[PATCH v2 0/2] Add RZ/G2L POEG support

[PATCH v2 0/2] Add RZ/G2L POEG support

[Biju Das]

The output pins of the general PWM timer (GPT) can be disabled by using the port
output enabling function for the GPT (POEG). Specifically, either of the
following ways can be used.

  * Input level detection of the GTETRGA to GTETRGD pins.
  * Output-disable request from the GPT.
  * Register setting(ie, by setting POEGGn.SSF to 1)

This patch series add support for controlling output disable function using sysfs.

For output disable operation, POEG group needs to be linked with GPT.
Plan to send a follow up patch with renesas,poeg-group as numeric
property in pwm bindings for linking both GPT and POEG devices.

v1->v2:
 * Updated binding description.
 * Renamed the file poeg-rzg2l->rzg2l-poeg
 * Removed the macro POEGG as there is only single register and
   updated rzg2l_poeg_write() and rzg2l_poeg_read()
 * Updated error handling in probe()
REF->v1:
 * Modelled as pincontrol as most of its configuration is intended to be
   static and moved driver files from soc to pincontrol directory.
 * Updated reg size in dt binding example.
 * Updated Kconfig

REF:
https://lore.kernel.org/linux-renesas-soc/20220510151112.16249-1-biju.das.jz@bp.renesas.com/

Biju Das (2):
  dt-bindings: pinctrl: renesas: Add RZ/G2L POEG binding
  drivers: pinctrl: renesas: Add RZ/G2L POEG driver support

 .../bindings/pinctrl/renesas,rzg2l-poeg.yaml  |  68 ++++++++
 drivers/pinctrl/renesas/Kconfig               |   2 +
 drivers/pinctrl/renesas/Makefile              |   2 +
 drivers/pinctrl/renesas/poeg/Kconfig          |  12 ++
 drivers/pinctrl/renesas/poeg/Makefile         |   2 +
 drivers/pinctrl/renesas/poeg/rzg2l-poeg.c     | 147 ++++++++++++++++++
 6 files changed, 233 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-poeg.yaml
 create mode 100644 drivers/pinctrl/renesas/poeg/Kconfig
 create mode 100644 drivers/pinctrl/renesas/poeg/Makefile
 create mode 100644 drivers/pinctrl/renesas/poeg/rzg2l-poeg.c

-- 
2.25.1

[PATCH v2 1/2] dt-bindings: pinctrl: renesas: Add RZ/G2L POEG binding

[Biju Das]

Add device tree bindings for the RZ/G2L Port Output Enable for GPT (POEG).

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v1->v2:
 * Updated the description.
REF->v1:
 * Modelled as pincontrol as most of its configuration is intended to be
   static.
 * Updated reg size in example.
---
 .../bindings/pinctrl/renesas,rzg2l-poeg.yaml  | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-poeg.yaml

diff --git a/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-poeg.yaml b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-poeg.yaml
new file mode 100644
index 000000000000..decd87aa7b56
--- /dev/null
+++ b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-poeg.yaml
@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/renesas,rzg2l-poeg.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/G2L Port Output Enable for GPT (POEG)
+
+maintainers:
+  - Biju Das <biju.das.jz@bp.renesas.com>
+
+description: |
+  The output pins(GTIOCxA and GTIOCxB) of the general PWM timer (GPT) can be
+  disabled by using the port output enabling function for the GPT (POEG).
+  Specifically, either of the following ways can be used.
+  * Input level detection of the GTETRGA to GTETRGD pins.
+  * Output-disable request from the GPT.
+  * SSF bit setting(ie, by setting POEGGn.SSF to 1)
+
+  The state of the GTIOCxA and the GTIOCxB pins when the output is disabled,
+  are controlled by the GPT module.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - renesas,r9a07g044-poeg  # RZ/G2{L,LC}
+          - renesas,r9a07g054-poeg  # RZ/V2L
+      - const: renesas,rzg2l-poeg
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - power-domains
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/r9a07g044-cpg.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    poeggd: poeg@10049400 {
+        compatible = "renesas,r9a07g044-poeg", "renesas,rzg2l-poeg";
+        reg = <0x10049400 0x400>;
+        interrupts = <GIC_SPI 325 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&cpg CPG_MOD R9A07G044_POEG_D_CLKP>;
+        power-domains = <&cpg>;
+        resets = <&cpg R9A07G044_POEG_D_RST>;
+    };
-- 
2.25.1

[PATCH v2 2/2] drivers: pinctrl: renesas: Add RZ/G2L POEG driver support

[Biju Das]

The output pins of the RZ/G2L general PWM timer (GPT) can be disabled
by using the port output enabling function for the GPT (POEG).

This patch series add basic support using s/w control through
sysfs to enable/disable output from GPT.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v1->v2:
 * Renamed the file poeg-rzg2l->rzg2l-poeg
 * Removed the macro POEGG as there is only single register and
   updated rzg2l_poeg_write() and rzg2l_poeg_read()
 * Updated error handling in probe()
Ref->v1:
 * Moved driver files from soc to pincontrol directory
 * Updated KConfig
---
 drivers/pinctrl/renesas/Kconfig           |   2 +
 drivers/pinctrl/renesas/Makefile          |   2 +
 drivers/pinctrl/renesas/poeg/Kconfig      |  12 ++
 drivers/pinctrl/renesas/poeg/Makefile     |   2 +
 drivers/pinctrl/renesas/poeg/rzg2l-poeg.c | 147 ++++++++++++++++++++++
 5 files changed, 165 insertions(+)
 create mode 100644 drivers/pinctrl/renesas/poeg/Kconfig
 create mode 100644 drivers/pinctrl/renesas/poeg/Makefile
 create mode 100644 drivers/pinctrl/renesas/poeg/rzg2l-poeg.c

diff --git a/drivers/pinctrl/renesas/Kconfig b/drivers/pinctrl/renesas/Kconfig
index 6cc6aa7304bb..5cc6f94a4105 100644
--- a/drivers/pinctrl/renesas/Kconfig
+++ b/drivers/pinctrl/renesas/Kconfig
@@ -311,4 +311,6 @@ config PINCTRL_PFC_SHX3
 	bool "pin control support for SH-X3" if COMPILE_TEST
 	select PINCTRL_SH_FUNC_GPIO
 
+source "drivers/pinctrl/renesas/poeg/Kconfig"
+
 endmenu
diff --git a/drivers/pinctrl/renesas/Makefile b/drivers/pinctrl/renesas/Makefile
index 558b30ce0dec..de1bb592fbf3 100644
--- a/drivers/pinctrl/renesas/Makefile
+++ b/drivers/pinctrl/renesas/Makefile
@@ -52,6 +52,8 @@ obj-$(CONFIG_PINCTRL_RZG2L)	+= pinctrl-rzg2l.o
 obj-$(CONFIG_PINCTRL_RZN1)	+= pinctrl-rzn1.o
 obj-$(CONFIG_PINCTRL_RZV2M)	+= pinctrl-rzv2m.o
 
+obj-$(CONFIG_POEG_RZG2L)	+= poeg/
+
 ifeq ($(CONFIG_COMPILE_TEST),y)
 CFLAGS_pfc-sh7203.o	+= -I$(srctree)/arch/sh/include/cpu-sh2a
 CFLAGS_pfc-sh7264.o	+= -I$(srctree)/arch/sh/include/cpu-sh2a
diff --git a/drivers/pinctrl/renesas/poeg/Kconfig b/drivers/pinctrl/renesas/poeg/Kconfig
new file mode 100644
index 000000000000..efea83a60a11
--- /dev/null
+++ b/drivers/pinctrl/renesas/poeg/Kconfig
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+config POEG_RZG2L
+	tristate "RZ/G2L poeg support"
+	depends on ARCH_RZG2L
+	depends on PWM_RZG2L_GPT
+	depends on HAS_IOMEM
+	help
+	  This driver exposes the General Port Output Enable for PWM found
+	  in RZ/G2L.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called poeg-rzg2l.
diff --git a/drivers/pinctrl/renesas/poeg/Makefile b/drivers/pinctrl/renesas/poeg/Makefile
new file mode 100644
index 000000000000..610bdd6182be
--- /dev/null
+++ b/drivers/pinctrl/renesas/poeg/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_POEG_RZG2L)	+= rzg2l-poeg.o
diff --git a/drivers/pinctrl/renesas/poeg/rzg2l-poeg.c b/drivers/pinctrl/renesas/poeg/rzg2l-poeg.c
new file mode 100644
index 000000000000..0c73637f3b2c
--- /dev/null
+++ b/drivers/pinctrl/renesas/poeg/rzg2l-poeg.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/G2L Port Output Enable for GPT (POEG) driver
+ *
+ * Copyright (C) 2022 Renesas Electronics Corporation
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+
+#define POEGG_SSF	BIT(3)
+
+struct rzg2l_poeg_chip {
+	struct reset_control *rstc;
+	void __iomem *mmio;
+};
+
+static void rzg2l_poeg_write(struct rzg2l_poeg_chip *chip, u32 data)
+{
+	iowrite32(data, chip->mmio);
+}
+
+static u32 rzg2l_poeg_read(struct rzg2l_poeg_chip *chip)
+{
+	return ioread32(chip->mmio);
+}
+
+static ssize_t output_disable_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rzg2l_poeg_chip *chip = platform_get_drvdata(pdev);
+	unsigned int val;
+	u32 reg_val;
+	int ret;
+
+	ret = kstrtouint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	reg_val = rzg2l_poeg_read(chip);
+	if (val)
+		reg_val |= POEGG_SSF;
+	else
+		reg_val &= ~POEGG_SSF;
+
+	rzg2l_poeg_write(chip, reg_val);
+
+	return ret ? : count;
+}
+
+static ssize_t output_disable_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rzg2l_poeg_chip *chip = platform_get_drvdata(pdev);
+	u32 reg;
+
+	reg = rzg2l_poeg_read(chip);
+
+	return sprintf(buf, "%u\n", (reg & POEGG_SSF) ? 1 : 0);
+}
+static DEVICE_ATTR_RW(output_disable);
+
+static const struct of_device_id rzg2l_poeg_of_table[] = {
+	{ .compatible = "renesas,rzg2l-poeg", },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rzg2l_poeg_of_table);
+
+static int rzg2l_poeg_probe(struct platform_device *pdev)
+{
+	struct rzg2l_poeg_chip *chip;
+	int ret;
+
+	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->mmio = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(chip->mmio))
+		return PTR_ERR(chip->mmio);
+
+	chip->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(chip->rstc))
+		return dev_err_probe(&pdev->dev, PTR_ERR(chip->rstc),
+				     "get reset failed\n");
+
+	ret = reset_control_deassert(chip->rstc);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, chip);
+	pm_runtime_enable(&pdev->dev);
+	ret = pm_runtime_resume_and_get(&pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pm_runtime_resume_and_get failed: %d\n", ret);
+		goto err_pm;
+	}
+
+	ret = device_create_file(&pdev->dev, &dev_attr_output_disable);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to create poeg sysfs: %d\n", ret);
+		goto err_file;
+	}
+
+	return 0;
+
+err_file:
+	pm_runtime_put(&pdev->dev);
+err_pm:
+	pm_runtime_disable(&pdev->dev);
+	reset_control_assert(chip->rstc);
+
+	return ret;
+}
+
+static int rzg2l_poeg_remove(struct platform_device *pdev)
+{
+	struct rzg2l_poeg_chip *chip = platform_get_drvdata(pdev);
+
+	device_remove_file(&pdev->dev, &dev_attr_output_disable);
+	pm_runtime_put(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	reset_control_assert(chip->rstc);
+
+	return 0;
+}
+
+static struct platform_driver rzg2l_poeg_driver = {
+	.driver = {
+		.name = "rzg2l-poeg",
+		.of_match_table = of_match_ptr(rzg2l_poeg_of_table),
+	},
+	.probe = rzg2l_poeg_probe,
+	.remove = rzg2l_poeg_remove,
+};
+module_platform_driver(rzg2l_poeg_driver);
+
+MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
+MODULE_DESCRIPTION("Renesas RZ/G2L POEG Driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1

Re: [PATCH v2 1/2] dt-bindings: pinctrl: renesas: Add RZ/G2L POEG binding

[Rob Herring]

On Fri, 29 Jul 2022 13:24:47 +0100, Biju Das wrote:
> Add device tree bindings for the RZ/G2L Port Output Enable for GPT (POEG).
> 
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v1->v2:
>  * Updated the description.
> REF->v1:
>  * Modelled as pincontrol as most of its configuration is intended to be
>    static.
>  * Updated reg size in example.
> ---
>  .../bindings/pinctrl/renesas,rzg2l-poeg.yaml  | 68 +++++++++++++++++++
>  1 file changed, 68 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-poeg.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH v2 2/2] drivers: pinctrl: renesas: Add RZ/G2L POEG driver support

[Geert Uytterhoeven]

Hi Biju,

On Fri, Jul 29, 2022 at 2:25 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> The output pins of the RZ/G2L general PWM timer (GPT) can be disabled
> by using the port output enabling function for the GPT (POEG).
>
> This patch series add basic support using s/w control through
> sysfs to enable/disable output from GPT.
>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v1->v2:
>  * Renamed the file poeg-rzg2l->rzg2l-poeg
>  * Removed the macro POEGG as there is only single register and
>    updated rzg2l_poeg_write() and rzg2l_poeg_read()
>  * Updated error handling in probe()

Thanks for the update!

> --- /dev/null
> +++ b/drivers/pinctrl/renesas/poeg/Kconfig
> @@ -0,0 +1,12 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config POEG_RZG2L
> +       tristate "RZ/G2L poeg support"
> +       depends on ARCH_RZG2L
> +       depends on PWM_RZG2L_GPT

These are not hard dependencies, right?
And PWM_RZG2L_GPT (sort of) implies ARCH_RZG2L.

So I think the above two lines should be replaced by

     depends on PWM_RZG2L_GPT || COMPILE_TEST

> +       depends on HAS_IOMEM
> +       help
> +         This driver exposes the General Port Output Enable for PWM found
> +         in RZ/G2L.
> +
> +         To compile this driver as a module, choose M here: the module
> +         will be called poeg-rzg2l.

> --- /dev/null
> +++ b/drivers/pinctrl/renesas/poeg/rzg2l-poeg.c
> @@ -0,0 +1,147 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas RZ/G2L Port Output Enable for GPT (POEG) driver
> + *
> + * Copyright (C) 2022 Renesas Electronics Corporation
> + */
> +
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +
> +#define POEGG_SSF      BIT(3)
> +
> +struct rzg2l_poeg_chip {
> +       struct reset_control *rstc;
> +       void __iomem *mmio;
> +};
> +
> +static void rzg2l_poeg_write(struct rzg2l_poeg_chip *chip, u32 data)
> +{
> +       iowrite32(data, chip->mmio);
> +}
> +
> +static u32 rzg2l_poeg_read(struct rzg2l_poeg_chip *chip)
> +{
> +       return ioread32(chip->mmio);
> +}
> +
> +static ssize_t output_disable_store(struct device *dev,
> +                                   struct device_attribute *attr,
> +                                   const char *buf, size_t count)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct rzg2l_poeg_chip *chip = platform_get_drvdata(pdev);

chip = dev_get_drvdata(dev)

> +       unsigned int val;
> +       u32 reg_val;
> +       int ret;
> +
> +       ret = kstrtouint(buf, 0, &val);
> +       if (ret)
> +               return ret;
> +
> +       reg_val = rzg2l_poeg_read(chip);
> +       if (val)
> +               reg_val |= POEGG_SSF;
> +       else
> +               reg_val &= ~POEGG_SSF;
> +
> +       rzg2l_poeg_write(chip, reg_val);
> +
> +       return ret ? : count;
> +}
> +
> +static ssize_t output_disable_show(struct device *dev,
> +                                  struct device_attribute *attr, char *buf)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct rzg2l_poeg_chip *chip = platform_get_drvdata(pdev);

chip = dev_get_drvdata(dev)

> +       u32 reg;
> +
> +       reg = rzg2l_poeg_read(chip);
> +
> +       return sprintf(buf, "%u\n", (reg & POEGG_SSF) ? 1 : 0);

sysfs_emit().

> +}
> +static DEVICE_ATTR_RW(output_disable);

Probably you want to document these properties under Documentation/,
or do you intend to have this as an interim solution?
TBH, I still don't know if this is the proper way to handle POEG,
but I see no better alternative...

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

RE: [PATCH v2 2/2] drivers: pinctrl: renesas: Add RZ/G2L POEG driver support

[Biju Das]

Hi Geert,

Thanks for the feedback.

> Subject: Re: [PATCH v2 2/2] drivers: pinctrl: renesas: Add RZ/G2L POEG
> driver support
> 
> Hi Biju,
> 
> On Fri, Jul 29, 2022 at 2:25 PM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> > The output pins of the RZ/G2L general PWM timer (GPT) can be disabled
> > by using the port output enabling function for the GPT (POEG).
> >
> > This patch series add basic support using s/w control through sysfs to
> > enable/disable output from GPT.
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > ---
> > v1->v2:
> >  * Renamed the file poeg-rzg2l->rzg2l-poeg
> >  * Removed the macro POEGG as there is only single register and
> >    updated rzg2l_poeg_write() and rzg2l_poeg_read()
> >  * Updated error handling in probe()
> 
> Thanks for the update!
> 
> > --- /dev/null
> > +++ b/drivers/pinctrl/renesas/poeg/Kconfig
> > @@ -0,0 +1,12 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +config POEG_RZG2L
> > +       tristate "RZ/G2L poeg support"
> > +       depends on ARCH_RZG2L
> > +       depends on PWM_RZG2L_GPT
> 
> These are not hard dependencies, right?
> And PWM_RZG2L_GPT (sort of) implies ARCH_RZG2L.
> 
> So I think the above two lines should be replaced by
> 
>      depends on PWM_RZG2L_GPT || COMPILE_TEST

Agreed.

> 
> > +       depends on HAS_IOMEM
> > +       help
> > +         This driver exposes the General Port Output Enable for PWM
> found
> > +         in RZ/G2L.
> > +
> > +         To compile this driver as a module, choose M here: the
> module
> > +         will be called poeg-rzg2l.
> 
> > --- /dev/null
> > +++ b/drivers/pinctrl/renesas/poeg/rzg2l-poeg.c
> > @@ -0,0 +1,147 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Renesas RZ/G2L Port Output Enable for GPT (POEG) driver
> > + *
> > + * Copyright (C) 2022 Renesas Electronics Corporation  */
> > +
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/reset.h>
> > +
> > +#define POEGG_SSF      BIT(3)
> > +
> > +struct rzg2l_poeg_chip {
> > +       struct reset_control *rstc;
> > +       void __iomem *mmio;
> > +};
> > +
> > +static void rzg2l_poeg_write(struct rzg2l_poeg_chip *chip, u32 data)
> > +{
> > +       iowrite32(data, chip->mmio);
> > +}
> > +
> > +static u32 rzg2l_poeg_read(struct rzg2l_poeg_chip *chip) {
> > +       return ioread32(chip->mmio);
> > +}
> > +
> > +static ssize_t output_disable_store(struct device *dev,
> > +                                   struct device_attribute *attr,
> > +                                   const char *buf, size_t count) {
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +       struct rzg2l_poeg_chip *chip = platform_get_drvdata(pdev);
> 
> chip = dev_get_drvdata(dev)

OK.

> 
> > +       unsigned int val;
> > +       u32 reg_val;
> > +       int ret;
> > +
> > +       ret = kstrtouint(buf, 0, &val);
> > +       if (ret)
> > +               return ret;
> > +
> > +       reg_val = rzg2l_poeg_read(chip);
> > +       if (val)
> > +               reg_val |= POEGG_SSF;
> > +       else
> > +               reg_val &= ~POEGG_SSF;
> > +
> > +       rzg2l_poeg_write(chip, reg_val);
> > +
> > +       return ret ? : count;
> > +}
> > +
> > +static ssize_t output_disable_show(struct device *dev,
> > +                                  struct device_attribute *attr, char
> > +*buf) {
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +       struct rzg2l_poeg_chip *chip = platform_get_drvdata(pdev);
> 
> chip = dev_get_drvdata(dev)
OK.

> 
> > +       u32 reg;
> > +
> > +       reg = rzg2l_poeg_read(chip);
> > +
> > +       return sprintf(buf, "%u\n", (reg & POEGG_SSF) ? 1 : 0);
> 
> sysfs_emit().
> 
> > +}
> > +static DEVICE_ATTR_RW(output_disable);
> 
> Probably you want to document these properties under Documentation/,

OK, will document this as it is one of the option supported by hardware.

 or
> do you intend to have this as an interim solution?

User space can decide and disable the output, if needed using the above property.

> TBH, I still don't know if this is the proper way to handle POEG, but I
> see no better alternative...

Going forward will add more POEG features like

* Input level detection of the GTETRGA to GTETRGD pins.
* Output-disable request from the GPT.

Already BSP has some implementation for handling some of this features[1]

[1] https://github.com/renesas-rz/rz_linux-cip/blob/rz-5.10-cip3/drivers/pwm/gpt-rzg2l.c#L517

Cheers,
Biju