power: reset: at91-poweroff: do not procede if at91_shdwc is allocated

[ Upstream commit 9f1e44774be578fb92776add95f1fcaf8284d692 ]

There should be only one instance of struct shdwc in the system. This is
referenced through at91_shdwc. Return in probe if at91_shdwc is already
allocated.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/power/reset/at91-sama5d2_shdwc.c b/drivers/power/reset/at91-sama5d2_shdwc.c
index 0206cce..d9493e8 100644 (file)
--- a/drivers/power/reset/at91-sama5d2_shdwc.c
+++ b/drivers/power/reset/at91-sama5d2_shdwc.c
@@ -246,6 +246,9 @@ static int __init at91_shdwc_probe(struct platform_device *pdev)
        if (!pdev->dev.of_node)
                return -ENODEV;
 
+       if (at91_shdwc)
+               return -EBUSY;
+
        at91_shdwc = devm_kzalloc(&pdev->dev, sizeof(*at91_shdwc), GFP_KERNEL);
        if (!at91_shdwc)
                return -ENOMEM;