[PATCH v2 18/22] watchdog: ziirave_wdt: Fix RESET_PROCESSOR payload

[Andrey Smirnov]

Bootloader firmware expects the following traffic for
RESET_PROCESSOR:

S Addr Wr [A] 0x0b [A] 0x01 [A] P

using ziirave_firm_write_byte() will result in

S Addr Wr [A] 0x0b [A] 0x01 [A] 0x01 [A] P

which happens to work because firmware will ignore any extra bytes and
expected magic value matches byte count sent by
i2c_smbus_write_block_data(). Fix this by converting the code to use
i2c_smbus_write_byte_data() instead.

Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
Cc: Chris Healy <cphealy@xxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Rick Ramstetter <rick@xxxxxxxxxxxxxxx>
Cc: linux-watchdog@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 drivers/watchdog/ziirave_wdt.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
index a598780d73d3..92df27350e41 100644
--- a/drivers/watchdog/ziirave_wdt.c
+++ b/drivers/watchdog/ziirave_wdt.c
@@ -73,6 +73,7 @@ static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
 #define ZIIRAVE_CMD_DOWNLOAD_PACKET		0x0e
 
 #define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC	1
+#define ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC	1
 
 #define ZIIRAVE_FW_VERSION_FMT	"02.%02u.%02u"
 #define ZIIRAVE_BL_VERSION_FMT	"01.%02u.%02u"
@@ -433,8 +434,9 @@ static int ziirave_firm_upload(struct watchdog_device *wdd,
 	}
 
 	/* Reset the processor */
-	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_RESET_PROCESSOR, 1,
-				      false);
+	ret = i2c_smbus_write_byte_data(client,
+					ZIIRAVE_CMD_RESET_PROCESSOR,
+					ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC);
 	if (ret) {
 		dev_err(&client->dev,
 			"Failed to reset the watchdog: %d\n", ret);
-- 
2.21.0