Re: [PATCH v5 2/2] drm: panel: Add novatek nt36672a panel driver

From: Sam Ravnborg
Date: Sat Aug 29 2020 - 17:32:07 EST


Hi Sumit.

On Wed, Aug 26, 2020 at 09:33:08PM +0530, Sumit Semwal wrote:
> Novatek NT36672a is a generic DSI IC that drives command and video mode
> panels. Add the driver for it.
>
> Right now adding support for some Poco F1 phones that have an LCD panel
> from Tianma connected with this IC, with a resolution of 1080x2246 that
> operates in DSI video mode.
>
> During testing, Benni Steini <bennisteinir@xxxxxxxxx> helped us fix
> the reset sequence timing (from 10ms to 20ms), to get the bootanimation
> to work on Android.
>
> With current AOSP, we need to increase it to 200ms - this seems to be a
> safe high value to avoid a white screen occasionally.
>
> Signed-off-by: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
> Cc: Benni Steini <bennisteinir@xxxxxxxxx>
>
> ---
> v2: increase reset sequence timing to a safe 200ms
> v4: Since "0425662fdf05: drm: Nuke mode->vrefresh", we have to calculate
> vrefresh on demand. Update for it.
> v5: Fixed review comments from Sam:
> - rebased on top of drm-misc-next
> remove return of drm_panel_add()
> remove drm_panel_detach()
> - renamed the panel driver file to reflect that this is a novatek
> nt36672a display driver and not only for tianma panels.
> Adjusted some internal names also to reflect the same.
> - corrected changelog to add info about the generic Novatek DSI IC
> - corrected compatible string accordingly
> - removed pinctrl
> - used drm_panel* API for prepare/unprepare/disable/remove
Thanks for the detailed follow-up - very nice.

A few things slipped thought last review and we have gained support for
dv_err_probe() now. Also dev_err() and friends are now the right choice
for panel drivers.

Sam

> ---
> MAINTAINERS | 7 +
> drivers/gpu/drm/panel/Kconfig | 10 +
> drivers/gpu/drm/panel/Makefile | 1 +
> .../gpu/drm/panel/panel-novatek-nt36672a.c | 767 ++++++++++++++++++
> 4 files changed, 785 insertions(+)
> create mode 100644 drivers/gpu/drm/panel/panel-novatek-nt36672a.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 01fb9ee6b951..aeecade2d65f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5619,6 +5619,13 @@ T: git git://anongit.freedesktop.org/drm/drm-misc
> F: Documentation/devicetree/bindings/display/ste,mcde.txt
> F: drivers/gpu/drm/mcde/
>
> +DRM DRIVER FOR TIANMA NT36672A PANELS
> +M: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
> +S: Maintained
> +T: git git://anongit.freedesktop.org/drm/drm-misc
> +F: Documentation/devicetree/bindings/display/panel/tianma,nt36672a-panel.yaml
> +F: drivers/gpu/drm/panel/panel-tianma-nt36672a.c
> +
> DRM DRIVER FOR TDFX VIDEO CARDS
> S: Orphan / Obsolete
> F: drivers/gpu/drm/tdfx/
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 8d97d07c5871..02600f12a063 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -208,6 +208,16 @@ config DRM_PANEL_NOVATEK_NT35510
> around the Novatek NT35510 display controller, such as some
> Hydis panels.
>
> +config DRM_PANEL_NOVATEK_NT36672A
> + tristate "Novatek NT36672A DSI 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 the panels built
> + around the Novatek NT36672A display controller, such as some
> + Tianma panels used in a few Xiaomi Poco F1 mobile phone.
> +
> config DRM_PANEL_NOVATEK_NT39016
> tristate "Novatek NT39016 RGB/SPI panel"
> depends on OF && SPI
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 15a4e7752951..4a36eb45f670 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -19,6 +19,7 @@ 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_NOVATEK_NT35510) += panel-novatek-nt35510.o
> +obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36672A) += panel-novatek-nt36672a.o
> obj-$(CONFIG_DRM_PANEL_NOVATEK_NT39016) += panel-novatek-nt39016.o
> obj-$(CONFIG_DRM_PANEL_MANTIX_MLAF057WE51) += panel-mantix-mlaf057we51.o
> obj-$(CONFIG_DRM_PANEL_OLIMEX_LCD_OLINUXINO) += panel-olimex-lcd-olinuxino.o
> diff --git a/drivers/gpu/drm/panel/panel-novatek-nt36672a.c b/drivers/gpu/drm/panel/panel-novatek-nt36672a.c
> new file mode 100644
> index 000000000000..3f0c18e46818
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-novatek-nt36672a.c
> @@ -0,0 +1,767 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2020 Linaro Ltd
> + * Author: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
> + *
> + * This driver is for the DSI interface to panels using the NT36672A display driver IC
> + * from Novatek.
> + * Currently supported are the Tianma FHD+ panels found in some Xiaomi phones, including
> + * some variants of the Poco F1 phone.
> + *
> + * Panels using the Novatek NT37762A IC should add appropriate configuration per-panel and
> + * use this driver.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +
> +#include <linux/gpio/consumer.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <drm/drm_device.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
panels no longer use DRM_* for error print - use dev_err() and friends.
And then this include can go as well.

> +
> +#include <video/mipi_display.h>
> +
> +struct panel_cmd {
> + size_t len;
> + const char *data;
> +};
> +
> +#define _INIT_CMD(...) { \
> + .len = sizeof((char[]){__VA_ARGS__}), \
> + .data = (char[]){__VA_ARGS__} }
> +
> +static const char * const regulator_names[] = {
> + "vddio",
> + "vddpos",
> + "vddneg",
> +};
> +
> +static unsigned long const regulator_enable_loads[] = {
> + 62000,
> + 100000,
> + 100000
> +};
> +
> +static unsigned long const regulator_disable_loads[] = {
> + 80,
> + 100,
> + 100
> +};
> +
> +struct panel_desc {
> + const struct drm_display_mode *display_mode;
> + const char *panel_name;
> +
> + unsigned int width_mm;
> + unsigned int height_mm;
> +
> + unsigned long mode_flags;
> + enum mipi_dsi_pixel_format format;
> + unsigned int lanes;
> +
> + const struct panel_cmd *on_cmds_1;
> + const struct panel_cmd *on_cmds_2;
> +
> + const struct panel_cmd *off_cmds;
> +};
> +
> +struct panel_info {
> + struct drm_panel base;
> + struct mipi_dsi_device *link;
> + const struct panel_desc *desc;
> +
> + struct regulator_bulk_data supplies[ARRAY_SIZE(regulator_names)];
> +
> + struct gpio_desc *reset_gpio;
> +
> + bool prepared;
> + bool enabled;
There is no need for the enabled flag.

> +};
> +
> +static inline struct panel_info *to_panel_info(struct drm_panel *panel)
> +{
> + return container_of(panel, struct panel_info, base);
> +}
> +
> +static int send_mipi_cmds(struct drm_panel *panel, const struct panel_cmd *cmds)
> +{
> + struct panel_info *pinfo = to_panel_info(panel);
> + unsigned int i = 0;
> + int err;
> +
> + if (!cmds)
> + return -EFAULT;
> +
> + for (i = 0; cmds[i].len != 0; i++) {
> + const struct panel_cmd *cmd = &cmds[i];
> +
> + if (cmd->len == 2)
> + err = mipi_dsi_dcs_write(pinfo->link,
> + cmd->data[1], NULL, 0);
> + else
> + err = mipi_dsi_dcs_write(pinfo->link,
> + cmd->data[1], cmd->data + 2,
> + cmd->len - 2);
> +
> + if (err < 0)
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +static int nt36672a_panel_disable(struct drm_panel *panel)
> +{
> + struct panel_info *pinfo = to_panel_info(panel);
> +
> + pinfo->enabled = false;
> +
> + return 0;
> +}
The nt36672a_panel_disable() does not do anything - delete it.

> +
> +static int novatek_panel_power_off(struct drm_panel *panel)
> +{
> + struct panel_info *pinfo = to_panel_info(panel);
> + int i, ret = 0;
> +
> + gpiod_set_value(pinfo->reset_gpio, 0);
> +
> + for (i = 0; i < ARRAY_SIZE(pinfo->supplies); i++) {
> + ret = regulator_set_load(pinfo->supplies[i].consumer,
> + regulator_disable_loads[i]);
> + if (ret) {
> + DRM_DEV_ERROR(panel->dev, "regulator_set_load failed %d\n", ret);
USe dev_err(...) here, likewise for other similar uses.

> + return ret;
> + }
> + }
> +
> + ret = regulator_bulk_disable(ARRAY_SIZE(pinfo->supplies), pinfo->supplies);
> + if (ret)
> + DRM_DEV_ERROR(panel->dev, "regulator_bulk_disable failed %d\n", ret);
> +
> + return ret;
> +}
> +
> +static int nt36672a_panel_unprepare(struct drm_panel *panel)
> +{
> + struct panel_info *pinfo = to_panel_info(panel);
> + int ret;
> +
> + if (!pinfo->prepared)
> + return 0;
> +
> + /* send off cmds */
> + ret = send_mipi_cmds(panel, pinfo->desc->off_cmds);
> +
> + if (ret < 0)
> + DRM_DEV_ERROR(panel->dev, "failed to send DCS off cmds: %d\n", ret);
> +
> + ret = mipi_dsi_dcs_set_display_off(pinfo->link);
> + if (ret < 0)
> + DRM_DEV_ERROR(panel->dev, "set_display_off cmd failed ret = %d\n", ret);
> +
> + /* 120ms delay required here as per DCS spec */
> + msleep(120);
> +
> + ret = mipi_dsi_dcs_enter_sleep_mode(pinfo->link);
> + if (ret < 0)
> + DRM_DEV_ERROR(panel->dev, "enter_sleep cmd failed ret = %d\n", ret);
> +
> + /* 0x3C = 60ms delay */
> + msleep(60);
> +
> + ret = novatek_panel_power_off(panel);
> + if (ret < 0)
> + DRM_DEV_ERROR(panel->dev, "power_off failed ret = %d\n", ret);
> +
> + pinfo->prepared = false;
> +
> + return ret;
> +}
> +
> +static int novatek_panel_power_on(struct panel_info *pinfo)
> +{
> + int ret, i;
> +
> + for (i = 0; i < ARRAY_SIZE(pinfo->supplies); i++) {
> + ret = regulator_set_load(pinfo->supplies[i].consumer,
> + regulator_enable_loads[i]);
> + if (ret)
> + return ret;
> + }
> +
> + ret = regulator_bulk_enable(ARRAY_SIZE(pinfo->supplies), pinfo->supplies);
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * As per downstream kernel, Reset sequence of Tianma FHD panel requires the panel to
> + * be out of reset for 10ms, followed by being held in reset for 10ms. But for Android
> + * AOSP, we needed to bump it upto 200ms otherwise we get white screen sometimes.
> + * FIXME: Try to reduce this 200ms to a lesser value.
> + */
> + gpiod_set_value(pinfo->reset_gpio, 0);
> + msleep(200);
> + gpiod_set_value(pinfo->reset_gpio, 1);
> + msleep(200);
> +
> + return 0;
> +}
> +
> +static int nt36672a_panel_prepare(struct drm_panel *panel)
> +{
> + struct panel_info *pinfo = to_panel_info(panel);
> + int err;
> +
> + if (pinfo->prepared)
> + return 0;
> +
> + err = novatek_panel_power_on(pinfo);
> + if (err < 0)
> + goto poweroff;
> +
> + /* send first part of init cmds */
> + err = send_mipi_cmds(panel, pinfo->desc->on_cmds_1);
> +
> + if (err < 0) {
> + DRM_DEV_ERROR(panel->dev, "failed to send DCS Init 1st Code: %d\n", err);
> + goto poweroff;
> + }
> +
> + err = mipi_dsi_dcs_exit_sleep_mode(pinfo->link);
> + if (err < 0) {
> + DRM_DEV_ERROR(panel->dev, "failed to exit sleep mode: %d\n", err);
> + goto poweroff;
> + }
> +
> + /* 0x46 = 70 ms delay */
> + msleep(70);
> +
> + err = mipi_dsi_dcs_set_display_on(pinfo->link);
> + if (err < 0) {
> + DRM_DEV_ERROR(panel->dev, "failed to Set Display ON: %d\n", err);
> + goto poweroff;
> + }
> +
> + /* Send rest of the init cmds */
> + err = send_mipi_cmds(panel, pinfo->desc->on_cmds_2);
> +
> + if (err < 0) {
> + DRM_DEV_ERROR(panel->dev, "failed to send DCS Init 2nd Code: %d\n", err);
> + goto poweroff;
> + }
> +
> + msleep(120);
> +
> + pinfo->prepared = true;
> +
> + return 0;
> +
> +poweroff:
> + gpiod_set_value(pinfo->reset_gpio, 1);
> + return err;
> +}
> +
> +static int nt36672a_panel_enable(struct drm_panel *panel)
> +{
> + struct panel_info *pinfo = to_panel_info(panel);
> +
> + pinfo->enabled = true;
> +
> + return 0;
> +}
This function do not do anything - drop it.
> +
> +static int nt36672a_panel_get_modes(struct drm_panel *panel,
> + struct drm_connector *connector)
> +{
> + struct panel_info *pinfo = to_panel_info(panel);
> + const struct drm_display_mode *m = pinfo->desc->display_mode;
> + struct drm_display_mode *mode;
> +
> + mode = drm_mode_duplicate(connector->dev, m);
> + if (!mode) {
> + DRM_DEV_ERROR(panel->dev, "failed to add mode %ux%u@%u\n",
> + m->hdisplay, m->vdisplay, drm_mode_vrefresh(m));
> + return -ENOMEM;
> + }
> +
> + connector->display_info.width_mm = pinfo->desc->width_mm;
> + connector->display_info.height_mm = pinfo->desc->height_mm;
> +
> + drm_mode_set_name(mode);
> + drm_mode_probed_add(connector, mode);
> +
> + return 1;
> +}
> +
> +static const struct drm_panel_funcs panel_funcs = {
> + .disable = nt36672a_panel_disable,
> + .unprepare = nt36672a_panel_unprepare,
> + .prepare = nt36672a_panel_prepare,
> + .enable = nt36672a_panel_enable,
> + .get_modes = nt36672a_panel_get_modes,
> +};
> +
> +static const struct panel_cmd tianma_fhd_video_on_cmds_1[] = {
> + /* skin enhancement mode */
> + _INIT_CMD(0x00, 0xFF, 0x22),
> + _INIT_CMD(0x00, 0x00, 0x40),
> + _INIT_CMD(0x00, 0x01, 0xC0),
> + _INIT_CMD(0x00, 0x02, 0x40),
> + _INIT_CMD(0x00, 0x03, 0x40),
> + _INIT_CMD(0x00, 0x04, 0x40),
> + _INIT_CMD(0x00, 0x05, 0x40),
> + _INIT_CMD(0x00, 0x06, 0x40),
> + _INIT_CMD(0x00, 0x07, 0x40),
> + _INIT_CMD(0x00, 0x08, 0x40),
> + _INIT_CMD(0x00, 0x09, 0x40),
> + _INIT_CMD(0x00, 0x0A, 0x40),
> + _INIT_CMD(0x00, 0x0B, 0x40),
> + _INIT_CMD(0x00, 0x0C, 0x40),
> + _INIT_CMD(0x00, 0x0D, 0x40),
> + _INIT_CMD(0x00, 0x0E, 0x40),
> + _INIT_CMD(0x00, 0x0F, 0x40),
> + _INIT_CMD(0x00, 0x10, 0x40),
> + _INIT_CMD(0x00, 0x11, 0x50),
> + _INIT_CMD(0x00, 0x12, 0x60),
> + _INIT_CMD(0x00, 0x13, 0x70),
> + _INIT_CMD(0x00, 0x14, 0x58),
> + _INIT_CMD(0x00, 0x15, 0x68),
> + _INIT_CMD(0x00, 0x16, 0x78),
> + _INIT_CMD(0x00, 0x17, 0x77),
> + _INIT_CMD(0x00, 0x18, 0x39),
> + _INIT_CMD(0x00, 0x19, 0x2D),
> + _INIT_CMD(0x00, 0x1A, 0x2E),
> + _INIT_CMD(0x00, 0x1B, 0x32),
> + _INIT_CMD(0x00, 0x1C, 0x37),
> + _INIT_CMD(0x00, 0x1D, 0x3A),
> + _INIT_CMD(0x00, 0x1E, 0x40),
> + _INIT_CMD(0x00, 0x1F, 0x40),
> + _INIT_CMD(0x00, 0x20, 0x40),
> + _INIT_CMD(0x00, 0x21, 0x40),
> + _INIT_CMD(0x00, 0x22, 0x40),
> + _INIT_CMD(0x00, 0x23, 0x40),
> + _INIT_CMD(0x00, 0x24, 0x40),
> + _INIT_CMD(0x00, 0x25, 0x40),
> + _INIT_CMD(0x00, 0x26, 0x40),
> + _INIT_CMD(0x00, 0x27, 0x40),
> + _INIT_CMD(0x00, 0x28, 0x40),
> + _INIT_CMD(0x00, 0x2D, 0x00),
> + _INIT_CMD(0x00, 0x2F, 0x40),
> + _INIT_CMD(0x00, 0x30, 0x40),
> + _INIT_CMD(0x00, 0x31, 0x40),
> + _INIT_CMD(0x00, 0x32, 0x40),
> + _INIT_CMD(0x00, 0x33, 0x40),
> + _INIT_CMD(0x00, 0x34, 0x40),
> + _INIT_CMD(0x00, 0x35, 0x40),
> + _INIT_CMD(0x00, 0x36, 0x40),
> + _INIT_CMD(0x00, 0x37, 0x40),
> + _INIT_CMD(0x00, 0x38, 0x40),
> + _INIT_CMD(0x00, 0x39, 0x40),
> + _INIT_CMD(0x00, 0x3A, 0x40),
> + _INIT_CMD(0x00, 0x3B, 0x40),
> + _INIT_CMD(0x00, 0x3D, 0x40),
> + _INIT_CMD(0x00, 0x3F, 0x40),
> + _INIT_CMD(0x00, 0x40, 0x40),
> + _INIT_CMD(0x00, 0x41, 0x40),
> + _INIT_CMD(0x00, 0x42, 0x40),
> + _INIT_CMD(0x00, 0x43, 0x40),
> + _INIT_CMD(0x00, 0x44, 0x40),
> + _INIT_CMD(0x00, 0x45, 0x40),
> + _INIT_CMD(0x00, 0x46, 0x40),
> + _INIT_CMD(0x00, 0x47, 0x40),
> + _INIT_CMD(0x00, 0x48, 0x40),
> + _INIT_CMD(0x00, 0x49, 0x40),
> + _INIT_CMD(0x00, 0x4A, 0x40),
> + _INIT_CMD(0x00, 0x4B, 0x40),
> + _INIT_CMD(0x00, 0x4C, 0x40),
> + _INIT_CMD(0x00, 0x4D, 0x40),
> + _INIT_CMD(0x00, 0x4E, 0x40),
> + _INIT_CMD(0x00, 0x4F, 0x40),
> + _INIT_CMD(0x00, 0x50, 0x40),
> + _INIT_CMD(0x00, 0x51, 0x40),
> + _INIT_CMD(0x00, 0x52, 0x40),
> + _INIT_CMD(0x00, 0x53, 0x01),
> + _INIT_CMD(0x00, 0x54, 0x01),
> + _INIT_CMD(0x00, 0x55, 0xFE),
> + _INIT_CMD(0x00, 0x56, 0x77),
> + _INIT_CMD(0x00, 0x58, 0xCD),
> + _INIT_CMD(0x00, 0x59, 0xD0),
> + _INIT_CMD(0x00, 0x5A, 0xD0),
> + _INIT_CMD(0x00, 0x5B, 0x50),
> + _INIT_CMD(0x00, 0x5C, 0x50),
> + _INIT_CMD(0x00, 0x5D, 0x50),
> + _INIT_CMD(0x00, 0x5E, 0x50),
> + _INIT_CMD(0x00, 0x5F, 0x50),
> + _INIT_CMD(0x00, 0x60, 0x50),
> + _INIT_CMD(0x00, 0x61, 0x50),
> + _INIT_CMD(0x00, 0x62, 0x50),
> + _INIT_CMD(0x00, 0x63, 0x50),
> + _INIT_CMD(0x00, 0x64, 0x50),
> + _INIT_CMD(0x00, 0x65, 0x50),
> + _INIT_CMD(0x00, 0x66, 0x50),
> + _INIT_CMD(0x00, 0x67, 0x50),
> + _INIT_CMD(0x00, 0x68, 0x50),
> + _INIT_CMD(0x00, 0x69, 0x50),
> + _INIT_CMD(0x00, 0x6A, 0x50),
> + _INIT_CMD(0x00, 0x6B, 0x50),
> + _INIT_CMD(0x00, 0x6C, 0x50),
> + _INIT_CMD(0x00, 0x6D, 0x50),
> + _INIT_CMD(0x00, 0x6E, 0x50),
> + _INIT_CMD(0x00, 0x6F, 0x50),
> + _INIT_CMD(0x00, 0x70, 0x07),
> + _INIT_CMD(0x00, 0x71, 0x00),
> + _INIT_CMD(0x00, 0x72, 0x00),
> + _INIT_CMD(0x00, 0x73, 0x00),
> + _INIT_CMD(0x00, 0x74, 0x06),
> + _INIT_CMD(0x00, 0x75, 0x0C),
> + _INIT_CMD(0x00, 0x76, 0x03),
> + _INIT_CMD(0x00, 0x77, 0x09),
> + _INIT_CMD(0x00, 0x78, 0x0F),
> + _INIT_CMD(0x00, 0x79, 0x68),
> + _INIT_CMD(0x00, 0x7A, 0x88),
> + _INIT_CMD(0x00, 0x7C, 0x80),
> + _INIT_CMD(0x00, 0x7D, 0x80),
> + _INIT_CMD(0x00, 0x7E, 0x80),
> + _INIT_CMD(0x00, 0x7F, 0x00),
> + _INIT_CMD(0x00, 0x80, 0x00),
> + _INIT_CMD(0x00, 0x81, 0x00),
> + _INIT_CMD(0x00, 0x83, 0x01),
> + _INIT_CMD(0x00, 0x84, 0x00),
> + _INIT_CMD(0x00, 0x85, 0x80),
> + _INIT_CMD(0x00, 0x86, 0x80),
> + _INIT_CMD(0x00, 0x87, 0x80),
> + _INIT_CMD(0x00, 0x88, 0x40),
> + _INIT_CMD(0x00, 0x89, 0x91),
> + _INIT_CMD(0x00, 0x8A, 0x98),
> + _INIT_CMD(0x00, 0x8B, 0x80),
> + _INIT_CMD(0x00, 0x8C, 0x80),
> + _INIT_CMD(0x00, 0x8D, 0x80),
> + _INIT_CMD(0x00, 0x8E, 0x80),
> + _INIT_CMD(0x00, 0x8F, 0x80),
> + _INIT_CMD(0x00, 0x90, 0x80),
> + _INIT_CMD(0x00, 0x91, 0x80),
> + _INIT_CMD(0x00, 0x92, 0x80),
> + _INIT_CMD(0x00, 0x93, 0x80),
> + _INIT_CMD(0x00, 0x94, 0x80),
> + _INIT_CMD(0x00, 0x95, 0x80),
> + _INIT_CMD(0x00, 0x96, 0x80),
> + _INIT_CMD(0x00, 0x97, 0x80),
> + _INIT_CMD(0x00, 0x98, 0x80),
> + _INIT_CMD(0x00, 0x99, 0x80),
> + _INIT_CMD(0x00, 0x9A, 0x80),
> + _INIT_CMD(0x00, 0x9B, 0x80),
> + _INIT_CMD(0x00, 0x9C, 0x80),
> + _INIT_CMD(0x00, 0x9D, 0x80),
> + _INIT_CMD(0x00, 0x9E, 0x80),
> + _INIT_CMD(0x00, 0x9F, 0x80),
> + _INIT_CMD(0x00, 0xA0, 0x8A),
> + _INIT_CMD(0x00, 0xA2, 0x80),
> + _INIT_CMD(0x00, 0xA6, 0x80),
> + _INIT_CMD(0x00, 0xA7, 0x80),
> + _INIT_CMD(0x00, 0xA9, 0x80),
> + _INIT_CMD(0x00, 0xAA, 0x80),
> + _INIT_CMD(0x00, 0xAB, 0x80),
> + _INIT_CMD(0x00, 0xAC, 0x80),
> + _INIT_CMD(0x00, 0xAD, 0x80),
> + _INIT_CMD(0x00, 0xAE, 0x80),
> + _INIT_CMD(0x00, 0xAF, 0x80),
> + _INIT_CMD(0x00, 0xB7, 0x76),
> + _INIT_CMD(0x00, 0xB8, 0x76),
> + _INIT_CMD(0x00, 0xB9, 0x05),
> + _INIT_CMD(0x00, 0xBA, 0x0D),
> + _INIT_CMD(0x00, 0xBB, 0x14),
> + _INIT_CMD(0x00, 0xBC, 0x0F),
> + _INIT_CMD(0x00, 0xBD, 0x18),
> + _INIT_CMD(0x00, 0xBE, 0x1F),
> + _INIT_CMD(0x00, 0xBF, 0x05),
> + _INIT_CMD(0x00, 0xC0, 0x0D),
> + _INIT_CMD(0x00, 0xC1, 0x14),
> + _INIT_CMD(0x00, 0xC2, 0x03),
> + _INIT_CMD(0x00, 0xC3, 0x07),
> + _INIT_CMD(0x00, 0xC4, 0x0A),
> + _INIT_CMD(0x00, 0xC5, 0xA0),
> + _INIT_CMD(0x00, 0xC6, 0x55),
> + _INIT_CMD(0x00, 0xC7, 0xFF),
> + _INIT_CMD(0x00, 0xC8, 0x39),
> + _INIT_CMD(0x00, 0xC9, 0x44),
> + _INIT_CMD(0x00, 0xCA, 0x12),
> + _INIT_CMD(0x00, 0xCD, 0x80),
> + _INIT_CMD(0x00, 0xDB, 0x80),
> + _INIT_CMD(0x00, 0xDC, 0x80),
> + _INIT_CMD(0x00, 0xDD, 0x80),
> + _INIT_CMD(0x00, 0xE0, 0x80),
> + _INIT_CMD(0x00, 0xE1, 0x80),
> + _INIT_CMD(0x00, 0xE2, 0x80),
> + _INIT_CMD(0x00, 0xE3, 0x80),
> + _INIT_CMD(0x00, 0xE4, 0x80),
> + _INIT_CMD(0x00, 0xE5, 0x40),
> + _INIT_CMD(0x00, 0xE6, 0x40),
> + _INIT_CMD(0x00, 0xE7, 0x40),
> + _INIT_CMD(0x00, 0xE8, 0x40),
> + _INIT_CMD(0x00, 0xE9, 0x40),
> + _INIT_CMD(0x00, 0xEA, 0x40),
> + _INIT_CMD(0x00, 0xEB, 0x40),
> + _INIT_CMD(0x00, 0xEC, 0x40),
> + _INIT_CMD(0x00, 0xED, 0x40),
> + _INIT_CMD(0x00, 0xEE, 0x40),
> + _INIT_CMD(0x00, 0xEF, 0x40),
> + _INIT_CMD(0x00, 0xF0, 0x40),
> + _INIT_CMD(0x00, 0xF1, 0x40),
> + _INIT_CMD(0x00, 0xF2, 0x40),
> + _INIT_CMD(0x00, 0xF3, 0x40),
> + _INIT_CMD(0x00, 0xF4, 0x40),
> + _INIT_CMD(0x00, 0xF5, 0x40),
> + _INIT_CMD(0x00, 0xF6, 0x40),
> + _INIT_CMD(0x00, 0xFB, 0x1),
> + _INIT_CMD(0x00, 0xFF, 0x23),
> + _INIT_CMD(0x00, 0xFB, 0x01),
> + /* dimming enable */
> + _INIT_CMD(0x00, 0x01, 0x84),
> + _INIT_CMD(0x00, 0x05, 0x2D),
> + _INIT_CMD(0x00, 0x06, 0x00),
> + /* resolution 1080*2246 */
> + _INIT_CMD(0x00, 0x11, 0x01),
> + _INIT_CMD(0x00, 0x12, 0x7B),
> + _INIT_CMD(0x00, 0x15, 0x6F),
> + _INIT_CMD(0x00, 0x16, 0x0B),
> + /* UI mode */
> + _INIT_CMD(0x00, 0x29, 0x0A),
> + _INIT_CMD(0x00, 0x30, 0xFF),
> + _INIT_CMD(0x00, 0x31, 0xFF),
> + _INIT_CMD(0x00, 0x32, 0xFF),
> + _INIT_CMD(0x00, 0x33, 0xFF),
> + _INIT_CMD(0x00, 0x34, 0xFF),
> + _INIT_CMD(0x00, 0x35, 0xFF),
> + _INIT_CMD(0x00, 0x36, 0xFF),
> + _INIT_CMD(0x00, 0x37, 0xFF),
> + _INIT_CMD(0x00, 0x38, 0xFC),
> + _INIT_CMD(0x00, 0x39, 0xF8),
> + _INIT_CMD(0x00, 0x3A, 0xF4),
> + _INIT_CMD(0x00, 0x3B, 0xF1),
> + _INIT_CMD(0x00, 0x3D, 0xEE),
> + _INIT_CMD(0x00, 0x3F, 0xEB),
> + _INIT_CMD(0x00, 0x40, 0xE8),
> + _INIT_CMD(0x00, 0x41, 0xE5),
> + /* STILL mode */
> + _INIT_CMD(0x00, 0x2A, 0x13),
> + _INIT_CMD(0x00, 0x45, 0xFF),
> + _INIT_CMD(0x00, 0x46, 0xFF),
> + _INIT_CMD(0x00, 0x47, 0xFF),
> + _INIT_CMD(0x00, 0x48, 0xFF),
> + _INIT_CMD(0x00, 0x49, 0xFF),
> + _INIT_CMD(0x00, 0x4A, 0xFF),
> + _INIT_CMD(0x00, 0x4B, 0xFF),
> + _INIT_CMD(0x00, 0x4C, 0xFF),
> + _INIT_CMD(0x00, 0x4D, 0xED),
> + _INIT_CMD(0x00, 0x4E, 0xD5),
> + _INIT_CMD(0x00, 0x4F, 0xBF),
> + _INIT_CMD(0x00, 0x50, 0xA6),
> + _INIT_CMD(0x00, 0x51, 0x96),
> + _INIT_CMD(0x00, 0x52, 0x86),
> + _INIT_CMD(0x00, 0x53, 0x76),
> + _INIT_CMD(0x00, 0x54, 0x66),
> + /* MOVING mode */
> + _INIT_CMD(0x00, 0x2B, 0x0E),
> + _INIT_CMD(0x00, 0x58, 0xFF),
> + _INIT_CMD(0x00, 0x59, 0xFF),
> + _INIT_CMD(0x00, 0x5A, 0xFF),
> + _INIT_CMD(0x00, 0x5B, 0xFF),
> + _INIT_CMD(0x00, 0x5C, 0xFF),
> + _INIT_CMD(0x00, 0x5D, 0xFF),
> + _INIT_CMD(0x00, 0x5E, 0xFF),
> + _INIT_CMD(0x00, 0x5F, 0xFF),
> + _INIT_CMD(0x00, 0x60, 0xF6),
> + _INIT_CMD(0x00, 0x61, 0xEA),
> + _INIT_CMD(0x00, 0x62, 0xE1),
> + _INIT_CMD(0x00, 0x63, 0xD8),
> + _INIT_CMD(0x00, 0x64, 0xCE),
> + _INIT_CMD(0x00, 0x65, 0xC3),
> + _INIT_CMD(0x00, 0x66, 0xBA),
> + _INIT_CMD(0x00, 0x67, 0xB3),
> + _INIT_CMD(0x00, 0xFF, 0x25),
> + _INIT_CMD(0x00, 0xFB, 0x01),
> + _INIT_CMD(0x00, 0x05, 0x04),
> + _INIT_CMD(0x00, 0xFF, 0x26),
> + _INIT_CMD(0x00, 0xFB, 0x01),
> + _INIT_CMD(0x00, 0x1C, 0xAF),
> + _INIT_CMD(0x00, 0xFF, 0x10),
> + _INIT_CMD(0x00, 0xFB, 0x01),
> + _INIT_CMD(0x00, 0x51, 0xFF),
> + _INIT_CMD(0x00, 0x53, 0x24),
> + _INIT_CMD(0x00, 0x55, 0x00),
> +
> + {},
> +};
> +
> +static const struct panel_cmd tianma_fhd_video_on_cmds_2[] = {
> + _INIT_CMD(0x00, 0xFF, 0x24),
> + _INIT_CMD(0x00, 0xFB, 0x01),
> + _INIT_CMD(0x00, 0xC3, 0x01),
> + _INIT_CMD(0x00, 0xC4, 0x54),
> + _INIT_CMD(0x00, 0xFF, 0x10),
> +
> + {},
> +};
> +
> +static const struct panel_cmd tianma_fhd_video_off_cmds[] = {
> + _INIT_CMD(0x00, 0xFF, 0x24),
> + _INIT_CMD(0x00, 0xFB, 0x01),
> + _INIT_CMD(0x00, 0xC3, 0x01),
> + _INIT_CMD(0x00, 0xFF, 0x10),
> +
> + {},
> +};
> +
> +static const struct drm_display_mode tianma_fhd_video_panel_default_mode = {
> + .clock = 161331,
> +
> + .hdisplay = 1080,
> + .hsync_start = 1080 + 40,
> + .hsync_end = 1080 + 40 + 20,
> + .htotal = 1080 + 40 + 20 + 44,
> +
> + .vdisplay = 2246,
> + .vsync_start = 2246 + 15,
> + .vsync_end = 2246 + 15 + 2,
> + .vtotal = 2246 + 15 + 2 + 8,
> +
> + .type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
> +};
> +
> +static const struct panel_desc tianma_fhd_video_panel_desc = {
> + .display_mode = &tianma_fhd_video_panel_default_mode,
> +
> + .width_mm = 68,
> + .height_mm = 136,
> +
> + .mode_flags = MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_VIDEO
> + | MIPI_DSI_MODE_VIDEO_HSE
> + | MIPI_DSI_CLOCK_NON_CONTINUOUS
> + | MIPI_DSI_MODE_VIDEO_BURST,
> + .format = MIPI_DSI_FMT_RGB888,
> + .lanes = 4,
> + .on_cmds_1 = tianma_fhd_video_on_cmds_1,
> + .on_cmds_2 = tianma_fhd_video_on_cmds_2,
> + .off_cmds = tianma_fhd_video_off_cmds
> +};
> +
> +static int panel_add(struct panel_info *pinfo)
> +{
> + struct device *dev = &pinfo->link->dev;
> + int i, ret;
> +
> + for (i = 0; i < ARRAY_SIZE(pinfo->supplies); i++)
> + pinfo->supplies[i].supply = regulator_names[i];
> +
> + ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(pinfo->supplies),
> + pinfo->supplies);
> + if (ret < 0)
> + return ret;
Use dev_err_probe() here - so the driver then also support -EPROBE_DEFER
correct in this case.

> +
> + pinfo->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> + if (IS_ERR(pinfo->reset_gpio)) {
> + DRM_DEV_ERROR(dev, "cannot get reset gpio %ld\n",
> + PTR_ERR(pinfo->reset_gpio));
> + return PTR_ERR(pinfo->reset_gpio);
> + }
Use dev_Err_probe() here, thus also fixing that the driver then supports
-EPROBE_DEFER.

> +
> + drm_panel_init(&pinfo->base, dev, &panel_funcs,
> + DRM_MODE_CONNECTOR_DSI);
> +
> + drm_panel_add(&pinfo->base);
> +
> + return 0;
> +}
> +
> +static int panel_probe(struct mipi_dsi_device *dsi)
> +{
> + struct panel_info *pinfo;
> + const struct panel_desc *desc;
> + int err;
> +
> + pinfo = devm_kzalloc(&dsi->dev, sizeof(*pinfo), GFP_KERNEL);
> + if (!pinfo)
> + return -ENOMEM;
> +
> + desc = of_device_get_match_data(&dsi->dev);
> + dsi->mode_flags = desc->mode_flags;
> + dsi->format = desc->format;
> + dsi->lanes = desc->lanes;
> + pinfo->desc = desc;
> + pinfo->link = dsi;
> +
> + mipi_dsi_set_drvdata(dsi, pinfo);
> +
> + err = panel_add(pinfo);
> + if (err < 0)
> + return err;
> +
> + return mipi_dsi_attach(dsi);
> +}
> +
> +static int panel_remove(struct mipi_dsi_device *dsi)
> +{
> + struct panel_info *pinfo = mipi_dsi_get_drvdata(dsi);
> + int err;
> +
> + err = drm_panel_unprepare(&pinfo->base);
> + if (err < 0)
> + DRM_DEV_ERROR(&dsi->dev, "failed to unprepare panel: %d\n",
> + err);
> +
> + err = drm_panel_disable(&pinfo->base);
> + if (err < 0)
> + DRM_DEV_ERROR(&dsi->dev, "failed to disable panel: %d\n", err);
> +
> + err = mipi_dsi_detach(dsi);
> + if (err < 0)
> + DRM_DEV_ERROR(&dsi->dev, "failed to detach from DSI host: %d\n",
> + err);
> +
> + drm_panel_remove(&pinfo->base);
> +
> + return 0;
> +}
> +
> +static void panel_shutdown(struct mipi_dsi_device *dsi)
> +{
> + struct panel_info *pinfo = mipi_dsi_get_drvdata(dsi);
> +
> + drm_panel_disable(&pinfo->base);
> + drm_panel_unprepare(&pinfo->base);
> +}
> +
> +static const struct of_device_id tianma_fhd_video_of_match[] = {
> + { .compatible = "tianma,fhd-video",
> + .data = &tianma_fhd_video_panel_desc
> + },
> + {
> + /* sentinel */
> + }
> +};
> +MODULE_DEVICE_TABLE(of, tianma_fhd_video_of_match);
> +
> +static struct mipi_dsi_driver panel_driver = {
> + .driver = {
> + .name = "panel-tianma-nt36672a",
> + .of_match_table = tianma_fhd_video_of_match,
> + },
> + .probe = panel_probe,
> + .remove = panel_remove,
> + .shutdown = panel_shutdown,
> +};
> +module_mipi_dsi_driver(panel_driver);
> +
> +MODULE_AUTHOR("Sumit Semwal <sumit.semwal@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("NOVATEK NT36672A based MIPI-DSI LCD panel driver");
> +MODULE_LICENSE("GPL");
> --
> 2.28.0