linux-kernel - [PATCH] watchdog: rzg2l_wdt: Issue a reset before we put the PM clocks

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Message-Id: <20221114180843.1125308-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
Date:   Mon, 14 Nov 2022 18:08:43 +0000
From:   Prabhakar <prabhakar.csengg@...il.com>
To:     Geert Uytterhoeven <geert+renesas@...der.be>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        linux-watchdog@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        Prabhakar <prabhakar.csengg@...il.com>,
        Biju Das <biju.das.jz@...renesas.com>,
        Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: [PATCH] watchdog: rzg2l_wdt: Issue a reset before we put the PM clocks

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>

On RZ/Five SoC it was observed that setting timeout (to say 1 sec)
wouldn't reset the system. To fix this we make sure we issue a reset
before putting the PM clocks to make sure the registers have been cleared.

While at it re-used rzg2l_wdt_stop() in rzg2l_wdt_set_timeout() as
we were calling the same functions here.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
---
Note,
- This patch has been tested on RZ/G2L, RZ/V2M and RZ/Five.
- My initial investigation showed adding the delay after pm_runtime_get_sync()
  also fixed this issue.
- Do I need add the fixes tag ? what should be the operation PUT->RESET/RESET->PUT?
  in case we need the tag is:
  Fixes: 4055ee81009e6 ("watchdog: rzg2l_wdt: Add set_timeout callback")
---
 drivers/watchdog/rzg2l_wdt.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
index 00438ceed17a..d1271cc7750f 100644
--- a/drivers/watchdog/rzg2l_wdt.c
+++ b/drivers/watchdog/rzg2l_wdt.c
@@ -115,16 +115,14 @@ static int rzg2l_wdt_stop(struct watchdog_device *wdev)
 {
 	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
 
-	pm_runtime_put(wdev->parent);
 	reset_control_reset(priv->rstc);
+	pm_runtime_put(wdev->parent);
 
 	return 0;
 }
 
 static int rzg2l_wdt_set_timeout(struct watchdog_device *wdev, unsigned int timeout)
 {
-	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
-
 	wdev->timeout = timeout;
 
 	/*
@@ -132,8 +130,7 @@ static int rzg2l_wdt_set_timeout(struct watchdog_device *wdev, unsigned int time
 	 * register so that it is updated with new timeout values.
 	 */
 	if (watchdog_active(wdev)) {
-		pm_runtime_put(wdev->parent);
-		reset_control_reset(priv->rstc);
+		rzg2l_wdt_stop(wdev);
 		rzg2l_wdt_start(wdev);
 	}
 
-- 
2.25.1