Re: [PATCH v4 2/2] drm/panel: Add driver for Novatek NT36523

Konrad Dybcio
2023-03-10T18:10:41Z

On 10.03.2023 14:21, Jianhua Lu wrote:
> Add a driver for panels using the Novatek NT36523 display driver IC.
>
> Signed-off-by: Jianhua Lu <lujianhua000@gmail.com>
> ---
> Changes in v4:
> - add multiple modes support
> - use dev_err_probe helper
> - fix dsi_info type string
> - reimplement mipi_dsi_dual_dcs_write_seq() macro
>
> Changes in v3:
> - Refactor source code
>
> Changes in v2:
> - Refactor and clean up source code
>
> MAINTAINERS | 7 +
> drivers/gpu/drm/panel/Kconfig | 10 +
> drivers/gpu/drm/panel/Makefile | 1 +
> drivers/gpu/drm/panel/panel-novatek-nt36523.c | 771 ++++++++++++++++++
> 4 files changed, 789 insertions(+)
> create mode 100644 drivers/gpu/drm/panel/panel-novatek-nt36523.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5383af5d3b45..3586248bb05d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6537,6 +6537,13 @@ T: git git://anongit.freedesktop.org/drm/drm-misc
> F: Documentation/devicetree/bindings/display/panel/sony,acx424akp.yaml
> F: drivers/gpu/drm/panel/panel-novatek-nt35560.c
>
> +DRM DRIVER FOR NOVATEK NT36523 PANELS
> +M: Jianhua Lu <lujianhua000@gmail.com>
> +S: Maintained
> +T: git git://anongit.freedesktop.org/drm/drm-misc
> +F: Documentation/devicetree/bindings/display/panel/novatek,nt36523.yaml
> +F: drivers/gpu/drm/panel/panel-novatek-nt36523.c
> +
> DRM DRIVER FOR NOVATEK NT36672A PANELS
> M: Sumit Semwal <sumit.semwal@linaro.org>
> S: Maintained
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 8eeee71c0000..268508743b5c 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -377,6 +377,16 @@ config DRM_PANEL_NOVATEK_NT35950
> Sharp panels used in Sony Xperia Z5 Premium and XZ Premium
> mobile phones.
>
> +config DRM_PANEL_NOVATEK_NT36523
> + tristate "Novatek NT36523 panel driver"
> + 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 NT36523 display controller, such as some
> + Boe panels used in Xiaomi Mi Pad 5 and 5 Pro tablets.
> +
> config DRM_PANEL_NOVATEK_NT36672A
> tristate "Novatek NT36672A DSI panel"
> depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index c05aa9e23907..570eab8bf2b2 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -35,6 +35,7 @@ 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
> +obj-$(CONFIG_DRM_PANEL_NOVATEK_NT36523) += panel-novatek-nt36523.o
> obj-$(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
> diff --git a/drivers/gpu/drm/panel/panel-novatek-nt36523.c b/drivers/gpu/drm/panel/panel-novatek-nt36523.c
> new file mode 100644
> index 000000000000..78232c2735ff
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-novatek-nt36523.c
> @@ -0,0 +1,771 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Novatek NT36523 DriverIC panels driver
> + *
> + * Copyright (c) 2022, 2023 Jianhua Lu <lujianhua000@gmail.com>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/of_graph.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <drm/drm_connector.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +
> +#define DSI_NUM_MIN 1
> +
> +#define mipi_dsi_dual_dcs_write_seq(dsi0, dsi1, cmd, seq...) \
> + do { \
> + mipi_dsi_dcs_write_seq(dsi0, cmd, seq); \
> + mipi_dsi_dcs_write_seq(dsi1, cmd, seq); \
> + } while (0)
This should be in the same file as mipi_dsi_dcs_write_seq, imo

[...]

> +static int elish_boe_init_sequence(struct panel_info *pinfo)
> +{
> + struct mipi_dsi_device *dsi0 = pinfo->dsi[0];
> + struct mipi_dsi_device *dsi1 = pinfo->dsi[1];
> + /* No datasheet, so write magic init sequence directly */
> + mipi_dsi_dual_dcs_write_seq(dsi0, dsi1, 0xFF, 0x10);
> + mipi_dsi_dual_dcs_write_seq(dsi0, dsi1, 0xFB, 0x01);
> + mipi_dsi_dual_dcs_write_seq(dsi0, dsi1, 0xB9, 0x05);
Non-#defines should use lowercase hex

[...]

> + msleep(70);
> + mipi_dsi_dual_dcs_write_seq(dsi0, dsi1, 0x29);
> + return 0;
I think it's a general practice to add a newline before the return
statement, but that's just a nit that triggered my OCD..

[...]

> + struct drm_connector *connector)
> +{
> + struct panel_info *pinfo = to_panel_info(panel);
> + int i;
> +
> + for (i =0; i < pinfo->desc->num_modes; i++) {
missing space after =
> + const struct drm_display_mode *m = &pinfo->desc->modes[i];
> + struct drm_display_mode *mode;
Missing newline between declarations and code

> + mode = drm_mode_duplicate(connector->dev, m);
> + if (!mode) {
> + dev_err(panel->dev, "failed to add mode %ux%u@%u\n",
> + m->hdisplay, m->vdisplay, drm_mode_vrefresh(m));
> + return -ENOMEM;
> + }
> + mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
DRM_MODE_TYPE_PREFERRED: Preferred mode, usually the native resolution of an LCD panel. There should only be one preferred mode per connector at any given time.

https://docs.kernel.org/gpu/drm-kms.html

I'd suggest adding something like:

if (i == 0)
mode->type |= DRM_MODE_TYPE_PREFERRED

I think I've ran out of things to complain about.. And that's
a good thing! :D

Konrad
> + drm_mode_set_name(mode);
> + drm_mode_probed_add(connector, mode);
> + }
> +
> + connector->display_info.width_mm = pinfo->desc->width_mm;
> + connector->display_info.height_mm = pinfo->desc->height_mm;
> + connector->display_info.bpc = pinfo->desc->bpc;
> +
> + return pinfo->desc->num_modes;
> +}
> +
> +static const struct drm_panel_funcs nt36523_panel_funcs = {
> + .disable = nt36523_disable,
> + .prepare = nt36523_prepare,
> + .unprepare = nt36523_unprepare,
> + .get_modes = nt36523_get_modes,
> +};
> +
> +static int nt36523_probe(struct mipi_dsi_device *dsi)
> +{
> + struct device *dev = &dsi->dev;
> + struct device_node *dsi1;
> + struct mipi_dsi_host *dsi1_host;
> + struct panel_info *pinfo;
> + const struct mipi_dsi_device_info *info;
> + int i, ret;
> +
> + pinfo = devm_kzalloc(dev, sizeof(*pinfo), GFP_KERNEL);
> + if (!pinfo)
> + return -ENOMEM;
> +
> + pinfo->vddio = devm_regulator_get(dev, "vddio");
> + if (IS_ERR(pinfo->vddio))
> + return dev_err_probe(dev, PTR_ERR(pinfo->vddio), "failed to get vddio regulator\n");
> +
> + pinfo->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> + if (IS_ERR(pinfo->reset_gpio))
> + return dev_err_probe(dev, PTR_ERR(pinfo->reset_gpio), "failed to get reset gpio\n");
> +
> + pinfo->desc = of_device_get_match_data(dev);
> + if (!pinfo->desc)
> + return -ENODEV;
> +
> + /* If the panel is dual dsi, register DSI1 */
> + if (pinfo->desc->is_dual_dsi) {
> + info = &pinfo->desc->dsi_info;
> +
> + dsi1 = of_graph_get_remote_node(dsi->dev.of_node, 1, -1);
> + if (!dsi1) {
> + dev_err(dev, "cannot get secondary DSI node.\n");
> + return -ENODEV;
> + }
> +
> + dsi1_host = of_find_mipi_dsi_host_by_node(dsi1);
> + of_node_put(dsi1);
> + if (!dsi1_host) {
> + return dev_err_probe(dev, -EPROBE_DEFER, "cannot get secondary DSI host\n");
> + }
> +
> + pinfo->dsi[1] = mipi_dsi_device_register_full(dsi1_host, info);
> + if (!pinfo->dsi[1]) {
> + dev_err(dev, "cannot get secondary DSI device\n");
> + return -ENODEV;
> + }
> + }
> +
> + pinfo->dsi[0] = dsi;
> + mipi_dsi_set_drvdata(dsi, pinfo);
> + drm_panel_init(&pinfo->panel, dev, &nt36523_panel_funcs, DRM_MODE_CONNECTOR_DSI);
> +
> + ret = drm_panel_of_backlight(&pinfo->panel);
> + if (ret)
> + return dev_err_probe(dev, ret, "failed to get backlight\n");
> +
> + drm_panel_add(&pinfo->panel);
> +
> + for (i = 0; i < DSI_NUM_MIN + pinfo->desc->is_dual_dsi; i++) {
> + pinfo->dsi[i]->lanes = pinfo->desc->lanes;
> + pinfo->dsi[i]->format = pinfo->desc->format;
> + pinfo->dsi[i]->mode_flags = pinfo->desc->mode_flags;
> +
> + ret = mipi_dsi_attach(pinfo->dsi[i]);
> + if (ret < 0)
> + return dev_err_probe(dev, ret, "cannot attach to DSI%d host.\n", i);
> + }
> +
> + return 0;
> +}
> +
> +static const struct of_device_id nt36523_of_match[] = {
> + {
> + .compatible = "xiaomi,elish-boe-nt36523",
> + .data = &elish_boe_desc,
> + },
> + {
> + .compatible = "xiaomi,elish-csot-nt36523",
> + .data = &elish_csot_desc,
> + },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, nt36523_of_match);
> +
> +static struct mipi_dsi_driver nt36523_driver = {
> + .probe = nt36523_probe,
> + .remove = nt36523_remove,
> + .driver = {
> + .name = "panel-novatek-nt36523",
> + .of_match_table = nt36523_of_match,
> + },
> +};
> +module_mipi_dsi_driver(nt36523_driver);
> +
> +MODULE_AUTHOR("Jianhua Lu <lujianhua000@gmail.com>");
> +MODULE_DESCRIPTION("DRM driver for Novatek NT36523 based MIPI DSI panels");
> +MODULE_LICENSE("GPL");