[PATCH v2 0/4] Add JDI LPM102A188A display panel support

[PATCH v2 0/4] Add JDI LPM102A188A display panel support

[Diogo Ivo]

Hello,

These patches add support for the JDI LPM102A188A display panel,
found in the Google Pixel C.

Patch 1 adds the DT bindings for the panel.

Patch 2 adds a register clear to the Tegra DSI driver, needed for the
panel initialization commands to be properly sent.

Patch 3 adds the panel driver, which is based on the downstream
kernel driver published by Google and developed by Sean Paul.

Patch 4 adds the DT node for the Google Pixel C. 

The first version of this patch series can be found at:
https://lore.kernel.org/all/20220929170502.1034040-1-diogo.ivo@tecnico.ulisboa.pt/

Changes in v2:
 - Patch 1: remove touchscreen reset gpio property
 - Patch 2: clear register based on its value rather than a DT property
 - Patch 3: tune backlight delay values
 - Patch 4: add generic node names, remove underscores 

Thank you.

Diogo Ivo (4):

  dt-bindings: display: Add bindings for JDI LPM102A188A
  drm/tegra: dsi: Clear enable register if powered by bootloader
  drm/panel: Add driver for JDI LPM102A188A
  arm64: dts: smaug: Add display panel node

 .../display/panel/jdi,lpm102a188a.yaml        |  94 ++++
 arch/arm64/boot/dts/nvidia/tegra210-smaug.dts |  70 +++
 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 509 ++++++++++++++++++
 drivers/gpu/drm/tegra/dsi.c                   |   9 +
 6 files changed, 694 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c

-- 
2.38.1

[PATCH v2 0/4] Add JDI LPM102A188A display panel support

[Diogo Ivo]

Hello,

These patches add support for the JDI LPM102A188A display panel,
found in the Google Pixel C.

Patch 1 adds the DT bindings for the panel.

Patch 2 adds a register clear to the Tegra DSI driver, needed for the
panel initialization commands to be properly sent.

Patch 3 adds the panel driver, which is based on the downstream
kernel driver published by Google and developed by Sean Paul.

Patch 4 adds the DT node for the Google Pixel C. 

The first version of this patch series can be found at:
https://lore.kernel.org/all/20220929170502.1034040-1-diogo.ivo@tecnico.ulisboa.pt/

Changes in v2:
 - Patch 1: remove touchscreen reset gpio property
 - Patch 2: clear register based on its value rather than a DT property
 - Patch 3: tune backlight delay values
 - Patch 4: add generic node names, remove underscores 

Thank you.

Diogo Ivo (4):

  dt-bindings: display: Add bindings for JDI LPM102A188A
  drm/tegra: dsi: Clear enable register if powered by bootloader
  drm/panel: Add driver for JDI LPM102A188A
  arm64: dts: smaug: Add display panel node

 .../display/panel/jdi,lpm102a188a.yaml        |  94 ++++
 arch/arm64/boot/dts/nvidia/tegra210-smaug.dts |  70 +++
 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 509 ++++++++++++++++++
 drivers/gpu/drm/tegra/dsi.c                   |   9 +
 6 files changed, 694 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c

-- 
2.38.1

[PATCH v2 1/4] dt-bindings: display: Add bindings for JDI LPM102A188A

[Diogo Ivo]

The LPM102A188A is a 10.2" 2560x1800 IPS panel found in
the Google Pixel C.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
 - removed the touch screen property

 .../display/panel/jdi,lpm102a188a.yaml        | 94 +++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml

diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml b/Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml
new file mode 100644
index 000000000000..2f4d27a309a7
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml
@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/jdi,lpm102a188a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: JDI LPM102A188A 2560x1800 10.2" DSI Panel
+
+maintainers:
+  - Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
+
+description: |
+  This panel requires a dual-channel DSI host to operate. It supports two modes:
+  - left-right: each channel drives the left or right half of the screen
+  - even-odd: each channel drives the even or odd lines of the screen
+
+  Each of the DSI channels controls a separate DSI peripheral. The peripheral
+  driven by the first link (DSI-LINK1) is considered the primary peripheral
+  and controls the device. The 'link2' property contains a phandle to the
+  peripheral driven by the second link (DSI-LINK2).
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: jdi,lpm102a188a
+
+  reg: true
+  enable-gpios: true
+  reset-gpios: true
+  power-supply: true
+  backlight: true
+
+  ddi-supply:
+    description: The regulator that provides IOVCC (1.8V).
+
+  link2:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: |
+      phandle to the DSI peripheral on the secondary link. Note that the
+      presence of this property marks the containing node as DSI-LINK1.
+
+required:
+  - compatible
+  - reg
+
+if:
+  required:
+    - link2
+then:
+  required:
+    - power-supply
+    - ddi-supply
+    - enable-gpios
+    - reset-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/gpio/tegra-gpio.h>
+
+    dsia: dsi@54300000 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        reg = <0x0 0x54300000 0x0 0x00040000>;
+
+        link2: panel@0 {
+            compatible = "jdi,lpm102a188a";
+            reg = <0>;
+        };
+    };
+
+    dsib: dsi@54400000{
+        #address-cells = <1>;
+        #size-cells = <0>;
+        reg = <0x0 0x54400000 0x0 0x00040000>;
+        nvidia,ganged-mode = <&dsia>;
+
+        link1: panel@0 {
+            compatible = "jdi,lpm102a188a";
+            reg = <0>;
+            power-supply = <&pplcd_vdd>;
+            ddi-supply = <&pp1800_lcdio>;
+            enable-gpios = <&gpio TEGRA_GPIO(V, 1) GPIO_ACTIVE_HIGH>;
+            reset-gpios = <&gpio TEGRA_GPIO(V, 2) GPIO_ACTIVE_LOW>;
+            link2 = <&link2>;
+            backlight = <&backlight>;
+        };
+    };
+
+...
-- 
2.38.1

[PATCH v2 1/4] dt-bindings: display: Add bindings for JDI LPM102A188A

[Diogo Ivo]

The LPM102A188A is a 10.2" 2560x1800 IPS panel found in
the Google Pixel C.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
 - removed the touch screen property

 .../display/panel/jdi,lpm102a188a.yaml        | 94 +++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml

diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml b/Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml
new file mode 100644
index 000000000000..2f4d27a309a7
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/jdi,lpm102a188a.yaml
@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/jdi,lpm102a188a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: JDI LPM102A188A 2560x1800 10.2" DSI Panel
+
+maintainers:
+  - Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
+
+description: |
+  This panel requires a dual-channel DSI host to operate. It supports two modes:
+  - left-right: each channel drives the left or right half of the screen
+  - even-odd: each channel drives the even or odd lines of the screen
+
+  Each of the DSI channels controls a separate DSI peripheral. The peripheral
+  driven by the first link (DSI-LINK1) is considered the primary peripheral
+  and controls the device. The 'link2' property contains a phandle to the
+  peripheral driven by the second link (DSI-LINK2).
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: jdi,lpm102a188a
+
+  reg: true
+  enable-gpios: true
+  reset-gpios: true
+  power-supply: true
+  backlight: true
+
+  ddi-supply:
+    description: The regulator that provides IOVCC (1.8V).
+
+  link2:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: |
+      phandle to the DSI peripheral on the secondary link. Note that the
+      presence of this property marks the containing node as DSI-LINK1.
+
+required:
+  - compatible
+  - reg
+
+if:
+  required:
+    - link2
+then:
+  required:
+    - power-supply
+    - ddi-supply
+    - enable-gpios
+    - reset-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/gpio/tegra-gpio.h>
+
+    dsia: dsi@54300000 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        reg = <0x0 0x54300000 0x0 0x00040000>;
+
+        link2: panel@0 {
+            compatible = "jdi,lpm102a188a";
+            reg = <0>;
+        };
+    };
+
+    dsib: dsi@54400000{
+        #address-cells = <1>;
+        #size-cells = <0>;
+        reg = <0x0 0x54400000 0x0 0x00040000>;
+        nvidia,ganged-mode = <&dsia>;
+
+        link1: panel@0 {
+            compatible = "jdi,lpm102a188a";
+            reg = <0>;
+            power-supply = <&pplcd_vdd>;
+            ddi-supply = <&pp1800_lcdio>;
+            enable-gpios = <&gpio TEGRA_GPIO(V, 1) GPIO_ACTIVE_HIGH>;
+            reset-gpios = <&gpio TEGRA_GPIO(V, 2) GPIO_ACTIVE_LOW>;
+            link2 = <&link2>;
+            backlight = <&backlight>;
+        };
+    };
+
+...
-- 
2.38.1

[PATCH v2 2/4] drm/tegra: dsi: Clear enable register if powered by bootloader

[Diogo Ivo]

In cases where the DSI module is left on by the bootloader
some panels may fail to initialize if the enable register is not cleared
before the panel's initialization sequence is sent, so clear it if that
is the case. 

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
 - detect if the DSI module is on based on the register value,
   instead of a DT property.
 - remove Display Controller clear, since it is redundant.

 drivers/gpu/drm/tegra/dsi.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/tegra/dsi.c b/drivers/gpu/drm/tegra/dsi.c
index de1333dc0d86..5954676a7ab1 100644
--- a/drivers/gpu/drm/tegra/dsi.c
+++ b/drivers/gpu/drm/tegra/dsi.c
@@ -912,6 +912,15 @@ static void tegra_dsi_encoder_enable(struct drm_encoder *encoder)
 	u32 value;
 	int err;
 
+	/* If the bootloader enabled DSI it needs to be disabled
+	 * in order for the panel initialization commands to be
+	 * properly sent.
+	 */
+	value = tegra_dsi_readl(dsi, DSI_POWER_CONTROL);
+
+	if (value & DSI_POWER_CONTROL_ENABLE)
+		tegra_dsi_disable(dsi);
+
 	err = tegra_dsi_prepare(dsi);
 	if (err < 0) {
 		dev_err(dsi->dev, "failed to prepare: %d\n", err);
-- 
2.38.1

[PATCH v2 2/4] drm/tegra: dsi: Clear enable register if powered by bootloader

[Diogo Ivo]

In cases where the DSI module is left on by the bootloader
some panels may fail to initialize if the enable register is not cleared
before the panel's initialization sequence is sent, so clear it if that
is the case. 

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
 - detect if the DSI module is on based on the register value,
   instead of a DT property.
 - remove Display Controller clear, since it is redundant.

 drivers/gpu/drm/tegra/dsi.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/tegra/dsi.c b/drivers/gpu/drm/tegra/dsi.c
index de1333dc0d86..5954676a7ab1 100644
--- a/drivers/gpu/drm/tegra/dsi.c
+++ b/drivers/gpu/drm/tegra/dsi.c
@@ -912,6 +912,15 @@ static void tegra_dsi_encoder_enable(struct drm_encoder *encoder)
 	u32 value;
 	int err;
 
+	/* If the bootloader enabled DSI it needs to be disabled
+	 * in order for the panel initialization commands to be
+	 * properly sent.
+	 */
+	value = tegra_dsi_readl(dsi, DSI_POWER_CONTROL);
+
+	if (value & DSI_POWER_CONTROL_ENABLE)
+		tegra_dsi_disable(dsi);
+
 	err = tegra_dsi_prepare(dsi);
 	if (err < 0) {
 		dev_err(dsi->dev, "failed to prepare: %d\n", err);
-- 
2.38.1

[PATCH v2 3/4] drm/panel: Add driver for JDI LPM102A188A

[Diogo Ivo]

The JDI LPM102A188A is a 2560x1800 IPS panel found in the Google Pixel C.
This driver is based on the downstream GPLv2 driver released by Google
written by Sean Paul [1], which was then adapted to the newer kernel APIs.

[1]: https://android.googlesource.com/kernel/tegra/+/refs/heads/android-tegra-dragon-3.18-oreo/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
 - tuned backlight delays

 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 509 ++++++++++++++++++
 3 files changed, 521 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index a582ddd583c2..80eda8f6bee0 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -214,6 +214,17 @@ config DRM_PANEL_JDI_LT070ME05000
 	  The panel has a 1200(RGB)×1920 (WUXGA) resolution and uses
 	  24 bit per pixel.
 
+config DRM_PANEL_JDI_LPM102A188A
+	tristate "JDI LPM102A188A DSI panel"
+	depends on OF && GPIOLIB
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y here if you want to enable support for JDI LPM102A188A DSI
+	  control mode panel as found in Google Pixel C devices.
+	  The panel has a 2560×1800 resolution. It provides a MIPI DSI interface
+	  to the host.
+
 config DRM_PANEL_JDI_R63452
 	tristate "JDI R63452 Full HD DSI panel"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 34e717382dbb..2870cba96d14 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9881C) += panel-ilitek-ili9881c.o
 obj-$(CONFIG_DRM_PANEL_INNOLUX_EJ030NA) += panel-innolux-ej030na.o
 obj-$(CONFIG_DRM_PANEL_INNOLUX_P079ZCA) += panel-innolux-p079zca.o
 obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
+obj-$(CONFIG_DRM_PANEL_JDI_LPM102A188A) += panel-jdi-lpm102a188a.o
 obj-$(CONFIG_DRM_PANEL_JDI_R63452) += panel-jdi-fhd-r63452.o
 obj-$(CONFIG_DRM_PANEL_KHADAS_TS050) += panel-khadas-ts050.o
 obj-$(CONFIG_DRM_PANEL_KINGDISPLAY_KD097D04) += panel-kingdisplay-kd097d04.o
diff --git a/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
new file mode 100644
index 000000000000..980af82ad6d6
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
@@ -0,0 +1,509 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * Copyright (C) 2022 Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
+ *
+ * Adapted from the downstream Pixel C driver written by Sean Paul
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_crtc.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_panel.h>
+
+struct jdi_panel {
+	struct drm_panel base;
+	struct mipi_dsi_device *link1;
+	struct mipi_dsi_device *link2;
+
+	struct regulator *supply;
+	struct regulator *ddi_supply;
+	struct backlight_device *backlight;
+
+	struct gpio_desc *enable_gpio;
+	struct gpio_desc *reset_gpio;
+
+	const struct drm_display_mode *mode;
+
+	bool prepared;
+	bool enabled;
+};
+
+static inline struct jdi_panel *to_panel_jdi(struct drm_panel *panel)
+{
+	return container_of(panel, struct jdi_panel, base);
+}
+
+static void jdi_wait_frames(struct jdi_panel *jdi, unsigned int frames)
+{
+	unsigned int refresh = drm_mode_vrefresh(jdi->mode);
+
+	if (WARN_ON(frames > refresh))
+		return;
+
+	msleep(1000 / (refresh / frames));
+}
+
+static int jdi_panel_disable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+
+	if (!jdi->enabled)
+		return 0;
+
+	backlight_disable(jdi->backlight);
+
+	jdi_wait_frames(jdi, 2);
+
+	jdi->enabled = false;
+
+	return 0;
+}
+
+static int jdi_panel_unprepare(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+	int ret;
+
+	if (!jdi->prepared)
+		return 0;
+
+	ret = mipi_dsi_dcs_set_display_off(jdi->link1);
+	if (ret < 0)
+		dev_err(panel->dev, "failed to set display off: %d\n", ret);
+	ret = mipi_dsi_dcs_set_display_off(jdi->link2);
+	if (ret < 0)
+		dev_err(panel->dev, "failed to set display off: %d\n", ret);
+
+	/* Specified by JDI @ 50ms, subject to change */
+	msleep(50);
+
+	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link1);
+	if (ret < 0)
+		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
+	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link2);
+	if (ret < 0)
+		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
+
+	/* Specified by JDI @ 150ms, subject to change */
+	msleep(150);
+
+	gpiod_set_value(jdi->reset_gpio, 1);
+
+	/* T4 = 1ms */
+	usleep_range(1000, 3000);
+
+	gpiod_set_value(jdi->enable_gpio, 0);
+
+	/* T5 = 2ms */
+	usleep_range(2000, 4000);
+
+	regulator_disable(jdi->ddi_supply);
+
+	/* T6 = 2ms */
+	usleep_range(5000, 6000);
+
+	regulator_disable(jdi->supply);
+
+	jdi->prepared = false;
+
+	return 0;
+}
+
+static int jdi_setup_symmetrical_split(struct mipi_dsi_device *left,
+				       struct mipi_dsi_device *right,
+				       const struct drm_display_mode *mode)
+{
+	int err;
+
+	err = mipi_dsi_dcs_set_column_address(left, 0, mode->hdisplay / 2 - 1);
+	if (err < 0) {
+		dev_err(&left->dev, "failed to set column address: %d\n", err);
+		return err;
+	}
+
+	err = mipi_dsi_dcs_set_column_address(right, 0, mode->hdisplay / 2 - 1);
+	if (err < 0) {
+		dev_err(&right->dev, "failed to set column address: %d\n", err);
+		return err;
+	}
+
+	err = mipi_dsi_dcs_set_page_address(left, 0, mode->vdisplay - 1);
+	if (err < 0) {
+		dev_err(&left->dev, "failed to set page address: %d\n", err);
+		return err;
+	}
+
+	err = mipi_dsi_dcs_set_page_address(right, 0, mode->vdisplay - 1);
+	if (err < 0) {
+		dev_err(&right->dev, "failed to set page address: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static int jdi_panel_prepare(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+	u8 format = MIPI_DCS_PIXEL_FMT_24BIT;
+	int err;
+
+	if (jdi->prepared)
+		return 0;
+
+	/* Disable backlight to avoid showing random pixels
+	 * with a conservative delay for it to take effect.
+	 */
+	backlight_disable(jdi->backlight);
+	msleep(100);
+
+	jdi->link1->mode_flags |= MIPI_DSI_MODE_LPM;
+	jdi->link2->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	err = regulator_enable(jdi->supply);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to enable supply: %d\n", err);
+		return err;
+	}
+	/* T1 = 2ms */
+	usleep_range(2000, 4000);
+
+	err = regulator_enable(jdi->ddi_supply);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to enable ddi_supply: %d\n", err);
+		return err;
+	}
+	/* T2 = 1ms */
+	usleep_range(1000, 3000);
+
+	gpiod_set_value(jdi->enable_gpio, 1);
+	/* T3 = 10ms */
+	usleep_range(10000, 15000);
+
+	gpiod_set_value(jdi->reset_gpio, 0);
+	/* Specified by JDI @ 3ms, subject to change */
+	usleep_range(3000, 5000);
+
+	/*
+	 * TODO: The device supports both left-right and even-odd split
+	 * configurations, but this driver currently supports only the left-
+	 * right split. To support a different mode a mechanism needs to be
+	 * put in place to communicate the configuration back to the DSI host
+	 * controller.
+	 */
+
+	err = jdi_setup_symmetrical_split(jdi->link1, jdi->link2,
+					    jdi->mode);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to set up symmetrical split: %d\n",
+			err);
+		goto poweroff;
+	}
+
+	err = mipi_dsi_dcs_set_tear_scanline(jdi->link1,
+					     jdi->mode->vdisplay - 16);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
+
+	err = mipi_dsi_dcs_set_tear_scanline(jdi->link2,
+					     jdi->mode->vdisplay - 16);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
+
+	err = mipi_dsi_dcs_set_tear_on(jdi->link1,
+				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set tear on: %d\n", err);
+
+	err = mipi_dsi_dcs_set_tear_on(jdi->link2,
+				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set tear on: %d\n", err);
+
+	err = mipi_dsi_dcs_set_pixel_format(jdi->link1, format);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
+		goto poweroff;
+	}
+
+	err = mipi_dsi_dcs_set_pixel_format(jdi->link2, format);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
+		goto poweroff;
+	}
+
+	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link1);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
+		goto poweroff;
+	}
+
+	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link2);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
+		goto poweroff;
+	}
+
+	/*
+	 * We need to wait 150ms between mipi_dsi_dcs_exit_sleep_mode() and
+	 * mipi_dsi_dcs_set_display_on().
+	 */
+	msleep(150);
+
+	err = mipi_dsi_dcs_set_display_on(jdi->link1);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set display on: %d\n", err);
+
+
+	err = mipi_dsi_dcs_set_display_on(jdi->link2);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set display on: %d\n", err);
+
+	jdi->prepared = true;
+
+	jdi->link1->mode_flags &= ~MIPI_DSI_MODE_LPM;
+	jdi->link2->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	return 0;
+
+poweroff:
+	regulator_disable(jdi->ddi_supply);
+
+	/* T6 = 2ms */
+	usleep_range(7000, 9000);
+
+	regulator_disable(jdi->supply);
+
+	return err;
+}
+
+static int jdi_panel_enable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+
+	if (jdi->enabled)
+		return 0;
+
+	/*
+	 * Ensure we send image data before turning the backlight on,
+	 * to avoid the display showing random pixels (colored snow).
+	 */
+	jdi_wait_frames(jdi, 3);
+
+	backlight_enable(jdi->backlight);
+
+	jdi->enabled = true;
+
+	return 0;
+}
+
+static const struct drm_display_mode default_mode = {
+	.clock = 331334,
+	.hdisplay = 2560,
+	.hsync_start = 2560 + 80,
+	.hsync_end = 2560 + 80 + 80,
+	.htotal = 2560 + 80 + 80 + 80,
+	.vdisplay = 1800,
+	.vsync_start = 1800 + 4,
+	.vsync_end = 1800 + 4 + 4,
+	.vtotal = 1800 + 4 + 4 + 4,
+	.flags = 0,
+};
+
+static int jdi_panel_get_modes(struct drm_panel *panel,
+			       struct drm_connector *connector)
+{
+	struct drm_display_mode *mode;
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+	struct device *dev = &jdi->link1->dev;
+
+	mode = drm_mode_duplicate(connector->dev, &default_mode);
+	if (!mode) {
+		dev_err(dev, "failed to add mode %ux%ux@%u\n",
+			default_mode.hdisplay, default_mode.vdisplay,
+			drm_mode_vrefresh(&default_mode));
+		return -ENOMEM;
+	}
+
+	drm_mode_set_name(mode);
+
+	drm_mode_probed_add(connector, mode);
+
+	connector->display_info.width_mm = 211;
+	connector->display_info.height_mm = 148;
+	connector->display_info.bpc = 8;
+
+	return 1;
+}
+
+static const struct drm_panel_funcs jdi_panel_funcs = {
+	.prepare = jdi_panel_prepare,
+	.enable = jdi_panel_enable,
+	.disable = jdi_panel_disable,
+	.unprepare = jdi_panel_unprepare,
+	.get_modes = jdi_panel_get_modes,
+};
+
+static const struct of_device_id jdi_of_match[] = {
+	{ .compatible = "jdi,lpm102a188a", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, jdi_of_match);
+
+static int jdi_panel_add(struct jdi_panel *jdi)
+{
+	struct device *dev = &jdi->link1->dev;
+
+	jdi->mode = &default_mode;
+
+	jdi->supply = devm_regulator_get(dev, "power");
+	if (IS_ERR(jdi->supply))
+		return dev_err_probe(dev, PTR_ERR(jdi->supply),
+				     "failed to get power regulator\n");
+
+	jdi->ddi_supply = devm_regulator_get(dev, "ddi");
+	if (IS_ERR(jdi->ddi_supply))
+		return dev_err_probe(dev, PTR_ERR(jdi->ddi_supply),
+				     "failed to get ddi regulator\n");
+
+	jdi->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(jdi->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(jdi->reset_gpio),
+				     "failed to get reset gpio\n");
+	usleep_range(1000, 3000);
+
+	jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(jdi->enable_gpio))
+		return dev_err_probe(dev, PTR_ERR(jdi->enable_gpio),
+				     "failed to get enable gpio\n");
+	usleep_range(2000, 4000);
+
+	jdi->backlight = devm_of_find_backlight(dev);
+	if (IS_ERR(jdi->backlight))
+		return dev_err_probe(dev, PTR_ERR(jdi->backlight),
+				     "failed to create backlight\n");
+
+	drm_panel_init(&jdi->base, &jdi->link1->dev, &jdi_panel_funcs,
+		       DRM_MODE_CONNECTOR_DSI);
+
+	drm_panel_add(&jdi->base);
+
+	return 0;
+}
+
+static void jdi_panel_del(struct jdi_panel *jdi)
+{
+	if (jdi->base.dev)
+		drm_panel_remove(&jdi->base);
+
+	if (jdi->link2)
+		put_device(&jdi->link2->dev);
+}
+
+static int jdi_panel_dsi_probe(struct mipi_dsi_device *dsi)
+{
+	struct mipi_dsi_device *secondary = NULL;
+	struct jdi_panel *jdi;
+	struct device_node *np;
+	int err;
+
+	dsi->lanes = 4;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = 0;
+
+	/* Find DSI-LINK1 */
+	np = of_parse_phandle(dsi->dev.of_node, "link2", 0);
+	if (np) {
+		secondary = of_find_mipi_dsi_device_by_node(np);
+		of_node_put(np);
+
+		if (!secondary)
+			return -EPROBE_DEFER;
+	}
+
+	/* register a panel for only the DSI-LINK1 interface */
+	if (secondary) {
+		jdi = devm_kzalloc(&dsi->dev, sizeof(*jdi), GFP_KERNEL);
+		if (!jdi) {
+			put_device(&secondary->dev);
+			return -ENOMEM;
+		}
+
+		mipi_dsi_set_drvdata(dsi, jdi);
+
+		jdi->link1 = dsi;
+		jdi->link2 = secondary;
+
+		err = jdi_panel_add(jdi);
+		if (err < 0) {
+			put_device(&secondary->dev);
+			return err;
+		}
+	}
+
+	err = mipi_dsi_attach(dsi);
+	if (err < 0) {
+		if (secondary)
+			jdi_panel_del(jdi);
+
+		return err;
+	}
+
+	return 0;
+}
+
+static void jdi_panel_dsi_remove(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
+	int err;
+
+	/* only detach from host for the DSI-LINK2 interface */
+	if (!jdi)
+		mipi_dsi_detach(dsi);
+
+	err = jdi_panel_disable(&jdi->base);
+	if (err < 0)
+		dev_err(&dsi->dev, "failed to disable panel: %d\n", err);
+
+	err = mipi_dsi_detach(dsi);
+	if (err < 0)
+		dev_err(&dsi->dev, "failed to detach from DSI host: %d\n", err);
+
+	jdi_panel_del(jdi);
+}
+
+static void jdi_panel_dsi_shutdown(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
+
+	if (!jdi)
+		return;
+
+	jdi_panel_disable(&jdi->base);
+}
+
+static struct mipi_dsi_driver jdi_panel_dsi_driver = {
+	.driver = {
+		.name = "panel-jdi-lpm102a188a-dsi",
+		.of_match_table = jdi_of_match,
+	},
+	.probe = jdi_panel_dsi_probe,
+	.remove = jdi_panel_dsi_remove,
+	.shutdown = jdi_panel_dsi_shutdown,
+};
+module_mipi_dsi_driver(jdi_panel_dsi_driver);
+
+MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
+MODULE_AUTHOR("Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>");
+MODULE_DESCRIPTION("DRM Driver for JDI LPM102A188A DSI panel, command mode");
+MODULE_LICENSE("GPL");
-- 
2.38.1

[PATCH v2 3/4] drm/panel: Add driver for JDI LPM102A188A

[Diogo Ivo]

The JDI LPM102A188A is a 2560x1800 IPS panel found in the Google Pixel C.
This driver is based on the downstream GPLv2 driver released by Google
written by Sean Paul [1], which was then adapted to the newer kernel APIs.

[1]: https://android.googlesource.com/kernel/tegra/+/refs/heads/android-tegra-dragon-3.18-oreo/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
 - tuned backlight delays

 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 509 ++++++++++++++++++
 3 files changed, 521 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index a582ddd583c2..80eda8f6bee0 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -214,6 +214,17 @@ config DRM_PANEL_JDI_LT070ME05000
 	  The panel has a 1200(RGB)×1920 (WUXGA) resolution and uses
 	  24 bit per pixel.
 
+config DRM_PANEL_JDI_LPM102A188A
+	tristate "JDI LPM102A188A DSI panel"
+	depends on OF && GPIOLIB
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  Say Y here if you want to enable support for JDI LPM102A188A DSI
+	  control mode panel as found in Google Pixel C devices.
+	  The panel has a 2560×1800 resolution. It provides a MIPI DSI interface
+	  to the host.
+
 config DRM_PANEL_JDI_R63452
 	tristate "JDI R63452 Full HD DSI panel"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 34e717382dbb..2870cba96d14 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9881C) += panel-ilitek-ili9881c.o
 obj-$(CONFIG_DRM_PANEL_INNOLUX_EJ030NA) += panel-innolux-ej030na.o
 obj-$(CONFIG_DRM_PANEL_INNOLUX_P079ZCA) += panel-innolux-p079zca.o
 obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
+obj-$(CONFIG_DRM_PANEL_JDI_LPM102A188A) += panel-jdi-lpm102a188a.o
 obj-$(CONFIG_DRM_PANEL_JDI_R63452) += panel-jdi-fhd-r63452.o
 obj-$(CONFIG_DRM_PANEL_KHADAS_TS050) += panel-khadas-ts050.o
 obj-$(CONFIG_DRM_PANEL_KINGDISPLAY_KD097D04) += panel-kingdisplay-kd097d04.o
diff --git a/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
new file mode 100644
index 000000000000..980af82ad6d6
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
@@ -0,0 +1,509 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * Copyright (C) 2022 Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
+ *
+ * Adapted from the downstream Pixel C driver written by Sean Paul
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_crtc.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_panel.h>
+
+struct jdi_panel {
+	struct drm_panel base;
+	struct mipi_dsi_device *link1;
+	struct mipi_dsi_device *link2;
+
+	struct regulator *supply;
+	struct regulator *ddi_supply;
+	struct backlight_device *backlight;
+
+	struct gpio_desc *enable_gpio;
+	struct gpio_desc *reset_gpio;
+
+	const struct drm_display_mode *mode;
+
+	bool prepared;
+	bool enabled;
+};
+
+static inline struct jdi_panel *to_panel_jdi(struct drm_panel *panel)
+{
+	return container_of(panel, struct jdi_panel, base);
+}
+
+static void jdi_wait_frames(struct jdi_panel *jdi, unsigned int frames)
+{
+	unsigned int refresh = drm_mode_vrefresh(jdi->mode);
+
+	if (WARN_ON(frames > refresh))
+		return;
+
+	msleep(1000 / (refresh / frames));
+}
+
+static int jdi_panel_disable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+
+	if (!jdi->enabled)
+		return 0;
+
+	backlight_disable(jdi->backlight);
+
+	jdi_wait_frames(jdi, 2);
+
+	jdi->enabled = false;
+
+	return 0;
+}
+
+static int jdi_panel_unprepare(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+	int ret;
+
+	if (!jdi->prepared)
+		return 0;
+
+	ret = mipi_dsi_dcs_set_display_off(jdi->link1);
+	if (ret < 0)
+		dev_err(panel->dev, "failed to set display off: %d\n", ret);
+	ret = mipi_dsi_dcs_set_display_off(jdi->link2);
+	if (ret < 0)
+		dev_err(panel->dev, "failed to set display off: %d\n", ret);
+
+	/* Specified by JDI @ 50ms, subject to change */
+	msleep(50);
+
+	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link1);
+	if (ret < 0)
+		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
+	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link2);
+	if (ret < 0)
+		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
+
+	/* Specified by JDI @ 150ms, subject to change */
+	msleep(150);
+
+	gpiod_set_value(jdi->reset_gpio, 1);
+
+	/* T4 = 1ms */
+	usleep_range(1000, 3000);
+
+	gpiod_set_value(jdi->enable_gpio, 0);
+
+	/* T5 = 2ms */
+	usleep_range(2000, 4000);
+
+	regulator_disable(jdi->ddi_supply);
+
+	/* T6 = 2ms */
+	usleep_range(5000, 6000);
+
+	regulator_disable(jdi->supply);
+
+	jdi->prepared = false;
+
+	return 0;
+}
+
+static int jdi_setup_symmetrical_split(struct mipi_dsi_device *left,
+				       struct mipi_dsi_device *right,
+				       const struct drm_display_mode *mode)
+{
+	int err;
+
+	err = mipi_dsi_dcs_set_column_address(left, 0, mode->hdisplay / 2 - 1);
+	if (err < 0) {
+		dev_err(&left->dev, "failed to set column address: %d\n", err);
+		return err;
+	}
+
+	err = mipi_dsi_dcs_set_column_address(right, 0, mode->hdisplay / 2 - 1);
+	if (err < 0) {
+		dev_err(&right->dev, "failed to set column address: %d\n", err);
+		return err;
+	}
+
+	err = mipi_dsi_dcs_set_page_address(left, 0, mode->vdisplay - 1);
+	if (err < 0) {
+		dev_err(&left->dev, "failed to set page address: %d\n", err);
+		return err;
+	}
+
+	err = mipi_dsi_dcs_set_page_address(right, 0, mode->vdisplay - 1);
+	if (err < 0) {
+		dev_err(&right->dev, "failed to set page address: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static int jdi_panel_prepare(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+	u8 format = MIPI_DCS_PIXEL_FMT_24BIT;
+	int err;
+
+	if (jdi->prepared)
+		return 0;
+
+	/* Disable backlight to avoid showing random pixels
+	 * with a conservative delay for it to take effect.
+	 */
+	backlight_disable(jdi->backlight);
+	msleep(100);
+
+	jdi->link1->mode_flags |= MIPI_DSI_MODE_LPM;
+	jdi->link2->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	err = regulator_enable(jdi->supply);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to enable supply: %d\n", err);
+		return err;
+	}
+	/* T1 = 2ms */
+	usleep_range(2000, 4000);
+
+	err = regulator_enable(jdi->ddi_supply);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to enable ddi_supply: %d\n", err);
+		return err;
+	}
+	/* T2 = 1ms */
+	usleep_range(1000, 3000);
+
+	gpiod_set_value(jdi->enable_gpio, 1);
+	/* T3 = 10ms */
+	usleep_range(10000, 15000);
+
+	gpiod_set_value(jdi->reset_gpio, 0);
+	/* Specified by JDI @ 3ms, subject to change */
+	usleep_range(3000, 5000);
+
+	/*
+	 * TODO: The device supports both left-right and even-odd split
+	 * configurations, but this driver currently supports only the left-
+	 * right split. To support a different mode a mechanism needs to be
+	 * put in place to communicate the configuration back to the DSI host
+	 * controller.
+	 */
+
+	err = jdi_setup_symmetrical_split(jdi->link1, jdi->link2,
+					    jdi->mode);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to set up symmetrical split: %d\n",
+			err);
+		goto poweroff;
+	}
+
+	err = mipi_dsi_dcs_set_tear_scanline(jdi->link1,
+					     jdi->mode->vdisplay - 16);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
+
+	err = mipi_dsi_dcs_set_tear_scanline(jdi->link2,
+					     jdi->mode->vdisplay - 16);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
+
+	err = mipi_dsi_dcs_set_tear_on(jdi->link1,
+				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set tear on: %d\n", err);
+
+	err = mipi_dsi_dcs_set_tear_on(jdi->link2,
+				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set tear on: %d\n", err);
+
+	err = mipi_dsi_dcs_set_pixel_format(jdi->link1, format);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
+		goto poweroff;
+	}
+
+	err = mipi_dsi_dcs_set_pixel_format(jdi->link2, format);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
+		goto poweroff;
+	}
+
+	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link1);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
+		goto poweroff;
+	}
+
+	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link2);
+	if (err < 0) {
+		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
+		goto poweroff;
+	}
+
+	/*
+	 * We need to wait 150ms between mipi_dsi_dcs_exit_sleep_mode() and
+	 * mipi_dsi_dcs_set_display_on().
+	 */
+	msleep(150);
+
+	err = mipi_dsi_dcs_set_display_on(jdi->link1);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set display on: %d\n", err);
+
+
+	err = mipi_dsi_dcs_set_display_on(jdi->link2);
+	if (err < 0)
+		dev_err(panel->dev, "failed to set display on: %d\n", err);
+
+	jdi->prepared = true;
+
+	jdi->link1->mode_flags &= ~MIPI_DSI_MODE_LPM;
+	jdi->link2->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	return 0;
+
+poweroff:
+	regulator_disable(jdi->ddi_supply);
+
+	/* T6 = 2ms */
+	usleep_range(7000, 9000);
+
+	regulator_disable(jdi->supply);
+
+	return err;
+}
+
+static int jdi_panel_enable(struct drm_panel *panel)
+{
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+
+	if (jdi->enabled)
+		return 0;
+
+	/*
+	 * Ensure we send image data before turning the backlight on,
+	 * to avoid the display showing random pixels (colored snow).
+	 */
+	jdi_wait_frames(jdi, 3);
+
+	backlight_enable(jdi->backlight);
+
+	jdi->enabled = true;
+
+	return 0;
+}
+
+static const struct drm_display_mode default_mode = {
+	.clock = 331334,
+	.hdisplay = 2560,
+	.hsync_start = 2560 + 80,
+	.hsync_end = 2560 + 80 + 80,
+	.htotal = 2560 + 80 + 80 + 80,
+	.vdisplay = 1800,
+	.vsync_start = 1800 + 4,
+	.vsync_end = 1800 + 4 + 4,
+	.vtotal = 1800 + 4 + 4 + 4,
+	.flags = 0,
+};
+
+static int jdi_panel_get_modes(struct drm_panel *panel,
+			       struct drm_connector *connector)
+{
+	struct drm_display_mode *mode;
+	struct jdi_panel *jdi = to_panel_jdi(panel);
+	struct device *dev = &jdi->link1->dev;
+
+	mode = drm_mode_duplicate(connector->dev, &default_mode);
+	if (!mode) {
+		dev_err(dev, "failed to add mode %ux%ux@%u\n",
+			default_mode.hdisplay, default_mode.vdisplay,
+			drm_mode_vrefresh(&default_mode));
+		return -ENOMEM;
+	}
+
+	drm_mode_set_name(mode);
+
+	drm_mode_probed_add(connector, mode);
+
+	connector->display_info.width_mm = 211;
+	connector->display_info.height_mm = 148;
+	connector->display_info.bpc = 8;
+
+	return 1;
+}
+
+static const struct drm_panel_funcs jdi_panel_funcs = {
+	.prepare = jdi_panel_prepare,
+	.enable = jdi_panel_enable,
+	.disable = jdi_panel_disable,
+	.unprepare = jdi_panel_unprepare,
+	.get_modes = jdi_panel_get_modes,
+};
+
+static const struct of_device_id jdi_of_match[] = {
+	{ .compatible = "jdi,lpm102a188a", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, jdi_of_match);
+
+static int jdi_panel_add(struct jdi_panel *jdi)
+{
+	struct device *dev = &jdi->link1->dev;
+
+	jdi->mode = &default_mode;
+
+	jdi->supply = devm_regulator_get(dev, "power");
+	if (IS_ERR(jdi->supply))
+		return dev_err_probe(dev, PTR_ERR(jdi->supply),
+				     "failed to get power regulator\n");
+
+	jdi->ddi_supply = devm_regulator_get(dev, "ddi");
+	if (IS_ERR(jdi->ddi_supply))
+		return dev_err_probe(dev, PTR_ERR(jdi->ddi_supply),
+				     "failed to get ddi regulator\n");
+
+	jdi->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(jdi->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(jdi->reset_gpio),
+				     "failed to get reset gpio\n");
+	usleep_range(1000, 3000);
+
+	jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(jdi->enable_gpio))
+		return dev_err_probe(dev, PTR_ERR(jdi->enable_gpio),
+				     "failed to get enable gpio\n");
+	usleep_range(2000, 4000);
+
+	jdi->backlight = devm_of_find_backlight(dev);
+	if (IS_ERR(jdi->backlight))
+		return dev_err_probe(dev, PTR_ERR(jdi->backlight),
+				     "failed to create backlight\n");
+
+	drm_panel_init(&jdi->base, &jdi->link1->dev, &jdi_panel_funcs,
+		       DRM_MODE_CONNECTOR_DSI);
+
+	drm_panel_add(&jdi->base);
+
+	return 0;
+}
+
+static void jdi_panel_del(struct jdi_panel *jdi)
+{
+	if (jdi->base.dev)
+		drm_panel_remove(&jdi->base);
+
+	if (jdi->link2)
+		put_device(&jdi->link2->dev);
+}
+
+static int jdi_panel_dsi_probe(struct mipi_dsi_device *dsi)
+{
+	struct mipi_dsi_device *secondary = NULL;
+	struct jdi_panel *jdi;
+	struct device_node *np;
+	int err;
+
+	dsi->lanes = 4;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = 0;
+
+	/* Find DSI-LINK1 */
+	np = of_parse_phandle(dsi->dev.of_node, "link2", 0);
+	if (np) {
+		secondary = of_find_mipi_dsi_device_by_node(np);
+		of_node_put(np);
+
+		if (!secondary)
+			return -EPROBE_DEFER;
+	}
+
+	/* register a panel for only the DSI-LINK1 interface */
+	if (secondary) {
+		jdi = devm_kzalloc(&dsi->dev, sizeof(*jdi), GFP_KERNEL);
+		if (!jdi) {
+			put_device(&secondary->dev);
+			return -ENOMEM;
+		}
+
+		mipi_dsi_set_drvdata(dsi, jdi);
+
+		jdi->link1 = dsi;
+		jdi->link2 = secondary;
+
+		err = jdi_panel_add(jdi);
+		if (err < 0) {
+			put_device(&secondary->dev);
+			return err;
+		}
+	}
+
+	err = mipi_dsi_attach(dsi);
+	if (err < 0) {
+		if (secondary)
+			jdi_panel_del(jdi);
+
+		return err;
+	}
+
+	return 0;
+}
+
+static void jdi_panel_dsi_remove(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
+	int err;
+
+	/* only detach from host for the DSI-LINK2 interface */
+	if (!jdi)
+		mipi_dsi_detach(dsi);
+
+	err = jdi_panel_disable(&jdi->base);
+	if (err < 0)
+		dev_err(&dsi->dev, "failed to disable panel: %d\n", err);
+
+	err = mipi_dsi_detach(dsi);
+	if (err < 0)
+		dev_err(&dsi->dev, "failed to detach from DSI host: %d\n", err);
+
+	jdi_panel_del(jdi);
+}
+
+static void jdi_panel_dsi_shutdown(struct mipi_dsi_device *dsi)
+{
+	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
+
+	if (!jdi)
+		return;
+
+	jdi_panel_disable(&jdi->base);
+}
+
+static struct mipi_dsi_driver jdi_panel_dsi_driver = {
+	.driver = {
+		.name = "panel-jdi-lpm102a188a-dsi",
+		.of_match_table = jdi_of_match,
+	},
+	.probe = jdi_panel_dsi_probe,
+	.remove = jdi_panel_dsi_remove,
+	.shutdown = jdi_panel_dsi_shutdown,
+};
+module_mipi_dsi_driver(jdi_panel_dsi_driver);
+
+MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
+MODULE_AUTHOR("Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>");
+MODULE_DESCRIPTION("DRM Driver for JDI LPM102A188A DSI panel, command mode");
+MODULE_LICENSE("GPL");
-- 
2.38.1

[PATCH v2 4/4] arm64: dts: smaug: Add display panel node

[Diogo Ivo]

The Google Pixel C has a JDI LPM102A188A display panel. Add a
DT node for it. Tested on Pixel C.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
 - renamed backlight node to a generic name
 - removed underscores

 arch/arm64/boot/dts/nvidia/tegra210-smaug.dts | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts b/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
index 84ec4d8b7f10..5db0b25c8d58 100644
--- a/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
+++ b/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
@@ -31,6 +31,37 @@ memory {
 	};
 
 	host1x@50000000 {
+		dc@54200000 {
+			status = "okay";
+		};
+
+		dsia: dsi@54300000 {
+			avdd-dsi-csi-supply = <&vdd_dsi_csi>;
+			status = "okay";
+
+			link2: panel@0 {
+				compatible = "jdi,lpm102a188a";
+				reg = <0>;
+			};
+		};
+
+		dsib: dsi@54400000 {
+			avdd-dsi-csi-supply = <&vdd_dsi_csi>;
+			nvidia,ganged-mode = <&dsia>;
+			status = "okay";
+
+			link1: panel@0 {
+				compatible = "jdi,lpm102a188a";
+				reg = <0>;
+				power-supply = <&pplcd_vdd>;
+				ddi-supply = <&pp1800_lcdio>;
+				enable-gpios = <&gpio TEGRA_GPIO(V, 1) GPIO_ACTIVE_HIGH>;
+				reset-gpios = <&gpio TEGRA_GPIO(V, 2) GPIO_ACTIVE_LOW>;
+				link2 = <&link2>;
+				backlight = <&backlight>;
+			};
+		};
+
 		dpaux: dpaux@545c0000 {
 			status = "okay";
 		};
@@ -1627,6 +1658,37 @@ nau8825@1a {
 			status = "okay";
 		};
 
+		backlight: backlight@2c {
+			compatible = "ti,lp8557";
+			reg = <0x2c>;
+			power-supply = <&pplcd_vdd>;
+			enable-supply = <&pp1800_lcdio>;
+			bl-name = "lp8557-backlight";
+			dev-ctrl = /bits/ 8 <0x01>;
+			init-brt = /bits/ 8 <0x80>;
+
+			/* Full scale current, 20mA */
+			rom-11h {
+				rom-addr = /bits/ 8 <0x11>;
+				rom-val = /bits/ 8 <0x05>;
+			};
+			/* Frequency = 4.9kHz, magic undocumented val */
+			rom-12h {
+				rom-addr = /bits/ 8 <0x12>;
+				rom-val = /bits/ 8 <0x29>;
+			};
+			/* Boost freq = 1MHz, BComp option = 1 */
+			rom-13h {
+				rom-addr = /bits/ 8 <0x13>;
+				rom-val = /bits/ 8 <0x03>;
+			};
+			/* 4V OV, 6 output LED string enabled */
+			rom-14h {
+				rom-addr = /bits/ 8 <0x14>;
+				rom-val = /bits/ 8 <0xbf>;
+			};
+		};
+
 		audio-codec@2d {
 			compatible = "realtek,rt5677";
 			reg = <0x2d>;
@@ -1908,4 +1970,12 @@ usbc_vbus: regulator-usbc-vbus {
 		regulator-min-microvolt = <5000000>;
 		regulator-max-microvolt = <5000000>;
 	};
+
+	vdd_dsi_csi: regulator-vdd-dsi-csi {
+		compatible = "regulator-fixed";
+		regulator-name = "AVDD_DSI_CSI_1V2";
+		regulator-min-microvolt = <1200000>;
+		regulator-max-microvolt = <1200000>;
+		vin-supply = <&pp1200_avdd>;
+	};
 };
-- 
2.38.1

[PATCH v2 4/4] arm64: dts: smaug: Add display panel node

[Diogo Ivo]

The Google Pixel C has a JDI LPM102A188A display panel. Add a
DT node for it. Tested on Pixel C.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
 - renamed backlight node to a generic name
 - removed underscores

 arch/arm64/boot/dts/nvidia/tegra210-smaug.dts | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts b/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
index 84ec4d8b7f10..5db0b25c8d58 100644
--- a/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
+++ b/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
@@ -31,6 +31,37 @@ memory {
 	};
 
 	host1x@50000000 {
+		dc@54200000 {
+			status = "okay";
+		};
+
+		dsia: dsi@54300000 {
+			avdd-dsi-csi-supply = <&vdd_dsi_csi>;
+			status = "okay";
+
+			link2: panel@0 {
+				compatible = "jdi,lpm102a188a";
+				reg = <0>;
+			};
+		};
+
+		dsib: dsi@54400000 {
+			avdd-dsi-csi-supply = <&vdd_dsi_csi>;
+			nvidia,ganged-mode = <&dsia>;
+			status = "okay";
+
+			link1: panel@0 {
+				compatible = "jdi,lpm102a188a";
+				reg = <0>;
+				power-supply = <&pplcd_vdd>;
+				ddi-supply = <&pp1800_lcdio>;
+				enable-gpios = <&gpio TEGRA_GPIO(V, 1) GPIO_ACTIVE_HIGH>;
+				reset-gpios = <&gpio TEGRA_GPIO(V, 2) GPIO_ACTIVE_LOW>;
+				link2 = <&link2>;
+				backlight = <&backlight>;
+			};
+		};
+
 		dpaux: dpaux@545c0000 {
 			status = "okay";
 		};
@@ -1627,6 +1658,37 @@ nau8825@1a {
 			status = "okay";
 		};
 
+		backlight: backlight@2c {
+			compatible = "ti,lp8557";
+			reg = <0x2c>;
+			power-supply = <&pplcd_vdd>;
+			enable-supply = <&pp1800_lcdio>;
+			bl-name = "lp8557-backlight";
+			dev-ctrl = /bits/ 8 <0x01>;
+			init-brt = /bits/ 8 <0x80>;
+
+			/* Full scale current, 20mA */
+			rom-11h {
+				rom-addr = /bits/ 8 <0x11>;
+				rom-val = /bits/ 8 <0x05>;
+			};
+			/* Frequency = 4.9kHz, magic undocumented val */
+			rom-12h {
+				rom-addr = /bits/ 8 <0x12>;
+				rom-val = /bits/ 8 <0x29>;
+			};
+			/* Boost freq = 1MHz, BComp option = 1 */
+			rom-13h {
+				rom-addr = /bits/ 8 <0x13>;
+				rom-val = /bits/ 8 <0x03>;
+			};
+			/* 4V OV, 6 output LED string enabled */
+			rom-14h {
+				rom-addr = /bits/ 8 <0x14>;
+				rom-val = /bits/ 8 <0xbf>;
+			};
+		};
+
 		audio-codec@2d {
 			compatible = "realtek,rt5677";
 			reg = <0x2d>;
@@ -1908,4 +1970,12 @@ usbc_vbus: regulator-usbc-vbus {
 		regulator-min-microvolt = <5000000>;
 		regulator-max-microvolt = <5000000>;
 	};
+
+	vdd_dsi_csi: regulator-vdd-dsi-csi {
+		compatible = "regulator-fixed";
+		regulator-name = "AVDD_DSI_CSI_1V2";
+		regulator-min-microvolt = <1200000>;
+		regulator-max-microvolt = <1200000>;
+		vin-supply = <&pp1200_avdd>;
+	};
 };
-- 
2.38.1

Re: [PATCH v2 1/4] dt-bindings: display: Add bindings for JDI LPM102A188A

[Krzysztof Kozlowski]

On 25/10/2022 11:37, Diogo Ivo wrote:
> The LPM102A188A is a 10.2" 2560x1800 IPS panel found in
> the Google Pixel C.
> 
> Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> ---


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

Best regards,
Krzysztof

Re: [PATCH v2 1/4] dt-bindings: display: Add bindings for JDI LPM102A188A

[Krzysztof Kozlowski]

On 25/10/2022 11:37, Diogo Ivo wrote:
> The LPM102A188A is a 10.2" 2560x1800 IPS panel found in
> the Google Pixel C.
> 
> Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> ---


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

Best regards,
Krzysztof

Re: [v2,3/4] drm/panel: Add driver for JDI LPM102A188A

[Rayyan Ansari]

Hello,

On 25/10/2022 16:37, Diogo Ivo wrote:
> The JDI LPM102A188A is a 2560x1800 IPS panel found in the Google Pixel C.
> This driver is based on the downstream GPLv2 driver released by Google
> written by Sean Paul [1], which was then adapted to the newer kernel APIs.
> 
> [1]: https://android.googlesource.com/kernel/tegra/+/refs/heads/android-tegra-dragon-3.18-oreo/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
> 
> Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> ---
> Changes in v2:
>   - tuned backlight delays
> 
>   drivers/gpu/drm/panel/Kconfig                 |  11 +
>   drivers/gpu/drm/panel/Makefile                |   1 +
>   drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 509 ++++++++++++++++++
>   3 files changed, 521 insertions(+)
>   create mode 100644 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index a582ddd583c2..80eda8f6bee0 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -214,6 +214,17 @@ config DRM_PANEL_JDI_LT070ME05000
>   	  The panel has a 1200(RGB)×1920 (WUXGA) resolution and uses
>   	  24 bit per pixel.
>   
> +config DRM_PANEL_JDI_LPM102A188A
> +	tristate "JDI LPM102A188A DSI panel"
> +	depends on OF && GPIOLIB
> +	depends on DRM_MIPI_DSI
> +	depends on BACKLIGHT_CLASS_DEVICE
> +	help
> +	  Say Y here if you want to enable support for JDI LPM102A188A DSI
> +	  control mode panel as found in Google Pixel C devices.
Shouldn't this be "command mode panel" instead of "control mode panel"?
> +	  The panel has a 2560×1800 resolution. It provides a MIPI DSI interface
> +	  to the host.
> +
>   config DRM_PANEL_JDI_R63452
>   	tristate "JDI R63452 Full HD DSI panel"
>   	depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 34e717382dbb..2870cba96d14 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9881C) += panel-ilitek-ili9881c.o
>   obj-$(CONFIG_DRM_PANEL_INNOLUX_EJ030NA) += panel-innolux-ej030na.o
>   obj-$(CONFIG_DRM_PANEL_INNOLUX_P079ZCA) += panel-innolux-p079zca.o
>   obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
> +obj-$(CONFIG_DRM_PANEL_JDI_LPM102A188A) += panel-jdi-lpm102a188a.o
>   obj-$(CONFIG_DRM_PANEL_JDI_R63452) += panel-jdi-fhd-r63452.o
>   obj-$(CONFIG_DRM_PANEL_KHADAS_TS050) += panel-khadas-ts050.o
>   obj-$(CONFIG_DRM_PANEL_KINGDISPLAY_KD097D04) += panel-kingdisplay-kd097d04.o
> diff --git a/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
> new file mode 100644
> index 000000000000..980af82ad6d6
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
> @@ -0,0 +1,509 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2014 Google, Inc.
> + *
> + * Copyright (C) 2022 Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> + *
> + * Adapted from the downstream Pixel C driver written by Sean Paul
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <video/mipi_display.h>
> +
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_panel.h>
> +
> +struct jdi_panel {
> +	struct drm_panel base;
> +	struct mipi_dsi_device *link1;
> +	struct mipi_dsi_device *link2;
> +
> +	struct regulator *supply;
> +	struct regulator *ddi_supply;
> +	struct backlight_device *backlight;
> +
> +	struct gpio_desc *enable_gpio;
> +	struct gpio_desc *reset_gpio;
> +
> +	const struct drm_display_mode *mode;
> +
> +	bool prepared;
> +	bool enabled;
> +};
> +
> +static inline struct jdi_panel *to_panel_jdi(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct jdi_panel, base);
> +}
> +
> +static void jdi_wait_frames(struct jdi_panel *jdi, unsigned int frames)
> +{
> +	unsigned int refresh = drm_mode_vrefresh(jdi->mode);
> +
> +	if (WARN_ON(frames > refresh))
> +		return;
> +
> +	msleep(1000 / (refresh / frames));
> +}
> +
> +static int jdi_panel_disable(struct drm_panel *panel)
> +{
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +
> +	if (!jdi->enabled)
> +		return 0;
> +
> +	backlight_disable(jdi->backlight);
> +
> +	jdi_wait_frames(jdi, 2);
> +
> +	jdi->enabled = false;
> +
> +	return 0;
> +}
> +
> +static int jdi_panel_unprepare(struct drm_panel *panel)
> +{
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +	int ret;
> +
> +	if (!jdi->prepared)
> +		return 0;
> +
> +	ret = mipi_dsi_dcs_set_display_off(jdi->link1);
> +	if (ret < 0)
> +		dev_err(panel->dev, "failed to set display off: %d\n", ret);
> +	ret = mipi_dsi_dcs_set_display_off(jdi->link2);
> +	if (ret < 0)
> +		dev_err(panel->dev, "failed to set display off: %d\n", ret);
> +
> +	/* Specified by JDI @ 50ms, subject to change */
> +	msleep(50);
> +
> +	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link1);
> +	if (ret < 0)
> +		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
> +	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link2);
> +	if (ret < 0)
> +		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
> +
> +	/* Specified by JDI @ 150ms, subject to change */
> +	msleep(150);
> +
> +	gpiod_set_value(jdi->reset_gpio, 1);
> +
> +	/* T4 = 1ms */
> +	usleep_range(1000, 3000);
> +
> +	gpiod_set_value(jdi->enable_gpio, 0);
> +
> +	/* T5 = 2ms */
> +	usleep_range(2000, 4000);
> +
> +	regulator_disable(jdi->ddi_supply);
> +
> +	/* T6 = 2ms */
> +	usleep_range(5000, 6000);
> +
> +	regulator_disable(jdi->supply);
> +
> +	jdi->prepared = false;
> +
> +	return 0;
> +}
> +
> +static int jdi_setup_symmetrical_split(struct mipi_dsi_device *left,
> +				       struct mipi_dsi_device *right,
> +				       const struct drm_display_mode *mode)
> +{
> +	int err;
> +
> +	err = mipi_dsi_dcs_set_column_address(left, 0, mode->hdisplay / 2 - 1);
> +	if (err < 0) {
> +		dev_err(&left->dev, "failed to set column address: %d\n", err);
> +		return err;
> +	}
> +
> +	err = mipi_dsi_dcs_set_column_address(right, 0, mode->hdisplay / 2 - 1);
> +	if (err < 0) {
> +		dev_err(&right->dev, "failed to set column address: %d\n", err);
> +		return err;
> +	}
> +
> +	err = mipi_dsi_dcs_set_page_address(left, 0, mode->vdisplay - 1);
> +	if (err < 0) {
> +		dev_err(&left->dev, "failed to set page address: %d\n", err);
> +		return err;
> +	}
> +
> +	err = mipi_dsi_dcs_set_page_address(right, 0, mode->vdisplay - 1);
> +	if (err < 0) {
> +		dev_err(&right->dev, "failed to set page address: %d\n", err);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int jdi_panel_prepare(struct drm_panel *panel)
> +{
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +	u8 format = MIPI_DCS_PIXEL_FMT_24BIT;
> +	int err;
> +
> +	if (jdi->prepared)
> +		return 0;
> +
> +	/* Disable backlight to avoid showing random pixels
> +	 * with a conservative delay for it to take effect.
> +	 */
> +	backlight_disable(jdi->backlight);
> +	msleep(100);
> +
> +	jdi->link1->mode_flags |= MIPI_DSI_MODE_LPM;
> +	jdi->link2->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	err = regulator_enable(jdi->supply);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to enable supply: %d\n", err);
> +		return err;
> +	}
> +	/* T1 = 2ms */
> +	usleep_range(2000, 4000);
> +
> +	err = regulator_enable(jdi->ddi_supply);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to enable ddi_supply: %d\n", err);
> +		return err;
> +	}
> +	/* T2 = 1ms */
> +	usleep_range(1000, 3000);
> +
> +	gpiod_set_value(jdi->enable_gpio, 1);
> +	/* T3 = 10ms */
> +	usleep_range(10000, 15000);
> +
> +	gpiod_set_value(jdi->reset_gpio, 0);
> +	/* Specified by JDI @ 3ms, subject to change */
> +	usleep_range(3000, 5000);
> +
> +	/*
> +	 * TODO: The device supports both left-right and even-odd split
> +	 * configurations, but this driver currently supports only the left-
> +	 * right split. To support a different mode a mechanism needs to be
> +	 * put in place to communicate the configuration back to the DSI host
> +	 * controller.
> +	 */
> +
> +	err = jdi_setup_symmetrical_split(jdi->link1, jdi->link2,
> +					    jdi->mode);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to set up symmetrical split: %d\n",
> +			err);
> +		goto poweroff;
> +	}
> +
> +	err = mipi_dsi_dcs_set_tear_scanline(jdi->link1,
> +					     jdi->mode->vdisplay - 16);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
> +
> +	err = mipi_dsi_dcs_set_tear_scanline(jdi->link2,
> +					     jdi->mode->vdisplay - 16);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
> +
> +	err = mipi_dsi_dcs_set_tear_on(jdi->link1,
> +				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set tear on: %d\n", err);
> +
> +	err = mipi_dsi_dcs_set_tear_on(jdi->link2,
> +				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set tear on: %d\n", err);
> +
> +	err = mipi_dsi_dcs_set_pixel_format(jdi->link1, format);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
> +		goto poweroff;
> +	}
> +
> +	err = mipi_dsi_dcs_set_pixel_format(jdi->link2, format);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
> +		goto poweroff;
> +	}
> +
> +	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link1);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
> +		goto poweroff;
> +	}
> +
> +	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link2);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
> +		goto poweroff;
> +	}
> +
> +	/*
> +	 * We need to wait 150ms between mipi_dsi_dcs_exit_sleep_mode() and
> +	 * mipi_dsi_dcs_set_display_on().
> +	 */
> +	msleep(150);
> +
> +	err = mipi_dsi_dcs_set_display_on(jdi->link1);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set display on: %d\n", err);
> +
> +
> +	err = mipi_dsi_dcs_set_display_on(jdi->link2);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set display on: %d\n", err);
> +
> +	jdi->prepared = true;
> +
> +	jdi->link1->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +	jdi->link2->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	return 0;
> +
> +poweroff:
> +	regulator_disable(jdi->ddi_supply);
> +
> +	/* T6 = 2ms */
> +	usleep_range(7000, 9000);
> +
> +	regulator_disable(jdi->supply);
> +
> +	return err;
> +}
> +
> +static int jdi_panel_enable(struct drm_panel *panel)
> +{
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +
> +	if (jdi->enabled)
> +		return 0;
> +
> +	/*
> +	 * Ensure we send image data before turning the backlight on,
> +	 * to avoid the display showing random pixels (colored snow).
> +	 */
> +	jdi_wait_frames(jdi, 3);
> +
> +	backlight_enable(jdi->backlight);
> +
> +	jdi->enabled = true;
> +
> +	return 0;
> +}
> +
> +static const struct drm_display_mode default_mode = {
> +	.clock = 331334,
> +	.hdisplay = 2560,
> +	.hsync_start = 2560 + 80,
> +	.hsync_end = 2560 + 80 + 80,
> +	.htotal = 2560 + 80 + 80 + 80,
> +	.vdisplay = 1800,
> +	.vsync_start = 1800 + 4,
> +	.vsync_end = 1800 + 4 + 4,
> +	.vtotal = 1800 + 4 + 4 + 4,
> +	.flags = 0,
> +};
> +
> +static int jdi_panel_get_modes(struct drm_panel *panel,
> +			       struct drm_connector *connector)
> +{
> +	struct drm_display_mode *mode;
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +	struct device *dev = &jdi->link1->dev;
> +
> +	mode = drm_mode_duplicate(connector->dev, &default_mode);
> +	if (!mode) {
> +		dev_err(dev, "failed to add mode %ux%ux@%u\n",
> +			default_mode.hdisplay, default_mode.vdisplay,
> +			drm_mode_vrefresh(&default_mode));
> +		return -ENOMEM;
> +	}
> +
> +	drm_mode_set_name(mode);
> +
> +	drm_mode_probed_add(connector, mode);
> +
> +	connector->display_info.width_mm = 211;
> +	connector->display_info.height_mm = 148;
> +	connector->display_info.bpc = 8;
> +
> +	return 1;
> +}
> +
> +static const struct drm_panel_funcs jdi_panel_funcs = {
> +	.prepare = jdi_panel_prepare,
> +	.enable = jdi_panel_enable,
> +	.disable = jdi_panel_disable,
> +	.unprepare = jdi_panel_unprepare,
> +	.get_modes = jdi_panel_get_modes,
> +};
> +
> +static const struct of_device_id jdi_of_match[] = {
> +	{ .compatible = "jdi,lpm102a188a", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, jdi_of_match);
> +
> +static int jdi_panel_add(struct jdi_panel *jdi)
> +{
> +	struct device *dev = &jdi->link1->dev;
> +
> +	jdi->mode = &default_mode;
> +
> +	jdi->supply = devm_regulator_get(dev, "power");
> +	if (IS_ERR(jdi->supply))
> +		return dev_err_probe(dev, PTR_ERR(jdi->supply),
> +				     "failed to get power regulator\n");
> +
> +	jdi->ddi_supply = devm_regulator_get(dev, "ddi");
> +	if (IS_ERR(jdi->ddi_supply))
> +		return dev_err_probe(dev, PTR_ERR(jdi->ddi_supply),
> +				     "failed to get ddi regulator\n");
> +
> +	jdi->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(jdi->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(jdi->reset_gpio),
> +				     "failed to get reset gpio\n");
> +	usleep_range(1000, 3000);
> +
> +	jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
> +	if (IS_ERR(jdi->enable_gpio))
> +		return dev_err_probe(dev, PTR_ERR(jdi->enable_gpio),
> +				     "failed to get enable gpio\n");
> +	usleep_range(2000, 4000);
> +
> +	jdi->backlight = devm_of_find_backlight(dev);
> +	if (IS_ERR(jdi->backlight))
> +		return dev_err_probe(dev, PTR_ERR(jdi->backlight),
> +				     "failed to create backlight\n");
> +
> +	drm_panel_init(&jdi->base, &jdi->link1->dev, &jdi_panel_funcs,
> +		       DRM_MODE_CONNECTOR_DSI);
> +
> +	drm_panel_add(&jdi->base);
> +
> +	return 0;
> +}
> +
> +static void jdi_panel_del(struct jdi_panel *jdi)
> +{
> +	if (jdi->base.dev)
> +		drm_panel_remove(&jdi->base);
> +
> +	if (jdi->link2)
> +		put_device(&jdi->link2->dev);
> +}
> +
> +static int jdi_panel_dsi_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct mipi_dsi_device *secondary = NULL;
> +	struct jdi_panel *jdi;
> +	struct device_node *np;
> +	int err;
> +
> +	dsi->lanes = 4;
> +	dsi->format = MIPI_DSI_FMT_RGB888;
> +	dsi->mode_flags = 0;
> +
> +	/* Find DSI-LINK1 */
> +	np = of_parse_phandle(dsi->dev.of_node, "link2", 0);
> +	if (np) {
> +		secondary = of_find_mipi_dsi_device_by_node(np);
> +		of_node_put(np);
> +
> +		if (!secondary)
> +			return -EPROBE_DEFER;
> +	}
> +
> +	/* register a panel for only the DSI-LINK1 interface */
> +	if (secondary) {
> +		jdi = devm_kzalloc(&dsi->dev, sizeof(*jdi), GFP_KERNEL);
> +		if (!jdi) {
> +			put_device(&secondary->dev);
> +			return -ENOMEM;
> +		}
> +
> +		mipi_dsi_set_drvdata(dsi, jdi);
> +
> +		jdi->link1 = dsi;
> +		jdi->link2 = secondary;
> +
> +		err = jdi_panel_add(jdi);
> +		if (err < 0) {
> +			put_device(&secondary->dev);
> +			return err;
> +		}
> +	}
> +
> +	err = mipi_dsi_attach(dsi);
> +	if (err < 0) {
> +		if (secondary)
> +			jdi_panel_del(jdi);
> +
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static void jdi_panel_dsi_remove(struct mipi_dsi_device *dsi)
> +{
> +	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
> +	int err;
> +
> +	/* only detach from host for the DSI-LINK2 interface */
> +	if (!jdi)
> +		mipi_dsi_detach(dsi);
> +
> +	err = jdi_panel_disable(&jdi->base);
> +	if (err < 0)
> +		dev_err(&dsi->dev, "failed to disable panel: %d\n", err);
> +
> +	err = mipi_dsi_detach(dsi);
> +	if (err < 0)
> +		dev_err(&dsi->dev, "failed to detach from DSI host: %d\n", err);
> +
> +	jdi_panel_del(jdi);
> +}
> +
> +static void jdi_panel_dsi_shutdown(struct mipi_dsi_device *dsi)
> +{
> +	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
> +
> +	if (!jdi)
> +		return;
> +
> +	jdi_panel_disable(&jdi->base);
> +}
> +
> +static struct mipi_dsi_driver jdi_panel_dsi_driver = {
> +	.driver = {
> +		.name = "panel-jdi-lpm102a188a-dsi",
Is the "-dsi" suffix needed here? Other panel drivers don't have this.
> +		.of_match_table = jdi_of_match,
> +	},
> +	.probe = jdi_panel_dsi_probe,
> +	.remove = jdi_panel_dsi_remove,
> +	.shutdown = jdi_panel_dsi_shutdown,
> +};
> +module_mipi_dsi_driver(jdi_panel_dsi_driver);
> +
> +MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
> +MODULE_AUTHOR("Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>");
> +MODULE_DESCRIPTION("DRM Driver for JDI LPM102A188A DSI panel, command mode");
> +MODULE_LICENSE("GPL");

-- 
Rayyan Ansari
https://ansari.sh

Re: [v2,3/4] drm/panel: Add driver for JDI LPM102A188A

[Rayyan Ansari]

Hello,

On 25/10/2022 16:37, Diogo Ivo wrote:
> The JDI LPM102A188A is a 2560x1800 IPS panel found in the Google Pixel C.
> This driver is based on the downstream GPLv2 driver released by Google
> written by Sean Paul [1], which was then adapted to the newer kernel APIs.
> 
> [1]: https://android.googlesource.com/kernel/tegra/+/refs/heads/android-tegra-dragon-3.18-oreo/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
> 
> Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> ---
> Changes in v2:
>   - tuned backlight delays
> 
>   drivers/gpu/drm/panel/Kconfig                 |  11 +
>   drivers/gpu/drm/panel/Makefile                |   1 +
>   drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c | 509 ++++++++++++++++++
>   3 files changed, 521 insertions(+)
>   create mode 100644 drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index a582ddd583c2..80eda8f6bee0 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -214,6 +214,17 @@ config DRM_PANEL_JDI_LT070ME05000
>   	  The panel has a 1200(RGB)×1920 (WUXGA) resolution and uses
>   	  24 bit per pixel.
>   
> +config DRM_PANEL_JDI_LPM102A188A
> +	tristate "JDI LPM102A188A DSI panel"
> +	depends on OF && GPIOLIB
> +	depends on DRM_MIPI_DSI
> +	depends on BACKLIGHT_CLASS_DEVICE
> +	help
> +	  Say Y here if you want to enable support for JDI LPM102A188A DSI
> +	  control mode panel as found in Google Pixel C devices.
Shouldn't this be "command mode panel" instead of "control mode panel"?
> +	  The panel has a 2560×1800 resolution. It provides a MIPI DSI interface
> +	  to the host.
> +
>   config DRM_PANEL_JDI_R63452
>   	tristate "JDI R63452 Full HD DSI panel"
>   	depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 34e717382dbb..2870cba96d14 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9881C) += panel-ilitek-ili9881c.o
>   obj-$(CONFIG_DRM_PANEL_INNOLUX_EJ030NA) += panel-innolux-ej030na.o
>   obj-$(CONFIG_DRM_PANEL_INNOLUX_P079ZCA) += panel-innolux-p079zca.o
>   obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
> +obj-$(CONFIG_DRM_PANEL_JDI_LPM102A188A) += panel-jdi-lpm102a188a.o
>   obj-$(CONFIG_DRM_PANEL_JDI_R63452) += panel-jdi-fhd-r63452.o
>   obj-$(CONFIG_DRM_PANEL_KHADAS_TS050) += panel-khadas-ts050.o
>   obj-$(CONFIG_DRM_PANEL_KINGDISPLAY_KD097D04) += panel-kingdisplay-kd097d04.o
> diff --git a/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
> new file mode 100644
> index 000000000000..980af82ad6d6
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-jdi-lpm102a188a.c
> @@ -0,0 +1,509 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2014 Google, Inc.
> + *
> + * Copyright (C) 2022 Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> + *
> + * Adapted from the downstream Pixel C driver written by Sean Paul
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <video/mipi_display.h>
> +
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_panel.h>
> +
> +struct jdi_panel {
> +	struct drm_panel base;
> +	struct mipi_dsi_device *link1;
> +	struct mipi_dsi_device *link2;
> +
> +	struct regulator *supply;
> +	struct regulator *ddi_supply;
> +	struct backlight_device *backlight;
> +
> +	struct gpio_desc *enable_gpio;
> +	struct gpio_desc *reset_gpio;
> +
> +	const struct drm_display_mode *mode;
> +
> +	bool prepared;
> +	bool enabled;
> +};
> +
> +static inline struct jdi_panel *to_panel_jdi(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct jdi_panel, base);
> +}
> +
> +static void jdi_wait_frames(struct jdi_panel *jdi, unsigned int frames)
> +{
> +	unsigned int refresh = drm_mode_vrefresh(jdi->mode);
> +
> +	if (WARN_ON(frames > refresh))
> +		return;
> +
> +	msleep(1000 / (refresh / frames));
> +}
> +
> +static int jdi_panel_disable(struct drm_panel *panel)
> +{
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +
> +	if (!jdi->enabled)
> +		return 0;
> +
> +	backlight_disable(jdi->backlight);
> +
> +	jdi_wait_frames(jdi, 2);
> +
> +	jdi->enabled = false;
> +
> +	return 0;
> +}
> +
> +static int jdi_panel_unprepare(struct drm_panel *panel)
> +{
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +	int ret;
> +
> +	if (!jdi->prepared)
> +		return 0;
> +
> +	ret = mipi_dsi_dcs_set_display_off(jdi->link1);
> +	if (ret < 0)
> +		dev_err(panel->dev, "failed to set display off: %d\n", ret);
> +	ret = mipi_dsi_dcs_set_display_off(jdi->link2);
> +	if (ret < 0)
> +		dev_err(panel->dev, "failed to set display off: %d\n", ret);
> +
> +	/* Specified by JDI @ 50ms, subject to change */
> +	msleep(50);
> +
> +	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link1);
> +	if (ret < 0)
> +		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
> +	ret = mipi_dsi_dcs_enter_sleep_mode(jdi->link2);
> +	if (ret < 0)
> +		dev_err(panel->dev, "failed to enter sleep mode: %d\n", ret);
> +
> +	/* Specified by JDI @ 150ms, subject to change */
> +	msleep(150);
> +
> +	gpiod_set_value(jdi->reset_gpio, 1);
> +
> +	/* T4 = 1ms */
> +	usleep_range(1000, 3000);
> +
> +	gpiod_set_value(jdi->enable_gpio, 0);
> +
> +	/* T5 = 2ms */
> +	usleep_range(2000, 4000);
> +
> +	regulator_disable(jdi->ddi_supply);
> +
> +	/* T6 = 2ms */
> +	usleep_range(5000, 6000);
> +
> +	regulator_disable(jdi->supply);
> +
> +	jdi->prepared = false;
> +
> +	return 0;
> +}
> +
> +static int jdi_setup_symmetrical_split(struct mipi_dsi_device *left,
> +				       struct mipi_dsi_device *right,
> +				       const struct drm_display_mode *mode)
> +{
> +	int err;
> +
> +	err = mipi_dsi_dcs_set_column_address(left, 0, mode->hdisplay / 2 - 1);
> +	if (err < 0) {
> +		dev_err(&left->dev, "failed to set column address: %d\n", err);
> +		return err;
> +	}
> +
> +	err = mipi_dsi_dcs_set_column_address(right, 0, mode->hdisplay / 2 - 1);
> +	if (err < 0) {
> +		dev_err(&right->dev, "failed to set column address: %d\n", err);
> +		return err;
> +	}
> +
> +	err = mipi_dsi_dcs_set_page_address(left, 0, mode->vdisplay - 1);
> +	if (err < 0) {
> +		dev_err(&left->dev, "failed to set page address: %d\n", err);
> +		return err;
> +	}
> +
> +	err = mipi_dsi_dcs_set_page_address(right, 0, mode->vdisplay - 1);
> +	if (err < 0) {
> +		dev_err(&right->dev, "failed to set page address: %d\n", err);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int jdi_panel_prepare(struct drm_panel *panel)
> +{
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +	u8 format = MIPI_DCS_PIXEL_FMT_24BIT;
> +	int err;
> +
> +	if (jdi->prepared)
> +		return 0;
> +
> +	/* Disable backlight to avoid showing random pixels
> +	 * with a conservative delay for it to take effect.
> +	 */
> +	backlight_disable(jdi->backlight);
> +	msleep(100);
> +
> +	jdi->link1->mode_flags |= MIPI_DSI_MODE_LPM;
> +	jdi->link2->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	err = regulator_enable(jdi->supply);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to enable supply: %d\n", err);
> +		return err;
> +	}
> +	/* T1 = 2ms */
> +	usleep_range(2000, 4000);
> +
> +	err = regulator_enable(jdi->ddi_supply);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to enable ddi_supply: %d\n", err);
> +		return err;
> +	}
> +	/* T2 = 1ms */
> +	usleep_range(1000, 3000);
> +
> +	gpiod_set_value(jdi->enable_gpio, 1);
> +	/* T3 = 10ms */
> +	usleep_range(10000, 15000);
> +
> +	gpiod_set_value(jdi->reset_gpio, 0);
> +	/* Specified by JDI @ 3ms, subject to change */
> +	usleep_range(3000, 5000);
> +
> +	/*
> +	 * TODO: The device supports both left-right and even-odd split
> +	 * configurations, but this driver currently supports only the left-
> +	 * right split. To support a different mode a mechanism needs to be
> +	 * put in place to communicate the configuration back to the DSI host
> +	 * controller.
> +	 */
> +
> +	err = jdi_setup_symmetrical_split(jdi->link1, jdi->link2,
> +					    jdi->mode);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to set up symmetrical split: %d\n",
> +			err);
> +		goto poweroff;
> +	}
> +
> +	err = mipi_dsi_dcs_set_tear_scanline(jdi->link1,
> +					     jdi->mode->vdisplay - 16);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
> +
> +	err = mipi_dsi_dcs_set_tear_scanline(jdi->link2,
> +					     jdi->mode->vdisplay - 16);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set tear scanline: %d\n", err);
> +
> +	err = mipi_dsi_dcs_set_tear_on(jdi->link1,
> +				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set tear on: %d\n", err);
> +
> +	err = mipi_dsi_dcs_set_tear_on(jdi->link2,
> +				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set tear on: %d\n", err);
> +
> +	err = mipi_dsi_dcs_set_pixel_format(jdi->link1, format);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
> +		goto poweroff;
> +	}
> +
> +	err = mipi_dsi_dcs_set_pixel_format(jdi->link2, format);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to set pixel format: %d\n", err);
> +		goto poweroff;
> +	}
> +
> +	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link1);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
> +		goto poweroff;
> +	}
> +
> +	err = mipi_dsi_dcs_exit_sleep_mode(jdi->link2);
> +	if (err < 0) {
> +		dev_err(panel->dev, "failed to exit sleep mode: %d\n", err);
> +		goto poweroff;
> +	}
> +
> +	/*
> +	 * We need to wait 150ms between mipi_dsi_dcs_exit_sleep_mode() and
> +	 * mipi_dsi_dcs_set_display_on().
> +	 */
> +	msleep(150);
> +
> +	err = mipi_dsi_dcs_set_display_on(jdi->link1);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set display on: %d\n", err);
> +
> +
> +	err = mipi_dsi_dcs_set_display_on(jdi->link2);
> +	if (err < 0)
> +		dev_err(panel->dev, "failed to set display on: %d\n", err);
> +
> +	jdi->prepared = true;
> +
> +	jdi->link1->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +	jdi->link2->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	return 0;
> +
> +poweroff:
> +	regulator_disable(jdi->ddi_supply);
> +
> +	/* T6 = 2ms */
> +	usleep_range(7000, 9000);
> +
> +	regulator_disable(jdi->supply);
> +
> +	return err;
> +}
> +
> +static int jdi_panel_enable(struct drm_panel *panel)
> +{
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +
> +	if (jdi->enabled)
> +		return 0;
> +
> +	/*
> +	 * Ensure we send image data before turning the backlight on,
> +	 * to avoid the display showing random pixels (colored snow).
> +	 */
> +	jdi_wait_frames(jdi, 3);
> +
> +	backlight_enable(jdi->backlight);
> +
> +	jdi->enabled = true;
> +
> +	return 0;
> +}
> +
> +static const struct drm_display_mode default_mode = {
> +	.clock = 331334,
> +	.hdisplay = 2560,
> +	.hsync_start = 2560 + 80,
> +	.hsync_end = 2560 + 80 + 80,
> +	.htotal = 2560 + 80 + 80 + 80,
> +	.vdisplay = 1800,
> +	.vsync_start = 1800 + 4,
> +	.vsync_end = 1800 + 4 + 4,
> +	.vtotal = 1800 + 4 + 4 + 4,
> +	.flags = 0,
> +};
> +
> +static int jdi_panel_get_modes(struct drm_panel *panel,
> +			       struct drm_connector *connector)
> +{
> +	struct drm_display_mode *mode;
> +	struct jdi_panel *jdi = to_panel_jdi(panel);
> +	struct device *dev = &jdi->link1->dev;
> +
> +	mode = drm_mode_duplicate(connector->dev, &default_mode);
> +	if (!mode) {
> +		dev_err(dev, "failed to add mode %ux%ux@%u\n",
> +			default_mode.hdisplay, default_mode.vdisplay,
> +			drm_mode_vrefresh(&default_mode));
> +		return -ENOMEM;
> +	}
> +
> +	drm_mode_set_name(mode);
> +
> +	drm_mode_probed_add(connector, mode);
> +
> +	connector->display_info.width_mm = 211;
> +	connector->display_info.height_mm = 148;
> +	connector->display_info.bpc = 8;
> +
> +	return 1;
> +}
> +
> +static const struct drm_panel_funcs jdi_panel_funcs = {
> +	.prepare = jdi_panel_prepare,
> +	.enable = jdi_panel_enable,
> +	.disable = jdi_panel_disable,
> +	.unprepare = jdi_panel_unprepare,
> +	.get_modes = jdi_panel_get_modes,
> +};
> +
> +static const struct of_device_id jdi_of_match[] = {
> +	{ .compatible = "jdi,lpm102a188a", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, jdi_of_match);
> +
> +static int jdi_panel_add(struct jdi_panel *jdi)
> +{
> +	struct device *dev = &jdi->link1->dev;
> +
> +	jdi->mode = &default_mode;
> +
> +	jdi->supply = devm_regulator_get(dev, "power");
> +	if (IS_ERR(jdi->supply))
> +		return dev_err_probe(dev, PTR_ERR(jdi->supply),
> +				     "failed to get power regulator\n");
> +
> +	jdi->ddi_supply = devm_regulator_get(dev, "ddi");
> +	if (IS_ERR(jdi->ddi_supply))
> +		return dev_err_probe(dev, PTR_ERR(jdi->ddi_supply),
> +				     "failed to get ddi regulator\n");
> +
> +	jdi->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(jdi->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(jdi->reset_gpio),
> +				     "failed to get reset gpio\n");
> +	usleep_range(1000, 3000);
> +
> +	jdi->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
> +	if (IS_ERR(jdi->enable_gpio))
> +		return dev_err_probe(dev, PTR_ERR(jdi->enable_gpio),
> +				     "failed to get enable gpio\n");
> +	usleep_range(2000, 4000);
> +
> +	jdi->backlight = devm_of_find_backlight(dev);
> +	if (IS_ERR(jdi->backlight))
> +		return dev_err_probe(dev, PTR_ERR(jdi->backlight),
> +				     "failed to create backlight\n");
> +
> +	drm_panel_init(&jdi->base, &jdi->link1->dev, &jdi_panel_funcs,
> +		       DRM_MODE_CONNECTOR_DSI);
> +
> +	drm_panel_add(&jdi->base);
> +
> +	return 0;
> +}
> +
> +static void jdi_panel_del(struct jdi_panel *jdi)
> +{
> +	if (jdi->base.dev)
> +		drm_panel_remove(&jdi->base);
> +
> +	if (jdi->link2)
> +		put_device(&jdi->link2->dev);
> +}
> +
> +static int jdi_panel_dsi_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct mipi_dsi_device *secondary = NULL;
> +	struct jdi_panel *jdi;
> +	struct device_node *np;
> +	int err;
> +
> +	dsi->lanes = 4;
> +	dsi->format = MIPI_DSI_FMT_RGB888;
> +	dsi->mode_flags = 0;
> +
> +	/* Find DSI-LINK1 */
> +	np = of_parse_phandle(dsi->dev.of_node, "link2", 0);
> +	if (np) {
> +		secondary = of_find_mipi_dsi_device_by_node(np);
> +		of_node_put(np);
> +
> +		if (!secondary)
> +			return -EPROBE_DEFER;
> +	}
> +
> +	/* register a panel for only the DSI-LINK1 interface */
> +	if (secondary) {
> +		jdi = devm_kzalloc(&dsi->dev, sizeof(*jdi), GFP_KERNEL);
> +		if (!jdi) {
> +			put_device(&secondary->dev);
> +			return -ENOMEM;
> +		}
> +
> +		mipi_dsi_set_drvdata(dsi, jdi);
> +
> +		jdi->link1 = dsi;
> +		jdi->link2 = secondary;
> +
> +		err = jdi_panel_add(jdi);
> +		if (err < 0) {
> +			put_device(&secondary->dev);
> +			return err;
> +		}
> +	}
> +
> +	err = mipi_dsi_attach(dsi);
> +	if (err < 0) {
> +		if (secondary)
> +			jdi_panel_del(jdi);
> +
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static void jdi_panel_dsi_remove(struct mipi_dsi_device *dsi)
> +{
> +	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
> +	int err;
> +
> +	/* only detach from host for the DSI-LINK2 interface */
> +	if (!jdi)
> +		mipi_dsi_detach(dsi);
> +
> +	err = jdi_panel_disable(&jdi->base);
> +	if (err < 0)
> +		dev_err(&dsi->dev, "failed to disable panel: %d\n", err);
> +
> +	err = mipi_dsi_detach(dsi);
> +	if (err < 0)
> +		dev_err(&dsi->dev, "failed to detach from DSI host: %d\n", err);
> +
> +	jdi_panel_del(jdi);
> +}
> +
> +static void jdi_panel_dsi_shutdown(struct mipi_dsi_device *dsi)
> +{
> +	struct jdi_panel *jdi = mipi_dsi_get_drvdata(dsi);
> +
> +	if (!jdi)
> +		return;
> +
> +	jdi_panel_disable(&jdi->base);
> +}
> +
> +static struct mipi_dsi_driver jdi_panel_dsi_driver = {
> +	.driver = {
> +		.name = "panel-jdi-lpm102a188a-dsi",
Is the "-dsi" suffix needed here? Other panel drivers don't have this.
> +		.of_match_table = jdi_of_match,
> +	},
> +	.probe = jdi_panel_dsi_probe,
> +	.remove = jdi_panel_dsi_remove,
> +	.shutdown = jdi_panel_dsi_shutdown,
> +};
> +module_mipi_dsi_driver(jdi_panel_dsi_driver);
> +
> +MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
> +MODULE_AUTHOR("Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>");
> +MODULE_DESCRIPTION("DRM Driver for JDI LPM102A188A DSI panel, command mode");
> +MODULE_LICENSE("GPL");

-- 
Rayyan Ansari
https://ansari.sh

Re: [v2,3/4] drm/panel: Add driver for JDI LPM102A188A

[Diogo Ivo]

Hello,

On Fri, Dec 23, 2022 at 03:33:40PM +0000, Rayyan Ansari wrote:
> On 25/10/2022 16:37, Diogo Ivo wrote:
> > +config DRM_PANEL_JDI_LPM102A188A
> > +	tristate "JDI LPM102A188A DSI panel"
> > +	depends on OF && GPIOLIB
> > +	depends on DRM_MIPI_DSI
> > +	depends on BACKLIGHT_CLASS_DEVICE
> > +	help
> > +	  Say Y here if you want to enable support for JDI LPM102A188A DSI
> > +	  control mode panel as found in Google Pixel C devices.
> Shouldn't this be "command mode panel" instead of "control mode panel"?

Yes, it should.

> > +static struct mipi_dsi_driver jdi_panel_dsi_driver = {
> > +	.driver = {
> > +		.name = "panel-jdi-lpm102a188a-dsi",
> Is the "-dsi" suffix needed here? Other panel drivers don't have this.

I had not noticed this, and I will drop it.

Thank you for your review and attention to detail. I will address these
points in the next version.

Diogo Ivo

Re: [v2,3/4] drm/panel: Add driver for JDI LPM102A188A

[Diogo Ivo]

Hello,

On Fri, Dec 23, 2022 at 03:33:40PM +0000, Rayyan Ansari wrote:
> On 25/10/2022 16:37, Diogo Ivo wrote:
> > +config DRM_PANEL_JDI_LPM102A188A
> > +	tristate "JDI LPM102A188A DSI panel"
> > +	depends on OF && GPIOLIB
> > +	depends on DRM_MIPI_DSI
> > +	depends on BACKLIGHT_CLASS_DEVICE
> > +	help
> > +	  Say Y here if you want to enable support for JDI LPM102A188A DSI
> > +	  control mode panel as found in Google Pixel C devices.
> Shouldn't this be "command mode panel" instead of "control mode panel"?

Yes, it should.

> > +static struct mipi_dsi_driver jdi_panel_dsi_driver = {
> > +	.driver = {
> > +		.name = "panel-jdi-lpm102a188a-dsi",
> Is the "-dsi" suffix needed here? Other panel drivers don't have this.

I had not noticed this, and I will drop it.

Thank you for your review and attention to detail. I will address these
points in the next version.

Diogo Ivo

Re: [PATCH v2 0/4] Add JDI LPM102A188A display panel support

[Diogo Ivo]

On Tue, Oct 25, 2022 at 04:37:43PM +0100, Diogo Ivo wrote:
> Hello,
> 
> These patches add support for the JDI LPM102A188A display panel,
> found in the Google Pixel C.
> 
> Patch 1 adds the DT bindings for the panel.
> 
> Patch 2 adds a register clear to the Tegra DSI driver, needed for the
> panel initialization commands to be properly sent.
> 
> Patch 3 adds the panel driver, which is based on the downstream
> kernel driver published by Google and developed by Sean Paul.
> 
> Patch 4 adds the DT node for the Google Pixel C. 
> 
> The first version of this patch series can be found at:
> https://lore.kernel.org/all/20220929170502.1034040-1-diogo.ivo@tecnico.ulisboa.pt/
> 
> Changes in v2:
>  - Patch 1: remove touchscreen reset gpio property
>  - Patch 2: clear register based on its value rather than a DT property
>  - Patch 3: tune backlight delay values
>  - Patch 4: add generic node names, remove underscores 
> 
Hello,

Gentle ping on this series.

Thank you,

Diogo