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authorMarco Felsch <m.felsch@pengutronix.de>2020-01-15 19:23:07 +0300
committerWim Van Sebroeck <wim@linux-watchdog.org>2020-01-27 17:55:49 +0300
commit057b52b4b3d58f4ee5944171da50f77b00a1bb0d (patch)
treeb7153c6afbc701725f038e778d0898ef301de0f5 /drivers/watchdog
parent9e5236e7cec110610f3bc824a4d535c1271e4bb5 (diff)
downloadlinux-057b52b4b3d58f4ee5944171da50f77b00a1bb0d.tar.xz
watchdog: da9062: make restart handler atomic safe
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") to address this use case. Using regmap within an atomic context is allowed only if the regmap type is MMIO and the cache type 'flat' or no cache is used. Using the i2c_smbus_write_byte_data() function can be done without additional tests because: 1) the DA9062 is an i2c-only device and 2) the i2c framework emulates the smbus protocol if the host adapter does not support smbus_xfer by using the master_xfer. Signed-off-by: Marco Felsch <m.felsch@pengutronix.de> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Stefan Lengfeld <contact@stefanchrist.eu> Tested-by: Stefan Lengfeld <contact@stefanchrist.eu> Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com> Link: https://lore.kernel.org/r/20200115162307.7336-1-m.felsch@pengutronix.de Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Diffstat (limited to 'drivers/watchdog')
-rw-r--r--drivers/watchdog/da9062_wdt.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
index 2a1e7de25b71..47eefe072b40 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>
@@ -147,12 +148,13 @@ 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);
int ret;
- ret = regmap_write(wdt->hw->regmap,
- DA9062AA_CONTROL_F,
- DA9062AA_SHUTDOWN_MASK);
- if (ret)
+ /* Don't use regmap because it is not atomic safe */
+ ret = i2c_smbus_write_byte_data(client, DA9062AA_CONTROL_F,
+ DA9062AA_SHUTDOWN_MASK);
+ if (ret < 0)
dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
ret);