Re: [PATCH 21/21] panel: startek-kd070fhfid015: add support of this display

From: Neil Armstrong
Date: Thu Mar 09 2023 - 09:54:15 EST


Hi,

On 09/03/2023 15:23, Alexandre Mergnat wrote:
From: Guillaume La Roque <glaroque@xxxxxxxxxxxx>

This driver support the Startek KD070FHFID015, which is a 7-inch TFT LCD
display using MIPI DSI interface.

Signed-off-by: Guillaume La Roque <glaroque@xxxxxxxxxxxx>
Signed-off-by: Alexandre Mergnat <amergnat@xxxxxxxxxxxx>
---
drivers/gpu/drm/panel/Kconfig | 12 +
drivers/gpu/drm/panel/Makefile | 1 +
.../gpu/drm/panel/panel-startek-kd070fhfid015.c | 483 +++++++++++++++++++++
3 files changed, 496 insertions(+)

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 737edcdf9eef..3fccf025013b 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -666,6 +666,17 @@ config DRM_PANEL_SONY_TULIP_TRULY_NT35521
NT35521 1280x720 video mode panel as found on Sony Xperia M4
Aqua phone.
+config DRM_PANEL_STARTEK_KD070FHFID015
+ tristate "STARTEK KD070FHFID015 panel"
+ depends on OF
+ depends on DRM_MIPI_DSI
+ depends on BACKLIGHT_CLASS_DEVICE
+ help
+ Say Y here if you want to enable support for STARTEK KD070FHFID015 DSI panel
+ based on RENESAS-R69429 controller. The pannel is a 7-inch TFT LCD display
+ with a resolution of 1024 x 600 pixels. It provides a MIPI DSI interface to
+ the host, a built-in LED backlight and touch controller.
+
config DRM_PANEL_TDO_TL070WSH30
tristate "TDO TL070WSH30 DSI panel"
depends on OF
@@ -736,4 +747,5 @@ config DRM_PANEL_XINPENG_XPP055C272
Say Y here if you want to enable support for the Xinpeng
XPP055C272 controller for 720x1280 LCD panels with MIPI/RGB/SPI
system interfaces.
+

Spurious new line

endmenu
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index f8f9d9f6a307..35771fc51187 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7703) += panel-sitronix-st7703.o
obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7789V) += panel-sitronix-st7789v.o
obj-$(CONFIG_DRM_PANEL_SONY_ACX565AKM) += panel-sony-acx565akm.o
obj-$(CONFIG_DRM_PANEL_SONY_TULIP_TRULY_NT35521) += panel-sony-tulip-truly-nt35521.o
+obj-$(CONFIG_DRM_PANEL_STARTEK_KD070FHFID015) += panel-startek-kd070fhfid015.o
obj-$(CONFIG_DRM_PANEL_TDO_TL070WSH30) += panel-tdo-tl070wsh30.o
obj-$(CONFIG_DRM_PANEL_TPO_TD028TTEC1) += panel-tpo-td028ttec1.o
obj-$(CONFIG_DRM_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o
diff --git a/drivers/gpu/drm/panel/panel-startek-kd070fhfid015.c b/drivers/gpu/drm/panel/panel-startek-kd070fhfid015.c
new file mode 100644
index 000000000000..88466bf6428d
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-startek-kd070fhfid015.c
@@ -0,0 +1,483 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2016 InforceComputing
+ * Copyright (C) 2016 Linaro Ltd
+ * Copyright (C) 2023 BayLibre, SAS
+ *
+ * Author:

NIT: Authors

+ * - Vinay Simha BN <simhavcs@xxxxxxxxx>
+ * - Sumit Semwal <sumit.semwal@xxxxxxxxxx>
+ * - Guillaume La Roque <glaroque@xxxxxxxxxxxx>
+ *
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_crtc.h>

Is this include needed ?

+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+#define DSI_REG_MCAP 0xB0
+#define DSI_REG_IS 0xB3 /* Interface Setting */
+#define DSI_REG_IIS 0xB4 /* Interface ID Setting */
+#define DSI_REG_CTRL 0xB6
+
+struct stk_panel {
+ struct drm_panel base;
+ struct mipi_dsi_device *dsi;
+
+ struct gpio_desc *enable_gpio;
+ struct gpio_desc *reset_gpio;
+ struct gpio_desc *dcdc_en_gpio;

Isn't this "DCDC" a regulator ???

+ struct backlight_device *backlight;
+ struct regulator *iovcc_supply;
+ struct regulator *power_supply;
+
+ bool prepared;
+ bool enabled;
+
+ const struct drm_display_mode *mode;
+};
+
+static inline struct stk_panel *to_stk_panel(struct drm_panel *panel)
+{
+ return container_of(panel, struct stk_panel, base);
+}
+
+static int stk_panel_init(struct stk_panel *stk)
+{
+ struct mipi_dsi_device *dsi = stk->dsi;
+ struct device *dev = &stk->dsi->dev;
+ int ret;
+
+ ret = mipi_dsi_dcs_soft_reset(dsi);
+ if (ret < 0) {
+ dev_err(dev, "failed to mipi_dsi_dcs_soft_reset: %d\n", ret);
+ return ret;
+ }
+ mdelay(5);
+
+ ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
+ if (ret < 0) {
+ dev_err(dev, "failed to set exit sleep mode: %d\n", ret);
+ return ret;
+ }
+ msleep(120);
+
+ ret = mipi_dsi_generic_write(dsi, (u8[]){DSI_REG_MCAP, 0x04}, 2);
+ if (ret < 0) {
+ dev_err(dev, "failed to set mcap: %d\n", ret);
+ return ret;
+ }
+ /* Interface setting, video mode */
+ ret = mipi_dsi_generic_write(dsi,
+ (u8[]){DSI_REG_IS, 0x14, 0x08, 0x00, 0x22, 0x00}, 6);
+ if (ret < 0) {
+ dev_err(dev, "failed to set display interface setting: %d\n",
+ ret);
+ return ret;
+ }

Use mipi_dsi_generic_write_seq(dsi, DSI_REG_IS, 0x14, 0x08, 0x00, 0x22, 0x00); instead,
it's simpler and doesn't need explicit return check.

+
+ ret = mipi_dsi_generic_write(dsi, (u8[]){DSI_REG_IIS, 0x0C, 0x00}, 3);
+ if (ret < 0) {
+ dev_err(dev, "failed to set Interface ID setting: %d\n", ret);
+ return ret;
+ }
+
+ ret = mipi_dsi_generic_write(dsi, (u8[]){ DSI_REG_CTRL, 0x3A, 0xD3}, 3);
+ if (ret < 0) {
+ dev_err(dev, "failed to set DSI control: %d\n", ret);
+ return ret;
+ }
+
+ ret = mipi_dsi_dcs_set_display_brightness(dsi, 0x77);
+ if (ret < 0) {
+ dev_err(dev, "failed to write display brightness: %d\n", ret);
+ return ret;
+ }
+
+ ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY,
+ (u8[]){ MIPI_DCS_WRITE_MEMORY_START }, 1);
+ if (ret < 0) {
+ dev_err(dev, "failed to write control display: %d\n", ret);
+ return ret;
+ }
+
+ ret = mipi_dsi_dcs_set_pixel_format(dsi, 0x77);
+ if (ret < 0) {
+ dev_err(dev, "failed to set pixel format: %d\n", ret);
+ return ret;
+ }
+
+ ret = mipi_dsi_dcs_set_column_address(dsi, 0, stk->mode->hdisplay - 1);
+ if (ret < 0) {
+ dev_err(dev, "failed to set column address: %d\n", ret);
+ return ret;
+ }
+
+ ret = mipi_dsi_dcs_set_page_address(dsi, 0, stk->mode->vdisplay - 1);
+ if (ret < 0) {
+ dev_err(dev, "failed to set page address: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int stk_panel_on(struct stk_panel *stk)
+{
+ struct mipi_dsi_device *dsi = stk->dsi;
+ struct device *dev = &stk->dsi->dev;
+ int ret;
+
+ ret = mipi_dsi_dcs_set_display_on(dsi);
+ if (ret < 0)
+ dev_err(dev, "failed to set display on: %d\n", ret);
+
+ mdelay(20);
+
+ return ret;
+}
+
+static void stk_panel_off(struct stk_panel *stk)
+{
+ struct mipi_dsi_device *dsi = stk->dsi;
+ struct device *dev = &stk->dsi->dev;
+ int ret;
+
+ dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+ ret = mipi_dsi_dcs_set_display_off(dsi);
+ if (ret < 0)
+ dev_err(dev, "failed to set display off: %d\n", ret);
+
+ ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
+ if (ret < 0)
+ dev_err(dev, "failed to enter sleep mode: %d\n", ret);
+
+ msleep(100);
+}
+
+static int stk_panel_disable(struct drm_panel *panel)
+{
+ struct stk_panel *stk = to_stk_panel(panel);
+
+ if (!stk->enabled)
+ return 0;
+
+ backlight_disable(stk->backlight);
+
+ stk->enabled = false;
+
+ return 0;
+}
+
+static int stk_panel_unprepare(struct drm_panel *panel)
+{
+ struct stk_panel *stk = to_stk_panel(panel);
+
+ if (!stk->prepared)
+ return 0;
+
+ stk_panel_off(stk);
+ regulator_disable(stk->iovcc_supply);
+ regulator_disable(stk->power_supply);
+ gpiod_set_value(stk->reset_gpio, 0);
+ gpiod_set_value(stk->dcdc_en_gpio, 1);
+
+ stk->prepared = false;
+
+ return 0;
+}
+
+static int stk_panel_prepare(struct drm_panel *panel)
+{
+ struct stk_panel *stk = to_stk_panel(panel);
+ struct device *dev = &stk->dsi->dev;
+ int ret;
+
+ if (stk->prepared)
+ return 0;
+
+ gpiod_set_value(stk->reset_gpio, 0);
+ gpiod_set_value(stk->dcdc_en_gpio, 0);
+ gpiod_set_value(stk->enable_gpio, 0);
+ ret = regulator_enable(stk->iovcc_supply);
+ if (ret < 0)
+ return ret;
+ mdelay(8);
+ ret = regulator_enable(stk->power_supply);
+ if (ret < 0)
+ goto iovccoff;

Add blank lines between code blocks for readability

+ mdelay(20);
+ gpiod_set_value(stk->dcdc_en_gpio, 1);
+ mdelay(20);
+ gpiod_set_value(stk->reset_gpio, 1);
+ mdelay(10);
+
+ ret = stk_panel_init(stk);
+ if (ret < 0) {
+ dev_err(dev, "failed to init panel: %d\n", ret);
+ goto poweroff;
+ }
+
+ ret = stk_panel_on(stk);
+ if (ret < 0) {
+ dev_err(dev, "failed to set panel on: %d\n", ret);
+ goto poweroff;
+ }
+
+ stk->prepared = true;
+
+ return 0;
+
+poweroff:
+ regulator_disable(stk->power_supply);
+iovccoff:
+ regulator_disable(stk->iovcc_supply);
+ gpiod_set_value(stk->enable_gpio, 0);
+ gpiod_set_value(stk->reset_gpio, 0);
+ gpiod_set_value(stk->dcdc_en_gpio, 0);
+
+ return ret;
+}
+
+static int stk_panel_enable(struct drm_panel *panel)
+{
+ struct stk_panel *stk = to_stk_panel(panel);
+
+ if (stk->enabled)
+ return 0;
+
+ backlight_enable(stk->backlight);
+
+ stk->enabled = true;
+
+ return 0;
+}

Is this really needed ? the backlight core will enable it automatically.

+
+static const struct drm_display_mode default_mode = {
+ .clock = 163204,
+ .hdisplay = 1200,
+ .hsync_start = 1200 + 144,
+ .hsync_end = 1200 + 144 + 16,
+ .htotal = 1200 + 144 + 16 + 45, // 1405

No need for the comment

+ .vdisplay = 1920,
+ .vsync_start = 1920 + 8,
+ .vsync_end = 1920 + 8 + 4,
+ .vtotal = 1920 + 8 + 4 + 4, // 1936

You can also set .width_mm & .height_mm and copy them to connector->display_info later.

+};
+
+static int stk_panel_get_modes(struct drm_panel *panel,
+ struct drm_connector *connector)
+{
+ struct drm_display_mode *mode;
+
+ mode = drm_mode_duplicate(connector->dev, &default_mode);
+ if (!mode) {
+ dev_err(panel->dev, "failed to add mode %ux%ux@%u\n",
+ default_mode.hdisplay, default_mode.vdisplay,
+ drm_mode_vrefresh(&default_mode));
+ return -ENOMEM;
+ }
+
+ drm_mode_set_name(mode);
+
+ drm_mode_probed_add(connector, mode);
+
+ connector->display_info.width_mm = 95;
+ connector->display_info.height_mm = 151;
+
+ return 1;
+}
+
+static int dsi_dcs_bl_get_brightness(struct backlight_device *bl)
+{
+ struct mipi_dsi_device *dsi = bl_get_data(bl);
+ int ret;
+ u16 brightness = bl->props.brightness;
+
+ dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+ ret = mipi_dsi_dcs_get_display_brightness(dsi, &brightness);
+ if (ret < 0)
+ return ret;
+ dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+ return brightness & 0xff;
+}
+
+static int dsi_dcs_bl_update_status(struct backlight_device *bl)
+{
+ struct mipi_dsi_device *dsi = bl_get_data(bl);
+ struct device *dev = &dsi->dev;
+ int ret;
+
+ dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+ ret = mipi_dsi_dcs_set_display_brightness(dsi, bl->props.brightness);
+ if (ret < 0) {
+ dev_err(dev, "failed to set DSI control: %d\n", ret);
+ return ret;
+ }
+
+ dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+ return 0;
+}
+
+static const struct backlight_ops dsi_bl_ops = {
+ .update_status = dsi_dcs_bl_update_status,
+ .get_brightness = dsi_dcs_bl_get_brightness,
+};
+
+static struct backlight_device *
+drm_panel_create_dsi_backlight(struct mipi_dsi_device *dsi)
+{
+ struct device *dev = &dsi->dev;
+ struct backlight_properties props;
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_RAW;
+ props.brightness = 255;
+ props.max_brightness = 255;

You could write :
struct backlight_properties props = {
.type = BACKLIGHT_RAW,
.brightness = 255,
.max_brightness = 255,
};

+
+ return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
+ &dsi_bl_ops, &props);
+}
+
+static const struct drm_panel_funcs stk_panel_funcs = {
+ .disable = stk_panel_disable,
+ .unprepare = stk_panel_unprepare,
+ .prepare = stk_panel_prepare,
+ .enable = stk_panel_enable,
+ .get_modes = stk_panel_get_modes,
+};
+
+static const struct of_device_id stk_of_match[] = {
+ { .compatible = "startek,kd070fhfid015", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, stk_of_match);
+
+static int stk_panel_add(struct stk_panel *stk)
+{
+ struct device *dev = &stk->dsi->dev;
+ int ret;
+
+ stk->mode = &default_mode;
+
+ stk->iovcc_supply = devm_regulator_get(dev, "iovcc");
+ if (IS_ERR(stk->iovcc_supply))
+ return PTR_ERR(stk->iovcc_supply);
+
+ stk->power_supply = devm_regulator_get(dev, "power");
+ if (IS_ERR(stk->power_supply))
+ return PTR_ERR(stk->power_supply);

You can switch to devm_regulator_bulk_get() to simplify code.

+
+ stk->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(stk->reset_gpio)) {
+ ret = PTR_ERR(stk->reset_gpio);
+ dev_err(dev, "cannot get reset-gpios %d\n", ret);
+ return ret;
+ }
+
+ stk->dcdc_en_gpio = devm_gpiod_get(dev, "dcdc", GPIOD_OUT_LOW);
+ if (IS_ERR(stk->dcdc_en_gpio)) {
+ ret = PTR_ERR(stk->dcdc_en_gpio);
+ dev_err(dev, "cannot get dcdc-en-gpio %d\n", ret);
+ return ret;
+ }
+
+ stk->backlight = drm_panel_create_dsi_backlight(stk->dsi);
+ if (IS_ERR(stk->backlight)) {
+ ret = PTR_ERR(stk->backlight);
+ dev_err(dev, "failed to register backlight %d\n", ret);
+ return ret;
+ }
+
+ drm_panel_init(&stk->base, &stk->dsi->dev, &stk_panel_funcs,
+ DRM_MODE_CONNECTOR_DSI);
+
+ drm_panel_add(&stk->base);
+
+ return 0;
+}
+
+static void stk_panel_del(struct stk_panel *stk)
+{
+ if (stk->base.dev)
+ drm_panel_remove(&stk->base);

Is the if() necessary ? Not sure, you can remove it and directly call drm_panel_remove(&stk->base);

+}
+
+static int stk_panel_probe(struct mipi_dsi_device *dsi)
+{
+ struct stk_panel *stk;
+ int ret;
+
+ dsi->lanes = 4;
+ dsi->format = MIPI_DSI_FMT_RGB888;
+ dsi->mode_flags = (MIPI_DSI_MODE_VIDEO |
+ MIPI_DSI_MODE_LPM);

This could be on a single line

+
+ stk = devm_kzalloc(&dsi->dev, sizeof(*stk), GFP_KERNEL);
+ if (!stk)
+ return -ENOMEM;
+
+ mipi_dsi_set_drvdata(dsi, stk);
+
+ stk->dsi = dsi;
+
+ ret = stk_panel_add(stk);
+ if (ret < 0)
+ return ret;
+
+ return mipi_dsi_attach(dsi);

You should call drm_panel_remove() if attach fails

+}
+
+static void stk_panel_remove(struct mipi_dsi_device *dsi)
+{
+ struct stk_panel *stk = mipi_dsi_get_drvdata(dsi);
+ int err;
+
+ err = stk_panel_disable(&stk->base);
+ if (err < 0)
+ dev_err(&dsi->dev, "failed to disable panel: %d\n", err) > +
+ err = mipi_dsi_detach(dsi);
+ if (err < 0)
+ dev_err(&dsi->dev, "failed to detach from DSI host: %d\n",
+ err);
+
+ stk_panel_del(stk);

Move the content of stk_panel_del() here, no need for a separate function.


+}
+
+static void stk_panel_shutdown(struct mipi_dsi_device *dsi)
+{
+ struct stk_panel *stk = mipi_dsi_get_drvdata(dsi);
+
+ stk_panel_disable(&stk->base);
+}
+
+static struct mipi_dsi_driver stk_panel_driver = {
+ .driver = {
+ .name = "panel-startek-kd070fhfid015",
+ .of_match_table = stk_of_match,
+ },
+ .probe = stk_panel_probe,
+ .remove = stk_panel_remove,
+ .shutdown = stk_panel_shutdown,
+};
+module_mipi_dsi_driver(stk_panel_driver);
+
+MODULE_AUTHOR("Guillaume La Roque <glaroque@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("STARTEK KD070FHFID015");
+MODULE_LICENSE("GPL");


Thanks,
Neil