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From: Dario Binacchi <dariobin@libero.it>
To: u-boot@lists.denx.de
Cc: Dario Binacchi <dariobin@libero.it>, Lokesh Vutla <lokeshvutla@ti.com>
Subject: [PATCH v2 5/8] rtc: davinci: use unlock/lock mechanism
Date: Wed,  2 Jun 2021 22:38:02 +0200	[thread overview]
Message-ID: <20210602203805.11494-6-dariobin@libero.it> (raw)
In-Reply-To: <20210602203805.11494-1-dariobin@libero.it>

The RTC module contains a kicker mechanism to prevent any spurious
writes from changing the register values. To set the time, you must
first unlock the TC registers, update them and then lock.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
---

(no changes since v1)

 drivers/rtc/davinci.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/rtc/davinci.c b/drivers/rtc/davinci.c
index 7b8c729f3b..82e5eb3b43 100644
--- a/drivers/rtc/davinci.c
+++ b/drivers/rtc/davinci.c
@@ -16,6 +16,18 @@
 #define RTC_BASE DAVINCI_RTC_BASE
 #endif
 
+static void davinci_rtc_lock(struct davinci_rtc *rtc)
+{
+	writel(0, &rtc->kick0r);
+	writel(0, &rtc->kick1r);
+}
+
+static void davinci_rtc_unlock(struct davinci_rtc *rtc)
+{
+	writel(RTC_KICK0R_WE, &rtc->kick0r);
+	writel(RTC_KICK1R_WE, &rtc->kick1r);
+}
+
 static int davinci_rtc_wait_not_busy(struct davinci_rtc *rtc)
 {
 	int count;
@@ -89,6 +101,7 @@ int rtc_set(struct rtc_time *tmp)
 	if (ret)
 		return ret;
 
+	davinci_rtc_unlock(rtc);
 	writeb(bin2bcd(tmp->tm_year % 100), &rtc->year);
 	writeb(bin2bcd(tmp->tm_mon), &rtc->month);
 
@@ -97,6 +110,7 @@ int rtc_set(struct rtc_time *tmp)
 	writeb(bin2bcd(tmp->tm_hour), &rtc->hours);
 	writeb(bin2bcd(tmp->tm_min), &rtc->minutes);
 	writeb(bin2bcd(tmp->tm_sec), &rtc->second);
+	davinci_rtc_lock(rtc);
 
 	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 	      tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
-- 
2.17.1


  parent reply	other threads:[~2021-06-02 20:39 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-02 20:37 [PATCH v2 0/8] rtc: davinci: add driver model support Dario Binacchi
2021-06-02 20:37 ` [PATCH v2 1/8] rtc: davinci: enable compilation for omap architectures Dario Binacchi
2021-06-02 20:37 ` [PATCH v2 2/8] rtc: davinci: fix compiler errors Dario Binacchi
2021-06-02 20:38 ` [PATCH v2 3/8] rtc: davinci: replace 32bit access with 8bit access Dario Binacchi
2021-06-02 20:38 ` [PATCH v2 4/8] rtc: davinci: check BUSY bit before set TC registers Dario Binacchi
2021-06-02 20:38 ` Dario Binacchi [this message]
2021-06-02 20:38 ` [PATCH v2 6/8] arm: dts: sync rtc node of am335x boards with Linux 5.9-rc7 Dario Binacchi
2021-06-02 20:38 ` [PATCH v2 7/8] rtc: davinci: add driver model support Dario Binacchi
2021-06-02 20:38 ` [PATCH v2 8/8] rtc: davinci: fix date loaded on reset Dario Binacchi
2021-06-09 16:55 ` [PATCH v2 0/8] rtc: davinci: add driver model support Lokesh Vutla

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