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* [PATCH] watchdog: da9062: make restart handler atomic safe
@ 2020-01-13  9:15 Marco Felsch
  2020-01-13 20:28 ` Guenter Roeck
  2020-01-14 20:00 ` Stefan Lengfeld
  0 siblings, 2 replies; 5+ messages in thread
From: Marco Felsch @ 2020-01-13  9:15 UTC (permalink / raw)
  To: support.opensource, linux, contact, Adam.Thomson.Opensource
  Cc: linux-watchdog, linux-kernel, kernel

The restart handler is executed during the shutdown phase which is
atomic/irq-less. The i2c framework supports atomic transfers since
commit 63b96983a5dd ("i2c: core: introduce callbacks for atomic
transfers") but unfortunately the regmap framework doesn't support it
yet. Hard coding the i2c stuff can be done without worries since the
DA9062 is an i2c-only device.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
Hi,

This patch is based on Stefan Lengfeld's RFC Patch [1].

[1] https://patchwork.ozlabs.org/patch/1085942/
---
 drivers/watchdog/da9062_wdt.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
index c9b9d6394525..84c5a0a455b2 100644
--- a/drivers/watchdog/da9062_wdt.c
+++ b/drivers/watchdog/da9062_wdt.c
@@ -11,6 +11,7 @@
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
+#include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/jiffies.h>
 #include <linux/mfd/da9062/registers.h>
@@ -149,12 +150,18 @@ static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 			      void *data)
 {
 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+	struct i2c_client *client = to_i2c_client(wdt->hw->dev);
+	u8 buf[] = {DA9062AA_CONTROL_F, DA9062AA_SHUTDOWN_MASK};
+	struct i2c_msg msg = {
+		.addr = client->addr,
+		.flags = 0,
+		.len = sizeof(buf),
+		.buf = buf,
+	};
 	int ret;
 
-	ret = regmap_write(wdt->hw->regmap,
-			   DA9062AA_CONTROL_F,
-			   DA9062AA_SHUTDOWN_MASK);
-	if (ret)
+	ret = i2c_transfer(client->adapter, &msg, 1);
+	if (ret < 0)
 		dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
 			  ret);
 
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-01-15  7:20 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-13  9:15 [PATCH] watchdog: da9062: make restart handler atomic safe Marco Felsch
2020-01-13 20:28 ` Guenter Roeck
2020-01-14 17:30   ` Marco Felsch
2020-01-14 20:00 ` Stefan Lengfeld
2020-01-15  7:19   ` Marco Felsch

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