Commit aecb583c authored by Konrad Dybcio's avatar Konrad Dybcio Committed by Neil Armstrong
Browse files

drm/panel: nt36523: Add DCS backlight support 



This chip supports controlling the backlight via DCS commands, on at
least some panels. Add support for doing so.

Note this may only concern the NT36523*W* variant. Nobody knows, really,
there's no docs.

Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: default avatarJianhua Lu <lujianhua000@gmail.com>
Signed-off-by: default avatarKonrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: default avatarNeil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230412-topic-lenovopanel-v3-2-bcf9ba4de46f@linaro.org
parent b4b26ab2

drivers/gpu/drm/panel/panel-novatek-nt36523.c

+65 −3
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 * Copyright (c) 2022, 2023 Jianhua Lu <lujianhua000@gmail.com>

 */



#include <linux/backlight.h>

#include <linux/delay.h>

#include <linux/gpio/consumer.h>

#include <linux/module.h>
@@ -53,6 +54,7 @@ struct panel_desc { 
	int (*init_sequence)(struct panel_info *pinfo);



	bool is_dual_dsi;

	bool has_dcs_backlight;

};



static inline struct panel_info *to_panel_info(struct drm_panel *panel)
@@ -679,6 +681,59 @@ static const struct drm_panel_funcs nt36523_panel_funcs = { 
	.get_modes = nt36523_get_modes,

};



static int nt36523_bl_update_status(struct backlight_device *bl)

{

	struct mipi_dsi_device *dsi = bl_get_data(bl);

	u16 brightness = backlight_get_brightness(bl);

	int ret;



	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;



	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);

	if (ret < 0)

		return ret;



	dsi->mode_flags |= MIPI_DSI_MODE_LPM;



	return 0;

}



static int nt36523_bl_get_brightness(struct backlight_device *bl)

{

	struct mipi_dsi_device *dsi = bl_get_data(bl);

	u16 brightness;

	int ret;



	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;



	ret = mipi_dsi_dcs_get_display_brightness_large(dsi, &brightness);

	if (ret < 0)

		return ret;



	dsi->mode_flags |= MIPI_DSI_MODE_LPM;



	return brightness;

}



static const struct backlight_ops nt36523_bl_ops = {

	.update_status = nt36523_bl_update_status,

	.get_brightness = nt36523_bl_get_brightness,

};



static struct backlight_device *nt36523_create_backlight(struct mipi_dsi_device *dsi)

{

	struct device *dev = &dsi->dev;

	const struct backlight_properties props = {

		.type = BACKLIGHT_RAW,

		.brightness = 512,

		.max_brightness = 4095,

		.scale = BACKLIGHT_SCALE_NON_LINEAR,

	};



	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,

					      &nt36523_bl_ops, &props);

}



static int nt36523_probe(struct mipi_dsi_device *dsi)

{

	struct device *dev = &dsi->dev;
@@ -730,9 +785,16 @@ static int nt36523_probe(struct mipi_dsi_device *dsi) 
	mipi_dsi_set_drvdata(dsi, pinfo);

	drm_panel_init(&pinfo->panel, dev, &nt36523_panel_funcs, DRM_MODE_CONNECTOR_DSI);



	if (pinfo->desc->has_dcs_backlight) {

		pinfo->panel.backlight = nt36523_create_backlight(dsi);

		if (IS_ERR(pinfo->panel.backlight))

			return dev_err_probe(dev, PTR_ERR(pinfo->panel.backlight),

					     "Failed to create backlight\n");

	} else {

		ret = drm_panel_of_backlight(&pinfo->panel);

		if (ret)

		return dev_err_probe(dev, ret, "failed to get backlight\n");

			return dev_err_probe(dev, ret, "Failed to get backlight\n");

	}



	drm_panel_add(&pinfo->panel);