[PATCH v3 2/2] power: reset: syscon-reboot: Add parental syscon support

[Serge Semin <Sergey.Semin@baikalelectronics.ru>]

Since normally syscon-reboot block is supposed to be a part of a system
controller, lets look for the syscon regmap in a parental DT node if
regmap property isn't specified. DT binding from now considers the regmap
property as deprecated.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org

---

Changelog v2:
- This is a new patch created as a result of the discussion:
  https://lore.kernel.org/linux-pm/20200306130402.1F4F0803079F@mail.baikalelectronics.ru/

Changelog v3:
- Resend
---
 drivers/power/reset/syscon-reboot.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/power/reset/syscon-reboot.c b/drivers/power/reset/syscon-reboot.c
index 62fbba0df971..510e363381ca 100644
--- a/drivers/power/reset/syscon-reboot.c
+++ b/drivers/power/reset/syscon-reboot.c
@@ -51,8 +51,11 @@ static int syscon_reboot_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	ctx->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
-	if (IS_ERR(ctx->map))
-		return PTR_ERR(ctx->map);
+	if (IS_ERR(ctx->map)) {
+		ctx->map = syscon_node_to_regmap(dev->parent->of_node);
+		if (IS_ERR(ctx->map))
+			return PTR_ERR(ctx->map);
+	}
 
 	if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset))
 		return -EINVAL;
-- 
2.26.2