From 0dbbf25561b29ffab5ba6277429760abdf49ceff Mon Sep 17 00:00:00 2001
From: Vincent Palatin <vpalatin@chromium.org>
Date: Wed, 18 Apr 2018 12:23:58 +0200
Subject: [PATCH] mfd: cros_ec: Fail early if we cannot identify the EC
Git-commit: 0dbbf25561b29ffab5ba6277429760abdf49ceff
Patch-mainline: v4.18-rc1
References: bsc#1051510

If we cannot communicate with the EC chip to detect the protocol version
and its features, it's very likely useless to continue. Else we will
commit all kind of uninformed mistakes (using the wrong protocol, the
wrong buffer size, mixing the EC with other chips).

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Acked-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/mfd/cros_ec.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index c221163d5b9e..1e5276970778 100644
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -112,7 +112,11 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 
 	mutex_init(&ec_dev->lock);
 
-	cros_ec_query_all(ec_dev);
+	err = cros_ec_query_all(ec_dev);
+	if (err) {
+		dev_err(dev, "Cannot identify the EC: error %d\n", err);
+		return err;
+	}
 
 	if (ec_dev->irq) {
 		err = request_threaded_irq(ec_dev->irq, NULL, ec_irq_thread,
-- 
2.18.0