[PATCH v3 0/2] Add support for the AUO A030JTN01 TFT LCD

[PATCH v3 0/2] Add support for the AUO A030JTN01 TFT LCD

[Christophe Branchereau]

Changes since v2:
 - added macros for stanby mode (untested, please review @pcercuei)
 - added SPI table_id
 - changed description in the bindings to describe the hw more

---
Changes since v1: 
- fixed the dt-bindings maintainer email adress
- dropped backlight, port, power-supply and reset-gpios as they're
  provided by panel-common.yaml as pointed by Krzysztof Kozlowski
- changed reg: true to reg : maxItems: 1 

Christophe Branchereau (1):
  drm/panel: Add driver for the AUO A030JTN01 TFT LCD

Paul Cercueil (1):
  dt-bindings: display/panel: Add AUO A030JTN01

 .../bindings/display/panel/auo,a030jtn01.yaml |  54 +++
 drivers/gpu/drm/panel/Kconfig                 |   8 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-auo-a030jtn01.c   | 307 ++++++++++++++++++
 4 files changed, 370 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/auo,a030jtn01.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-auo-a030jtn01.c

-- 
2.35.1

[PATCH v3 1/2] drm/panel: Add driver for the AUO A030JTN01 TFT LCD

[Christophe Branchereau]

Add driver for the AUO A030JTN01 panel, which is a 320x480 3.0" 4:3
24-bit TFT LCD panel with non-square pixels and a delta-RGB 8-bit
interface.

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 drivers/gpu/drm/panel/Kconfig               |   8 +
 drivers/gpu/drm/panel/Makefile              |   1 +
 drivers/gpu/drm/panel/panel-auo-a030jtn01.c | 307 ++++++++++++++++++++
 3 files changed, 316 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-auo-a030jtn01.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 737edcdf9eef..23cf0f4ba2e6 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -8,6 +8,14 @@ config DRM_PANEL
 menu "Display Panels"
 	depends on DRM && DRM_PANEL
 
+config DRM_PANEL_AUO_A030JTN01
+	tristate "AUO A030JTN01"
+	depends on SPI
+	select REGMAP_SPI
+	help
+	  Say Y here to enable support for the AUO A030JTN01 320x480 3.0" panel
+	  as found in the YLM RS-97 handheld gaming console.
+
 config DRM_PANEL_ABT_Y030XX067A
 	tristate "ABT Y030XX067A 320x480 LCD panel"
 	depends on OF && SPI
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index f8f9d9f6a307..af88658abcab 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_DRM_PANEL_AUO_A030JTN01) += panel-auo-a030jtn01.o
 obj-$(CONFIG_DRM_PANEL_ABT_Y030XX067A) += panel-abt-y030xx067a.o
 obj-$(CONFIG_DRM_PANEL_ARM_VERSATILE) += panel-arm-versatile.o
 obj-$(CONFIG_DRM_PANEL_ASUS_Z00T_TM5P5_NT35596) += panel-asus-z00t-tm5p5-n35596.o
diff --git a/drivers/gpu/drm/panel/panel-auo-a030jtn01.c b/drivers/gpu/drm/panel/panel-auo-a030jtn01.c
new file mode 100644
index 000000000000..b9fc64f9e49c
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-auo-a030jtn01.c
@@ -0,0 +1,307 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AU Optronics A030JTN01.0 TFT LCD panel driver
+ *
+ * Copyright (C) 2020, Paul Cercueil <paul@crapouillou.net>
+ * Copyright (C) 2020, Christophe Branchereau <cbranchereau@gmail.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/media-bus-format.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+#define REG05		0x05
+#define REG05_STDBY	BIT(0)
+
+struct a030jtn01_info {
+	const struct drm_display_mode *display_modes;
+	unsigned int num_modes;
+	u16 width_mm, height_mm;
+	u32 bus_format, bus_flags;
+};
+
+struct a030jtn01 {
+	struct drm_panel panel;
+	struct spi_device *spi;
+	struct regmap *map;
+
+	const struct a030jtn01_info *panel_info;
+
+	struct regulator *supply;
+	struct gpio_desc *reset_gpio;
+};
+
+static inline struct a030jtn01 *to_a030jtn01(struct drm_panel *panel)
+{
+	return container_of(panel, struct a030jtn01, panel);
+}
+
+static int a030jtn01_prepare(struct drm_panel *panel)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+	struct device *dev = &priv->spi->dev;
+	int err;
+
+	err = regulator_enable(priv->supply);
+	if (err) {
+		dev_err(dev, "Failed to enable power supply: %d\n", err);
+		return err;
+	}
+
+	usleep_range(1000, 8000);
+
+	/* Reset the chip */
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	usleep_range(100, 8000);
+	gpiod_set_value_cansleep(priv->reset_gpio, 0);
+	usleep_range(2000, 8000);
+
+	/*
+	 * No idea why two writes are needed. If this write is commented,
+	 * the colors are wrong. Doesn't seem to be timing-related, since
+	 * a msleep(200) doesn't fix it.
+	 */
+	regmap_write(priv->map, 0x06, 0x00);
+
+	/* Use (24 + 6) == 0x1e as the vertical back porch */
+	err = regmap_write(priv->map, 0x06, 0x1e);
+	if (err)
+		goto err_disable_regulator;
+
+	/* Use (42 + 30) * 3 == 0xd8 as the horizontal back porch */
+	err = regmap_write(priv->map, 0x07, 0xd8);
+	if (err)
+		goto err_disable_regulator;
+
+	regmap_write(priv->map, 0x05, 0x74);
+
+	return 0;
+
+err_disable_regulator:
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	regulator_disable(priv->supply);
+	return err;
+}
+
+static int a030jtn01_unprepare(struct drm_panel *panel)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	regulator_disable(priv->supply);
+
+	return 0;
+}
+
+static int a030jtn01_enable(struct drm_panel *panel)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+	int ret;
+
+	ret = regmap_set_bits(priv->map, REG05, REG05_STDBY);
+	if (ret)
+		return ret;
+
+	/* Wait for the picture to be stable */
+	if (panel->backlight)
+		msleep(100);
+
+	return 0;
+}
+
+static int a030jtn01_disable(struct drm_panel *panel)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+
+	return regmap_clear_bits(priv->map, REG05, REG05_STDBY);
+}
+
+static int a030jtn01_get_modes(struct drm_panel *panel,
+				struct drm_connector *connector)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+	const struct a030jtn01_info *panel_info = priv->panel_info;
+	struct drm_display_mode *mode;
+	unsigned int i;
+
+	for (i = 0; i < panel_info->num_modes; i++) {
+		mode = drm_mode_duplicate(connector->dev,
+					  &panel_info->display_modes[i]);
+		if (!mode)
+			return -ENOMEM;
+
+		drm_mode_set_name(mode);
+
+		mode->type = DRM_MODE_TYPE_DRIVER;
+		if (panel_info->num_modes == 1)
+			mode->type |= DRM_MODE_TYPE_PREFERRED;
+
+		drm_mode_probed_add(connector, mode);
+	}
+
+	connector->display_info.bpc = 8;
+	connector->display_info.width_mm = panel_info->width_mm;
+	connector->display_info.height_mm = panel_info->height_mm;
+
+	drm_display_info_set_bus_formats(&connector->display_info,
+					 &panel_info->bus_format, 1);
+	connector->display_info.bus_flags = panel_info->bus_flags;
+
+	return panel_info->num_modes;
+}
+
+static const struct drm_panel_funcs a030jtn01_funcs = {
+	.prepare	= a030jtn01_prepare,
+	.unprepare	= a030jtn01_unprepare,
+	.enable		= a030jtn01_enable,
+	.disable	= a030jtn01_disable,
+	.get_modes	= a030jtn01_get_modes,
+};
+
+static bool a030jtn01_has_reg(struct device *dev, unsigned int reg)
+{
+	static const u32 a030jtn01_regs_mask = 0x001823f1fb;
+
+	return a030jtn01_regs_mask & BIT(reg);
+};
+
+static const struct regmap_config a030jtn01_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.read_flag_mask = 0x40,
+	.max_register = 0x1c,
+	.readable_reg = a030jtn01_has_reg,
+	.writeable_reg = a030jtn01_has_reg,
+};
+
+static int a030jtn01_probe(struct spi_device *spi)
+{
+	const struct spi_device_id *id = spi_get_device_id(spi);
+	struct device *dev = &spi->dev;
+	struct a030jtn01 *priv;
+	int err;
+
+	spi->mode |= SPI_MODE_3 | SPI_3WIRE;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->spi = spi;
+	spi_set_drvdata(spi, priv);
+
+	priv->map = devm_regmap_init_spi(spi, &a030jtn01_regmap_config);
+	if (IS_ERR(priv->map)) {
+		dev_err(dev, "Unable to init regmap\n");
+		return PTR_ERR(priv->map);
+	}
+
+	priv->panel_info = (const struct a030jtn01_info *) id->driver_data;
+	if (!priv->panel_info)
+		return -EINVAL;
+
+	priv->supply = devm_regulator_get(dev, "power");
+	if (IS_ERR(priv->supply)) {
+		dev_err(dev, "Failed to get power supply\n");
+		return PTR_ERR(priv->supply);
+	}
+
+	priv->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->reset_gpio)) {
+		dev_err(dev, "Failed to get reset GPIO\n");
+		return PTR_ERR(priv->reset_gpio);
+	}
+
+	drm_panel_init(&priv->panel, dev, &a030jtn01_funcs,
+		       DRM_MODE_CONNECTOR_DPI);
+
+	err = drm_panel_of_backlight(&priv->panel);
+	if (err)
+		return err;
+
+	drm_panel_add(&priv->panel);
+
+	return 0;
+}
+
+static void a030jtn01_remove(struct spi_device *spi)
+{
+	struct a030jtn01 *priv = spi_get_drvdata(spi);
+
+	drm_panel_remove(&priv->panel);
+	drm_panel_disable(&priv->panel);
+	drm_panel_unprepare(&priv->panel);
+}
+
+static const struct drm_display_mode a030jtn01_modes[] = {
+	{ /* 60 Hz */
+		.clock = 14400,
+		.hdisplay = 320,
+		.hsync_start = 320 + 8,
+		.hsync_end = 320 + 8 + 42,
+		.htotal = 320 + 8 + 42 + 30,
+		.vdisplay = 480,
+		.vsync_start = 480 + 90,
+		.vsync_end = 480 + 90 + 24,
+		.vtotal = 480 + 90 + 24 + 6,
+		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	},
+	{ /* 50 Hz */
+		.clock = 12000,
+		.hdisplay = 320,
+		.hsync_start = 320 + 8,
+		.hsync_end = 320 + 8 + 42,
+		.htotal = 320 + 8 + 42 + 30,
+		.vdisplay = 480,
+		.vsync_start = 480 + 90,
+		.vsync_end = 480 + 90 + 24,
+		.vtotal = 480 + 90 + 24 + 6,
+		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	},
+};
+
+static const struct a030jtn01_info a030jtn01_info = {
+	.display_modes = a030jtn01_modes,
+	.num_modes = ARRAY_SIZE(a030jtn01_modes),
+	.width_mm = 70,
+	.height_mm = 51,
+	.bus_format = MEDIA_BUS_FMT_RGB888_3X8_DELTA,
+	.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
+};
+
+static const struct spi_device_id a030jtn01_id[] = {
+	{ "a030jtn01", (kernel_ulong_t) &a030jtn01_info },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(spi, a030jtn01_id);
+
+static const struct of_device_id a030jtn01_of_match[] = {
+	{ .compatible = "auo,a030jtn01" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, a030jtn01_of_match);
+
+static struct spi_driver a030jtn01_driver = {
+	.driver = {
+		.name = "auo-a030jtn01",
+		.of_match_table = a030jtn01_of_match,
+	},
+	.id_table = a030jtn01_id,
+	.probe = a030jtn01_probe,
+	.remove = a030jtn01_remove,
+};
+module_spi_driver(a030jtn01_driver);
+
+MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
+MODULE_AUTHOR("Christophe Branchereau <cbranchereau@gmail.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.35.1

[PATCH v3 2/2] dt-bindings: display/panel: Add AUO A030JTN01

[Christophe Branchereau]

From: Paul Cercueil <paul@crapouillou.net>

Add binding for the AUO A030JTN01 panel, which is a 320x480 3.0" 4:3
24-bit TFT LCD panel with non-square pixels and a delta-RGB 8-bit
interface.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 .../bindings/display/panel/auo,a030jtn01.yaml | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/auo,a030jtn01.yaml

diff --git a/Documentation/devicetree/bindings/display/panel/auo,a030jtn01.yaml b/Documentation/devicetree/bindings/display/panel/auo,a030jtn01.yaml
new file mode 100644
index 000000000000..0d1e6b45b0f7
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/auo,a030jtn01.yaml
@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/auo,a030jtn01.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AUO A030JTN01 3.0" (320x480 pixels) 24-bit TFT LCD panel
+
+description: |
+  Delta RGB 8-bit panel found in some Retrogame handhelds
+
+maintainers:
+  - Paul Cercueil <paul@crapouillou.net>
+  - Christophe Branchereau <cbranchereau@gmail.com>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: auo,a030jtn01
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - power-supply
+  - reset-gpios
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    panel@0 {
+      compatible = "auo,a030jtn01";
+      reg = <0>;
+
+      spi-max-frequency = <10000000>;
+
+      reset-gpios = <&gpe 4 GPIO_ACTIVE_LOW>;
+      power-supply = <&lcd_power>;
+
+      backlight = <&backlight>;
+
+      port {
+        panel_input: endpoint {
+          remote-endpoint = <&panel_output>;
+        };
+      };
+    };
-- 
2.35.1

Re: [PATCH v3 2/2] dt-bindings: display/panel: Add AUO A030JTN01

[Rob Herring]

On Tue, 20 Dec 2022 13:01:08 +0100, Christophe Branchereau wrote:
> From: Paul Cercueil <paul@crapouillou.net>
> 
> Add binding for the AUO A030JTN01 panel, which is a 320x480 3.0" 4:3
> 24-bit TFT LCD panel with non-square pixels and a delta-RGB 8-bit
> interface.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
>  .../bindings/display/panel/auo,a030jtn01.yaml | 54 +++++++++++++++++++
>  1 file changed, 54 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/panel/auo,a030jtn01.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/display/panel/auo,a030jtn01.example.dts:22.11-21: Warning (reg_format): /example-0/panel@0:reg: property has invalid length (4 bytes) (#address-cells == 1, #size-cells == 1)
Documentation/devicetree/bindings/display/panel/auo,a030jtn01.example.dtb: Warning (pci_device_reg): Failed prerequisite 'reg_format'
Documentation/devicetree/bindings/display/panel/auo,a030jtn01.example.dtb: Warning (pci_device_bus_num): Failed prerequisite 'reg_format'
Documentation/devicetree/bindings/display/panel/auo,a030jtn01.example.dtb: Warning (simple_bus_reg): Failed prerequisite 'reg_format'
Documentation/devicetree/bindings/display/panel/auo,a030jtn01.example.dtb: Warning (i2c_bus_reg): Failed prerequisite 'reg_format'
Documentation/devicetree/bindings/display/panel/auo,a030jtn01.example.dtb: Warning (spi_bus_reg): Failed prerequisite 'reg_format'
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/display/panel/auo,a030jtn01.example.dtb: panel@0: Unevaluated properties are not allowed ('spi-max-frequency' was unexpected)
	From schema: /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/display/panel/auo,a030jtn01.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20221220120108.481554-3-cbranchereau@gmail.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH v3 2/2] dt-bindings: display/panel: Add AUO A030JTN01

[Krzysztof Kozlowski]

On 20/12/2022 13:01, Christophe Branchereau wrote:
> From: Paul Cercueil <paul@crapouillou.net>
> 
> Add binding for the AUO A030JTN01 panel, which is a 320x480 3.0" 4:3
> 24-bit TFT LCD panel with non-square pixels and a delta-RGB 8-bit
> interface.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Drop my review, code is not correct anymore and you did not test it
before sending.


Best regards,
Krzysztof

Re: [PATCH v3 1/2] drm/panel: Add driver for the AUO A030JTN01 TFT LCD

[Paul Cercueil]

Hi Christophe,

Le mardi 20 décembre 2022 à 13:01 +0100, Christophe Branchereau a
écrit :
> Add driver for the AUO A030JTN01 panel, which is a 320x480 3.0" 4:3
> 24-bit TFT LCD panel with non-square pixels and a delta-RGB 8-bit
> interface.
> 
> Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  drivers/gpu/drm/panel/Kconfig               |   8 +
>  drivers/gpu/drm/panel/Makefile              |   1 +
>  drivers/gpu/drm/panel/panel-auo-a030jtn01.c | 307
> ++++++++++++++++++++
>  3 files changed, 316 insertions(+)
>  create mode 100644 drivers/gpu/drm/panel/panel-auo-a030jtn01.c
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig
> b/drivers/gpu/drm/panel/Kconfig
> index 737edcdf9eef..23cf0f4ba2e6 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -8,6 +8,14 @@ config DRM_PANEL
>  menu "Display Panels"
>         depends on DRM && DRM_PANEL
>  
> +config DRM_PANEL_AUO_A030JTN01
> +       tristate "AUO A030JTN01"
> +       depends on SPI
> +       select REGMAP_SPI
> +       help
> +         Say Y here to enable support for the AUO A030JTN01 320x480
> 3.0" panel
> +         as found in the YLM RS-97 handheld gaming console.
> +
>  config DRM_PANEL_ABT_Y030XX067A
>         tristate "ABT Y030XX067A 320x480 LCD panel"
>         depends on OF && SPI
> diff --git a/drivers/gpu/drm/panel/Makefile
> b/drivers/gpu/drm/panel/Makefile
> index f8f9d9f6a307..af88658abcab 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -1,4 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0
> +obj-$(CONFIG_DRM_PANEL_AUO_A030JTN01) += panel-auo-a030jtn01.o
>  obj-$(CONFIG_DRM_PANEL_ABT_Y030XX067A) += panel-abt-y030xx067a.o
>  obj-$(CONFIG_DRM_PANEL_ARM_VERSATILE) += panel-arm-versatile.o
>  obj-$(CONFIG_DRM_PANEL_ASUS_Z00T_TM5P5_NT35596) += panel-asus-z00t-
> tm5p5-n35596.o
> diff --git a/drivers/gpu/drm/panel/panel-auo-a030jtn01.c
> b/drivers/gpu/drm/panel/panel-auo-a030jtn01.c
> new file mode 100644
> index 000000000000..b9fc64f9e49c
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-auo-a030jtn01.c
> @@ -0,0 +1,307 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * AU Optronics A030JTN01.0 TFT LCD panel driver
> + *
> + * Copyright (C) 2020, Paul Cercueil <paul@crapouillou.net>
> + * Copyright (C) 2020, Christophe Branchereau
> <cbranchereau@gmail.com>
> + */
> +
> +#include <linux/bits.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/media-bus-format.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +
> +#define REG05          0x05
> +#define REG05_STDBY    BIT(0)
> +
> +struct a030jtn01_info {
> +       const struct drm_display_mode *display_modes;
> +       unsigned int num_modes;
> +       u16 width_mm, height_mm;
> +       u32 bus_format, bus_flags;
> +};
> +
> +struct a030jtn01 {
> +       struct drm_panel panel;
> +       struct spi_device *spi;
> +       struct regmap *map;
> +
> +       const struct a030jtn01_info *panel_info;
> +
> +       struct regulator *supply;
> +       struct gpio_desc *reset_gpio;
> +};
> +
> +static inline struct a030jtn01 *to_a030jtn01(struct drm_panel
> *panel)
> +{
> +       return container_of(panel, struct a030jtn01, panel);
> +}
> +
> +static int a030jtn01_prepare(struct drm_panel *panel)
> +{
> +       struct a030jtn01 *priv = to_a030jtn01(panel);
> +       struct device *dev = &priv->spi->dev;
> +       int err;
> +
> +       err = regulator_enable(priv->supply);
> +       if (err) {
> +               dev_err(dev, "Failed to enable power supply: %d\n",
> err);
> +               return err;
> +       }
> +
> +       usleep_range(1000, 8000);
> +
> +       /* Reset the chip */
> +       gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +       usleep_range(100, 8000);
> +       gpiod_set_value_cansleep(priv->reset_gpio, 0);
> +       usleep_range(2000, 8000);
> +
> +       /*
> +        * No idea why two writes are needed. If this write is
> commented,
> +        * the colors are wrong. Doesn't seem to be timing-related,
> since
> +        * a msleep(200) doesn't fix it.
> +        */
> +       regmap_write(priv->map, 0x06, 0x00);
> +
> +       /* Use (24 + 6) == 0x1e as the vertical back porch */
> +       err = regmap_write(priv->map, 0x06, 0x1e);
> +       if (err)
> +               goto err_disable_regulator;
> +
> +       /* Use (42 + 30) * 3 == 0xd8 as the horizontal back porch */
> +       err = regmap_write(priv->map, 0x07, 0xd8);
> +       if (err)
> +               goto err_disable_regulator;
> +
> +       regmap_write(priv->map, 0x05, 0x74);

Do we have register names for these? It would be better with macros
than hardcoded addresses, e.g. AUO_REG_VPORCH and AUO_REG_HPORCH, with
AUO_REG_CTRL as a "generic" name for REG05.

(Besides, you actually have 'REG05' defined above and didn't use it
here)

> +
> +       return 0;
> +
> +err_disable_regulator:
> +       gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +       regulator_disable(priv->supply);
> +       return err;
> +}
> +
> +static int a030jtn01_unprepare(struct drm_panel *panel)
> +{
> +       struct a030jtn01 *priv = to_a030jtn01(panel);
> +
> +       gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +       regulator_disable(priv->supply);
> +
> +       return 0;
> +}
> +
> +static int a030jtn01_enable(struct drm_panel *panel)
> +{
> +       struct a030jtn01 *priv = to_a030jtn01(panel);
> +       int ret;
> +
> +       ret = regmap_set_bits(priv->map, REG05, REG05_STDBY);
> +       if (ret)
> +               return ret;
> +
> +       /* Wait for the picture to be stable */
> +       if (panel->backlight)
> +               msleep(100);
> +
> +       return 0;
> +}
> +
> +static int a030jtn01_disable(struct drm_panel *panel)
> +{
> +       struct a030jtn01 *priv = to_a030jtn01(panel);
> +
> +       return regmap_clear_bits(priv->map, REG05, REG05_STDBY);
> +}
> +
> +static int a030jtn01_get_modes(struct drm_panel *panel,
> +                               struct drm_connector *connector)
> +{
> +       struct a030jtn01 *priv = to_a030jtn01(panel);
> +       const struct a030jtn01_info *panel_info = priv->panel_info;
> +       struct drm_display_mode *mode;
> +       unsigned int i;
> +
> +       for (i = 0; i < panel_info->num_modes; i++) {
> +               mode = drm_mode_duplicate(connector->dev,
> +                                         &panel_info-
> >display_modes[i]);
> +               if (!mode)
> +                       return -ENOMEM;
> +
> +               drm_mode_set_name(mode);
> +
> +               mode->type = DRM_MODE_TYPE_DRIVER;
> +               if (panel_info->num_modes == 1)
> +                       mode->type |= DRM_MODE_TYPE_PREFERRED;
> +
> +               drm_mode_probed_add(connector, mode);
> +       }
> +
> +       connector->display_info.bpc = 8;
> +       connector->display_info.width_mm = panel_info->width_mm;
> +       connector->display_info.height_mm = panel_info->height_mm;
> +
> +       drm_display_info_set_bus_formats(&connector->display_info,
> +                                        &panel_info->bus_format, 1);
> +       connector->display_info.bus_flags = panel_info->bus_flags;
> +
> +       return panel_info->num_modes;
> +}
> +
> +static const struct drm_panel_funcs a030jtn01_funcs = {
> +       .prepare        = a030jtn01_prepare,
> +       .unprepare      = a030jtn01_unprepare,
> +       .enable         = a030jtn01_enable,
> +       .disable        = a030jtn01_disable,
> +       .get_modes      = a030jtn01_get_modes,
> +};
> +
> +static bool a030jtn01_has_reg(struct device *dev, unsigned int reg)
> +{
> +       static const u32 a030jtn01_regs_mask = 0x001823f1fb;
> +
> +       return a030jtn01_regs_mask & BIT(reg);
> +};
> +
> +static const struct regmap_config a030jtn01_regmap_config = {
> +       .reg_bits = 8,
> +       .val_bits = 8,
> +       .read_flag_mask = 0x40,
> +       .max_register = 0x1c,
> +       .readable_reg = a030jtn01_has_reg,
> +       .writeable_reg = a030jtn01_has_reg,
> +};
> +
> +static int a030jtn01_probe(struct spi_device *spi)
> +{
> +       const struct spi_device_id *id = spi_get_device_id(spi);
> +       struct device *dev = &spi->dev;
> +       struct a030jtn01 *priv;
> +       int err;
> +
> +       spi->mode |= SPI_MODE_3 | SPI_3WIRE;
> +
> +       priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +       if (!priv)
> +               return -ENOMEM;
> +
> +       priv->spi = spi;
> +       spi_set_drvdata(spi, priv);
> +
> +       priv->map = devm_regmap_init_spi(spi,
> &a030jtn01_regmap_config);
> +       if (IS_ERR(priv->map)) {
> +               dev_err(dev, "Unable to init regmap\n");
> +               return PTR_ERR(priv->map);

return dev_err_probe(dev, PTR_ERR(priv->map), "Unable to init regmap");

> +       }
> +
> +       priv->panel_info = (const struct a030jtn01_info *) id-
> >driver_data;

priv->panel_info = spi_get_device_match_data(spi);

Then you don't even need the 'id' variable.

> +       if (!priv->panel_info)
> +               return -EINVAL;
> +
> +       priv->supply = devm_regulator_get(dev, "power");
> +       if (IS_ERR(priv->supply)) {
> +               dev_err(dev, "Failed to get power supply\n");
> +               return PTR_ERR(priv->supply);

use dev_err_probe() here too.

> +       }
> +
> +       priv->reset_gpio = devm_gpiod_get(dev, "reset",
> GPIOD_OUT_HIGH);
> +       if (IS_ERR(priv->reset_gpio)) {
> +               dev_err(dev, "Failed to get reset GPIO\n");
> +               return PTR_ERR(priv->reset_gpio);

And here.

The rest of the driver looks good to me overall.

Cheers,
-Paul

> +       }
> +
> +       drm_panel_init(&priv->panel, dev, &a030jtn01_funcs,
> +                      DRM_MODE_CONNECTOR_DPI);
> +
> +       err = drm_panel_of_backlight(&priv->panel);
> +       if (err)
> +               return err;
> +
> +       drm_panel_add(&priv->panel);
> +
> +       return 0;
> +}
> +
> +static void a030jtn01_remove(struct spi_device *spi)
> +{
> +       struct a030jtn01 *priv = spi_get_drvdata(spi);
> +
> +       drm_panel_remove(&priv->panel);
> +       drm_panel_disable(&priv->panel);
> +       drm_panel_unprepare(&priv->panel);
> +}
> +
> +static const struct drm_display_mode a030jtn01_modes[] = {
> +       { /* 60 Hz */
> +               .clock = 14400,
> +               .hdisplay = 320,
> +               .hsync_start = 320 + 8,
> +               .hsync_end = 320 + 8 + 42,
> +               .htotal = 320 + 8 + 42 + 30,
> +               .vdisplay = 480,
> +               .vsync_start = 480 + 90,
> +               .vsync_end = 480 + 90 + 24,
> +               .vtotal = 480 + 90 + 24 + 6,
> +               .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> +       },
> +       { /* 50 Hz */
> +               .clock = 12000,
> +               .hdisplay = 320,
> +               .hsync_start = 320 + 8,
> +               .hsync_end = 320 + 8 + 42,
> +               .htotal = 320 + 8 + 42 + 30,
> +               .vdisplay = 480,
> +               .vsync_start = 480 + 90,
> +               .vsync_end = 480 + 90 + 24,
> +               .vtotal = 480 + 90 + 24 + 6,
> +               .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> +       },
> +};
> +
> +static const struct a030jtn01_info a030jtn01_info = {
> +       .display_modes = a030jtn01_modes,
> +       .num_modes = ARRAY_SIZE(a030jtn01_modes),
> +       .width_mm = 70,
> +       .height_mm = 51,
> +       .bus_format = MEDIA_BUS_FMT_RGB888_3X8_DELTA,
> +       .bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
> +};
> +
> +static const struct spi_device_id a030jtn01_id[] = {
> +       { "a030jtn01", (kernel_ulong_t) &a030jtn01_info },
> +       { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(spi, a030jtn01_id);
> +
> +static const struct of_device_id a030jtn01_of_match[] = {
> +       { .compatible = "auo,a030jtn01" },
> +       { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, a030jtn01_of_match);
> +
> +static struct spi_driver a030jtn01_driver = {
> +       .driver = {
> +               .name = "auo-a030jtn01",
> +               .of_match_table = a030jtn01_of_match,
> +       },
> +       .id_table = a030jtn01_id,
> +       .probe = a030jtn01_probe,
> +       .remove = a030jtn01_remove,
> +};
> +module_spi_driver(a030jtn01_driver);
> +
> +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
> +MODULE_AUTHOR("Christophe Branchereau <cbranchereau@gmail.com>");
> +MODULE_LICENSE("GPL v2");