linux-kernel - [PATCH AUTOSEL 3.18 05/13] watchdog: lantiq: update register names to better match spec

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Message-Id: <20181104135433.88734-5-sashal@kernel.org>
Date:   Sun,  4 Nov 2018 08:54:25 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Hauke Mehrtens <hauke@...ke-m.de>,
        Guenter Roeck <linux@...ck-us.net>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 3.18 05/13] watchdog: lantiq: update register names to better match spec

From: Hauke Mehrtens <hauke@...ke-m.de>

[ Upstream commit 1f59f8aff98f200af7a6882184add7b85f5da741 ]

Some of the names of the bits were confusing to me.
Now the bits share the same prefix as the register they are set on.

The LTQ_WDT_CR_PWL register (bits 26:25) is the pre warning limit and it
does not turn anything on. It has 4 possible divers 1/2, 1/4, 1/8 and
1/16, this drivers only uses 1/16.
The LTQ_WDT_CR_CLKDIV register bits(25:24) is only configuring a clock
divers and do not turn any thing on too, all possible values are valid
dividers.
Using the LTQ_WDT_SR prefix is also wrong these bits are used in the
LTQ_WDT_CR registers, SR is the status register which is read only.

This uses GENMASK where it is a mask and it uses shifts when a value is
written to some bits.

Signed-off-by: Hauke Mehrtens <hauke@...ke-m.de>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@...ux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/watchdog/lantiq_wdt.c | 36 ++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/watchdog/lantiq_wdt.c b/drivers/watchdog/lantiq_wdt.c
index 021e84eb88eb..6ed207b31784 100644
--- a/drivers/watchdog/lantiq_wdt.c
+++ b/drivers/watchdog/lantiq_wdt.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/miscdevice.h>
+#include <linux/bitops.h>
 #include <linux/watchdog.h>
 #include <linux/of_platform.h>
 #include <linux/uaccess.h>
@@ -28,18 +29,19 @@
  * essentially the following two magic passwords need to be written to allow
  * IO access to the WDT core
  */
-#define LTQ_WDT_PW1		0x00BE0000
-#define LTQ_WDT_PW2		0x00DC0000
+#define LTQ_WDT_CR_PW1		0x00BE0000
+#define LTQ_WDT_CR_PW2		0x00DC0000
+
+#define LTQ_WDT_CR		0x0		/* watchdog control register */
+#define  LTQ_WDT_CR_GEN		BIT(31)		/* enable bit */
+/* Pre-warning limit set to 1/16 of max WDT period */
+#define  LTQ_WDT_CR_PWL		(0x3 << 26)
+/* set clock divider to 0x40000 */
+#define  LTQ_WDT_CR_CLKDIV	(0x3 << 24)
+#define  LTQ_WDT_CR_PW_MASK	GENMASK(23, 16)	/* Password field */
+#define  LTQ_WDT_CR_MAX_TIMEOUT	((1 << 16) - 1)	/* The reload field is 16 bit */
 
-#define LTQ_WDT_CR		0x0	/* watchdog control register */
-#define LTQ_WDT_SR		0x8	/* watchdog status register */
-
-#define LTQ_WDT_SR_EN		(0x1 << 31)	/* enable bit */
-#define LTQ_WDT_SR_PWD		(0x3 << 26)	/* turn on power */
-#define LTQ_WDT_SR_CLKDIV	(0x3 << 24)	/* turn on clock and set */
-						/* divider to 0x40000 */
 #define LTQ_WDT_DIVIDER		0x40000
-#define LTQ_MAX_TIMEOUT		((1 << 16) - 1)	/* the reload field is 16 bit */
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
 
@@ -56,26 +58,26 @@ ltq_wdt_enable(void)
 {
 	unsigned long int timeout = ltq_wdt_timeout *
 			(ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000;
-	if (timeout > LTQ_MAX_TIMEOUT)
-		timeout = LTQ_MAX_TIMEOUT;
+	if (timeout > LTQ_WDT_CR_MAX_TIMEOUT)
+		timeout = LTQ_WDT_CR_MAX_TIMEOUT;
 
 	/* write the first password magic */
-	ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
+	ltq_w32(LTQ_WDT_CR_PW1, ltq_wdt_membase + LTQ_WDT_CR);
 	/* write the second magic plus the configuration and new timeout */
-	ltq_w32(LTQ_WDT_SR_EN | LTQ_WDT_SR_PWD | LTQ_WDT_SR_CLKDIV |
-		LTQ_WDT_PW2 | timeout, ltq_wdt_membase + LTQ_WDT_CR);
+	ltq_w32(LTQ_WDT_CR_GEN | LTQ_WDT_CR_PWL | LTQ_WDT_CR_CLKDIV |
+		LTQ_WDT_CR_PW2 | timeout, ltq_wdt_membase + LTQ_WDT_CR);
 }
 
 static void
 ltq_wdt_disable(void)
 {
 	/* write the first password magic */
-	ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
+	ltq_w32(LTQ_WDT_CR_PW1, ltq_wdt_membase + LTQ_WDT_CR);
 	/*
 	 * write the second password magic with no config
 	 * this turns the watchdog off
 	 */
-	ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR);
+	ltq_w32(LTQ_WDT_CR_PW2, ltq_wdt_membase + LTQ_WDT_CR);
 }
 
 static ssize_t
-- 
2.17.1