+#define NPCM7XX_Tx_OPER			GENMASK(28, 27)
 #define NPCM7XX_Tx_MIN_PRESCALE		0x1
 #define NPCM7XX_Tx_TDR_MASK_BITS	24
 #define NPCM7XX_Tx_MAX_CNT		0xFFFFFF
@@ -84,8 +84,6 @@ static int npcm7xx_timer_oneshot(struct clock_event_device *evt)
 
 	val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
 	val &= ~NPCM7XX_Tx_OPER;
-
-	val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
 	val |= NPCM7XX_START_ONESHOT_Tx;
 	writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
 
@@ -97,12 +95,11 @@ static int npcm7xx_timer_periodic(struct clock_event_device *evt)
 	struct timer_of *to = to_timer_of(evt);
 	u32 val;
 
+	writel(timer_of_period(to), timer_of_base(to) + NPCM7XX_REG_TICR0);
+
 	val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
 	val &= ~NPCM7XX_Tx_OPER;
-
-	writel(timer_of_period(to), timer_of_base(to) + NPCM7XX_REG_TICR0);
 	val |= NPCM7XX_START_PERIODIC_Tx;
-
 	writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
 
 	return 0;