[PATCH v2 0/3] Add IMX8 SCU GPIO support

[PATCH v2 0/3] Add IMX8 SCU GPIO support

[Shenwei Wang]

The system controller (SCU) is the central unit to manage the resources
on i.MX8 platforms. The SCU firmware provides a set of APIs to access
the GPIO PINs on the SCU domain.

This patch series implements the standard GPIO driver over the SCU
firmware APIs, so that the GPIOs on the SCU domain could be accessed
like a local GPIO PINs.

Changes in V2:
 - move the driver into the gpio directory per Krzysztof's feedback
 - change the subnode description in file fsl,scu.yaml
 - fix the dt_binding_check error

Shenwei Wang (3):
  dt-bindings: gpio: Add imx-scu gpio driver bindings
  dt-bindings: firmware: imx: Add imx-scu gpio node
  firmware: imx: add imx-scu GPIO driver

 .../devicetree/bindings/firmware/fsl,scu.yaml |   5 +
 .../bindings/gpio/fsl,imx8-scu-gpio.yaml      |  39 +++++
 drivers/gpio/Kconfig                          |   4 +
 drivers/gpio/Makefile                         |   1 +
 drivers/gpio/gpio-imx-scu.c                   | 139 ++++++++++++++++++
 5 files changed, 188 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml
 create mode 100644 drivers/gpio/gpio-imx-scu.c

--
2.25.1

[PATCH v2 1/3] dt-bindings: gpio: Add imx-scu gpio driver bindings

[Shenwei Wang]

Add binding document for the imx-scu gpio driver.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 .../bindings/gpio/fsl,imx8-scu-gpio.yaml      | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml

diff --git a/Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml b/Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml
new file mode 100644
index 000000000000..4cbe3108a612
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/fsl,imx8-scu-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: GPIO driver over IMX SCU firmware API
+
+maintainers:
+  - Shenwei Wang <shenwei.wang@nxp.com>
+
+description: |
+  This module provides the standard interface to control the
+  resource pins in SCU domain on i.MX8 platforms.
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx8-scu-gpio
+
+  "#gpio-cells":
+    const: 2
+
+  gpio-controller: true
+
+required:
+  - compatible
+  - "#gpio-cells"
+  - gpio-controller
+
+additionalProperties: false
+
+examples:
+  - |
+    gpio0: gpio {
+        compatible = "fsl,imx8-scu-gpio";
+        gpio-controller;
+        #gpio-cells = <2>;
+    };
-- 
2.25.1

[PATCH v2 2/3] dt-bindings: firmware: imx: Add imx-scu gpio node

[Shenwei Wang]

Add the description for imx-scu gpio subnode.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 Documentation/devicetree/bindings/firmware/fsl,scu.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/firmware/fsl,scu.yaml b/Documentation/devicetree/bindings/firmware/fsl,scu.yaml
index b40b0ef56978..afcfc8ea90c4 100644
--- a/Documentation/devicetree/bindings/firmware/fsl,scu.yaml
+++ b/Documentation/devicetree/bindings/firmware/fsl,scu.yaml
@@ -30,6 +30,11 @@ properties:
       Clock controller node that provides the clocks controlled by the SCU
     $ref: /schemas/clock/fsl,scu-clk.yaml
 
+  gpio:
+    description:
+      Control the GPIO PINs on SCU domain over the firmware APIs
+    $ref: /schemas/gpio/fsl,imx8-scu-gpio.yaml
+
   ocotp:
     description:
       OCOTP controller node provided by the SCU
-- 
2.25.1

[PATCH v2 3/3] firmware: imx: add imx-scu GPIO driver

[Shenwei Wang]

The SCU firmware on i.MX8 platforms provides a set of APIs to
control the GPIO PINs on the SCU domain. This patch implements the
standard GPIO driver interface to access those PINs on the
SCU domain over the SCU APIs.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 drivers/gpio/Kconfig        |   4 ++
 drivers/gpio/Makefile       |   1 +
 drivers/gpio/gpio-imx-scu.c | 139 ++++++++++++++++++++++++++++++++++++
 3 files changed, 144 insertions(+)
 create mode 100644 drivers/gpio/gpio-imx-scu.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 0499c2facbb0..b01310f6ebcc 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -341,6 +341,10 @@ config GPIO_ICH
 
 	  If unsure, say N.
 
+config GPIO_IMX_SCU
+       def_bool y
+       depends on IMX_SCU
+
 config GPIO_IOP
 	tristate "Intel IOP GPIO"
 	depends on ARCH_IOP32X || COMPILE_TEST
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 3fa4f3f93d85..b39ab87793ec 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_HTC_EGPIO)			+= gpio-htc-egpio.o
 obj-$(CONFIG_GPIO_I8255)		+= gpio-i8255.o
 obj-$(CONFIG_GPIO_ICH)			+= gpio-ich.o
 obj-$(CONFIG_GPIO_IDT3243X)		+= gpio-idt3243x.o
+obj-$(CONFIG_GPIO_IMX_SCU)		+= gpio-imx-scu.o
 obj-$(CONFIG_GPIO_IOP)			+= gpio-iop.o
 obj-$(CONFIG_GPIO_IT87)			+= gpio-it87.o
 obj-$(CONFIG_GPIO_IXP4XX)		+= gpio-ixp4xx.o
diff --git a/drivers/gpio/gpio-imx-scu.c b/drivers/gpio/gpio-imx-scu.c
new file mode 100644
index 000000000000..2f4a991a9ad6
--- /dev/null
+++ b/drivers/gpio/gpio-imx-scu.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2021~2022 NXP
+ *
+ * The driver exports a standard gpiochip interface
+ * to control the PIN resources on SCU domain.
+ */
+
+#include <linux/module.h>
+#include <linux/gpio/driver.h>
+#include <linux/platform_device.h>
+#include <linux/firmware/imx/svc/rm.h>
+#include <dt-bindings/firmware/imx/rsrc.h>
+
+struct scu_gpio_priv {
+	struct gpio_chip	chip;
+	struct mutex		lock;
+	struct device		*dev;
+	struct imx_sc_ipc	*handle;
+};
+
+static unsigned int scu_rsrc_arr[] = {
+	IMX_SC_R_BOARD_R0,
+	IMX_SC_R_BOARD_R1,
+	IMX_SC_R_BOARD_R2,
+	IMX_SC_R_BOARD_R3,
+	IMX_SC_R_BOARD_R4,
+	IMX_SC_R_BOARD_R5,
+	IMX_SC_R_BOARD_R6,
+	IMX_SC_R_BOARD_R7,
+};
+
+static int imx_scu_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct scu_gpio_priv *priv = gpiochip_get_data(chip);
+	int level;
+	int err;
+
+	if (offset >= chip->ngpio)
+		return -EINVAL;
+
+	mutex_lock(&priv->lock);
+
+	/* to read PIN state via scu api */
+	err = imx_sc_misc_get_control(priv->handle,
+			scu_rsrc_arr[offset], 0, &level);
+	mutex_unlock(&priv->lock);
+
+	if (err) {
+		dev_err(priv->dev, "SCU get failed: %d\n", err);
+		return err;
+	}
+
+	return level;
+}
+
+static void imx_scu_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+	struct scu_gpio_priv *priv = gpiochip_get_data(chip);
+	int err;
+
+	if (offset >= chip->ngpio)
+		return;
+
+	mutex_lock(&priv->lock);
+
+	/* to set PIN output level via scu api */
+	err = imx_sc_misc_set_control(priv->handle,
+			scu_rsrc_arr[offset], 0, value);
+	mutex_unlock(&priv->lock);
+
+	if (err)
+		dev_err(priv->dev, "SCU set (%d) failed: %d\n",
+				scu_rsrc_arr[offset], err);
+}
+
+static int imx_scu_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+	if (offset >= chip->ngpio)
+		return -EINVAL;
+
+	return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int imx_scu_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct scu_gpio_priv *priv;
+	struct gpio_chip *gc;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	ret = imx_scu_get_handle(&priv->handle);
+	if (ret)
+		return ret;
+
+	priv->dev = dev;
+	mutex_init(&priv->lock);
+
+	gc = &priv->chip;
+	gc->base = -1;
+	gc->parent = dev;
+	gc->ngpio = sizeof(scu_rsrc_arr)/sizeof(unsigned int);
+	gc->label = dev_name(dev);
+	gc->get = imx_scu_gpio_get;
+	gc->set = imx_scu_gpio_set;
+	gc->get_direction = imx_scu_gpio_get_direction;
+
+	platform_set_drvdata(pdev, priv);
+
+	return devm_gpiochip_add_data(dev, gc, priv);
+}
+
+static const struct of_device_id imx_scu_gpio_dt_ids[] = {
+	{ .compatible = "fsl,imx8-scu-gpio" },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver imx_scu_gpio_driver = {
+	.driver	= {
+		.name = "gpio-imx-scu",
+		.of_match_table = imx_scu_gpio_dt_ids,
+	},
+	.probe = imx_scu_gpio_probe,
+};
+
+static int __init _imx_scu_gpio_init(void)
+{
+	return platform_driver_register(&imx_scu_gpio_driver);
+}
+
+subsys_initcall_sync(_imx_scu_gpio_init);
+
+MODULE_AUTHOR("Shenwei Wang <shenwei.wang@nxp.com>");
+MODULE_DESCRIPTION("NXP GPIO over IMX SCU API");
+MODULE_LICENSE("GPL");
-- 
2.25.1

Re: [PATCH v2 1/3] dt-bindings: gpio: Add imx-scu gpio driver bindings

[Krzysztof Kozlowski]

On 09/08/2022 17:31, Shenwei Wang wrote:
> Add binding document for the imx-scu gpio driver.
> 
> Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
> ---
>  .../bindings/gpio/fsl,imx8-scu-gpio.yaml      | 39 +++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml
> 
> diff --git a/Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml b/Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml
> new file mode 100644
> index 000000000000..4cbe3108a612
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/fsl,imx8-scu-gpio.yaml
> @@ -0,0 +1,39 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/gpio/fsl,imx8-scu-gpio.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: GPIO driver over IMX SCU firmware API
> +
> +maintainers:
> +  - Shenwei Wang <shenwei.wang@nxp.com>
> +
> +description: |
> +  This module provides the standard interface to control the
> +  resource pins in SCU domain on i.MX8 platforms.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - fsl,imx8-scu-gpio

This should be rather a specific imx8 chip. See other imx8 SCU bindings.
Strictly speaking there is no "imx8" SoC and compatible should be
derived from SoC.



Best regards,
Krzysztof

Re: [PATCH v2 2/3] dt-bindings: firmware: imx: Add imx-scu gpio node

[Krzysztof Kozlowski]

On 09/08/2022 17:31, Shenwei Wang wrote:
> Add the description for imx-scu gpio subnode.
> 
> Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>


Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>


Best regards,
Krzysztof

RE: [EXT] Re: [PATCH v2 1/3] dt-bindings: gpio: Add imx-scu gpio driver bindings

[Shenwei Wang]

> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> Sent: Tuesday, August 9, 2022 11:05 AM
> To: Shenwei Wang <shenwei.wang@nxp.com>; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; linus.walleij@linaro.org; brgl@bgdev.pl;
> shawnguo@kernel.org; s.hauer@pengutronix.de; kernel@pengutronix.de;
> festevam@gmail.com; dl-linux-imx <linux-imx@nxp.com>
> Cc: devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-
> gpio@vger.kernel.org; linux-arm-kernel@lists.infradead.org; imx@lists.linux.dev
> Subject: [EXT] Re: [PATCH v2 1/3] dt-bindings: gpio: Add imx-scu gpio driver
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - fsl,imx8-scu-gpio
> 
> This should be rather a specific imx8 chip. See other imx8 SCU bindings.
> Strictly speaking there is no "imx8" SoC and compatible should be derived from
> SoC.

Make sense. Thank you very much for the comments.

Regards
Shenwei

> 
> 
> 
> Best regards,
> Krzysztof