TX2 enable a DSI LCD

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Hi all,
i want to enable a dsi lcd, From the L4T document, i see that L4T support panel-s-wuxga-8-0 defaultly. I modify some codes as following.

  1. Add some code to enable panel-s-wuxga-8-0 in file tegra186-quill-p3310-1000-c03-00-base.dts.

host1x {
nvdisplay@15200000 {
status = “okay”;
nvidia,dc-or-node = “/host1x/dsi”;
};
dsi {
status = “okay”;

panel-s-wuxga-8-0 {
status = “okay”;
};
};
};

  1. I do some modification in file panel-s-wuxga-8-0.dtsi about the lanes number and display-timings.

                             nvidia,dsi-instance = <DSI_INSTANCE_0>;
 		nvidia,dsi-n-data-lanes = <4>;
 		nvidia,dsi-pixel-format = <TEGRA_DSI_PIXEL_FORMAT_24BIT_P>;
 		nvidia,dsi-refresh-rate = <60>;
 		nvidia,dsi-video-data-type = <TEGRA_DSI_VIDEO_TYPE_VIDEO_MODE>;
 		nvidia,dsi-video-clock-mode = <TEGRA_DSI_VIDEO_CLOCK_CONTINUOUS>;
 		nvidia,dsi-video-burst-mode = <TEGRA_DSI_VIDEO_NONE_BURST_MODE_WITH_SYNC_END>;
 		nvidia,dsi-virtual-channel = <TEGRA_DSI_VIRTUAL_CHANNEL_0>;
 		nvidia,dsi-panel-reset = <TEGRA_DSI_ENABLE>;
 		nvidia,dsi-power-saving-suspend = <TEGRA_DSI_ENABLE>;
 		nvidia,dsi-ulpm-not-support = <TEGRA_DSI_ENABLE>;
 		nvidia,dsi-init-cmd = <TEGRA_DSI_DELAY_MS 160>,
 			<0x0 DSI_DCS_WRITE_0_PARAM DSI_DCS_EXIT_SLEEP_MODE 0x0 0x0>,
 			<TEGRA_DSI_SEND_FRAME 5>,
 			<TEGRA_DSI_DELAY_MS 200>,
 			<0x0 DSI_DCS_WRITE_0_PARAM DSI_DCS_SET_DISPLAY_ON 0x0 0x0>,
 			<TEGRA_DSI_DELAY_MS 200>;
 		nvidia,dsi-n-init-cmd = <6>;
 		nvidia,dsi-suspend-cmd = <0x0 DSI_DCS_WRITE_0_PARAM DSI_DCS_SET_DISPLAY_OFF 0x0 0x0>,
 					<0x0 DSI_DCS_WRITE_0_PARAM DSI_DCS_ENTER_SLEEP_MODE 0x0 0x0>,
 					<TEGRA_DSI_DELAY_MS 60>;
 		nvidia,dsi-n-suspend-cmd = <3>;
 		disp-default-out {
 			nvidia,out-type = <TEGRA_DC_OUT_DSI>;
 			nvidia,out-width = <62>;
 			nvidia,out-height = <110>;
 			nvidia,out-flags = <TEGRA_DC_OUT_CONTINUOUS_MODE TEGRA_DC_OUT_INITIALIZED_MODE>;
 			nvidia,out-xres = <720>;
 			nvidia,out-yres = <1280>;
 		};
 		display-timings {
 			720x1280-32 {
 				clock-frequency = <60192000>;
 				hactive = <720>;
 				vactive = <1280>;
 				hfront-porch = <10>;
 				hback-porch = <20>;
 				hsync-len = <10>;
 				vfront-porch = <10>;
 				vback-porch = <15>;
 				vsync-len = <15>;
 				nvidia,h-ref-to-sync = <2>;
 				nvidia,v-ref-to-sync = <1>;
 			};
 		};

  2. Then I modify the panel-s-wuxga-8-0.c and comment the codes in funciton “dsi_s_wuxga_8_0_regulator_get” as following,
    because if not, driver cant’t find the regulator “outp” and “outn”.i don’t know why driver can’t find the “outp” and “outn”.

I can capture some signal at clock pin and data lane pins with high bandwidth oscilloscope. The lcd show nothing, but the backlight can be turned on and off.

2

Could you share your driver code?

3

As I know, outp and outn is from tps65132 and dts is set to disabled by default.

4

panel-s-wuxga-8-0.c listed as following

#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/regulator/consumer.h>

#include “…/dc.h”
#include “board.h”
#include “board-panel.h”

#define DSI_PANEL_RESET 1

static bool reg_requested;
static struct regulator *avdd_lcd_3v0;
static struct regulator *dvdd_lcd_1v8;
static struct regulator *vpp_lcd;
static struct regulator *vmm_lcd;
static struct device *dc_dev;
static u16 en_panel_rst;
static u16 en_backlight;
static u16 en_panel;
static bool vmm_vpp_fixed_regulators;

static int dsi_s_wuxga_8_0_regulator_get(struct device *dev)
{
int err = 0;

if (reg_requested)
	return 0;

avdd_lcd_3v0 = regulator_get(dev, "avdd_lcd");
if (IS_ERR_OR_NULL(avdd_lcd_3v0)) {
	pr_err("avdd_lcd regulator get failed\n");
	err = PTR_ERR(avdd_lcd_3v0);
	avdd_lcd_3v0 = NULL;
	goto fail;
}

dvdd_lcd_1v8 = regulator_get(dev, "dvdd_lcd");
if (IS_ERR_OR_NULL(dvdd_lcd_1v8)) {
	pr_err("dvdd_lcd_1v8 regulator get failed\n");
	err = PTR_ERR(dvdd_lcd_1v8);
	dvdd_lcd_1v8 = NULL;
	goto dvdd_lcd_fail;
}

/****
vpp_lcd = regulator_get(dev, “outp”);
if (IS_ERR_OR_NULL(vpp_lcd)) {
pr_err(“vpp_lcd regulator get failed\n”);
err = PTR_ERR(vpp_lcd);
vpp_lcd = NULL;
goto vpp_lcd_fail;
}

vmm_lcd = regulator_get(dev, "outn");
if (IS_ERR_OR_NULL(vmm_lcd)) {
	pr_err("vmm_lcd regulator get failed\n");
	err = PTR_ERR(vmm_lcd);
	vmm_lcd = NULL;
	goto vmm_lcd_fail;
}

reg_requested = true;
return 0;

vmm_lcd_fail:
if (vpp_lcd) {
regulator_put(vpp_lcd);
vpp_lcd = NULL;
}
vpp_lcd_fail:
if (dvdd_lcd_1v8) {
regulator_put(dvdd_lcd_1v8);
dvdd_lcd_1v8 = NULL;
}
*****/

dvdd_lcd_fail:
if (avdd_lcd_3v0) {
regulator_put(avdd_lcd_3v0);
avdd_lcd_3v0 = NULL;
}
fail:
return err;
}

static int dsi_s_wuxga_8_0_enable(struct device *dev)
{
int err = 0;

err = tegra_panel_check_regulator_dt_support("s,wuxga-8-0",
	&panel_of);
if (err < 0) {
	pr_err("display regulator dt check failed\n");
	goto fail;
} else {
	vmm_vpp_fixed_regulators = panel_of.en_vmm_vpp_i2c_config;
}

err = dsi_s_wuxga_8_0_regulator_get(dev);
if (err < 0) {
	pr_err("dsi regulator get failed\n");
	goto fail;
}

err = tegra_panel_gpio_get_dt("s,wuxga-8-0", &panel_of);
if (err < 0) {
	pr_err("display gpio get failed\n");
	goto fail;
}

if (gpio_is_valid(panel_of.panel_gpio[TEGRA_GPIO_RESET]))
	en_panel_rst = panel_of.panel_gpio[TEGRA_GPIO_RESET];
else {
	pr_err("display reset gpio invalid\n");
	goto fail;
}

if (gpio_is_valid(panel_of.panel_gpio[TEGRA_GPIO_BL_ENABLE]))
	en_backlight = panel_of.panel_gpio[TEGRA_GPIO_BL_ENABLE];
else
	pr_err("display backlight enable gpio invalid\n");

if (gpio_is_valid(panel_of.panel_gpio[TEGRA_GPIO_PANEL_EN]))
	en_panel = panel_of.panel_gpio[TEGRA_GPIO_PANEL_EN];
else
	pr_err("display panel enable gpio invalid\n");

if (dvdd_lcd_1v8) {
	err = regulator_enable(dvdd_lcd_1v8);
	if (err < 0) {
		pr_err("dvdd_lcd regulator enable failed\n");
		goto fail;
	}
}

usleep_range(1000, 1500);

if (avdd_lcd_3v0) {
	err = regulator_enable(avdd_lcd_3v0);
	if (err < 0) {
		pr_err("avdd_lcd regulator enable failed\n");
		goto fail;
	}
}

usleep_range(3000, 3500);

if (gpio_is_valid(en_backlight))
	gpio_direction_output(en_backlight, 1);

if (en_panel)
	gpio_direction_output(en_panel, 1);

if (vpp_lcd) {
	err = regulator_enable(vpp_lcd);
	if (err < 0) {
		pr_err("vpp_lcd regulator enable failed\n");
		goto fail;
	}

	if (!vmm_vpp_fixed_regulators) {
		err = regulator_set_voltage(vpp_lcd, 5500000, 5500000);
		if (err < 0) {
			pr_err("vpp_lcd regulator failed changing voltage\n");
			goto fail;
		}
	}
}

usleep_range(2000, 2500);

if (vmm_lcd) {
	err = regulator_enable(vmm_lcd);
	if (err < 0) {
		pr_err("vmm_lcd regulator enable failed\n");
		goto fail;
	}

	if (!vmm_vpp_fixed_regulators) {
		err = regulator_set_voltage(vmm_lcd, 5500000, 5500000);
		if (err < 0) {
			pr_err("vmm_lcd regulator failed changing voltage\n");
			goto fail;
		}
	}
}

usleep_range(15000, 15500);

#if DSI_PANEL_RESET
if (!tegra_dc_initialized(dev)) {
err = gpio_direction_output(en_panel_rst, 1);
if (err < 0) {
pr_err(“setting display reset gpio value failed\n”);
goto fail;
}
err = gpio_direction_output(en_panel_rst, 0);
if (err < 0) {
pr_err(“setting display reset gpio value 0 failed\n”);
goto fail;
}
err = gpio_direction_output(en_panel_rst, 1);
if (err < 0) {
pr_err(“setting display reset gpio value 1 failed\n”);
goto fail;
}
}
#endif
dc_dev = dev;
return 0;
fail:
return err;
}

static int dsi_s_wuxga_8_0_disable(struct device dev)
{
if (gpio_is_valid(en_panel_rst)) {
/ Wait for 50ms before triggering panel reset */
msleep(50);
gpio_set_value(en_panel_rst, 0);
usleep_range(500, 1000);
} else
pr_err(“ERROR! display reset gpio invalid\n”);

if (vmm_lcd)
	regulator_disable(vmm_lcd);

usleep_range(2000, 2500);

if (vpp_lcd)
	regulator_disable(vpp_lcd);

msleep(125);

if (gpio_is_valid(en_panel))
	gpio_direction_output(en_panel, 0);

if (gpio_is_valid(en_backlight))
            gpio_direction_output(en_backlight, 0);


if (avdd_lcd_3v0)
	regulator_disable(avdd_lcd_3v0);

msleep(780);

if (dvdd_lcd_1v8)
	regulator_disable(dvdd_lcd_1v8);

/* Min delay of 140ms required to avoid turning
 * the panel on too soon after power off */
msleep(140);

dc_dev = NULL;

return 0;

}

static int dsi_s_wuxga_8_0_postsuspend(void)
{
return 0;
}

static int dsi_s_wuxga_8_0_bl_notify(struct device *dev, int brightness)
{
int cur_sd_brightness;
struct backlight_device *bl = NULL;
struct pwm_bl_data *pb = NULL;
bl = (struct backlight_device *)dev_get_drvdata(dev);
pb = (struct pwm_bl_data *)dev_get_drvdata(&bl->dev);

#ifdef CONFIG_TEGRA_NVDISPLAY
tegra_sd_check_prism_thresh(dc_dev, brightness);
#else
nvsd_check_prism_thresh(dc_dev, brightness);
#endif

cur_sd_brightness = atomic_read(&sd_brightness);
/* SD brightness is a percentage */
brightness = (brightness * cur_sd_brightness) / 255;

/* Apply any backlight response curve */
if (brightness > 255)
	pr_info("Error: Brightness > 255!\n");
else if (pb->bl_measured)
	brightness = pb->bl_measured[brightness];

return brightness;

}

static int dsi_s_wuxga_8_0_check_fb(struct device *dev,
struct fb_info *info)
{
struct platform_device *pdev = NULL;
pdev = to_platform_device(bus_find_device_by_name(
&platform_bus_type, NULL, “tegradc.0”));
return info->device == &pdev->dev;
}

static struct pwm_bl_data_dt_ops dsi_s_wuxga_8_0_pwm_bl_ops = {
.notify = dsi_s_wuxga_8_0_bl_notify,
.check_fb = dsi_s_wuxga_8_0_check_fb,
.blnode_compatible = “s,wuxga-8-0-bl”,
};
struct tegra_panel_ops dsi_s_wuxga_8_0_ops = {
.enable = dsi_s_wuxga_8_0_enable,
.disable = dsi_s_wuxga_8_0_disable,
.postsuspend = dsi_s_wuxga_8_0_postsuspend,
.pwm_bl_ops = &dsi_s_wuxga_8_0_pwm_bl_ops,
};

I modify the file “tegra186-quill-common.dtsi”, comment the “nvidia,panel-en-gpio” ,because i never use this pin, i only use the “panel-rst-gpio” and “panel-bl-en-gpio”.

                   dsi {	/* dsi@15300000 */
		nvidia,dsi-controller-vs = <DSI_VS_1>;
		status = "disabled";
		panel-s-wuxga-8-0 {
			status = "disabled";
			nvidia,panel-rst-gpio = <&tegra_main_gpio TEGRA_MAIN_GPIO(P, 3) 1>; /* PP3 */
			nvidia,panel-bl-pwm-gpio = <&tegra_aon_gpio TEGRA_AON_GPIO(U, 0) 1>; /* PU0 */
			nvidia,panel-bl-en-gpio = <&tegra_aon_gpio TEGRA_AON_GPIO(U, 3) 1>; /* PU3 */
		/*	nvidia,panel-en-gpio = <&gpio_i2c_0_77 4 1>;  tca9539 0x77 Pin 4 */

			nvidia,en-vmm-vpp-with-i2c-config;
			nvidia,default_color_space = <0>;
			disp-default-out {
				nvidia,out-parent-clk = "pll_d";
				nvidia,out-xres = <720>;
				nvidia,out-yres = <1280>;
                            };
5

I cannot tell which part is wrong. There is no enough information for me.

What I need to know is

  1. Whether outP and outN are needed for you? These two regulators are not enabled by default.
  2. If you already saw the error from Q1, I think it means display probing has started to checked DSI. Thus, please check if the power sequence is correct.
6

I don’t need outP and outN. If i don’t comment the codes about outP and outN in file “panel-s-wuxga-8-0.c”, this lcd panel can’t work, the backlight also can’t be turned on and off. I don’t make any other modification about the panel,except mentioned above.

7

Is there any error log? Do you follow the spec of your own panel?

8

NO error. The default config file is tegra18_defconfig,right?
I notice that kernel contain another config file “tegra_t186ref_gnu_linux_defconfig”, what is difference?

9

I don’t think you need to touch the defconfig for enabling DSI LCD. May I ask why do you need that?