[PATCH v4 0/4] Ingenic DRM bridge_atomic_enable proposal

[PATCH v4 0/4] Ingenic DRM bridge_atomic_enable proposal

[Christophe Branchereau]

v4: fix the bindings license

KR
Christophe

-----------------------

Hello, v3 :

Drop -spi in the compatible string, adjust bindings doc accordingly

KR
Christophe

------------------------

Hello, this is the v2 for my set of patches :

- use dev_err_probe() instead of dev_err() in the newvision panel
driver probe function

- add bindings documentation for the Leadtek ltk035c5444t

Cheers - Christophe

------------------------

Hello, this is a set of patches to allow the upstreaming of the
NV3052C panel found in the Anbernic RG350M mips gaming handheld.

It was never upstreamed so far due to a longstanding graphical
bug, which I propose to solve by introducing ingenic_drm_bridge_atomic_enable
in the drm driver so the CRTC can be enabled after the panel itself slept
out, and not before as it used to.

After the drm change, 2 of the existing panels have to be modified accordingly
to introduce missing .enable and .disable in their code.

Christophe Branchereau (4):
  drm/ingenic : add ingenic_drm_bridge_atomic_enable
  drm/panel: Add panel driver for NewVision NV3052C based LCDs
  drm/panel : innolux-ej030na and abt-y030xx067a : add .enable and
    .disable
  dt-bindings: display/panel: Add Leadtek ltk035c5444t

 .../display/panel/leadtek,ltk035c5444t.yaml   |  59 +++
 drivers/gpu/drm/ingenic/ingenic-drm-drv.c     |  19 +-
 drivers/gpu/drm/panel/Kconfig                 |   9 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-abt-y030xx067a.c  |  23 +-
 drivers/gpu/drm/panel/panel-innolux-ej030na.c |  31 +-
 .../gpu/drm/panel/panel-newvision-nv3052c.c   | 497 ++++++++++++++++++
 7 files changed, 627 insertions(+), 12 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-newvision-nv3052c.c

-- 
2.35.1

[PATCH v4 1/4] drm/ingenic : add ingenic_drm_bridge_atomic_enable

[Christophe Branchereau]

This allows the CRTC to be enabled after panels have slept out,
and before their display is turned on, solving a graphical bug
on the newvision nv3502c

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
---
 drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
index dcf44cb00821..51512f41263e 100644
--- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
+++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
@@ -226,6 +226,18 @@ static int ingenic_drm_update_pixclk(struct notifier_block *nb,
 	}
 }
 
+static void ingenic_drm_bridge_atomic_enable(struct drm_bridge *bridge,
+					     struct drm_bridge_state *old_bridge_state)
+{
+	struct ingenic_drm *priv = drm_device_get_priv(bridge->dev);
+
+	regmap_write(priv->map, JZ_REG_LCD_STATE, 0);
+
+	regmap_update_bits(priv->map, JZ_REG_LCD_CTRL,
+			   JZ_LCD_CTRL_ENABLE | JZ_LCD_CTRL_DISABLE,
+			   JZ_LCD_CTRL_ENABLE);
+}
+
 static void ingenic_drm_crtc_atomic_enable(struct drm_crtc *crtc,
 					   struct drm_atomic_state *state)
 {
@@ -237,17 +249,11 @@ static void ingenic_drm_crtc_atomic_enable(struct drm_crtc *crtc,
 	if (WARN_ON(IS_ERR(priv_state)))
 		return;
 
-	regmap_write(priv->map, JZ_REG_LCD_STATE, 0);
-
 	/* Set addresses of our DMA descriptor chains */
 	next_id = priv_state->use_palette ? HWDESC_PALETTE : 0;
 	regmap_write(priv->map, JZ_REG_LCD_DA0, dma_hwdesc_addr(priv, next_id));
 	regmap_write(priv->map, JZ_REG_LCD_DA1, dma_hwdesc_addr(priv, 1));
 
-	regmap_update_bits(priv->map, JZ_REG_LCD_CTRL,
-			   JZ_LCD_CTRL_ENABLE | JZ_LCD_CTRL_DISABLE,
-			   JZ_LCD_CTRL_ENABLE);
-
 	drm_crtc_vblank_on(crtc);
 }
 
@@ -968,6 +974,7 @@ static const struct drm_encoder_helper_funcs ingenic_drm_encoder_helper_funcs =
 
 static const struct drm_bridge_funcs ingenic_drm_bridge_funcs = {
 	.attach			= ingenic_drm_bridge_attach,
+	.atomic_enable		= ingenic_drm_bridge_atomic_enable,
 	.atomic_check		= ingenic_drm_bridge_atomic_check,
 	.atomic_reset		= drm_atomic_helper_bridge_reset,
 	.atomic_duplicate_state	= drm_atomic_helper_bridge_duplicate_state,
-- 
2.35.1

Re: [PATCH v4 1/4] drm/ingenic : add ingenic_drm_bridge_atomic_enable

[Paul Cercueil]

Hi Christophe,

Le ven., mars 11 2022 at 18:02:37 +0100, Christophe Branchereau 
<cbranchereau@gmail.com> a écrit :
> This allows the CRTC to be enabled after panels have slept out,
> and before their display is turned on, solving a graphical bug
> on the newvision nv3502c
> 
> Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
> ---
>  drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c 
> b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> index dcf44cb00821..51512f41263e 100644
> --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> @@ -226,6 +226,18 @@ static int ingenic_drm_update_pixclk(struct 
> notifier_block *nb,
>  	}
>  }
> 
> +static void ingenic_drm_bridge_atomic_enable(struct drm_bridge 
> *bridge,
> +					     struct drm_bridge_state *old_bridge_state)
> +{
> +	struct ingenic_drm *priv = drm_device_get_priv(bridge->dev);
> +
> +	regmap_write(priv->map, JZ_REG_LCD_STATE, 0);
> +
> +	regmap_update_bits(priv->map, JZ_REG_LCD_CTRL,
> +			   JZ_LCD_CTRL_ENABLE | JZ_LCD_CTRL_DISABLE,
> +			   JZ_LCD_CTRL_ENABLE);
> +}
> +
>  static void ingenic_drm_crtc_atomic_enable(struct drm_crtc *crtc,
>  					   struct drm_atomic_state *state)
>  {
> @@ -237,17 +249,11 @@ static void 
> ingenic_drm_crtc_atomic_enable(struct drm_crtc *crtc,
>  	if (WARN_ON(IS_ERR(priv_state)))
>  		return;
> 
> -	regmap_write(priv->map, JZ_REG_LCD_STATE, 0);
> -
>  	/* Set addresses of our DMA descriptor chains */
>  	next_id = priv_state->use_palette ? HWDESC_PALETTE : 0;
>  	regmap_write(priv->map, JZ_REG_LCD_DA0, dma_hwdesc_addr(priv, 
> next_id));
>  	regmap_write(priv->map, JZ_REG_LCD_DA1, dma_hwdesc_addr(priv, 1));
> 
> -	regmap_update_bits(priv->map, JZ_REG_LCD_CTRL,
> -			   JZ_LCD_CTRL_ENABLE | JZ_LCD_CTRL_DISABLE,
> -			   JZ_LCD_CTRL_ENABLE);
> -
>  	drm_crtc_vblank_on(crtc);
>  }
> 
> @@ -968,6 +974,7 @@ static const struct drm_encoder_helper_funcs 
> ingenic_drm_encoder_helper_funcs =
> 
>  static const struct drm_bridge_funcs ingenic_drm_bridge_funcs = {
>  	.attach			= ingenic_drm_bridge_attach,
> +	.atomic_enable		= ingenic_drm_bridge_atomic_enable,

Shouldn't we have a .atomic_disable() as well? If the CRTC is now 
enabled in the bridge's .atomic_enable, it would make sense to have it 
disabled in the .atomic_disable().

Cheers,
-Paul

>  	.atomic_check		= ingenic_drm_bridge_atomic_check,
>  	.atomic_reset		= drm_atomic_helper_bridge_reset,
>  	.atomic_duplicate_state	= drm_atomic_helper_bridge_duplicate_state,
> --
> 2.35.1
> 

[PATCH v4 2/4] drm/panel: Add panel driver for NewVision NV3052C based LCDs

[Christophe Branchereau]

This driver supports the NewVision NV3052C based LCDs. Right now, it
only supports the LeadTek LTK035C5444T 2.4" 640x480 TFT LCD panel, which
can be found in the Anbernic RG-350M handheld console.

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
---
 drivers/gpu/drm/panel/Kconfig                 |   9 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../gpu/drm/panel/panel-newvision-nv3052c.c   | 497 ++++++++++++++++++
 3 files changed, 507 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-newvision-nv3052c.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index bb2e47229c68..40084f709789 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -283,6 +283,15 @@ config DRM_PANEL_NEC_NL8048HL11
 	  panel (found on the Zoom2/3/3630 SDP boards). To compile this driver
 	  as a module, choose M here.
 
+config DRM_PANEL_NEWVISION_NV3052C
+	tristate "NewVision NV3052C RGB/SPI panel"
+	depends on OF && SPI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select DRM_MIPI_DBI
+	help
+	  Say Y here if you want to enable support for the panels built
+	  around the NewVision NV3052C display controller.
+
 config DRM_PANEL_NOVATEK_NT35510
 	tristate "Novatek NT35510 RGB panel driver"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 5740911f637c..42a7ab54234b 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK500HD1829) += panel-leadtek-ltk500hd1829.o
 obj-$(CONFIG_DRM_PANEL_LG_LB035Q02) += panel-lg-lb035q02.o
 obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
 obj-$(CONFIG_DRM_PANEL_NEC_NL8048HL11) += panel-nec-nl8048hl11.o
+obj-$(CONFIG_DRM_PANEL_NEWVISION_NV3052C) += panel-newvision-nv3052c.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35510) += panel-novatek-nt35510.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35560) += panel-novatek-nt35560.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35950) += panel-novatek-nt35950.o
diff --git a/drivers/gpu/drm/panel/panel-newvision-nv3052c.c b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
new file mode 100644
index 000000000000..fc31df0dee12
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
@@ -0,0 +1,497 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NevVision NV3052C IPS LCD panel driver
+ *
+ * Copyright (C) 2020, Paul Cercueil <paul@crapouillou.net>
+ * Copyright (C) 2022, Christophe Branchereau <cbranchereau@gmail.com>
+ */
+
+#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/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_mipi_dbi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+struct nv3052c_panel_info {
+	const struct drm_display_mode *display_modes;
+	unsigned int num_modes;
+	u16 width_mm, height_mm;
+	u32 bus_format, bus_flags;
+};
+
+struct nv3052c {
+	struct device *dev;
+	struct drm_panel panel;
+	struct mipi_dbi dbi;
+
+	const struct nv3052c_panel_info *panel_info;
+
+	struct regulator *supply;
+	struct gpio_desc *reset_gpio;
+};
+
+struct nv3052c_reg {
+	u8 cmd;
+	u8 val;
+};
+
+static const struct nv3052c_reg nv3052c_panel_regs[] = {
+	{ 0xff, 0x30 },
+	{ 0xff, 0x52 },
+	{ 0xff, 0x01 },
+	{ 0xe3, 0x00 },
+	{ 0x40, 0x00 },
+	{ 0x03, 0x40 },
+	{ 0x04, 0x00 },
+	{ 0x05, 0x03 },
+	{ 0x08, 0x00 },
+	{ 0x09, 0x07 },
+	{ 0x0a, 0x01 },
+	{ 0x0b, 0x32 },
+	{ 0x0c, 0x32 },
+	{ 0x0d, 0x0b },
+	{ 0x0e, 0x00 },
+	{ 0x23, 0xa0 },
+
+	{ 0x24, 0x0c },
+	{ 0x25, 0x06 },
+	{ 0x26, 0x14 },
+	{ 0x27, 0x14 },
+
+	{ 0x38, 0xcc },
+	{ 0x39, 0xd7 },
+	{ 0x3a, 0x4a },
+
+	{ 0x28, 0x40 },
+	{ 0x29, 0x01 },
+	{ 0x2a, 0xdf },
+	{ 0x49, 0x3c },
+	{ 0x91, 0x77 },
+	{ 0x92, 0x77 },
+	{ 0xa0, 0x55 },
+	{ 0xa1, 0x50 },
+	{ 0xa4, 0x9c },
+	{ 0xa7, 0x02 },
+	{ 0xa8, 0x01 },
+	{ 0xa9, 0x01 },
+	{ 0xaa, 0xfc },
+	{ 0xab, 0x28 },
+	{ 0xac, 0x06 },
+	{ 0xad, 0x06 },
+	{ 0xae, 0x06 },
+	{ 0xaf, 0x03 },
+	{ 0xb0, 0x08 },
+	{ 0xb1, 0x26 },
+	{ 0xb2, 0x28 },
+	{ 0xb3, 0x28 },
+	{ 0xb4, 0x33 },
+	{ 0xb5, 0x08 },
+	{ 0xb6, 0x26 },
+	{ 0xb7, 0x08 },
+	{ 0xb8, 0x26 },
+	{ 0xf0, 0x00 },
+	{ 0xf6, 0xc0 },
+
+	{ 0xff, 0x30 },
+	{ 0xff, 0x52 },
+	{ 0xff, 0x02 },
+	{ 0xb0, 0x0b },
+	{ 0xb1, 0x16 },
+	{ 0xb2, 0x17 },
+	{ 0xb3, 0x2c },
+	{ 0xb4, 0x32 },
+	{ 0xb5, 0x3b },
+	{ 0xb6, 0x29 },
+	{ 0xb7, 0x40 },
+	{ 0xb8, 0x0d },
+	{ 0xb9, 0x05 },
+	{ 0xba, 0x12 },
+	{ 0xbb, 0x10 },
+	{ 0xbc, 0x12 },
+	{ 0xbd, 0x15 },
+	{ 0xbe, 0x19 },
+	{ 0xbf, 0x0e },
+	{ 0xc0, 0x16 },
+	{ 0xc1, 0x0a },
+	{ 0xd0, 0x0c },
+	{ 0xd1, 0x17 },
+	{ 0xd2, 0x14 },
+	{ 0xd3, 0x2e },
+	{ 0xd4, 0x32 },
+	{ 0xd5, 0x3c },
+	{ 0xd6, 0x22 },
+	{ 0xd7, 0x3d },
+	{ 0xd8, 0x0d },
+	{ 0xd9, 0x07 },
+	{ 0xda, 0x13 },
+	{ 0xdb, 0x13 },
+	{ 0xdc, 0x11 },
+	{ 0xdd, 0x15 },
+	{ 0xde, 0x19 },
+	{ 0xdf, 0x10 },
+	{ 0xe0, 0x17 },
+	{ 0xe1, 0x0a },
+
+	{ 0xff, 0x30 },
+	{ 0xff, 0x52 },
+	{ 0xff, 0x03 },
+	{ 0x00, 0x2a },
+	{ 0x01, 0x2a },
+	{ 0x02, 0x2a },
+	{ 0x03, 0x2a },
+	{ 0x04, 0x61 },
+	{ 0x05, 0x80 },
+	{ 0x06, 0xc7 },
+	{ 0x07, 0x01 },
+	{ 0x08, 0x03 },
+	{ 0x09, 0x04 },
+	{ 0x70, 0x22 },
+	{ 0x71, 0x80 },
+	{ 0x30, 0x2a },
+	{ 0x31, 0x2a },
+	{ 0x32, 0x2a },
+	{ 0x33, 0x2a },
+	{ 0x34, 0x61 },
+	{ 0x35, 0xc5 },
+	{ 0x36, 0x80 },
+	{ 0x37, 0x23 },
+	{ 0x40, 0x03 },
+	{ 0x41, 0x04 },
+	{ 0x42, 0x05 },
+	{ 0x43, 0x06 },
+	{ 0x44, 0x11 },
+	{ 0x45, 0xe8 },
+	{ 0x46, 0xe9 },
+	{ 0x47, 0x11 },
+	{ 0x48, 0xea },
+	{ 0x49, 0xeb },
+	{ 0x50, 0x07 },
+	{ 0x51, 0x08 },
+	{ 0x52, 0x09 },
+	{ 0x53, 0x0a },
+	{ 0x54, 0x11 },
+	{ 0x55, 0xec },
+	{ 0x56, 0xed },
+	{ 0x57, 0x11 },
+	{ 0x58, 0xef },
+	{ 0x59, 0xf0 },
+	{ 0xb1, 0x01 },
+	{ 0xb4, 0x15 },
+	{ 0xb5, 0x16 },
+	{ 0xb6, 0x09 },
+	{ 0xb7, 0x0f },
+	{ 0xb8, 0x0d },
+	{ 0xb9, 0x0b },
+	{ 0xba, 0x00 },
+	{ 0xc7, 0x02 },
+	{ 0xca, 0x17 },
+	{ 0xcb, 0x18 },
+	{ 0xcc, 0x0a },
+	{ 0xcd, 0x10 },
+	{ 0xce, 0x0e },
+	{ 0xcf, 0x0c },
+	{ 0xd0, 0x00 },
+	{ 0x81, 0x00 },
+	{ 0x84, 0x15 },
+	{ 0x85, 0x16 },
+	{ 0x86, 0x10 },
+	{ 0x87, 0x0a },
+	{ 0x88, 0x0c },
+	{ 0x89, 0x0e },
+	{ 0x8a, 0x02 },
+	{ 0x97, 0x00 },
+	{ 0x9a, 0x17 },
+	{ 0x9b, 0x18 },
+	{ 0x9c, 0x0f },
+	{ 0x9d, 0x09 },
+	{ 0x9e, 0x0b },
+	{ 0x9f, 0x0d },
+	{ 0xa0, 0x01 },
+
+	{ 0xff, 0x30 },
+	{ 0xff, 0x52 },
+	{ 0xff, 0x02 },
+	{ 0x01, 0x01 },
+	{ 0x02, 0xda },
+	{ 0x03, 0xba },
+	{ 0x04, 0xa8 },
+	{ 0x05, 0x9a },
+	{ 0x06, 0x70 },
+	{ 0x07, 0xff },
+	{ 0x08, 0x91 },
+	{ 0x09, 0x90 },
+	{ 0x0a, 0xff },
+	{ 0x0b, 0x8f },
+	{ 0x0c, 0x60 },
+	{ 0x0d, 0x58 },
+	{ 0x0e, 0x48 },
+	{ 0x0f, 0x38 },
+	{ 0x10, 0x2b },
+
+	{ 0xff, 0x30 },
+	{ 0xff, 0x52 },
+	{ 0xff, 0x00 },
+	{ 0x36, 0x0a },
+};
+
+static inline struct nv3052c *to_nv3052c(struct drm_panel *panel)
+{
+	return container_of(panel, struct nv3052c, panel);
+}
+
+static int nv3052c_prepare(struct drm_panel *panel)
+{
+	struct nv3052c *priv = to_nv3052c(panel);
+	struct mipi_dbi *dbi = &priv->dbi;
+	unsigned int i;
+	int err;
+
+	err = regulator_enable(priv->supply);
+	if (err) {
+		dev_err(priv->dev, "Failed to enable power supply: %d\n", err);
+		return err;
+	}
+
+	/* Reset the chip */
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	usleep_range(10, 1000);
+	gpiod_set_value_cansleep(priv->reset_gpio, 0);
+	msleep(5);
+
+	for (i = 0; i < ARRAY_SIZE(nv3052c_panel_regs); i++) {
+		err = mipi_dbi_command(dbi, nv3052c_panel_regs[i].cmd,
+				       nv3052c_panel_regs[i].val);
+
+		if (err) {
+			dev_err(priv->dev, "Unable to set register: %d\n", err);
+			goto err_disable_regulator;
+		}
+	}
+
+	err = mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
+	if (err) {
+		dev_err(priv->dev, "Unable to exit sleep mode: %d\n", err);
+		goto err_disable_regulator;
+	}
+
+	return 0;
+
+err_disable_regulator:
+	regulator_disable(priv->supply);
+	return err;
+}
+
+static int nv3052c_unprepare(struct drm_panel *panel)
+{
+	struct nv3052c *priv = to_nv3052c(panel);
+	struct mipi_dbi *dbi = &priv->dbi;
+	int err;
+
+	err = mipi_dbi_command(dbi, MIPI_DCS_ENTER_SLEEP_MODE);
+	if (err) {
+		dev_err(priv->dev, "Unable to enter sleep mode: %d\n", err);
+		return err;
+	}
+
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	regulator_disable(priv->supply);
+
+	return 0;
+}
+
+static int nv3052c_enable(struct drm_panel *panel)
+{
+	struct nv3052c *priv = to_nv3052c(panel);
+	struct mipi_dbi *dbi = &priv->dbi;
+	int err;
+
+	err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
+	if (err) {
+		dev_err(priv->dev, "Unable to enable display: %d\n", err);
+		return err;
+	}
+
+	if (panel->backlight) {
+		/* Wait for the picture to be ready before enabling backlight */
+		msleep(120);
+	}
+
+	return 0;
+}
+
+static int nv3052c_disable(struct drm_panel *panel)
+{
+	struct nv3052c *priv = to_nv3052c(panel);
+	struct mipi_dbi *dbi = &priv->dbi;
+	int err;
+
+	err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
+	if (err) {
+		dev_err(priv->dev, "Unable to disable display: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static int nv3052c_get_modes(struct drm_panel *panel,
+			     struct drm_connector *connector)
+{
+	struct nv3052c *priv = to_nv3052c(panel);
+	const struct nv3052c_panel_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 nv3052c_funcs = {
+	.prepare	= nv3052c_prepare,
+	.unprepare	= nv3052c_unprepare,
+	.enable		= nv3052c_enable,
+	.disable	= nv3052c_disable,
+	.get_modes	= nv3052c_get_modes,
+};
+
+static int nv3052c_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct nv3052c *priv;
+	int err;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+
+	priv->panel_info = of_device_get_match_data(dev);
+	if (!priv->panel_info)
+		return -EINVAL;
+
+	priv->supply = devm_regulator_get(dev, "power");
+	if (IS_ERR(priv->supply))
+		return dev_err_probe(dev, PTR_ERR(priv->supply), "Failed to get power supply\n");
+
+	priv->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(priv->reset_gpio), "Failed to get reset GPIO\n");
+
+	err = mipi_dbi_spi_init(spi, &priv->dbi, NULL);
+	if (err)
+		return dev_err_probe(dev, err, "MIPI DBI init failed\n");
+
+	priv->dbi.read_commands = NULL;
+
+	spi_set_drvdata(spi, priv);
+
+	drm_panel_init(&priv->panel, dev, &nv3052c_funcs,
+		       DRM_MODE_CONNECTOR_DPI);
+
+	err = drm_panel_of_backlight(&priv->panel);
+	if (err)
+		return dev_err_probe(dev, err, "Failed to attach backlight\n");
+
+	drm_panel_add(&priv->panel);
+
+	return 0;
+}
+
+static int nv3052c_remove(struct spi_device *spi)
+{
+	struct nv3052c *priv = spi_get_drvdata(spi);
+
+	drm_panel_remove(&priv->panel);
+	drm_panel_disable(&priv->panel);
+	drm_panel_unprepare(&priv->panel);
+
+	return 0;
+}
+
+static const struct drm_display_mode ltk035c5444t_modes[] = {
+	{ /* 60 Hz */
+		.clock = 24000,
+		.hdisplay = 640,
+		.hsync_start = 640 + 96,
+		.hsync_end = 640 + 96 + 16,
+		.htotal = 640 + 96 + 16 + 48,
+		.vdisplay = 480,
+		.vsync_start = 480 + 5,
+		.vsync_end = 480 + 5 + 2,
+		.vtotal = 480 + 5 + 2 + 13,
+		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	},
+	{ /* 50 Hz */
+		.clock = 18000,
+		.hdisplay = 640,
+		.hsync_start = 640 + 39,
+		.hsync_end = 640 + 39 + 2,
+		.htotal = 640 + 39 + 2 + 39,
+		.vdisplay = 480,
+		.vsync_start = 480 + 5,
+		.vsync_end = 480 + 5 + 2,
+		.vtotal = 480 + 5 + 2 + 13,
+		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	},
+};
+
+static const struct nv3052c_panel_info ltk035c5444t_panel_info = {
+	.display_modes = ltk035c5444t_modes,
+	.num_modes = ARRAY_SIZE(ltk035c5444t_modes),
+	.width_mm = 77,
+	.height_mm = 64,
+	.bus_format = MEDIA_BUS_FMT_RGB888_1X24,
+	.bus_flags = DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
+};
+
+static const struct of_device_id nv3052c_of_match[] = {
+	{ .compatible = "leadtek,ltk035c5444t", .data = &ltk035c5444t_panel_info },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, nv3052c_of_match);
+
+static struct spi_driver nv3052c_driver = {
+	.driver = {
+		.name = "nv3052c",
+		.of_match_table = nv3052c_of_match,
+	},
+	.probe = nv3052c_probe,
+	.remove = nv3052c_remove,
+};
+module_spi_driver(nv3052c_driver);
+
+MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
+MODULE_AUTHOR("Christophe Branchereau <cbranchereau@gmail.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.35.1

Re: [PATCH v4 2/4] drm/panel: Add panel driver for NewVision NV3052C based LCDs

[Paul Cercueil]

Hi Christophe,

Le ven., mars 11 2022 at 18:02:38 +0100, Christophe Branchereau 
<cbranchereau@gmail.com> a écrit :
> This driver supports the NewVision NV3052C based LCDs. Right now, it
> only supports the LeadTek LTK035C5444T 2.4" 640x480 TFT LCD panel, 
> which
> can be found in the Anbernic RG-350M handheld console.
> 
> Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
> ---
>  drivers/gpu/drm/panel/Kconfig                 |   9 +
>  drivers/gpu/drm/panel/Makefile                |   1 +
>  .../gpu/drm/panel/panel-newvision-nv3052c.c   | 497 
> ++++++++++++++++++
>  3 files changed, 507 insertions(+)
>  create mode 100644 drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig 
> b/drivers/gpu/drm/panel/Kconfig
> index bb2e47229c68..40084f709789 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -283,6 +283,15 @@ config DRM_PANEL_NEC_NL8048HL11
>  	  panel (found on the Zoom2/3/3630 SDP boards). To compile this 
> driver
>  	  as a module, choose M here.
> 
> +config DRM_PANEL_NEWVISION_NV3052C
> +	tristate "NewVision NV3052C RGB/SPI panel"
> +	depends on OF && SPI
> +	depends on BACKLIGHT_CLASS_DEVICE
> +	select DRM_MIPI_DBI
> +	help
> +	  Say Y here if you want to enable support for the panels built
> +	  around the NewVision NV3052C display controller.
> +
>  config DRM_PANEL_NOVATEK_NT35510
>  	tristate "Novatek NT35510 RGB panel driver"
>  	depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile 
> b/drivers/gpu/drm/panel/Makefile
> index 5740911f637c..42a7ab54234b 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK500HD1829) += 
> panel-leadtek-ltk500hd1829.o
>  obj-$(CONFIG_DRM_PANEL_LG_LB035Q02) += panel-lg-lb035q02.o
>  obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
>  obj-$(CONFIG_DRM_PANEL_NEC_NL8048HL11) += panel-nec-nl8048hl11.o
> +obj-$(CONFIG_DRM_PANEL_NEWVISION_NV3052C) += 
> panel-newvision-nv3052c.o
>  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35510) += panel-novatek-nt35510.o
>  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35560) += panel-novatek-nt35560.o
>  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35950) += panel-novatek-nt35950.o
> diff --git a/drivers/gpu/drm/panel/panel-newvision-nv3052c.c 
> b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> new file mode 100644
> index 000000000000..fc31df0dee12
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> @@ -0,0 +1,497 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * NevVision NV3052C IPS LCD panel driver

NewVision*

> + *
> + * Copyright (C) 2020, Paul Cercueil <paul@crapouillou.net>
> + * Copyright (C) 2022, Christophe Branchereau 
> <cbranchereau@gmail.com>
> + */
> +
> +#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/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +
> +#include <video/mipi_display.h>
> +
> +#include <drm/drm_mipi_dbi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +
> +struct nv3052c_panel_info {
> +	const struct drm_display_mode *display_modes;
> +	unsigned int num_modes;
> +	u16 width_mm, height_mm;
> +	u32 bus_format, bus_flags;
> +};
> +
> +struct nv3052c {
> +	struct device *dev;
> +	struct drm_panel panel;
> +	struct mipi_dbi dbi;
> +
> +	const struct nv3052c_panel_info *panel_info;
> +
> +	struct regulator *supply;
> +	struct gpio_desc *reset_gpio;
> +};
> +
> +struct nv3052c_reg {
> +	u8 cmd;
> +	u8 val;
> +};
> +
> +static const struct nv3052c_reg nv3052c_panel_regs[] = {
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x01 },
> +	{ 0xe3, 0x00 },
> +	{ 0x40, 0x00 },
> +	{ 0x03, 0x40 },
> +	{ 0x04, 0x00 },
> +	{ 0x05, 0x03 },
> +	{ 0x08, 0x00 },
> +	{ 0x09, 0x07 },
> +	{ 0x0a, 0x01 },
> +	{ 0x0b, 0x32 },
> +	{ 0x0c, 0x32 },
> +	{ 0x0d, 0x0b },
> +	{ 0x0e, 0x00 },
> +	{ 0x23, 0xa0 },
> +
> +	{ 0x24, 0x0c },
> +	{ 0x25, 0x06 },
> +	{ 0x26, 0x14 },
> +	{ 0x27, 0x14 },
> +
> +	{ 0x38, 0xcc },
> +	{ 0x39, 0xd7 },
> +	{ 0x3a, 0x4a },
> +
> +	{ 0x28, 0x40 },
> +	{ 0x29, 0x01 },
> +	{ 0x2a, 0xdf },
> +	{ 0x49, 0x3c },
> +	{ 0x91, 0x77 },
> +	{ 0x92, 0x77 },
> +	{ 0xa0, 0x55 },
> +	{ 0xa1, 0x50 },
> +	{ 0xa4, 0x9c },
> +	{ 0xa7, 0x02 },
> +	{ 0xa8, 0x01 },
> +	{ 0xa9, 0x01 },
> +	{ 0xaa, 0xfc },
> +	{ 0xab, 0x28 },
> +	{ 0xac, 0x06 },
> +	{ 0xad, 0x06 },
> +	{ 0xae, 0x06 },
> +	{ 0xaf, 0x03 },
> +	{ 0xb0, 0x08 },
> +	{ 0xb1, 0x26 },
> +	{ 0xb2, 0x28 },
> +	{ 0xb3, 0x28 },
> +	{ 0xb4, 0x33 },
> +	{ 0xb5, 0x08 },
> +	{ 0xb6, 0x26 },
> +	{ 0xb7, 0x08 },
> +	{ 0xb8, 0x26 },
> +	{ 0xf0, 0x00 },
> +	{ 0xf6, 0xc0 },
> +
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x02 },
> +	{ 0xb0, 0x0b },
> +	{ 0xb1, 0x16 },
> +	{ 0xb2, 0x17 },
> +	{ 0xb3, 0x2c },
> +	{ 0xb4, 0x32 },
> +	{ 0xb5, 0x3b },
> +	{ 0xb6, 0x29 },
> +	{ 0xb7, 0x40 },
> +	{ 0xb8, 0x0d },
> +	{ 0xb9, 0x05 },
> +	{ 0xba, 0x12 },
> +	{ 0xbb, 0x10 },
> +	{ 0xbc, 0x12 },
> +	{ 0xbd, 0x15 },
> +	{ 0xbe, 0x19 },
> +	{ 0xbf, 0x0e },
> +	{ 0xc0, 0x16 },
> +	{ 0xc1, 0x0a },
> +	{ 0xd0, 0x0c },
> +	{ 0xd1, 0x17 },
> +	{ 0xd2, 0x14 },
> +	{ 0xd3, 0x2e },
> +	{ 0xd4, 0x32 },
> +	{ 0xd5, 0x3c },
> +	{ 0xd6, 0x22 },
> +	{ 0xd7, 0x3d },
> +	{ 0xd8, 0x0d },
> +	{ 0xd9, 0x07 },
> +	{ 0xda, 0x13 },
> +	{ 0xdb, 0x13 },
> +	{ 0xdc, 0x11 },
> +	{ 0xdd, 0x15 },
> +	{ 0xde, 0x19 },
> +	{ 0xdf, 0x10 },
> +	{ 0xe0, 0x17 },
> +	{ 0xe1, 0x0a },
> +
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x03 },
> +	{ 0x00, 0x2a },
> +	{ 0x01, 0x2a },
> +	{ 0x02, 0x2a },
> +	{ 0x03, 0x2a },
> +	{ 0x04, 0x61 },
> +	{ 0x05, 0x80 },
> +	{ 0x06, 0xc7 },
> +	{ 0x07, 0x01 },
> +	{ 0x08, 0x03 },
> +	{ 0x09, 0x04 },
> +	{ 0x70, 0x22 },
> +	{ 0x71, 0x80 },
> +	{ 0x30, 0x2a },
> +	{ 0x31, 0x2a },
> +	{ 0x32, 0x2a },
> +	{ 0x33, 0x2a },
> +	{ 0x34, 0x61 },
> +	{ 0x35, 0xc5 },
> +	{ 0x36, 0x80 },
> +	{ 0x37, 0x23 },
> +	{ 0x40, 0x03 },
> +	{ 0x41, 0x04 },
> +	{ 0x42, 0x05 },
> +	{ 0x43, 0x06 },
> +	{ 0x44, 0x11 },
> +	{ 0x45, 0xe8 },
> +	{ 0x46, 0xe9 },
> +	{ 0x47, 0x11 },
> +	{ 0x48, 0xea },
> +	{ 0x49, 0xeb },
> +	{ 0x50, 0x07 },
> +	{ 0x51, 0x08 },
> +	{ 0x52, 0x09 },
> +	{ 0x53, 0x0a },
> +	{ 0x54, 0x11 },
> +	{ 0x55, 0xec },
> +	{ 0x56, 0xed },
> +	{ 0x57, 0x11 },
> +	{ 0x58, 0xef },
> +	{ 0x59, 0xf0 },
> +	{ 0xb1, 0x01 },
> +	{ 0xb4, 0x15 },
> +	{ 0xb5, 0x16 },
> +	{ 0xb6, 0x09 },
> +	{ 0xb7, 0x0f },
> +	{ 0xb8, 0x0d },
> +	{ 0xb9, 0x0b },
> +	{ 0xba, 0x00 },
> +	{ 0xc7, 0x02 },
> +	{ 0xca, 0x17 },
> +	{ 0xcb, 0x18 },
> +	{ 0xcc, 0x0a },
> +	{ 0xcd, 0x10 },
> +	{ 0xce, 0x0e },
> +	{ 0xcf, 0x0c },
> +	{ 0xd0, 0x00 },
> +	{ 0x81, 0x00 },
> +	{ 0x84, 0x15 },
> +	{ 0x85, 0x16 },
> +	{ 0x86, 0x10 },
> +	{ 0x87, 0x0a },
> +	{ 0x88, 0x0c },
> +	{ 0x89, 0x0e },
> +	{ 0x8a, 0x02 },
> +	{ 0x97, 0x00 },
> +	{ 0x9a, 0x17 },
> +	{ 0x9b, 0x18 },
> +	{ 0x9c, 0x0f },
> +	{ 0x9d, 0x09 },
> +	{ 0x9e, 0x0b },
> +	{ 0x9f, 0x0d },
> +	{ 0xa0, 0x01 },
> +
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x02 },
> +	{ 0x01, 0x01 },
> +	{ 0x02, 0xda },
> +	{ 0x03, 0xba },
> +	{ 0x04, 0xa8 },
> +	{ 0x05, 0x9a },
> +	{ 0x06, 0x70 },
> +	{ 0x07, 0xff },
> +	{ 0x08, 0x91 },
> +	{ 0x09, 0x90 },
> +	{ 0x0a, 0xff },
> +	{ 0x0b, 0x8f },
> +	{ 0x0c, 0x60 },
> +	{ 0x0d, 0x58 },
> +	{ 0x0e, 0x48 },
> +	{ 0x0f, 0x38 },
> +	{ 0x10, 0x2b },
> +
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x00 },
> +	{ 0x36, 0x0a },
> +};
> +
> +static inline struct nv3052c *to_nv3052c(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct nv3052c, panel);
> +}
> +
> +static int nv3052c_prepare(struct drm_panel *panel)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	struct mipi_dbi *dbi = &priv->dbi;
> +	unsigned int i;
> +	int err;
> +
> +	err = regulator_enable(priv->supply);
> +	if (err) {
> +		dev_err(priv->dev, "Failed to enable power supply: %d\n", err);
> +		return err;
> +	}
> +
> +	/* Reset the chip */
> +	gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +	usleep_range(10, 1000);
> +	gpiod_set_value_cansleep(priv->reset_gpio, 0);
> +	msleep(5);
> +
> +	for (i = 0; i < ARRAY_SIZE(nv3052c_panel_regs); i++) {
> +		err = mipi_dbi_command(dbi, nv3052c_panel_regs[i].cmd,
> +				       nv3052c_panel_regs[i].val);
> +
> +		if (err) {
> +			dev_err(priv->dev, "Unable to set register: %d\n", err);
> +			goto err_disable_regulator;
> +		}
> +	}
> +
> +	err = mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
> +	if (err) {
> +		dev_err(priv->dev, "Unable to exit sleep mode: %d\n", err);
> +		goto err_disable_regulator;
> +	}
> +
> +	return 0;
> +
> +err_disable_regulator:
> +	regulator_disable(priv->supply);
> +	return err;
> +}
> +
> +static int nv3052c_unprepare(struct drm_panel *panel)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	struct mipi_dbi *dbi = &priv->dbi;
> +	int err;
> +
> +	err = mipi_dbi_command(dbi, MIPI_DCS_ENTER_SLEEP_MODE);
> +	if (err) {
> +		dev_err(priv->dev, "Unable to enter sleep mode: %d\n", err);
> +		return err;
> +	}
> +
> +	gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +	regulator_disable(priv->supply);
> +
> +	return 0;
> +}
> +
> +static int nv3052c_enable(struct drm_panel *panel)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	struct mipi_dbi *dbi = &priv->dbi;
> +	int err;
> +
> +	err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
> +	if (err) {
> +		dev_err(priv->dev, "Unable to enable display: %d\n", err);
> +		return err;
> +	}
> +
> +	if (panel->backlight) {
> +		/* Wait for the picture to be ready before enabling backlight */
> +		msleep(120);

 From my own test this msleep can go. Modesets don't seem to cause any 
graphical glitches.

The driver looks fine to me overall, I just need somebody else (Sam?) 
to ack it before I can merge it.

Cheers,
-Paul

> +	}
> +
> +	return 0;
> +}
> +
> +static int nv3052c_disable(struct drm_panel *panel)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	struct mipi_dbi *dbi = &priv->dbi;
> +	int err;
> +
> +	err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
> +	if (err) {
> +		dev_err(priv->dev, "Unable to disable display: %d\n", err);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int nv3052c_get_modes(struct drm_panel *panel,
> +			     struct drm_connector *connector)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	const struct nv3052c_panel_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 nv3052c_funcs = {
> +	.prepare	= nv3052c_prepare,
> +	.unprepare	= nv3052c_unprepare,
> +	.enable		= nv3052c_enable,
> +	.disable	= nv3052c_disable,
> +	.get_modes	= nv3052c_get_modes,
> +};
> +
> +static int nv3052c_probe(struct spi_device *spi)
> +{
> +	struct device *dev = &spi->dev;
> +	struct nv3052c *priv;
> +	int err;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = dev;
> +
> +	priv->panel_info = of_device_get_match_data(dev);
> +	if (!priv->panel_info)
> +		return -EINVAL;
> +
> +	priv->supply = devm_regulator_get(dev, "power");
> +	if (IS_ERR(priv->supply))
> +		return dev_err_probe(dev, PTR_ERR(priv->supply), "Failed to get 
> power supply\n");
> +
> +	priv->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(priv->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(priv->reset_gpio), "Failed to 
> get reset GPIO\n");
> +
> +	err = mipi_dbi_spi_init(spi, &priv->dbi, NULL);
> +	if (err)
> +		return dev_err_probe(dev, err, "MIPI DBI init failed\n");
> +
> +	priv->dbi.read_commands = NULL;
> +
> +	spi_set_drvdata(spi, priv);
> +
> +	drm_panel_init(&priv->panel, dev, &nv3052c_funcs,
> +		       DRM_MODE_CONNECTOR_DPI);
> +
> +	err = drm_panel_of_backlight(&priv->panel);
> +	if (err)
> +		return dev_err_probe(dev, err, "Failed to attach backlight\n");
> +
> +	drm_panel_add(&priv->panel);
> +
> +	return 0;
> +}
> +
> +static int nv3052c_remove(struct spi_device *spi)
> +{
> +	struct nv3052c *priv = spi_get_drvdata(spi);
> +
> +	drm_panel_remove(&priv->panel);
> +	drm_panel_disable(&priv->panel);
> +	drm_panel_unprepare(&priv->panel);
> +
> +	return 0;
> +}
> +
> +static const struct drm_display_mode ltk035c5444t_modes[] = {
> +	{ /* 60 Hz */
> +		.clock = 24000,
> +		.hdisplay = 640,
> +		.hsync_start = 640 + 96,
> +		.hsync_end = 640 + 96 + 16,
> +		.htotal = 640 + 96 + 16 + 48,
> +		.vdisplay = 480,
> +		.vsync_start = 480 + 5,
> +		.vsync_end = 480 + 5 + 2,
> +		.vtotal = 480 + 5 + 2 + 13,
> +		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> +	},
> +	{ /* 50 Hz */
> +		.clock = 18000,
> +		.hdisplay = 640,
> +		.hsync_start = 640 + 39,
> +		.hsync_end = 640 + 39 + 2,
> +		.htotal = 640 + 39 + 2 + 39,
> +		.vdisplay = 480,
> +		.vsync_start = 480 + 5,
> +		.vsync_end = 480 + 5 + 2,
> +		.vtotal = 480 + 5 + 2 + 13,
> +		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> +	},
> +};
> +
> +static const struct nv3052c_panel_info ltk035c5444t_panel_info = {
> +	.display_modes = ltk035c5444t_modes,
> +	.num_modes = ARRAY_SIZE(ltk035c5444t_modes),
> +	.width_mm = 77,
> +	.height_mm = 64,
> +	.bus_format = MEDIA_BUS_FMT_RGB888_1X24,
> +	.bus_flags = DRM_BUS_FLAG_DE_HIGH | 
> DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
> +};
> +
> +static const struct of_device_id nv3052c_of_match[] = {
> +	{ .compatible = "leadtek,ltk035c5444t", .data = 
> &ltk035c5444t_panel_info },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, nv3052c_of_match);
> +
> +static struct spi_driver nv3052c_driver = {
> +	.driver = {
> +		.name = "nv3052c",
> +		.of_match_table = nv3052c_of_match,
> +	},
> +	.probe = nv3052c_probe,
> +	.remove = nv3052c_remove,
> +};
> +module_spi_driver(nv3052c_driver);
> +
> +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
> +MODULE_AUTHOR("Christophe Branchereau <cbranchereau@gmail.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.35.1
> 

Re: [PATCH v4 2/4] drm/panel: Add panel driver for NewVision NV3052C based LCDs

[Christophe Branchereau]

Hi Paul

On Mon, Mar 14, 2022 at 8:54 PM Paul Cercueil <paul@crapouillou.net> wrote:
>
> Hi Christophe,
>
> Le ven., mars 11 2022 at 18:02:38 +0100, Christophe Branchereau
> <cbranchereau@gmail.com> a écrit :
> > This driver supports the NewVision NV3052C based LCDs. Right now, it
> > only supports the LeadTek LTK035C5444T 2.4" 640x480 TFT LCD panel,
> > which
> > can be found in the Anbernic RG-350M handheld console.
> >
> > Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
> > ---
> >  drivers/gpu/drm/panel/Kconfig                 |   9 +
> >  drivers/gpu/drm/panel/Makefile                |   1 +
> >  .../gpu/drm/panel/panel-newvision-nv3052c.c   | 497
> > ++++++++++++++++++
> >  3 files changed, 507 insertions(+)
> >  create mode 100644 drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> >
> > diff --git a/drivers/gpu/drm/panel/Kconfig
> > b/drivers/gpu/drm/panel/Kconfig
> > index bb2e47229c68..40084f709789 100644
> > --- a/drivers/gpu/drm/panel/Kconfig
> > +++ b/drivers/gpu/drm/panel/Kconfig
> > @@ -283,6 +283,15 @@ config DRM_PANEL_NEC_NL8048HL11
> >         panel (found on the Zoom2/3/3630 SDP boards). To compile this
> > driver
> >         as a module, choose M here.
> >
> > +config DRM_PANEL_NEWVISION_NV3052C
> > +     tristate "NewVision NV3052C RGB/SPI panel"
> > +     depends on OF && SPI
> > +     depends on BACKLIGHT_CLASS_DEVICE
> > +     select DRM_MIPI_DBI
> > +     help
> > +       Say Y here if you want to enable support for the panels built
> > +       around the NewVision NV3052C display controller.
> > +
> >  config DRM_PANEL_NOVATEK_NT35510
> >       tristate "Novatek NT35510 RGB panel driver"
> >       depends on OF
> > diff --git a/drivers/gpu/drm/panel/Makefile
> > b/drivers/gpu/drm/panel/Makefile
> > index 5740911f637c..42a7ab54234b 100644
> > --- a/drivers/gpu/drm/panel/Makefile
> > +++ b/drivers/gpu/drm/panel/Makefile
> > @@ -26,6 +26,7 @@ obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK500HD1829) +=
> > panel-leadtek-ltk500hd1829.o
> >  obj-$(CONFIG_DRM_PANEL_LG_LB035Q02) += panel-lg-lb035q02.o
> >  obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
> >  obj-$(CONFIG_DRM_PANEL_NEC_NL8048HL11) += panel-nec-nl8048hl11.o
> > +obj-$(CONFIG_DRM_PANEL_NEWVISION_NV3052C) +=
> > panel-newvision-nv3052c.o
> >  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35510) += panel-novatek-nt35510.o
> >  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35560) += panel-novatek-nt35560.o
> >  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35950) += panel-novatek-nt35950.o
> > diff --git a/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> > b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> > new file mode 100644
> > index 000000000000..fc31df0dee12
> > --- /dev/null
> > +++ b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> > @@ -0,0 +1,497 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * NevVision NV3052C IPS LCD panel driver
>
> NewVision*
>
> > + *
> > + * Copyright (C) 2020, Paul Cercueil <paul@crapouillou.net>
> > + * Copyright (C) 2022, Christophe Branchereau
> > <cbranchereau@gmail.com>
> > + */
> > +
> > +#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/regulator/consumer.h>
> > +#include <linux/spi/spi.h>
> > +
> > +#include <video/mipi_display.h>
> > +
> > +#include <drm/drm_mipi_dbi.h>
> > +#include <drm/drm_modes.h>
> > +#include <drm/drm_panel.h>
> > +
> > +struct nv3052c_panel_info {
> > +     const struct drm_display_mode *display_modes;
> > +     unsigned int num_modes;
> > +     u16 width_mm, height_mm;
> > +     u32 bus_format, bus_flags;
> > +};
> > +
> > +struct nv3052c {
> > +     struct device *dev;
> > +     struct drm_panel panel;
> > +     struct mipi_dbi dbi;
> > +
> > +     const struct nv3052c_panel_info *panel_info;
> > +
> > +     struct regulator *supply;
> > +     struct gpio_desc *reset_gpio;
> > +};
> > +
> > +struct nv3052c_reg {
> > +     u8 cmd;
> > +     u8 val;
> > +};
> > +
> > +static const struct nv3052c_reg nv3052c_panel_regs[] = {
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x01 },
> > +     { 0xe3, 0x00 },
> > +     { 0x40, 0x00 },
> > +     { 0x03, 0x40 },
> > +     { 0x04, 0x00 },
> > +     { 0x05, 0x03 },
> > +     { 0x08, 0x00 },
> > +     { 0x09, 0x07 },
> > +     { 0x0a, 0x01 },
> > +     { 0x0b, 0x32 },
> > +     { 0x0c, 0x32 },
> > +     { 0x0d, 0x0b },
> > +     { 0x0e, 0x00 },
> > +     { 0x23, 0xa0 },
> > +
> > +     { 0x24, 0x0c },
> > +     { 0x25, 0x06 },
> > +     { 0x26, 0x14 },
> > +     { 0x27, 0x14 },
> > +
> > +     { 0x38, 0xcc },
> > +     { 0x39, 0xd7 },
> > +     { 0x3a, 0x4a },
> > +
> > +     { 0x28, 0x40 },
> > +     { 0x29, 0x01 },
> > +     { 0x2a, 0xdf },
> > +     { 0x49, 0x3c },
> > +     { 0x91, 0x77 },
> > +     { 0x92, 0x77 },
> > +     { 0xa0, 0x55 },
> > +     { 0xa1, 0x50 },
> > +     { 0xa4, 0x9c },
> > +     { 0xa7, 0x02 },
> > +     { 0xa8, 0x01 },
> > +     { 0xa9, 0x01 },
> > +     { 0xaa, 0xfc },
> > +     { 0xab, 0x28 },
> > +     { 0xac, 0x06 },
> > +     { 0xad, 0x06 },
> > +     { 0xae, 0x06 },
> > +     { 0xaf, 0x03 },
> > +     { 0xb0, 0x08 },
> > +     { 0xb1, 0x26 },
> > +     { 0xb2, 0x28 },
> > +     { 0xb3, 0x28 },
> > +     { 0xb4, 0x33 },
> > +     { 0xb5, 0x08 },
> > +     { 0xb6, 0x26 },
> > +     { 0xb7, 0x08 },
> > +     { 0xb8, 0x26 },
> > +     { 0xf0, 0x00 },
> > +     { 0xf6, 0xc0 },
> > +
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x02 },
> > +     { 0xb0, 0x0b },
> > +     { 0xb1, 0x16 },
> > +     { 0xb2, 0x17 },
> > +     { 0xb3, 0x2c },
> > +     { 0xb4, 0x32 },
> > +     { 0xb5, 0x3b },
> > +     { 0xb6, 0x29 },
> > +     { 0xb7, 0x40 },
> > +     { 0xb8, 0x0d },
> > +     { 0xb9, 0x05 },
> > +     { 0xba, 0x12 },
> > +     { 0xbb, 0x10 },
> > +     { 0xbc, 0x12 },
> > +     { 0xbd, 0x15 },
> > +     { 0xbe, 0x19 },
> > +     { 0xbf, 0x0e },
> > +     { 0xc0, 0x16 },
> > +     { 0xc1, 0x0a },
> > +     { 0xd0, 0x0c },
> > +     { 0xd1, 0x17 },
> > +     { 0xd2, 0x14 },
> > +     { 0xd3, 0x2e },
> > +     { 0xd4, 0x32 },
> > +     { 0xd5, 0x3c },
> > +     { 0xd6, 0x22 },
> > +     { 0xd7, 0x3d },
> > +     { 0xd8, 0x0d },
> > +     { 0xd9, 0x07 },
> > +     { 0xda, 0x13 },
> > +     { 0xdb, 0x13 },
> > +     { 0xdc, 0x11 },
> > +     { 0xdd, 0x15 },
> > +     { 0xde, 0x19 },
> > +     { 0xdf, 0x10 },
> > +     { 0xe0, 0x17 },
> > +     { 0xe1, 0x0a },
> > +
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x03 },
> > +     { 0x00, 0x2a },
> > +     { 0x01, 0x2a },
> > +     { 0x02, 0x2a },
> > +     { 0x03, 0x2a },
> > +     { 0x04, 0x61 },
> > +     { 0x05, 0x80 },
> > +     { 0x06, 0xc7 },
> > +     { 0x07, 0x01 },
> > +     { 0x08, 0x03 },
> > +     { 0x09, 0x04 },
> > +     { 0x70, 0x22 },
> > +     { 0x71, 0x80 },
> > +     { 0x30, 0x2a },
> > +     { 0x31, 0x2a },
> > +     { 0x32, 0x2a },
> > +     { 0x33, 0x2a },
> > +     { 0x34, 0x61 },
> > +     { 0x35, 0xc5 },
> > +     { 0x36, 0x80 },
> > +     { 0x37, 0x23 },
> > +     { 0x40, 0x03 },
> > +     { 0x41, 0x04 },
> > +     { 0x42, 0x05 },
> > +     { 0x43, 0x06 },
> > +     { 0x44, 0x11 },
> > +     { 0x45, 0xe8 },
> > +     { 0x46, 0xe9 },
> > +     { 0x47, 0x11 },
> > +     { 0x48, 0xea },
> > +     { 0x49, 0xeb },
> > +     { 0x50, 0x07 },
> > +     { 0x51, 0x08 },
> > +     { 0x52, 0x09 },
> > +     { 0x53, 0x0a },
> > +     { 0x54, 0x11 },
> > +     { 0x55, 0xec },
> > +     { 0x56, 0xed },
> > +     { 0x57, 0x11 },
> > +     { 0x58, 0xef },
> > +     { 0x59, 0xf0 },
> > +     { 0xb1, 0x01 },
> > +     { 0xb4, 0x15 },
> > +     { 0xb5, 0x16 },
> > +     { 0xb6, 0x09 },
> > +     { 0xb7, 0x0f },
> > +     { 0xb8, 0x0d },
> > +     { 0xb9, 0x0b },
> > +     { 0xba, 0x00 },
> > +     { 0xc7, 0x02 },
> > +     { 0xca, 0x17 },
> > +     { 0xcb, 0x18 },
> > +     { 0xcc, 0x0a },
> > +     { 0xcd, 0x10 },
> > +     { 0xce, 0x0e },
> > +     { 0xcf, 0x0c },
> > +     { 0xd0, 0x00 },
> > +     { 0x81, 0x00 },
> > +     { 0x84, 0x15 },
> > +     { 0x85, 0x16 },
> > +     { 0x86, 0x10 },
> > +     { 0x87, 0x0a },
> > +     { 0x88, 0x0c },
> > +     { 0x89, 0x0e },
> > +     { 0x8a, 0x02 },
> > +     { 0x97, 0x00 },
> > +     { 0x9a, 0x17 },
> > +     { 0x9b, 0x18 },
> > +     { 0x9c, 0x0f },
> > +     { 0x9d, 0x09 },
> > +     { 0x9e, 0x0b },
> > +     { 0x9f, 0x0d },
> > +     { 0xa0, 0x01 },
> > +
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x02 },
> > +     { 0x01, 0x01 },
> > +     { 0x02, 0xda },
> > +     { 0x03, 0xba },
> > +     { 0x04, 0xa8 },
> > +     { 0x05, 0x9a },
> > +     { 0x06, 0x70 },
> > +     { 0x07, 0xff },
> > +     { 0x08, 0x91 },
> > +     { 0x09, 0x90 },
> > +     { 0x0a, 0xff },
> > +     { 0x0b, 0x8f },
> > +     { 0x0c, 0x60 },
> > +     { 0x0d, 0x58 },
> > +     { 0x0e, 0x48 },
> > +     { 0x0f, 0x38 },
> > +     { 0x10, 0x2b },
> > +
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x00 },
> > +     { 0x36, 0x0a },
> > +};
> > +
> > +static inline struct nv3052c *to_nv3052c(struct drm_panel *panel)
> > +{
> > +     return container_of(panel, struct nv3052c, panel);
> > +}
> > +
> > +static int nv3052c_prepare(struct drm_panel *panel)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     struct mipi_dbi *dbi = &priv->dbi;
> > +     unsigned int i;
> > +     int err;
> > +
> > +     err = regulator_enable(priv->supply);
> > +     if (err) {
> > +             dev_err(priv->dev, "Failed to enable power supply: %d\n", err);
> > +             return err;
> > +     }
> > +
> > +     /* Reset the chip */
> > +     gpiod_set_value_cansleep(priv->reset_gpio, 1);
> > +     usleep_range(10, 1000);
> > +     gpiod_set_value_cansleep(priv->reset_gpio, 0);
> > +     msleep(5);
> > +
> > +     for (i = 0; i < ARRAY_SIZE(nv3052c_panel_regs); i++) {
> > +             err = mipi_dbi_command(dbi, nv3052c_panel_regs[i].cmd,
> > +                                    nv3052c_panel_regs[i].val);
> > +
> > +             if (err) {
> > +                     dev_err(priv->dev, "Unable to set register: %d\n", err);
> > +                     goto err_disable_regulator;
> > +             }
> > +     }
> > +
> > +     err = mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
> > +     if (err) {
> > +             dev_err(priv->dev, "Unable to exit sleep mode: %d\n", err);
> > +             goto err_disable_regulator;
> > +     }
> > +
> > +     return 0;
> > +
> > +err_disable_regulator:
> > +     regulator_disable(priv->supply);
> > +     return err;
> > +}
> > +
> > +static int nv3052c_unprepare(struct drm_panel *panel)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     struct mipi_dbi *dbi = &priv->dbi;
> > +     int err;
> > +
> > +     err = mipi_dbi_command(dbi, MIPI_DCS_ENTER_SLEEP_MODE);
> > +     if (err) {
> > +             dev_err(priv->dev, "Unable to enter sleep mode: %d\n", err);
> > +             return err;
> > +     }
> > +
> > +     gpiod_set_value_cansleep(priv->reset_gpio, 1);
> > +     regulator_disable(priv->supply);
> > +
> > +     return 0;
> > +}
> > +
> > +static int nv3052c_enable(struct drm_panel *panel)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     struct mipi_dbi *dbi = &priv->dbi;
> > +     int err;
> > +
> > +     err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
> > +     if (err) {
> > +             dev_err(priv->dev, "Unable to enable display: %d\n", err);
> > +             return err;
> > +     }
> > +
> > +     if (panel->backlight) {
> > +             /* Wait for the picture to be ready before enabling backlight */
> > +             msleep(120);
>
>  From my own test this msleep can go. Modesets don't seem to cause any
> graphical glitches.
>

Not in my own testing, maybe some panel variance there? 30ms is not
enough to get rid of artefacts when starting apps, but 120ms is. So I
suggest to just leave it there, it's not like such a short delay is
really noticeable anyway.

KR
CB

> The driver looks fine to me overall, I just need somebody else (Sam?)
> to ack it before I can merge it.
>
> Cheers,
> -Paul
>
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int nv3052c_disable(struct drm_panel *panel)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     struct mipi_dbi *dbi = &priv->dbi;
> > +     int err;
> > +
> > +     err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
> > +     if (err) {
> > +             dev_err(priv->dev, "Unable to disable display: %d\n", err);
> > +             return err;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int nv3052c_get_modes(struct drm_panel *panel,
> > +                          struct drm_connector *connector)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     const struct nv3052c_panel_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 nv3052c_funcs = {
> > +     .prepare        = nv3052c_prepare,
> > +     .unprepare      = nv3052c_unprepare,
> > +     .enable         = nv3052c_enable,
> > +     .disable        = nv3052c_disable,
> > +     .get_modes      = nv3052c_get_modes,
> > +};
> > +
> > +static int nv3052c_probe(struct spi_device *spi)
> > +{
> > +     struct device *dev = &spi->dev;
> > +     struct nv3052c *priv;
> > +     int err;
> > +
> > +     priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > +     if (!priv)
> > +             return -ENOMEM;
> > +
> > +     priv->dev = dev;
> > +
> > +     priv->panel_info = of_device_get_match_data(dev);
> > +     if (!priv->panel_info)
> > +             return -EINVAL;
> > +
> > +     priv->supply = devm_regulator_get(dev, "power");
> > +     if (IS_ERR(priv->supply))
> > +             return dev_err_probe(dev, PTR_ERR(priv->supply), "Failed to get
> > power supply\n");
> > +
> > +     priv->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> > +     if (IS_ERR(priv->reset_gpio))
> > +             return dev_err_probe(dev, PTR_ERR(priv->reset_gpio), "Failed to
> > get reset GPIO\n");
> > +
> > +     err = mipi_dbi_spi_init(spi, &priv->dbi, NULL);
> > +     if (err)
> > +             return dev_err_probe(dev, err, "MIPI DBI init failed\n");
> > +
> > +     priv->dbi.read_commands = NULL;
> > +
> > +     spi_set_drvdata(spi, priv);
> > +
> > +     drm_panel_init(&priv->panel, dev, &nv3052c_funcs,
> > +                    DRM_MODE_CONNECTOR_DPI);
> > +
> > +     err = drm_panel_of_backlight(&priv->panel);
> > +     if (err)
> > +             return dev_err_probe(dev, err, "Failed to attach backlight\n");
> > +
> > +     drm_panel_add(&priv->panel);
> > +
> > +     return 0;
> > +}
> > +
> > +static int nv3052c_remove(struct spi_device *spi)
> > +{
> > +     struct nv3052c *priv = spi_get_drvdata(spi);
> > +
> > +     drm_panel_remove(&priv->panel);
> > +     drm_panel_disable(&priv->panel);
> > +     drm_panel_unprepare(&priv->panel);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct drm_display_mode ltk035c5444t_modes[] = {
> > +     { /* 60 Hz */
> > +             .clock = 24000,
> > +             .hdisplay = 640,
> > +             .hsync_start = 640 + 96,
> > +             .hsync_end = 640 + 96 + 16,
> > +             .htotal = 640 + 96 + 16 + 48,
> > +             .vdisplay = 480,
> > +             .vsync_start = 480 + 5,
> > +             .vsync_end = 480 + 5 + 2,
> > +             .vtotal = 480 + 5 + 2 + 13,
> > +             .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> > +     },
> > +     { /* 50 Hz */
> > +             .clock = 18000,
> > +             .hdisplay = 640,
> > +             .hsync_start = 640 + 39,
> > +             .hsync_end = 640 + 39 + 2,
> > +             .htotal = 640 + 39 + 2 + 39,
> > +             .vdisplay = 480,
> > +             .vsync_start = 480 + 5,
> > +             .vsync_end = 480 + 5 + 2,
> > +             .vtotal = 480 + 5 + 2 + 13,
> > +             .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> > +     },
> > +};
> > +
> > +static const struct nv3052c_panel_info ltk035c5444t_panel_info = {
> > +     .display_modes = ltk035c5444t_modes,
> > +     .num_modes = ARRAY_SIZE(ltk035c5444t_modes),
> > +     .width_mm = 77,
> > +     .height_mm = 64,
> > +     .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
> > +     .bus_flags = DRM_BUS_FLAG_DE_HIGH |
> > DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
> > +};
> > +
> > +static const struct of_device_id nv3052c_of_match[] = {
> > +     { .compatible = "leadtek,ltk035c5444t", .data =
> > &ltk035c5444t_panel_info },
> > +     { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, nv3052c_of_match);
> > +
> > +static struct spi_driver nv3052c_driver = {
> > +     .driver = {
> > +             .name = "nv3052c",
> > +             .of_match_table = nv3052c_of_match,
> > +     },
> > +     .probe = nv3052c_probe,
> > +     .remove = nv3052c_remove,
> > +};
> > +module_spi_driver(nv3052c_driver);
> > +
> > +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
> > +MODULE_AUTHOR("Christophe Branchereau <cbranchereau@gmail.com>");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.35.1
> >
>
>

Re: [PATCH v4 2/4] drm/panel: Add panel driver for NewVision NV3052C based LCDs

[Sam Ravnborg]

Hi Christophe,
On Fri, Mar 11, 2022 at 06:02:38PM +0100, Christophe Branchereau wrote:
> This driver supports the NewVision NV3052C based LCDs. Right now, it
> only supports the LeadTek LTK035C5444T 2.4" 640x480 TFT LCD panel, which
> can be found in the Anbernic RG-350M handheld console.

I had to get away from my day-time job and you were the lucky winner.
A couple of comments in the following that you can address now or later.

> 
> Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
> ---
>  drivers/gpu/drm/panel/Kconfig                 |   9 +
>  drivers/gpu/drm/panel/Makefile                |   1 +
>  .../gpu/drm/panel/panel-newvision-nv3052c.c   | 497 ++++++++++++++++++
>  3 files changed, 507 insertions(+)
>  create mode 100644 drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index bb2e47229c68..40084f709789 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -283,6 +283,15 @@ config DRM_PANEL_NEC_NL8048HL11
>  	  panel (found on the Zoom2/3/3630 SDP boards). To compile this driver
>  	  as a module, choose M here.
>  
> +config DRM_PANEL_NEWVISION_NV3052C
> +	tristate "NewVision NV3052C RGB/SPI panel"
> +	depends on OF && SPI
> +	depends on BACKLIGHT_CLASS_DEVICE
> +	select DRM_MIPI_DBI
> +	help
> +	  Say Y here if you want to enable support for the panels built
> +	  around the NewVision NV3052C display controller.
> +
>  config DRM_PANEL_NOVATEK_NT35510
>  	tristate "Novatek NT35510 RGB panel driver"
>  	depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 5740911f637c..42a7ab54234b 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK500HD1829) += panel-leadtek-ltk500hd1829.o
>  obj-$(CONFIG_DRM_PANEL_LG_LB035Q02) += panel-lg-lb035q02.o
>  obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
>  obj-$(CONFIG_DRM_PANEL_NEC_NL8048HL11) += panel-nec-nl8048hl11.o
> +obj-$(CONFIG_DRM_PANEL_NEWVISION_NV3052C) += panel-newvision-nv3052c.o
>  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35510) += panel-novatek-nt35510.o
>  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35560) += panel-novatek-nt35560.o
>  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35950) += panel-novatek-nt35950.o
> diff --git a/drivers/gpu/drm/panel/panel-newvision-nv3052c.c b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> new file mode 100644
> index 000000000000..fc31df0dee12
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> @@ -0,0 +1,497 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * NevVision NV3052C IPS LCD panel driver
> + *
> + * Copyright (C) 2020, Paul Cercueil <paul@crapouillou.net>
> + * Copyright (C) 2022, Christophe Branchereau <cbranchereau@gmail.com>
> + */
> +
> +#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/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +
> +#include <video/mipi_display.h>
> +
> +#include <drm/drm_mipi_dbi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +
> +struct nv3052c_panel_info {
> +	const struct drm_display_mode *display_modes;
> +	unsigned int num_modes;
> +	u16 width_mm, height_mm;
> +	u32 bus_format, bus_flags;
> +};
> +
> +struct nv3052c {
> +	struct device *dev;
> +	struct drm_panel panel;
> +	struct mipi_dbi dbi;
> +
> +	const struct nv3052c_panel_info *panel_info;
> +
> +	struct regulator *supply;
> +	struct gpio_desc *reset_gpio;
> +};
> +
> +struct nv3052c_reg {
> +	u8 cmd;
> +	u8 val;
> +};
> +
> +static const struct nv3052c_reg nv3052c_panel_regs[] = {
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x01 },
> +	{ 0xe3, 0x00 },
> +	{ 0x40, 0x00 },
> +	{ 0x03, 0x40 },
> +	{ 0x04, 0x00 },
> +	{ 0x05, 0x03 },
> +	{ 0x08, 0x00 },
> +	{ 0x09, 0x07 },
> +	{ 0x0a, 0x01 },
> +	{ 0x0b, 0x32 },
> +	{ 0x0c, 0x32 },
> +	{ 0x0d, 0x0b },
> +	{ 0x0e, 0x00 },
> +	{ 0x23, 0xa0 },
> +
> +	{ 0x24, 0x0c },
> +	{ 0x25, 0x06 },
> +	{ 0x26, 0x14 },
> +	{ 0x27, 0x14 },
> +
> +	{ 0x38, 0xcc },
> +	{ 0x39, 0xd7 },
> +	{ 0x3a, 0x4a },
> +
> +	{ 0x28, 0x40 },
> +	{ 0x29, 0x01 },
> +	{ 0x2a, 0xdf },
> +	{ 0x49, 0x3c },
> +	{ 0x91, 0x77 },
> +	{ 0x92, 0x77 },
> +	{ 0xa0, 0x55 },
> +	{ 0xa1, 0x50 },
> +	{ 0xa4, 0x9c },
> +	{ 0xa7, 0x02 },
> +	{ 0xa8, 0x01 },
> +	{ 0xa9, 0x01 },
> +	{ 0xaa, 0xfc },
> +	{ 0xab, 0x28 },
> +	{ 0xac, 0x06 },
> +	{ 0xad, 0x06 },
> +	{ 0xae, 0x06 },
> +	{ 0xaf, 0x03 },
> +	{ 0xb0, 0x08 },
> +	{ 0xb1, 0x26 },
> +	{ 0xb2, 0x28 },
> +	{ 0xb3, 0x28 },
> +	{ 0xb4, 0x33 },
> +	{ 0xb5, 0x08 },
> +	{ 0xb6, 0x26 },
> +	{ 0xb7, 0x08 },
> +	{ 0xb8, 0x26 },
> +	{ 0xf0, 0x00 },
> +	{ 0xf6, 0xc0 },
> +
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x02 },
> +	{ 0xb0, 0x0b },
> +	{ 0xb1, 0x16 },
> +	{ 0xb2, 0x17 },
> +	{ 0xb3, 0x2c },
> +	{ 0xb4, 0x32 },
> +	{ 0xb5, 0x3b },
> +	{ 0xb6, 0x29 },
> +	{ 0xb7, 0x40 },
> +	{ 0xb8, 0x0d },
> +	{ 0xb9, 0x05 },
> +	{ 0xba, 0x12 },
> +	{ 0xbb, 0x10 },
> +	{ 0xbc, 0x12 },
> +	{ 0xbd, 0x15 },
> +	{ 0xbe, 0x19 },
> +	{ 0xbf, 0x0e },
> +	{ 0xc0, 0x16 },
> +	{ 0xc1, 0x0a },
> +	{ 0xd0, 0x0c },
> +	{ 0xd1, 0x17 },
> +	{ 0xd2, 0x14 },
> +	{ 0xd3, 0x2e },
> +	{ 0xd4, 0x32 },
> +	{ 0xd5, 0x3c },
> +	{ 0xd6, 0x22 },
> +	{ 0xd7, 0x3d },
> +	{ 0xd8, 0x0d },
> +	{ 0xd9, 0x07 },
> +	{ 0xda, 0x13 },
> +	{ 0xdb, 0x13 },
> +	{ 0xdc, 0x11 },
> +	{ 0xdd, 0x15 },
> +	{ 0xde, 0x19 },
> +	{ 0xdf, 0x10 },
> +	{ 0xe0, 0x17 },
> +	{ 0xe1, 0x0a },
> +
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x03 },
> +	{ 0x00, 0x2a },
> +	{ 0x01, 0x2a },
> +	{ 0x02, 0x2a },
> +	{ 0x03, 0x2a },
> +	{ 0x04, 0x61 },
> +	{ 0x05, 0x80 },
> +	{ 0x06, 0xc7 },
> +	{ 0x07, 0x01 },
> +	{ 0x08, 0x03 },
> +	{ 0x09, 0x04 },
> +	{ 0x70, 0x22 },
> +	{ 0x71, 0x80 },
> +	{ 0x30, 0x2a },
> +	{ 0x31, 0x2a },
> +	{ 0x32, 0x2a },
> +	{ 0x33, 0x2a },
> +	{ 0x34, 0x61 },
> +	{ 0x35, 0xc5 },
> +	{ 0x36, 0x80 },
> +	{ 0x37, 0x23 },
> +	{ 0x40, 0x03 },
> +	{ 0x41, 0x04 },
> +	{ 0x42, 0x05 },
> +	{ 0x43, 0x06 },
> +	{ 0x44, 0x11 },
> +	{ 0x45, 0xe8 },
> +	{ 0x46, 0xe9 },
> +	{ 0x47, 0x11 },
> +	{ 0x48, 0xea },
> +	{ 0x49, 0xeb },
> +	{ 0x50, 0x07 },
> +	{ 0x51, 0x08 },
> +	{ 0x52, 0x09 },
> +	{ 0x53, 0x0a },
> +	{ 0x54, 0x11 },
> +	{ 0x55, 0xec },
> +	{ 0x56, 0xed },
> +	{ 0x57, 0x11 },
> +	{ 0x58, 0xef },
> +	{ 0x59, 0xf0 },
> +	{ 0xb1, 0x01 },
> +	{ 0xb4, 0x15 },
> +	{ 0xb5, 0x16 },
> +	{ 0xb6, 0x09 },
> +	{ 0xb7, 0x0f },
> +	{ 0xb8, 0x0d },
> +	{ 0xb9, 0x0b },
> +	{ 0xba, 0x00 },
> +	{ 0xc7, 0x02 },
> +	{ 0xca, 0x17 },
> +	{ 0xcb, 0x18 },
> +	{ 0xcc, 0x0a },
> +	{ 0xcd, 0x10 },
> +	{ 0xce, 0x0e },
> +	{ 0xcf, 0x0c },
> +	{ 0xd0, 0x00 },
> +	{ 0x81, 0x00 },
> +	{ 0x84, 0x15 },
> +	{ 0x85, 0x16 },
> +	{ 0x86, 0x10 },
> +	{ 0x87, 0x0a },
> +	{ 0x88, 0x0c },
> +	{ 0x89, 0x0e },
> +	{ 0x8a, 0x02 },
> +	{ 0x97, 0x00 },
> +	{ 0x9a, 0x17 },
> +	{ 0x9b, 0x18 },
> +	{ 0x9c, 0x0f },
> +	{ 0x9d, 0x09 },
> +	{ 0x9e, 0x0b },
> +	{ 0x9f, 0x0d },
> +	{ 0xa0, 0x01 },
> +
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x02 },
> +	{ 0x01, 0x01 },
> +	{ 0x02, 0xda },
> +	{ 0x03, 0xba },
> +	{ 0x04, 0xa8 },
> +	{ 0x05, 0x9a },
> +	{ 0x06, 0x70 },
> +	{ 0x07, 0xff },
> +	{ 0x08, 0x91 },
> +	{ 0x09, 0x90 },
> +	{ 0x0a, 0xff },
> +	{ 0x0b, 0x8f },
> +	{ 0x0c, 0x60 },
> +	{ 0x0d, 0x58 },
> +	{ 0x0e, 0x48 },
> +	{ 0x0f, 0x38 },
> +	{ 0x10, 0x2b },
> +
> +	{ 0xff, 0x30 },
> +	{ 0xff, 0x52 },
> +	{ 0xff, 0x00 },
> +	{ 0x36, 0x0a },
> +};
There are some random (?) empty lines.
If they have any significance then a short comment would be nice.
If not, then drop the empty lines.

> +
> +static inline struct nv3052c *to_nv3052c(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct nv3052c, panel);
> +}
> +
> +static int nv3052c_prepare(struct drm_panel *panel)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	struct mipi_dbi *dbi = &priv->dbi;
> +	unsigned int i;
> +	int err;
> +
> +	err = regulator_enable(priv->supply);
> +	if (err) {
> +		dev_err(priv->dev, "Failed to enable power supply: %d\n", err);
> +		return err;
> +	}
> +
> +	/* Reset the chip */
> +	gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +	usleep_range(10, 1000);
> +	gpiod_set_value_cansleep(priv->reset_gpio, 0);
> +	msleep(5);
> +
> +	for (i = 0; i < ARRAY_SIZE(nv3052c_panel_regs); i++) {
> +		err = mipi_dbi_command(dbi, nv3052c_panel_regs[i].cmd,
> +				       nv3052c_panel_regs[i].val);
> +
> +		if (err) {
> +			dev_err(priv->dev, "Unable to set register: %d\n", err);
> +			goto err_disable_regulator;
> +		}
> +	}
> +
> +	err = mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
> +	if (err) {
> +		dev_err(priv->dev, "Unable to exit sleep mode: %d\n", err);
> +		goto err_disable_regulator;
> +	}
> +
> +	return 0;
> +
> +err_disable_regulator:
> +	regulator_disable(priv->supply);
> +	return err;
> +}
> +
> +static int nv3052c_unprepare(struct drm_panel *panel)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	struct mipi_dbi *dbi = &priv->dbi;
> +	int err;
> +
> +	err = mipi_dbi_command(dbi, MIPI_DCS_ENTER_SLEEP_MODE);
> +	if (err) {
> +		dev_err(priv->dev, "Unable to enter sleep mode: %d\n", err);
> +		return err;
Consider to just continue here. In case we fail to enter sleep mode we
will anyway reset the panel and disable the supply voltage.
So things will likely work anyway and we avoid a display with power
where it was supposed to be disabled.
I bet many panels uses the same pattern as this driver, but I think that
continue is the right thing to do here.


> +	}
> +
> +	gpiod_set_value_cansleep(priv->reset_gpio, 1);
> +	regulator_disable(priv->supply);
> +
> +	return 0;
> +}

Everything else looked good - nicely written driver.

	Sam

> +
> +static int nv3052c_enable(struct drm_panel *panel)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	struct mipi_dbi *dbi = &priv->dbi;
> +	int err;
> +
> +	err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
> +	if (err) {
> +		dev_err(priv->dev, "Unable to enable display: %d\n", err);
> +		return err;
> +	}
> +
> +	if (panel->backlight) {
> +		/* Wait for the picture to be ready before enabling backlight */
> +		msleep(120);
> +	}
> +
> +	return 0;
> +}
> +
> +static int nv3052c_disable(struct drm_panel *panel)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	struct mipi_dbi *dbi = &priv->dbi;
> +	int err;
> +
> +	err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
> +	if (err) {
> +		dev_err(priv->dev, "Unable to disable display: %d\n", err);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int nv3052c_get_modes(struct drm_panel *panel,
> +			     struct drm_connector *connector)
> +{
> +	struct nv3052c *priv = to_nv3052c(panel);
> +	const struct nv3052c_panel_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 nv3052c_funcs = {
> +	.prepare	= nv3052c_prepare,
> +	.unprepare	= nv3052c_unprepare,
> +	.enable		= nv3052c_enable,
> +	.disable	= nv3052c_disable,
> +	.get_modes	= nv3052c_get_modes,
> +};
> +
> +static int nv3052c_probe(struct spi_device *spi)
> +{
> +	struct device *dev = &spi->dev;
> +	struct nv3052c *priv;
> +	int err;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = dev;
> +
> +	priv->panel_info = of_device_get_match_data(dev);
> +	if (!priv->panel_info)
> +		return -EINVAL;
> +
> +	priv->supply = devm_regulator_get(dev, "power");
> +	if (IS_ERR(priv->supply))
> +		return dev_err_probe(dev, PTR_ERR(priv->supply), "Failed to get power supply\n");
> +
> +	priv->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(priv->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(priv->reset_gpio), "Failed to get reset GPIO\n");
> +
> +	err = mipi_dbi_spi_init(spi, &priv->dbi, NULL);
> +	if (err)
> +		return dev_err_probe(dev, err, "MIPI DBI init failed\n");
> +
> +	priv->dbi.read_commands = NULL;
> +
> +	spi_set_drvdata(spi, priv);
> +
> +	drm_panel_init(&priv->panel, dev, &nv3052c_funcs,
> +		       DRM_MODE_CONNECTOR_DPI);
> +
> +	err = drm_panel_of_backlight(&priv->panel);
> +	if (err)
> +		return dev_err_probe(dev, err, "Failed to attach backlight\n");
> +
> +	drm_panel_add(&priv->panel);
> +
> +	return 0;
> +}
> +
> +static int nv3052c_remove(struct spi_device *spi)
> +{
> +	struct nv3052c *priv = spi_get_drvdata(spi);
> +
> +	drm_panel_remove(&priv->panel);
> +	drm_panel_disable(&priv->panel);
> +	drm_panel_unprepare(&priv->panel);
> +
> +	return 0;
> +}
> +
> +static const struct drm_display_mode ltk035c5444t_modes[] = {
> +	{ /* 60 Hz */
> +		.clock = 24000,
> +		.hdisplay = 640,
> +		.hsync_start = 640 + 96,
> +		.hsync_end = 640 + 96 + 16,
> +		.htotal = 640 + 96 + 16 + 48,
> +		.vdisplay = 480,
> +		.vsync_start = 480 + 5,
> +		.vsync_end = 480 + 5 + 2,
> +		.vtotal = 480 + 5 + 2 + 13,
> +		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> +	},
> +	{ /* 50 Hz */
> +		.clock = 18000,
> +		.hdisplay = 640,
> +		.hsync_start = 640 + 39,
> +		.hsync_end = 640 + 39 + 2,
> +		.htotal = 640 + 39 + 2 + 39,
> +		.vdisplay = 480,
> +		.vsync_start = 480 + 5,
> +		.vsync_end = 480 + 5 + 2,
> +		.vtotal = 480 + 5 + 2 + 13,
> +		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> +	},
> +};
> +
> +static const struct nv3052c_panel_info ltk035c5444t_panel_info = {
> +	.display_modes = ltk035c5444t_modes,
> +	.num_modes = ARRAY_SIZE(ltk035c5444t_modes),
> +	.width_mm = 77,
> +	.height_mm = 64,
> +	.bus_format = MEDIA_BUS_FMT_RGB888_1X24,
> +	.bus_flags = DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
> +};
> +
> +static const struct of_device_id nv3052c_of_match[] = {
> +	{ .compatible = "leadtek,ltk035c5444t", .data = &ltk035c5444t_panel_info },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, nv3052c_of_match);
> +
> +static struct spi_driver nv3052c_driver = {
> +	.driver = {
> +		.name = "nv3052c",
> +		.of_match_table = nv3052c_of_match,
> +	},
> +	.probe = nv3052c_probe,
> +	.remove = nv3052c_remove,
> +};
> +module_spi_driver(nv3052c_driver);
> +
> +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
> +MODULE_AUTHOR("Christophe Branchereau <cbranchereau@gmail.com>");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.35.1

Re: [PATCH v4 2/4] drm/panel: Add panel driver for NewVision NV3052C based LCDs

[Christophe Branchereau]

Hello Sam

On Tue, Mar 15, 2022 at 9:23 PM Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Christophe,
> On Fri, Mar 11, 2022 at 06:02:38PM +0100, Christophe Branchereau wrote:
> > This driver supports the NewVision NV3052C based LCDs. Right now, it
> > only supports the LeadTek LTK035C5444T 2.4" 640x480 TFT LCD panel, which
> > can be found in the Anbernic RG-350M handheld console.
>
> I had to get away from my day-time job and you were the lucky winner.
> A couple of comments in the following that you can address now or later.
>
> >
> > Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
> > ---
> >  drivers/gpu/drm/panel/Kconfig                 |   9 +
> >  drivers/gpu/drm/panel/Makefile                |   1 +
> >  .../gpu/drm/panel/panel-newvision-nv3052c.c   | 497 ++++++++++++++++++
> >  3 files changed, 507 insertions(+)
> >  create mode 100644 drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> >
> > diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> > index bb2e47229c68..40084f709789 100644
> > --- a/drivers/gpu/drm/panel/Kconfig
> > +++ b/drivers/gpu/drm/panel/Kconfig
> > @@ -283,6 +283,15 @@ config DRM_PANEL_NEC_NL8048HL11
> >         panel (found on the Zoom2/3/3630 SDP boards). To compile this driver
> >         as a module, choose M here.
> >
> > +config DRM_PANEL_NEWVISION_NV3052C
> > +     tristate "NewVision NV3052C RGB/SPI panel"
> > +     depends on OF && SPI
> > +     depends on BACKLIGHT_CLASS_DEVICE
> > +     select DRM_MIPI_DBI
> > +     help
> > +       Say Y here if you want to enable support for the panels built
> > +       around the NewVision NV3052C display controller.
> > +
> >  config DRM_PANEL_NOVATEK_NT35510
> >       tristate "Novatek NT35510 RGB panel driver"
> >       depends on OF
> > diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> > index 5740911f637c..42a7ab54234b 100644
> > --- a/drivers/gpu/drm/panel/Makefile
> > +++ b/drivers/gpu/drm/panel/Makefile
> > @@ -26,6 +26,7 @@ obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK500HD1829) += panel-leadtek-ltk500hd1829.o
> >  obj-$(CONFIG_DRM_PANEL_LG_LB035Q02) += panel-lg-lb035q02.o
> >  obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
> >  obj-$(CONFIG_DRM_PANEL_NEC_NL8048HL11) += panel-nec-nl8048hl11.o
> > +obj-$(CONFIG_DRM_PANEL_NEWVISION_NV3052C) += panel-newvision-nv3052c.o
> >  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35510) += panel-novatek-nt35510.o
> >  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35560) += panel-novatek-nt35560.o
> >  obj-$(CONFIG_DRM_PANEL_NOVATEK_NT35950) += panel-novatek-nt35950.o
> > diff --git a/drivers/gpu/drm/panel/panel-newvision-nv3052c.c b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> > new file mode 100644
> > index 000000000000..fc31df0dee12
> > --- /dev/null
> > +++ b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> > @@ -0,0 +1,497 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * NevVision NV3052C IPS LCD panel driver
> > + *
> > + * Copyright (C) 2020, Paul Cercueil <paul@crapouillou.net>
> > + * Copyright (C) 2022, Christophe Branchereau <cbranchereau@gmail.com>
> > + */
> > +
> > +#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/regulator/consumer.h>
> > +#include <linux/spi/spi.h>
> > +
> > +#include <video/mipi_display.h>
> > +
> > +#include <drm/drm_mipi_dbi.h>
> > +#include <drm/drm_modes.h>
> > +#include <drm/drm_panel.h>
> > +
> > +struct nv3052c_panel_info {
> > +     const struct drm_display_mode *display_modes;
> > +     unsigned int num_modes;
> > +     u16 width_mm, height_mm;
> > +     u32 bus_format, bus_flags;
> > +};
> > +
> > +struct nv3052c {
> > +     struct device *dev;
> > +     struct drm_panel panel;
> > +     struct mipi_dbi dbi;
> > +
> > +     const struct nv3052c_panel_info *panel_info;
> > +
> > +     struct regulator *supply;
> > +     struct gpio_desc *reset_gpio;
> > +};
> > +
> > +struct nv3052c_reg {
> > +     u8 cmd;
> > +     u8 val;
> > +};
> > +
> > +static const struct nv3052c_reg nv3052c_panel_regs[] = {
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x01 },
> > +     { 0xe3, 0x00 },
> > +     { 0x40, 0x00 },
> > +     { 0x03, 0x40 },
> > +     { 0x04, 0x00 },
> > +     { 0x05, 0x03 },
> > +     { 0x08, 0x00 },
> > +     { 0x09, 0x07 },
> > +     { 0x0a, 0x01 },
> > +     { 0x0b, 0x32 },
> > +     { 0x0c, 0x32 },
> > +     { 0x0d, 0x0b },
> > +     { 0x0e, 0x00 },
> > +     { 0x23, 0xa0 },
> > +
> > +     { 0x24, 0x0c },
> > +     { 0x25, 0x06 },
> > +     { 0x26, 0x14 },
> > +     { 0x27, 0x14 },
> > +
> > +     { 0x38, 0xcc },
> > +     { 0x39, 0xd7 },
> > +     { 0x3a, 0x4a },
> > +
> > +     { 0x28, 0x40 },
> > +     { 0x29, 0x01 },
> > +     { 0x2a, 0xdf },
> > +     { 0x49, 0x3c },
> > +     { 0x91, 0x77 },
> > +     { 0x92, 0x77 },
> > +     { 0xa0, 0x55 },
> > +     { 0xa1, 0x50 },
> > +     { 0xa4, 0x9c },
> > +     { 0xa7, 0x02 },
> > +     { 0xa8, 0x01 },
> > +     { 0xa9, 0x01 },
> > +     { 0xaa, 0xfc },
> > +     { 0xab, 0x28 },
> > +     { 0xac, 0x06 },
> > +     { 0xad, 0x06 },
> > +     { 0xae, 0x06 },
> > +     { 0xaf, 0x03 },
> > +     { 0xb0, 0x08 },
> > +     { 0xb1, 0x26 },
> > +     { 0xb2, 0x28 },
> > +     { 0xb3, 0x28 },
> > +     { 0xb4, 0x33 },
> > +     { 0xb5, 0x08 },
> > +     { 0xb6, 0x26 },
> > +     { 0xb7, 0x08 },
> > +     { 0xb8, 0x26 },
> > +     { 0xf0, 0x00 },
> > +     { 0xf6, 0xc0 },
> > +
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x02 },
> > +     { 0xb0, 0x0b },
> > +     { 0xb1, 0x16 },
> > +     { 0xb2, 0x17 },
> > +     { 0xb3, 0x2c },
> > +     { 0xb4, 0x32 },
> > +     { 0xb5, 0x3b },
> > +     { 0xb6, 0x29 },
> > +     { 0xb7, 0x40 },
> > +     { 0xb8, 0x0d },
> > +     { 0xb9, 0x05 },
> > +     { 0xba, 0x12 },
> > +     { 0xbb, 0x10 },
> > +     { 0xbc, 0x12 },
> > +     { 0xbd, 0x15 },
> > +     { 0xbe, 0x19 },
> > +     { 0xbf, 0x0e },
> > +     { 0xc0, 0x16 },
> > +     { 0xc1, 0x0a },
> > +     { 0xd0, 0x0c },
> > +     { 0xd1, 0x17 },
> > +     { 0xd2, 0x14 },
> > +     { 0xd3, 0x2e },
> > +     { 0xd4, 0x32 },
> > +     { 0xd5, 0x3c },
> > +     { 0xd6, 0x22 },
> > +     { 0xd7, 0x3d },
> > +     { 0xd8, 0x0d },
> > +     { 0xd9, 0x07 },
> > +     { 0xda, 0x13 },
> > +     { 0xdb, 0x13 },
> > +     { 0xdc, 0x11 },
> > +     { 0xdd, 0x15 },
> > +     { 0xde, 0x19 },
> > +     { 0xdf, 0x10 },
> > +     { 0xe0, 0x17 },
> > +     { 0xe1, 0x0a },
> > +
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x03 },
> > +     { 0x00, 0x2a },
> > +     { 0x01, 0x2a },
> > +     { 0x02, 0x2a },
> > +     { 0x03, 0x2a },
> > +     { 0x04, 0x61 },
> > +     { 0x05, 0x80 },
> > +     { 0x06, 0xc7 },
> > +     { 0x07, 0x01 },
> > +     { 0x08, 0x03 },
> > +     { 0x09, 0x04 },
> > +     { 0x70, 0x22 },
> > +     { 0x71, 0x80 },
> > +     { 0x30, 0x2a },
> > +     { 0x31, 0x2a },
> > +     { 0x32, 0x2a },
> > +     { 0x33, 0x2a },
> > +     { 0x34, 0x61 },
> > +     { 0x35, 0xc5 },
> > +     { 0x36, 0x80 },
> > +     { 0x37, 0x23 },
> > +     { 0x40, 0x03 },
> > +     { 0x41, 0x04 },
> > +     { 0x42, 0x05 },
> > +     { 0x43, 0x06 },
> > +     { 0x44, 0x11 },
> > +     { 0x45, 0xe8 },
> > +     { 0x46, 0xe9 },
> > +     { 0x47, 0x11 },
> > +     { 0x48, 0xea },
> > +     { 0x49, 0xeb },
> > +     { 0x50, 0x07 },
> > +     { 0x51, 0x08 },
> > +     { 0x52, 0x09 },
> > +     { 0x53, 0x0a },
> > +     { 0x54, 0x11 },
> > +     { 0x55, 0xec },
> > +     { 0x56, 0xed },
> > +     { 0x57, 0x11 },
> > +     { 0x58, 0xef },
> > +     { 0x59, 0xf0 },
> > +     { 0xb1, 0x01 },
> > +     { 0xb4, 0x15 },
> > +     { 0xb5, 0x16 },
> > +     { 0xb6, 0x09 },
> > +     { 0xb7, 0x0f },
> > +     { 0xb8, 0x0d },
> > +     { 0xb9, 0x0b },
> > +     { 0xba, 0x00 },
> > +     { 0xc7, 0x02 },
> > +     { 0xca, 0x17 },
> > +     { 0xcb, 0x18 },
> > +     { 0xcc, 0x0a },
> > +     { 0xcd, 0x10 },
> > +     { 0xce, 0x0e },
> > +     { 0xcf, 0x0c },
> > +     { 0xd0, 0x00 },
> > +     { 0x81, 0x00 },
> > +     { 0x84, 0x15 },
> > +     { 0x85, 0x16 },
> > +     { 0x86, 0x10 },
> > +     { 0x87, 0x0a },
> > +     { 0x88, 0x0c },
> > +     { 0x89, 0x0e },
> > +     { 0x8a, 0x02 },
> > +     { 0x97, 0x00 },
> > +     { 0x9a, 0x17 },
> > +     { 0x9b, 0x18 },
> > +     { 0x9c, 0x0f },
> > +     { 0x9d, 0x09 },
> > +     { 0x9e, 0x0b },
> > +     { 0x9f, 0x0d },
> > +     { 0xa0, 0x01 },
> > +
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x02 },
> > +     { 0x01, 0x01 },
> > +     { 0x02, 0xda },
> > +     { 0x03, 0xba },
> > +     { 0x04, 0xa8 },
> > +     { 0x05, 0x9a },
> > +     { 0x06, 0x70 },
> > +     { 0x07, 0xff },
> > +     { 0x08, 0x91 },
> > +     { 0x09, 0x90 },
> > +     { 0x0a, 0xff },
> > +     { 0x0b, 0x8f },
> > +     { 0x0c, 0x60 },
> > +     { 0x0d, 0x58 },
> > +     { 0x0e, 0x48 },
> > +     { 0x0f, 0x38 },
> > +     { 0x10, 0x2b },
> > +
> > +     { 0xff, 0x30 },
> > +     { 0xff, 0x52 },
> > +     { 0xff, 0x00 },
> > +     { 0x36, 0x0a },
> > +};
> There are some random (?) empty lines.
> If they have any significance then a short comment would be nice.
> If not, then drop the empty lines.
>

The empty lines are not random no, to access a different page in the
init, one must write i.e.   { 0xff, 0x30 }, { 0xff, 0x52 }, { 0xff,
0x02 }, to access page 2, so they add a little bit of readability.

But I can drop them indeed. as well as for the includes and struct on
top, to make it more compact.

> > +
> > +static inline struct nv3052c *to_nv3052c(struct drm_panel *panel)
> > +{
> > +     return container_of(panel, struct nv3052c, panel);
> > +}
> > +
> > +static int nv3052c_prepare(struct drm_panel *panel)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     struct mipi_dbi *dbi = &priv->dbi;
> > +     unsigned int i;
> > +     int err;
> > +
> > +     err = regulator_enable(priv->supply);
> > +     if (err) {
> > +             dev_err(priv->dev, "Failed to enable power supply: %d\n", err);
> > +             return err;
> > +     }
> > +
> > +     /* Reset the chip */
> > +     gpiod_set_value_cansleep(priv->reset_gpio, 1);
> > +     usleep_range(10, 1000);
> > +     gpiod_set_value_cansleep(priv->reset_gpio, 0);
> > +     msleep(5);
> > +
> > +     for (i = 0; i < ARRAY_SIZE(nv3052c_panel_regs); i++) {
> > +             err = mipi_dbi_command(dbi, nv3052c_panel_regs[i].cmd,
> > +                                    nv3052c_panel_regs[i].val);
> > +
> > +             if (err) {
> > +                     dev_err(priv->dev, "Unable to set register: %d\n", err);
> > +                     goto err_disable_regulator;
> > +             }
> > +     }
> > +
> > +     err = mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
> > +     if (err) {
> > +             dev_err(priv->dev, "Unable to exit sleep mode: %d\n", err);
> > +             goto err_disable_regulator;
> > +     }
> > +
> > +     return 0;
> > +
> > +err_disable_regulator:
> > +     regulator_disable(priv->supply);
> > +     return err;
> > +}
> > +
> > +static int nv3052c_unprepare(struct drm_panel *panel)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     struct mipi_dbi *dbi = &priv->dbi;
> > +     int err;
> > +
> > +     err = mipi_dbi_command(dbi, MIPI_DCS_ENTER_SLEEP_MODE);
> > +     if (err) {
> > +             dev_err(priv->dev, "Unable to enter sleep mode: %d\n", err);
> > +             return err;
> Consider to just continue here. In case we fail to enter sleep mode we
> will anyway reset the panel and disable the supply voltage.
> So things will likely work anyway and we avoid a display with power
> where it was supposed to be disabled.
> I bet many panels uses the same pattern as this driver, but I think that
> continue is the right thing to do here.
>
Yes, you're right.

>
> > +     }
> > +
> > +     gpiod_set_value_cansleep(priv->reset_gpio, 1);
> > +     regulator_disable(priv->supply);
> > +
> > +     return 0;
> > +}
>
> Everything else looked good - nicely written driver.
>
>         Sam

Thank you

>
> > +
> > +static int nv3052c_enable(struct drm_panel *panel)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     struct mipi_dbi *dbi = &priv->dbi;
> > +     int err;
> > +
> > +     err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
> > +     if (err) {
> > +             dev_err(priv->dev, "Unable to enable display: %d\n", err);
> > +             return err;
> > +     }
> > +
> > +     if (panel->backlight) {
> > +             /* Wait for the picture to be ready before enabling backlight */
> > +             msleep(120);
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int nv3052c_disable(struct drm_panel *panel)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     struct mipi_dbi *dbi = &priv->dbi;
> > +     int err;
> > +
> > +     err = mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
> > +     if (err) {
> > +             dev_err(priv->dev, "Unable to disable display: %d\n", err);
> > +             return err;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int nv3052c_get_modes(struct drm_panel *panel,
> > +                          struct drm_connector *connector)
> > +{
> > +     struct nv3052c *priv = to_nv3052c(panel);
> > +     const struct nv3052c_panel_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 nv3052c_funcs = {
> > +     .prepare        = nv3052c_prepare,
> > +     .unprepare      = nv3052c_unprepare,
> > +     .enable         = nv3052c_enable,
> > +     .disable        = nv3052c_disable,
> > +     .get_modes      = nv3052c_get_modes,
> > +};
> > +
> > +static int nv3052c_probe(struct spi_device *spi)
> > +{
> > +     struct device *dev = &spi->dev;
> > +     struct nv3052c *priv;
> > +     int err;
> > +
> > +     priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > +     if (!priv)
> > +             return -ENOMEM;
> > +
> > +     priv->dev = dev;
> > +
> > +     priv->panel_info = of_device_get_match_data(dev);
> > +     if (!priv->panel_info)
> > +             return -EINVAL;
> > +
> > +     priv->supply = devm_regulator_get(dev, "power");
> > +     if (IS_ERR(priv->supply))
> > +             return dev_err_probe(dev, PTR_ERR(priv->supply), "Failed to get power supply\n");
> > +
> > +     priv->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> > +     if (IS_ERR(priv->reset_gpio))
> > +             return dev_err_probe(dev, PTR_ERR(priv->reset_gpio), "Failed to get reset GPIO\n");
> > +
> > +     err = mipi_dbi_spi_init(spi, &priv->dbi, NULL);
> > +     if (err)
> > +             return dev_err_probe(dev, err, "MIPI DBI init failed\n");
> > +
> > +     priv->dbi.read_commands = NULL;
> > +
> > +     spi_set_drvdata(spi, priv);
> > +
> > +     drm_panel_init(&priv->panel, dev, &nv3052c_funcs,
> > +                    DRM_MODE_CONNECTOR_DPI);
> > +
> > +     err = drm_panel_of_backlight(&priv->panel);
> > +     if (err)
> > +             return dev_err_probe(dev, err, "Failed to attach backlight\n");
> > +
> > +     drm_panel_add(&priv->panel);
> > +
> > +     return 0;
> > +}
> > +
> > +static int nv3052c_remove(struct spi_device *spi)
> > +{
> > +     struct nv3052c *priv = spi_get_drvdata(spi);
> > +
> > +     drm_panel_remove(&priv->panel);
> > +     drm_panel_disable(&priv->panel);
> > +     drm_panel_unprepare(&priv->panel);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct drm_display_mode ltk035c5444t_modes[] = {
> > +     { /* 60 Hz */
> > +             .clock = 24000,
> > +             .hdisplay = 640,
> > +             .hsync_start = 640 + 96,
> > +             .hsync_end = 640 + 96 + 16,
> > +             .htotal = 640 + 96 + 16 + 48,
> > +             .vdisplay = 480,
> > +             .vsync_start = 480 + 5,
> > +             .vsync_end = 480 + 5 + 2,
> > +             .vtotal = 480 + 5 + 2 + 13,
> > +             .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> > +     },
> > +     { /* 50 Hz */
> > +             .clock = 18000,
> > +             .hdisplay = 640,
> > +             .hsync_start = 640 + 39,
> > +             .hsync_end = 640 + 39 + 2,
> > +             .htotal = 640 + 39 + 2 + 39,
> > +             .vdisplay = 480,
> > +             .vsync_start = 480 + 5,
> > +             .vsync_end = 480 + 5 + 2,
> > +             .vtotal = 480 + 5 + 2 + 13,
> > +             .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
> > +     },
> > +};
> > +
> > +static const struct nv3052c_panel_info ltk035c5444t_panel_info = {
> > +     .display_modes = ltk035c5444t_modes,
> > +     .num_modes = ARRAY_SIZE(ltk035c5444t_modes),
> > +     .width_mm = 77,
> > +     .height_mm = 64,
> > +     .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
> > +     .bus_flags = DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
> > +};
> > +
> > +static const struct of_device_id nv3052c_of_match[] = {
> > +     { .compatible = "leadtek,ltk035c5444t", .data = &ltk035c5444t_panel_info },
> > +     { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, nv3052c_of_match);
> > +
> > +static struct spi_driver nv3052c_driver = {
> > +     .driver = {
> > +             .name = "nv3052c",
> > +             .of_match_table = nv3052c_of_match,
> > +     },
> > +     .probe = nv3052c_probe,
> > +     .remove = nv3052c_remove,
> > +};
> > +module_spi_driver(nv3052c_driver);
> > +
> > +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
> > +MODULE_AUTHOR("Christophe Branchereau <cbranchereau@gmail.com>");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.35.1

Re: [PATCH v4 2/4] drm/panel: Add panel driver for NewVision NV3052C based LCDs

[Sam Ravnborg]

Hi Christophe,

> > > +     { 0x0d, 0x58 },
> > > +     { 0x0e, 0x48 },
> > > +     { 0x0f, 0x38 },
> > > +     { 0x10, 0x2b },
> > > +
> > > +     { 0xff, 0x30 },
> > > +     { 0xff, 0x52 },
> > > +     { 0xff, 0x00 },
> > > +     { 0x36, 0x0a },
> > > +};
> > There are some random (?) empty lines.
> > If they have any significance then a short comment would be nice.
> > If not, then drop the empty lines.
> >
> 
> The empty lines are not random no, to access a different page in the
> init, one must write i.e.   { 0xff, 0x30 }, { 0xff, 0x52 }, { 0xff,
> 0x02 }, to access page 2, so they add a little bit of readability.
Then I suggest to just say what page is is like:

	/* Page 1 */
	{ 0xff, 0x30 },
	...

Etc. then it is obvious this is page boundaries.

	Sam

[PATCH v4 3/4] drm/panel : innolux-ej030na and abt-y030xx067a : add .enable and .disable

[Christophe Branchereau]

Following the introduction of bridge_atomic_enable in the ingenic
drm driver, the crtc is enabled between .prepare and .enable, if
it exists.

Add it so the backlight is only enabled after the crtc is, to avoid
graphical issues.

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
---
 drivers/gpu/drm/panel/panel-abt-y030xx067a.c  | 23 ++++++++++++--
 drivers/gpu/drm/panel/panel-innolux-ej030na.c | 31 ++++++++++++++++---
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-abt-y030xx067a.c b/drivers/gpu/drm/panel/panel-abt-y030xx067a.c
index f043b484055b..b5736344e3ec 100644
--- a/drivers/gpu/drm/panel/panel-abt-y030xx067a.c
+++ b/drivers/gpu/drm/panel/panel-abt-y030xx067a.c
@@ -183,8 +183,6 @@ static int y030xx067a_prepare(struct drm_panel *panel)
 		goto err_disable_regulator;
 	}
 
-	msleep(120);
-
 	return 0;
 
 err_disable_regulator:
@@ -202,6 +200,25 @@ static int y030xx067a_unprepare(struct drm_panel *panel)
 	return 0;
 }
 
+static int y030xx067a_enable(struct drm_panel *panel)
+{
+	if (panel->backlight) {
+		/* Wait for the picture to be ready before enabling backlight */
+		msleep(120);
+	}
+
+	return 0;
+}
+
+static int y030xx067a_disable(struct drm_panel *panel)
+{
+	struct y030xx067a *priv = to_y030xx067a(panel);
+
+	regmap_clear_bits(priv->map, 0x06, REG06_XPSAVE);
+
+	return 0;
+}
+
 static int y030xx067a_get_modes(struct drm_panel *panel,
 				struct drm_connector *connector)
 {
@@ -239,6 +256,8 @@ static int y030xx067a_get_modes(struct drm_panel *panel,
 static const struct drm_panel_funcs y030xx067a_funcs = {
 	.prepare	= y030xx067a_prepare,
 	.unprepare	= y030xx067a_unprepare,
+	.enable		= y030xx067a_enable,
+	.disable	= y030xx067a_disable,
 	.get_modes	= y030xx067a_get_modes,
 };
 
diff --git a/drivers/gpu/drm/panel/panel-innolux-ej030na.c b/drivers/gpu/drm/panel/panel-innolux-ej030na.c
index c558de3f99be..6de7370185cd 100644
--- a/drivers/gpu/drm/panel/panel-innolux-ej030na.c
+++ b/drivers/gpu/drm/panel/panel-innolux-ej030na.c
@@ -80,8 +80,6 @@ static const struct reg_sequence ej030na_init_sequence[] = {
 	{ 0x47, 0x08 },
 	{ 0x48, 0x0f },
 	{ 0x49, 0x0f },
-
-	{ 0x2b, 0x01 },
 };
 
 static int ej030na_prepare(struct drm_panel *panel)
@@ -109,8 +107,6 @@ static int ej030na_prepare(struct drm_panel *panel)
 		goto err_disable_regulator;
 	}
 
-	msleep(120);
-
 	return 0;
 
 err_disable_regulator:
@@ -128,6 +124,31 @@ static int ej030na_unprepare(struct drm_panel *panel)
 	return 0;
 }
 
+static int ej030na_enable(struct drm_panel *panel)
+{
+	struct ej030na *priv = to_ej030na(panel);
+
+	/* standby off */
+	regmap_write(priv->map, 0x2b, 0x01);
+
+	if (panel->backlight) {
+		/* Wait for the picture to be ready before enabling backlight */
+		msleep(120);
+	}
+
+	return 0;
+}
+
+static int ej030na_disable(struct drm_panel *panel)
+{
+	struct ej030na *priv = to_ej030na(panel);
+
+	/* standby on */
+	regmap_write(priv->map, 0x2b, 0x00);
+
+	return 0;
+}
+
 static int ej030na_get_modes(struct drm_panel *panel,
 			     struct drm_connector *connector)
 {
@@ -165,6 +186,8 @@ static int ej030na_get_modes(struct drm_panel *panel,
 static const struct drm_panel_funcs ej030na_funcs = {
 	.prepare	= ej030na_prepare,
 	.unprepare	= ej030na_unprepare,
+	.enable		= ej030na_enable,
+	.disable	= ej030na_disable,
 	.get_modes	= ej030na_get_modes,
 };
 
-- 
2.35.1

[PATCH v4 4/4] dt-bindings: display/panel: Add Leadtek ltk035c5444t

[Christophe Branchereau]

Add binding for the leadtek ltk035c5444t, which is a 640x480
mipi-dbi over spi / 24-bit RGB panel based on the newvision
NV03052C chipset.

It is found in the Anbernic RG350M mips handheld.

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
---
 .../display/panel/leadtek,ltk035c5444t.yaml   | 59 +++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml

diff --git a/Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml b/Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml
new file mode 100644
index 000000000000..817a9bed7d5a
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/leadtek,ltk035c5444t.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Leadtek ltk035c5444t 3.5" (640x480 pixels) 24-bit IPS LCD panel
+
+maintainers:
+  - Paul Cercueil <paul@crapouillou.net>
+  - Christophe Branchereau <cbranchereau@gmail.com>
+
+allOf:
+  - $ref: panel-common.yaml#
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    const: leadtek,ltk035c5444t
+
+  backlight: true
+  port: true
+  power-supply: true
+  reg: true
+  reset-gpios: true
+
+required:
+  - compatible
+  - power-supply
+  - reset-gpios
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        panel@0 {
+            compatible = "leadtek,ltk035c5444t";
+            reg = <0>;
+
+            spi-3wire;
+            spi-max-frequency = <3125000>;
+
+            reset-gpios = <&gpe 2 GPIO_ACTIVE_LOW>;
+
+            backlight = <&backlight>;
+            power-supply = <&vcc>;
+
+            port {
+                panel_input: endpoint {
+                    remote-endpoint = <&panel_output>;
+                };
+            };
+        };
+    };
-- 
2.35.1

Re: [PATCH v4 4/4] dt-bindings: display/panel: Add Leadtek ltk035c5444t

[Rob Herring]

On Fri, 11 Mar 2022 18:02:40 +0100, Christophe Branchereau wrote:
> Add binding for the leadtek ltk035c5444t, which is a 640x480
> mipi-dbi over spi / 24-bit RGB panel based on the newvision
> NV03052C chipset.
> 
> It is found in the Anbernic RG350M mips handheld.
> 
> Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
> ---
>  .../display/panel/leadtek,ltk035c5444t.yaml   | 59 +++++++++++++++++++
>  1 file changed, 59 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml
> 

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

Re: [PATCH v4 4/4] dt-bindings: display/panel: Add Leadtek ltk035c5444t

[Paul Cercueil]

Hi,

Le ven., mars 11 2022 at 18:02:40 +0100, Christophe Branchereau 
<cbranchereau@gmail.com> a écrit :
> Add binding for the leadtek ltk035c5444t, which is a 640x480
> mipi-dbi over spi / 24-bit RGB panel based on the newvision
> NV03052C chipset.
> 
> It is found in the Anbernic RG350M mips handheld.
> 
> Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>

Applied to drm-misc-next.

Thanks,
-Paul

> ---
>  .../display/panel/leadtek,ltk035c5444t.yaml   | 59 
> +++++++++++++++++++
>  1 file changed, 59 insertions(+)
>  create mode 100644 
> Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml
> 
> diff --git 
> a/Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml 
> b/Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml
> new file mode 100644
> index 000000000000..817a9bed7d5a
> --- /dev/null
> +++ 
> b/Documentation/devicetree/bindings/display/panel/leadtek,ltk035c5444t.yaml
> @@ -0,0 +1,59 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: 
> http://devicetree.org/schemas/display/panel/leadtek,ltk035c5444t.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Leadtek ltk035c5444t 3.5" (640x480 pixels) 24-bit IPS LCD 
> panel
> +
> +maintainers:
> +  - Paul Cercueil <paul@crapouillou.net>
> +  - Christophe Branchereau <cbranchereau@gmail.com>
> +
> +allOf:
> +  - $ref: panel-common.yaml#
> +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
> +
> +properties:
> +  compatible:
> +    const: leadtek,ltk035c5444t
> +
> +  backlight: true
> +  port: true
> +  power-supply: true
> +  reg: true
> +  reset-gpios: true
> +
> +required:
> +  - compatible
> +  - power-supply
> +  - reset-gpios
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    spi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        panel@0 {
> +            compatible = "leadtek,ltk035c5444t";
> +            reg = <0>;
> +
> +            spi-3wire;
> +            spi-max-frequency = <3125000>;
> +
> +            reset-gpios = <&gpe 2 GPIO_ACTIVE_LOW>;
> +
> +            backlight = <&backlight>;
> +            power-supply = <&vcc>;
> +
> +            port {
> +                panel_input: endpoint {
> +                    remote-endpoint = <&panel_output>;
> +                };
> +            };
> +        };
> +    };
> --
> 2.35.1
>