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authorKars de Jong <jongk@linux-m68k.org>2019-11-16 12:46:20 +0100
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2019-11-18 15:23:54 +0100
commit32c4d9e8a4eb286674dc1a3b93d51d791c7f645e (patch)
tree50570b50f40b17d5669058401b70bce0a5bc36c4 /drivers/rtc
parente34494c8df0cd96fc432efae121db3212c46ae48 (diff)
rtc: msm6242: Remove unneeded msm6242_set()/msm6242_clear() functions
The msm6242_set()/msm6242_clear() functions are used when writing to Control Register D to set or clear the HOLD bit when reading the current time from the RTC. Doing this with a read-modify-write cycle will potentially clear an interrupt condition which occurs between the read and the write. The datasheet states the following about this: When writing the HOLD or 30 second adjust bits of register D, it is necessary to write the IRQ FLAG bit to a "1". Since the only other bits in the register are the 30 second adjust bit (which is not used) and the BUSY bit (which is read-only), the read-modify-write cycle can be replaced by a simple write with the IRQ FLAG bit set to 1 and the other bits (except HOLD) set to 0. Tested-by: Kars de Jong <jongk@linux-m68k.org> Signed-off-by: Kars de Jong <jongk@linux-m68k.org> Link: https://lore.kernel.org/r/20191116114620.9193-1-jongk@linux-m68k.org Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/rtc-msm6242.c20
1 files changed, 4 insertions, 16 deletions
diff --git a/drivers/rtc/rtc-msm6242.c b/drivers/rtc/rtc-msm6242.c
index b1f2bedee77e..80e364baac53 100644
--- a/drivers/rtc/rtc-msm6242.c
+++ b/drivers/rtc/rtc-msm6242.c
@@ -88,28 +88,16 @@ static inline void msm6242_write(struct msm6242_priv *priv, unsigned int val,
__raw_writel(val, &priv->regs[reg]);
}
-static inline void msm6242_set(struct msm6242_priv *priv, unsigned int val,
- unsigned int reg)
-{
- msm6242_write(priv, msm6242_read(priv, reg) | val, reg);
-}
-
-static inline void msm6242_clear(struct msm6242_priv *priv, unsigned int val,
- unsigned int reg)
-{
- msm6242_write(priv, msm6242_read(priv, reg) & ~val, reg);
-}
-
static void msm6242_lock(struct msm6242_priv *priv)
{
int cnt = 5;
- msm6242_set(priv, MSM6242_CD_HOLD, MSM6242_CD);
+ msm6242_write(priv, MSM6242_CD_HOLD|MSM6242_CD_IRQ_FLAG, MSM6242_CD);
while ((msm6242_read(priv, MSM6242_CD) & MSM6242_CD_BUSY) && cnt) {
- msm6242_clear(priv, MSM6242_CD_HOLD, MSM6242_CD);
+ msm6242_write(priv, MSM6242_CD_IRQ_FLAG, MSM6242_CD);
udelay(70);
- msm6242_set(priv, MSM6242_CD_HOLD, MSM6242_CD);
+ msm6242_write(priv, MSM6242_CD_HOLD|MSM6242_CD_IRQ_FLAG, MSM6242_CD);
cnt--;
}
@@ -120,7 +108,7 @@ static void msm6242_lock(struct msm6242_priv *priv)
static void msm6242_unlock(struct msm6242_priv *priv)
{
- msm6242_clear(priv, MSM6242_CD_HOLD, MSM6242_CD);
+ msm6242_write(priv, MSM6242_CD_IRQ_FLAG, MSM6242_CD);
}
static int msm6242_read_time(struct device *dev, struct rtc_time *tm)