linux-kernel - [PATCH] power: reset: syscon-reboot: add a mask property

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Date:   Fri,  8 Mar 2019 08:49:30 +0100
From:   Martin Schiller <ms@....tdt.de>
To:     sre@...nel.org, robh+dt@...nel.org, mark.rutland@....com,
        fkan@....com
Cc:     linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Martin Schiller <ms@....tdt.de>
Subject: [PATCH] power: reset: syscon-reboot: add a mask property

Make the syscon-reboot driver accept value and mask instead of
just value.

Prior to this patch, the property name for the value was 'mask'. If
only the mask property is defined on a node, maintain compatibility
by using it as the value.

This patch is based on commit
f2c199db477e ("power: reset: syscon-poweroff: add a mask property")
and does the same change for the syscon-reboot driver.

Signed-off-by: Martin Schiller <ms@....tdt.de>
---
 .../devicetree/bindings/power/reset/syscon-reboot.txt | 11 +++++++++--
 drivers/power/reset/syscon-reboot.c                   | 19 +++++++++++++++++--
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt b/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
index 11906316b43d..e23dea8344f8 100644
--- a/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
+++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
@@ -3,13 +3,20 @@ Generic SYSCON mapped register reset driver
 This is a generic reset driver using syscon to map the reset register.
 The reset is generally performed with a write to the reset register
 defined by the register map pointed by syscon reference plus the offset
-with the mask defined in the reboot node.
+with the value and mask defined in the reboot node.
 
 Required properties:
 - compatible: should contain "syscon-reboot"
 - regmap: this is phandle to the register map node
 - offset: offset in the register map for the reboot register (in bytes)
-- mask: the reset value written to the reboot register (32 bit access)
+- value: the reset value written to the reboot register (32 bit access)
+
+Optional properties:
+- mask: update only the register bits defined by the mask (32 bit)
+
+Legacy usage:
+If a node doesn't contain a value property but contains a mask property, the
+mask property is used as the value.
 
 Default will be little endian mode, 32 bit access only.
 
diff --git a/drivers/power/reset/syscon-reboot.c b/drivers/power/reset/syscon-reboot.c
index 7d0d269a0837..5a6bb638c331 100644
--- a/drivers/power/reset/syscon-reboot.c
+++ b/drivers/power/reset/syscon-reboot.c
@@ -27,6 +27,7 @@
 struct syscon_reboot_context {
 	struct regmap *map;
 	u32 offset;
+	u32 value;
 	u32 mask;
 	struct notifier_block restart_handler;
 };
@@ -39,7 +40,7 @@ static int syscon_restart_handle(struct notifier_block *this,
 					restart_handler);
 
 	/* Issue the reboot */
-	regmap_write(ctx->map, ctx->offset, ctx->mask);
+	regmap_update_bits(ctx->map, ctx->offset, ctx->mask, ctx->value);
 
 	mdelay(1000);
 
@@ -51,6 +52,7 @@ static int syscon_reboot_probe(struct platform_device *pdev)
 {
 	struct syscon_reboot_context *ctx;
 	struct device *dev = &pdev->dev;
+	int mask_err, value_err;
 	int err;
 
 	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
@@ -64,8 +66,21 @@ static int syscon_reboot_probe(struct platform_device *pdev)
 	if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset))
 		return -EINVAL;
 
-	if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask))
+	value_err = of_property_read_u32(pdev->dev.of_node, "value", &ctx->value);
+	mask_err = of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask);
+	if (value_err && mask_err) {
+		dev_err(dev, "unable to read 'value' and 'mask'");
 		return -EINVAL;
+	}
+
+	if (value_err) {
+		/* support old binding */
+		ctx->value = ctx->mask;
+		ctx->mask = 0xFFFFFFFF;
+	} else if (mask_err) {
+		/* support value without mask*/
+		ctx->mask = 0xFFFFFFFF;
+	}
 
 	ctx->restart_handler.notifier_call = syscon_restart_handle;
 	ctx->restart_handler.priority = 192;
-- 
2.11.0