[PATCH 1/4] drm/mipi-dbi: Support separate I/O regulator

[PATCH 1/4] drm/mipi-dbi: Support separate I/O regulator

[Otto Pflüger]

The MIPI DBI specification defines separate vdd (panel power) and
vddi (I/O voltage) supplies. Displays that require different voltages
for the different supplies do exist, so the supplies cannot be
combined into one as they are now. Add a new io_regulator property to
the mipi_dbi_dev struct which can be set by the panel driver along
with the regulator property.

Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
---
 drivers/gpu/drm/drm_mipi_dbi.c | 14 ++++++++++++++
 include/drm/drm_mipi_dbi.h     |  7 ++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index a6ac56580876..047cab93a041 100644
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -427,6 +427,8 @@ void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe)
 
 	if (dbidev->regulator)
 		regulator_disable(dbidev->regulator);
+	if (dbidev->io_regulator)
+		regulator_disable(dbidev->io_regulator);
 }
 EXPORT_SYMBOL(mipi_dbi_pipe_disable);
 
@@ -652,6 +654,16 @@ static int mipi_dbi_poweron_reset_conditional(struct mipi_dbi_dev *dbidev, bool
 		}
 	}
 
+	if (dbidev->io_regulator) {
+		ret = regulator_enable(dbidev->io_regulator);
+		if (ret) {
+			DRM_DEV_ERROR(dev, "Failed to enable I/O regulator (%d)\n", ret);
+			if (dbidev->regulator)
+				regulator_disable(dbidev->regulator);
+			return ret;
+		}
+	}
+
 	if (cond && mipi_dbi_display_is_on(dbi))
 		return 1;
 
@@ -661,6 +673,8 @@ static int mipi_dbi_poweron_reset_conditional(struct mipi_dbi_dev *dbidev, bool
 		DRM_DEV_ERROR(dev, "Failed to send reset command (%d)\n", ret);
 		if (dbidev->regulator)
 			regulator_disable(dbidev->regulator);
+		if (dbidev->io_regulator)
+			regulator_disable(dbidev->io_regulator);
 		return ret;
 	}
 
diff --git a/include/drm/drm_mipi_dbi.h b/include/drm/drm_mipi_dbi.h
index 14eaecb1825c..e4efbd8ffc9d 100644
--- a/include/drm/drm_mipi_dbi.h
+++ b/include/drm/drm_mipi_dbi.h
@@ -122,10 +122,15 @@ struct mipi_dbi_dev {
 	struct backlight_device *backlight;
 
 	/**
-	 * @regulator: power regulator (optional)
+	 * @regulator: power regulator (Vdd) (optional)
 	 */
 	struct regulator *regulator;
 
+	/**
+	 * @io_regulator: I/O power regulator (Vddi) (optional)
+	 */
+	struct regulator *io_regulator;
+
 	/**
 	 * @dbi: MIPI DBI interface
 	 */
-- 
2.30.2

[PATCH 2/4] drm/tiny: panel-mipi-dbi: Read I/O supply from DT

[Otto Pflüger]

To support platforms with a separate I/O voltage supply, set the new
io_regulator property along with the regulator property of the DBI
device. Read the I/O supply from a new "io-supply" device tree
property.

Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
---
 drivers/gpu/drm/tiny/panel-mipi-dbi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/tiny/panel-mipi-dbi.c b/drivers/gpu/drm/tiny/panel-mipi-dbi.c
index 955a61d628e7..353356ee0397 100644
--- a/drivers/gpu/drm/tiny/panel-mipi-dbi.c
+++ b/drivers/gpu/drm/tiny/panel-mipi-dbi.c
@@ -297,6 +297,11 @@ static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
 		return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
 				     "Failed to get regulator 'power'\n");
 
+	dbidev->io_regulator = devm_regulator_get(dev, "io");
+	if (IS_ERR(dbidev->io_regulator))
+		return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
+				     "Failed to get regulator 'io'\n");
+
 	dbidev->backlight = devm_of_find_backlight(dev);
 	if (IS_ERR(dbidev->backlight))
 		return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");
-- 
2.30.2

[PATCH 3/4] dt-bindings: display: panel: mipi-dbi-spi: Add missing power-supply

[Otto Pflüger]

The power-supply property is only mentioned in the description and not
listed in the properties section of the binding. Add it there.

Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
---
 .../devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml  | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
index c2df8d28aaf5..d55bf12ecead 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
+++ b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
@@ -80,6 +80,9 @@ properties:
       Controller data/command selection (D/CX) in 4-line SPI mode.
       If not set, the controller is in 3-line SPI mode.
 
+  power-supply:
+    description: Power supply for the display module (Vdd).
+
 required:
   - compatible
   - reg
-- 
2.30.2

Re: [PATCH 3/4] dt-bindings: display: panel: mipi-dbi-spi: Add missing power-supply

[Rob Herring]

On Sun, Nov 27, 2022 at 08:14:32PM +0100, Otto Pflüger wrote:
> The power-supply property is only mentioned in the description and not
> listed in the properties section of the binding. Add it there.

That's because it is described in panel-common.yaml already.

But I guess it is somewhat useful to define it corresponds to Vdd.

> 
> Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
> ---
>  .../devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml  | 3 +++
>  1 file changed, 3 insertions(+)

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

[PATCH 4/4] dt-bindings: display: panel: mipi-dbi-spi: Add io-supply

[Otto Pflüger]

Add documentation for the new io-supply property, which specifies the
regulator for the I/O voltage supply on platforms where the panel
panel power and I/O supplies are separate.

Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
---
 .../bindings/display/panel/panel-mipi-dbi-spi.yaml        | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
index d55bf12ecead..68cbdfab5438 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
+++ b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
@@ -22,8 +22,9 @@ description: |
   The standard defines the following interface signals for type C:
   - Power:
     - Vdd: Power supply for display module
+      Called power-supply in this binding.
     - Vddi: Logic level supply for interface signals
-    Combined into one in this binding called: power-supply
+      Called io-supply in this binding.
   - Interface:
     - CSx: Chip select
     - SCL: Serial clock
@@ -80,6 +81,11 @@ properties:
       Controller data/command selection (D/CX) in 4-line SPI mode.
       If not set, the controller is in 3-line SPI mode.
 
+  io-supply:
+    description: |
+      Logic level supply for interface signals (Vddi).
+      No need to set if this is the same as power-supply.
+
   power-supply:
     description: Power supply for the display module (Vdd).
 
-- 
2.30.2

[PATCH 3/4] dt-bindings: display: panel: mipi-dbi-spi: Add missing power-supply

[Otto Pflüger]

The power-supply property is currently only mentioned in the
description, but not listed in the properties section as it should be.
Add it there.

Signed-off-by: Otto Pflüger <affenull2345@gmail.com>
---
  .../devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml  | 3 +++
  1 file changed, 3 insertions(+)

diff --git 
a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml 
b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
index c2df8d28aaf5..d55bf12ecead 100644
--- 
a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
+++ 
b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
@@ -80,6 +80,9 @@ properties:
        Controller data/command selection (D/CX) in 4-line SPI mode.
        If not set, the controller is in 3-line SPI mode.

+  power-supply:
+    description: Power supply for the display module (Vdd).
+
  required:
    - compatible
    - reg
-- 
2.30.2