From: Joel Stanley <joel@jms.id.au>
Date: Fri, 8 Nov 2019 13:59:05 +1030
Subject: watchdog: aspeed: Fix clock behaviour for ast2600
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Git-commit: c04571251b3d842096f1597f5d4badb508be016d
Patch-mainline: v5.5-rc1
References: git-fixes bnc#1151927 5.3.16

The ast2600 no longer uses bit 4 in the control register to indicate a
1MHz clock (It now controls whether this watchdog is reset by a SOC
reset). This means we do not want to set it. It also does not need to be
set for the ast2500, as it is read-only on that SoC.

The comment next to the clock rate selection wandered away from where it
was set, so put it back next to the register setting it's describing.

Fixes: b3528b487448 ("watchdog: aspeed: Add support for AST2600")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191108032905.22463-1-joel@jms.id.au
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/watchdog/aspeed_wdt.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -202,11 +202,6 @@ static int aspeed_wdt_probe(struct platf
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);
 
-	/*
-	 * The ast2400 wdt can run at PCLK, or 1MHz. The ast2500 only
-	 * runs at 1MHz. We chose to always run at 1MHz, as there's no
-	 * good reason to have a faster watchdog counter.
-	 */
 	wdt->wdd.info = &aspeed_wdt_info;
 	wdt->wdd.ops = &aspeed_wdt_ops;
 	wdt->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
@@ -222,7 +217,16 @@ static int aspeed_wdt_probe(struct platf
 		return -EINVAL;
 	config = ofdid->data;
 
-	wdt->ctrl = WDT_CTRL_1MHZ_CLK;
+	/*
+	 * On clock rates:
+	 *  - ast2400 wdt can run at PCLK, or 1MHz
+	 *  - ast2500 only runs at 1MHz, hard coding bit 4 to 1
+	 *  - ast2600 always runs at 1MHz
+	 *
+	 * Set the ast2400 to run at 1MHz as it simplifies the driver.
+	 */
+	if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
+		wdt->ctrl = WDT_CTRL_1MHZ_CLK;
 
 	/*
 	 * Control reset on a per-device basis to ensure the