[PATCH 1/2] dt-bindings: mailbox: Add the Spreadtrum mailbox documentation

[PATCH 1/2] dt-bindings: mailbox: Add the Spreadtrum mailbox documentation

[Baolin Wang]

From: Baolin Wang <baolin.wang@unisoc.com>

Add the Spreadtrum mailbox documentation.

Signed-off-by: Baolin Wang <baolin.wang@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
---
 .../devicetree/bindings/mailbox/sprd-mailbox.yaml  | 56 ++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml

diff --git a/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml b/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml
new file mode 100644
index 0000000..2f2fdcf
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/mailbox/sprd-mailbox.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Spreadtrum mailbox controller bindings
+
+maintainers:
+  - Orson Zhai <orsonzhai@gmail.com>
+  - Baolin Wang <baolin.wang7@gmail.com>
+  - Chunyan Zhang <zhang.lyra@gmail.com>
+
+properties:
+  compatible:
+    enum:
+      - sprd,sc9860-mailbox
+
+  reg:
+    minItems: 2
+
+  interrupts:
+    minItems: 2
+    description:
+      Contains the inbox and outbox interrupt information.
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: enable
+
+  "#mbox-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - "#mbox-cells"
+  - clocks
+  - clock-names
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    mailbox: mailbox@400a0000 {
+      compatible = "sprd,sc9860-mailbox";
+      reg = <0 0x400a0000 0 0x8000>, <0 0x400a8000 0 0x8000>;
+      #mbox-cells = <1>;
+      clock-names = "enable";
+      clocks = <&aon_gate 53>;
+      interrupts = <GIC_SPI 28 IRQ_TYPE_LEVEL_HIGH>, <GIC_SPI 29 IRQ_TYPE_LEVEL_HIGH>;
+    };
+...
-- 
1.9.1

[PATCH 2/2] mailbox: sprd: Add Spreadtrum mailbox driver

[Baolin Wang]

From: Baolin Wang <baolin.wang@unisoc.com>

The Spreadtrum mailbox controller supports 8 channels to communicate
with MCUs, and it contains 2 different parts: inbox and outbox, which
are used to send and receive messages by IRQ mode.

Signed-off-by: Baolin Wang <baolin.wang@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
---
 drivers/mailbox/Kconfig        |   8 +
 drivers/mailbox/Makefile       |   2 +
 drivers/mailbox/sprd-mailbox.c | 350 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 360 insertions(+)
 create mode 100644 drivers/mailbox/sprd-mailbox.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index ab4eb75..a33eaab 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -227,4 +227,12 @@ config ZYNQMP_IPI_MBOX
 	  message to the IPI buffer and will access the IPI control
 	  registers to kick the other processor or enquire status.
 
+config SPRD_MBOX
+	tristate "Spreadtrum Mailbox"
+	depends on ARCH_SPRD || COMPILE_TEST
+	help
+	  Mailbox driver implementation for the Spreadtrum platform. It is used
+	  to send message between application processors and MCU. Say Y here if
+	  you want to build the Spreatrum mailbox controller driver.
+
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index c22fad6..0f47b6b 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -48,3 +48,5 @@ obj-$(CONFIG_STM32_IPCC) 	+= stm32-ipcc.o
 obj-$(CONFIG_MTK_CMDQ_MBOX)	+= mtk-cmdq-mailbox.o
 
 obj-$(CONFIG_ZYNQMP_IPI_MBOX)	+= zynqmp-ipi-mailbox.o
+
+obj-$(CONFIG_SPRD_MBOX)		+= sprd-mailbox.o
diff --git a/drivers/mailbox/sprd-mailbox.c b/drivers/mailbox/sprd-mailbox.c
new file mode 100644
index 0000000..58e5388
--- /dev/null
+++ b/drivers/mailbox/sprd-mailbox.c
@@ -0,0 +1,350 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Spreadtrum mailbox driver
+ *
+ * Copyright (c) 2020 Spreadtrum Communications Inc.
+ */
+
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+
+#define SPRD_MBOX_ID		0x0
+#define SPRD_MBOX_MSG_LOW	0x4
+#define SPRD_MBOX_MSG_HIGH	0x8
+#define SPRD_MBOX_TRIGGER	0xc
+#define SPRD_MBOX_FIFO_RST	0x10
+#define SPRD_MBOX_FIFO_STS	0x14
+#define SPRD_MBOX_IRQ_STS	0x18
+#define SPRD_MBOX_IRQ_MSK	0x1c
+#define SPRD_MBOX_LOCK		0x20
+#define SPRD_MBOX_FIFO_DEPTH	0x24
+
+/* Bit and mask definiation for inbox's SPRD_MBOX_FIFO_STS register */
+#define SPRD_INBOX_FIFO_DELIVER_MASK		GENMASK(23, 16)
+#define SPRD_INBOX_FIFO_OVERLOW_MASK		GENMASK(15, 8)
+#define SPRD_INBOX_FIFO_DELIVER_SHIFT		16
+#define SPRD_INBOX_FIFO_BUSY_MASK		GENMASK(7, 0)
+
+/* Bit and mask definiation for SPRD_MBOX_IRQ_STS register */
+#define SPRD_MBOX_IRQ_CLR			BIT(0)
+
+/* Bit and mask definiation for outbox's SPRD_MBOX_FIFO_STS register */
+#define SPRD_OUTBOX_FIFO_FULL			BIT(0)
+#define SPRD_OUTBOX_FIFO_WR_SHIFT		16
+#define SPRD_OUTBOX_FIFO_RD_SHIFT		24
+#define SPRD_OUTBOX_FIFO_POS_MASK		GENMASK(7, 0)
+
+/* Bit and mask definiation for inbox's SPRD_MBOX_IRQ_MSK register */
+#define SPRD_INBOX_FIFO_BLOCK_IRQ		BIT(0)
+#define SPRD_INBOX_FIFO_OVERFLOW_IRQ		BIT(1)
+#define SPRD_INBOX_FIFO_DELIVER_IRQ		BIT(2)
+#define SPRD_INBOX_FIFO_IRQ_MASK		GENMASK(2, 0)
+
+/* Bit and mask definiation for outbox's SPRD_MBOX_IRQ_MSK register */
+#define SPRD_OUTBOX_FIFO_NOT_EMPTY_IRQ		BIT(0)
+#define SPRD_OUTBOX_FIFO_IRQ_MASK		GENMASK(4, 0)
+
+#define SPRD_MBOX_CHAN_MAX			8
+
+struct sprd_mbox_chan {
+	u8			id;
+	struct mbox_chan	*chan;
+};
+
+struct sprd_mbox_priv {
+	struct mbox_controller	mbox;
+	struct device		*dev;
+	void __iomem		*inbox_base;
+	void __iomem		*outbox_base;
+	struct clk		*clk;
+	u32			outbox_fifo_depth;
+
+	struct sprd_mbox_chan	mchan[SPRD_MBOX_CHAN_MAX];
+	struct mbox_chan	chan[SPRD_MBOX_CHAN_MAX];
+};
+
+static struct sprd_mbox_priv *to_sprd_mbox_priv(struct mbox_controller *mbox)
+{
+	return container_of(mbox, struct sprd_mbox_priv, mbox);
+}
+
+static u32 sprd_mbox_get_fifo_len(struct sprd_mbox_priv *priv, u32 fifo_sts)
+{
+	u32 wr_pos = (fifo_sts >> SPRD_OUTBOX_FIFO_WR_SHIFT) &
+		SPRD_OUTBOX_FIFO_POS_MASK;
+	u32 rd_pos = (fifo_sts >> SPRD_OUTBOX_FIFO_RD_SHIFT) &
+		SPRD_OUTBOX_FIFO_POS_MASK;
+	u32 fifo_len;
+
+	/*
+	 * If the read pointer is equal with write pointer, which means the fifo
+	 * is full or empty.
+	 */
+	if (wr_pos == rd_pos) {
+		if (fifo_sts & SPRD_OUTBOX_FIFO_FULL)
+			fifo_len = priv->outbox_fifo_depth;
+		else
+			fifo_len = 0;
+	} else if (wr_pos > rd_pos) {
+		fifo_len = wr_pos - rd_pos;
+	} else {
+		fifo_len = priv->outbox_fifo_depth - rd_pos + wr_pos;
+	}
+
+	return fifo_len;
+}
+
+static irqreturn_t sprd_mbox_outbox_isr(int irq, void *data)
+{
+	struct sprd_mbox_priv *priv = data;
+	struct sprd_mbox_chan *mchan;
+	u32 fifo_sts, fifo_len, msg[2];
+	int i, id;
+
+	fifo_sts = readl(priv->outbox_base + SPRD_MBOX_FIFO_STS);
+
+	fifo_len = sprd_mbox_get_fifo_len(priv, fifo_sts);
+	if (!fifo_len) {
+		dev_warn_ratelimited(priv->dev, "spurious outbox interrupt\n");
+		return IRQ_NONE;
+	}
+
+	for (i = 0; i < fifo_len; i++) {
+		msg[0] = readl(priv->outbox_base + SPRD_MBOX_MSG_LOW);
+		msg[1] = readl(priv->outbox_base + SPRD_MBOX_MSG_HIGH);
+		id = readl(priv->outbox_base + SPRD_MBOX_ID);
+
+		mchan = &priv->mchan[id];
+		mbox_chan_received_data(mchan->chan, (void *)msg);
+
+		/* Trigger to update outbox FIFO pointer */
+		writel(0x1, priv->outbox_base + SPRD_MBOX_TRIGGER);
+	}
+
+	/* Clear irq status after reading all message. */
+	writel(SPRD_MBOX_IRQ_CLR, priv->outbox_base + SPRD_MBOX_IRQ_STS);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t sprd_mbox_inbox_isr(int irq, void *data)
+{
+	struct sprd_mbox_priv *priv = data;
+	struct sprd_mbox_chan *mchan;
+	u32 fifo_sts, send_sts, id;
+
+	fifo_sts = readl(priv->inbox_base + SPRD_MBOX_FIFO_STS);
+
+	/* Get the inbox data delivery status */
+	send_sts = (fifo_sts & SPRD_INBOX_FIFO_DELIVER_MASK) >>
+		SPRD_INBOX_FIFO_DELIVER_SHIFT;
+	if (!send_sts) {
+		dev_warn_ratelimited(priv->dev, "spurious inbox interrupt\n");
+		return IRQ_NONE;
+	}
+
+	while (send_sts) {
+		id = __ffs(send_sts);
+		send_sts &= (send_sts - 1);
+
+		mchan = &priv->mchan[id];
+		mbox_chan_txdone(mchan->chan, 0);
+	}
+
+	/* Clear FIFO delivery and overflow status */
+	writel(fifo_sts &
+	       (SPRD_INBOX_FIFO_DELIVER_MASK | SPRD_INBOX_FIFO_OVERLOW_MASK),
+	       priv->inbox_base + SPRD_MBOX_FIFO_RST);
+
+	/* Clear irq status */
+	writel(SPRD_MBOX_IRQ_CLR, priv->inbox_base + SPRD_MBOX_IRQ_STS);
+
+	return IRQ_HANDLED;
+}
+
+static int sprd_mbox_send_data(struct mbox_chan *chan, void *msg)
+{
+	struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
+	struct sprd_mbox_chan *mchan = chan->con_priv;
+	u32 *data = msg, busy;
+
+	/*
+	 * Check if current channel is busy or not, and we can not send data
+	 * if current channel is busy.
+	 */
+	busy = readl(priv->inbox_base + SPRD_MBOX_FIFO_STS) &
+		SPRD_INBOX_FIFO_BUSY_MASK;
+	if (busy & BIT(mchan->id)) {
+		dev_err(priv->dev, "Channel %d is busy\n", mchan->id);
+		return -EBUSY;
+	}
+
+	/* Write data into inbox FIFO, and only support 8 bytes every time */
+	writel(data[0], priv->inbox_base + SPRD_MBOX_MSG_LOW);
+	writel(data[1], priv->inbox_base + SPRD_MBOX_MSG_HIGH);
+
+	/* Set target core id */
+	writel(mchan->id, priv->inbox_base + SPRD_MBOX_ID);
+
+	/* Trigger remote request */
+	writel(0x1, priv->inbox_base + SPRD_MBOX_TRIGGER);
+
+	return 0;
+}
+
+static int sprd_mbox_startup(struct mbox_chan *chan)
+{
+	struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
+	u32 val;
+
+	/* Select outbox FIFO mode and reset the outbox FIFO status */
+	writel(0x0, priv->outbox_base + SPRD_MBOX_FIFO_RST);
+
+	/* Enable inbox FIFO overflow and delivery interrupt */
+	val = readl(priv->inbox_base + SPRD_MBOX_IRQ_MSK);
+	val &= ~(SPRD_INBOX_FIFO_OVERFLOW_IRQ | SPRD_INBOX_FIFO_DELIVER_IRQ);
+	writel(val, priv->inbox_base + SPRD_MBOX_IRQ_MSK);
+
+	/* Enable outbox FIFO not empty interrupt */
+	val = readl(priv->outbox_base + SPRD_MBOX_IRQ_MSK);
+	val &= ~SPRD_OUTBOX_FIFO_NOT_EMPTY_IRQ;
+	writel(val, priv->outbox_base + SPRD_MBOX_IRQ_MSK);
+
+	return 0;
+}
+
+static void sprd_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct sprd_mbox_priv *priv = to_sprd_mbox_priv(chan->mbox);
+
+	/* Disable inbox & outbox interrupt */
+	writel(SPRD_INBOX_FIFO_IRQ_MASK, priv->inbox_base + SPRD_MBOX_IRQ_MSK);
+	writel(SPRD_OUTBOX_FIFO_IRQ_MASK, priv->outbox_base + SPRD_MBOX_IRQ_MSK);
+}
+
+static const struct mbox_chan_ops sprd_mbox_ops = {
+	.send_data    = sprd_mbox_send_data,
+	.startup      = sprd_mbox_startup,
+	.shutdown     = sprd_mbox_shutdown,
+};
+
+static void sprd_mbox_disable(void *data)
+{
+	struct sprd_mbox_priv *priv = data;
+
+	clk_disable_unprepare(priv->clk);
+}
+
+static int sprd_mbox_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sprd_mbox_priv *priv;
+	int i, ret, inbox_irq, outbox_irq;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+
+	/*
+	 * The Spreadtrum mailbox uses an inbox to send messages to the target
+	 * core, and uses an outbox to receive messages from other cores.
+	 *
+	 * Thus the mailbox controller supplies 2 different register addresses
+	 * and IRQ numbers for inbox and outbox.
+	 */
+	priv->inbox_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->inbox_base))
+		return PTR_ERR(priv->inbox_base);
+
+	priv->outbox_base = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(priv->outbox_base))
+		return PTR_ERR(priv->outbox_base);
+
+	priv->clk = devm_clk_get(dev, "enable");
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "failed to get mailbox clock\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, sprd_mbox_disable, priv);
+	if (ret) {
+		dev_err(dev, "failed to add mailbox disable action\n");
+		return ret;
+	}
+
+	inbox_irq = platform_get_irq(pdev, 0);
+	if (inbox_irq < 0)
+		return inbox_irq;
+
+	ret = devm_request_irq(dev, inbox_irq, sprd_mbox_inbox_isr,
+			       IRQF_NO_SUSPEND, dev_name(dev), priv);
+	if (ret) {
+		dev_err(dev, "failed to request inbox IRQ: %d\n", ret);
+		return ret;
+	}
+
+	outbox_irq = platform_get_irq(pdev, 1);
+	if (outbox_irq < 0)
+		return outbox_irq;
+
+	ret = devm_request_irq(dev, outbox_irq, sprd_mbox_outbox_isr,
+			       IRQF_NO_SUSPEND, dev_name(dev), priv);
+	if (ret) {
+		dev_err(dev, "failed to request outbox IRQ: %d\n", ret);
+		return ret;
+	}
+
+	/* Get the default outbox FIFO depth */
+	priv->outbox_fifo_depth =
+		readl(priv->outbox_base + SPRD_MBOX_FIFO_DEPTH) + 1;
+	priv->mbox.dev = dev;
+	priv->mbox.chans = &priv->chan[0];
+	priv->mbox.num_chans = SPRD_MBOX_CHAN_MAX;
+	priv->mbox.ops = &sprd_mbox_ops;
+	priv->mbox.txdone_irq = true;
+
+	for (i = 0; i < SPRD_MBOX_CHAN_MAX; i++) {
+		priv->chan[i].con_priv = &priv->mchan[i];
+
+		priv->mchan[i].chan = &priv->chan[i];
+		priv->mchan[i].id = i;
+	}
+
+	ret = devm_mbox_controller_register(dev, &priv->mbox);
+	if (ret) {
+		dev_err(dev, "failed to register mailbox: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id sprd_mbox_of_match[] = {
+	{ .compatible = "sprd,sc9860-mailbox", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sprd_mbox_of_match);
+
+static struct platform_driver sprd_mbox_driver = {
+	.driver = {
+		.name = "sprd-mailbox",
+		.of_match_table = sprd_mbox_of_match,
+	},
+	.probe	= sprd_mbox_probe,
+};
+module_platform_driver(sprd_mbox_driver);
+
+MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
+MODULE_DESCRIPTION("Spreadtrum mailbox driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

Re: [PATCH 1/2] dt-bindings: mailbox: Add the Spreadtrum mailbox documentation

[Rob Herring]

On Fri, Mar 06, 2020 at 02:07:21PM +0800, Baolin Wang wrote:
> From: Baolin Wang <baolin.wang@unisoc.com>
> 
> Add the Spreadtrum mailbox documentation.
> 
> Signed-off-by: Baolin Wang <baolin.wang@unisoc.com>
> Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
> ---
>  .../devicetree/bindings/mailbox/sprd-mailbox.yaml  | 56 ++++++++++++++++++++++
>  1 file changed, 56 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml b/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml
> new file mode 100644
> index 0000000..2f2fdcf
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml
> @@ -0,0 +1,56 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/mailbox/sprd-mailbox.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Spreadtrum mailbox controller bindings
> +
> +maintainers:
> +  - Orson Zhai <orsonzhai@gmail.com>
> +  - Baolin Wang <baolin.wang7@gmail.com>
> +  - Chunyan Zhang <zhang.lyra@gmail.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - sprd,sc9860-mailbox
> +
> +  reg:
> +    minItems: 2

Need to define what each entry is.

> +
> +  interrupts:
> +    minItems: 2
> +    description:
> +      Contains the inbox and outbox interrupt information.

The description should be split to define each entry:

items:
  - description: inbox interrupt
  - description: outbox interrupt

> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    items:
> +      - const: enable
> +
> +  "#mbox-cells":
> +    const: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - "#mbox-cells"
> +  - clocks
> +  - clock-names

Add:

additionalProperties: false

> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    mailbox: mailbox@400a0000 {
> +      compatible = "sprd,sc9860-mailbox";
> +      reg = <0 0x400a0000 0 0x8000>, <0 0x400a8000 0 0x8000>;
> +      #mbox-cells = <1>;
> +      clock-names = "enable";
> +      clocks = <&aon_gate 53>;
> +      interrupts = <GIC_SPI 28 IRQ_TYPE_LEVEL_HIGH>, <GIC_SPI 29 IRQ_TYPE_LEVEL_HIGH>;
> +    };
> +...
> -- 
> 1.9.1
> 

Re: [PATCH 1/2] dt-bindings: mailbox: Add the Spreadtrum mailbox documentation

[Baolin Wang]

Hi Rob,

On Fri, Mar 13, 2020 at 3:16 AM Rob Herring <robh@kernel.org> wrote:
>
> On Fri, Mar 06, 2020 at 02:07:21PM +0800, Baolin Wang wrote:
> > From: Baolin Wang <baolin.wang@unisoc.com>
> >
> > Add the Spreadtrum mailbox documentation.
> >
> > Signed-off-by: Baolin Wang <baolin.wang@unisoc.com>
> > Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
> > ---
> >  .../devicetree/bindings/mailbox/sprd-mailbox.yaml  | 56 ++++++++++++++++++++++
> >  1 file changed, 56 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml b/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml
> > new file mode 100644
> > index 0000000..2f2fdcf
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mailbox/sprd-mailbox.yaml
> > @@ -0,0 +1,56 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: "http://devicetree.org/schemas/mailbox/sprd-mailbox.yaml#"
> > +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> > +
> > +title: Spreadtrum mailbox controller bindings
> > +
> > +maintainers:
> > +  - Orson Zhai <orsonzhai@gmail.com>
> > +  - Baolin Wang <baolin.wang7@gmail.com>
> > +  - Chunyan Zhang <zhang.lyra@gmail.com>
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - sprd,sc9860-mailbox
> > +
> > +  reg:
> > +    minItems: 2
>
> Need to define what each entry is.

Sure

>
> > +
> > +  interrupts:
> > +    minItems: 2
> > +    description:
> > +      Contains the inbox and outbox interrupt information.
>
> The description should be split to define each entry:
>
> items:
>   - description: inbox interrupt
>   - description: outbox interrupt

Sure.

>
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  clock-names:
> > +    items:
> > +      - const: enable
> > +
> > +  "#mbox-cells":
> > +    const: 1
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +  - "#mbox-cells"
> > +  - clocks
> > +  - clock-names
>
> Add:
>
> additionalProperties: false

OK. Thanks for your comments.

-- 
Baolin Wang