[U-Boot] [PATCH v4 07/16] tegra: Add LCD driver

Simon Glass sjg at chromium.org
Tue Oct 9 00:02:24 CEST 2012


Hi Marc,

On Fri, Oct 5, 2012 at 7:21 AM, Marc Dietrich <marvin24 at gmx.de> wrote:
> Simon,
>
> I tried to adapt this for paz00. I only get backlight and an all white screen.

I'm not sure about that. One possibility is that your PWM is connected
up differently. On Seaboard at least, I found that without the PWM I
would get nothing on the display.

> On checking what's wrong I stumpled about something strange below...
>
> Marc
>
> On Thursday 27 September 2012 17:44:28 Simon Glass wrote:
>> This driver supports driving a single LCD and providing a U-Boot console
>> on it.
>>
>> Signed-off-by: Simon Glass <sjg at chromium.org>
>> ---
>> Changes in v2:
>> - Update LCD driver to deal with new fdt bindings
>>
>> Changes in v3:
>> - Move some fdt decode code from LCD driver to SOC display driver
>> - Rename fdt config structures
>> - Use new pwm binding from pre-linux-next
>> - Adjust LCD driver to use new SOC display driver structures
>>
>> Changes in v4:
>> - Rebase on top of new tegra common directory structure
>> - Change LCD panel GPIOs to be entirely optional
>> - Only indicate that LCD init is complete when all stages complete
>>
>>  drivers/video/Makefile |    1 +
>>  drivers/video/tegra.c  |  361
>> ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 362
>> insertions(+), 0 deletions(-)
>>  create mode 100644 drivers/video/tegra.c
>>
>> diff --git a/drivers/video/Makefile b/drivers/video/Makefile
>> index ebb6da8..78a7668 100644
>> --- a/drivers/video/Makefile
>> +++ b/drivers/video/Makefile
>> @@ -49,6 +49,7 @@ COBJS-$(CONFIG_VIDEO_OMAP3) += omap3_dss.o
>>  COBJS-$(CONFIG_VIDEO_SED13806) += sed13806.o
>>  COBJS-$(CONFIG_VIDEO_SM501) += sm501.o
>>  COBJS-$(CONFIG_VIDEO_SMI_LYNXEM) += smiLynxEM.o videomodes.o
>> +COBJS-$(CONFIG_VIDEO_TEGRA) += tegra.o
>>  COBJS-$(CONFIG_VIDEO_VCXK) += bus_vcxk.o
>>
>>  COBJS        := $(sort $(COBJS-y))
>> diff --git a/drivers/video/tegra.c b/drivers/video/tegra.c
>> new file mode 100644
>> index 0000000..9df2bd3
>> --- /dev/null
>> +++ b/drivers/video/tegra.c
>> @@ -0,0 +1,361 @@
>> +/*
>> + * Copyright (c) 2011 The Chromium OS Authors.
>> + * See file CREDITS for list of people who contributed to this
>> + * project.
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License as
>> + * published by the Free Software Foundation; either version 2 of
>> + * the License, or (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, write to the Free Software
>> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
>> + * MA 02111-1307 USA
>> + */
>> +
>> +#include <common.h>
>> +#include <fdtdec.h>
>> +#include <lcd.h>
>> +
>> +#include <asm/system.h>
>> +#include <asm/gpio.h>
>> +
>> +#include <asm/arch/clock.h>
>> +#include <asm/arch/funcmux.h>
>> +#include <asm/arch/pinmux.h>
>> +#include <asm/arch/pwm.h>
>> +#include <asm/arch/display.h>
>> +#include <asm/arch-tegra/timer.h>
>> +
>> +DECLARE_GLOBAL_DATA_PTR;
>> +
>> +/* These are the stages we go throuh in enabling the LCD */
>> +enum stage_t {
>> +     STAGE_START,
>> +     STAGE_LVDS,
>> +     STAGE_BACKLIGHT_VDD,
>> +     STAGE_PWM,
>> +     STAGE_BACKLIGHT_EN,
>> +     STAGE_DONE,
>> +};
>> +
>> +static enum stage_t stage;   /* Current stage we are at */
>> +static unsigned long timer_next; /* Time we can move onto next stage */
>> +
>> +/* Our LCD config, set up in handle_stage() */
>> +static struct fdt_panel_config config;
>> +struct fdt_disp_config *disp_config; /* Display controller config */
>> +
>> +enum {
>> +     /* Maximum LCD size we support */
>> +     LCD_MAX_WIDTH           = 1366,
>> +     LCD_MAX_HEIGHT          = 768,
>> +     LCD_MAX_LOG2_BPP        = 4,            /* 2^4 = 16 bpp */
>> +};
>> +
>> +int lcd_line_length;
>> +int lcd_color_fg;
>> +int lcd_color_bg;
>> +
>> +void *lcd_base;                      /* Start of framebuffer memory  */
>> +void *lcd_console_address;   /* Start of console buffer      */
>> +
>> +short console_col;
>> +short console_row;
>> +
>> +vidinfo_t panel_info = {
>> +     /* Insert a value here so that we don't end up in the BSS */
>> +     .vl_col = -1,
>> +};
>> +
>> +char lcd_cursor_enabled;
>> +
>> +ushort lcd_cursor_width;
>> +ushort lcd_cursor_height;
>> +
>> +#ifndef CONFIG_OF_CONTROL
>> +#error "You must enable CONFIG_OF_CONTROL to get Tegra LCD support"
>> +#endif
>> +
>> +void lcd_cursor_size(ushort width, ushort height)
>> +{
>> +     lcd_cursor_width = width;
>> +     lcd_cursor_height = height;
>> +}
>> +
>> +void lcd_toggle_cursor(void)
>> +{
>> +     ushort x, y;
>> +     uchar *dest;
>> +     ushort row;
>> +
>> +     x = console_col * lcd_cursor_width;
>> +     y = console_row * lcd_cursor_height;
>> +     dest = (uchar *)(lcd_base + y * lcd_line_length + x * (1 << LCD_BPP) /
>> +                     8);
>> +
>> +     for (row = 0; row < lcd_cursor_height; ++row, dest += lcd_line_length) {
>> +             ushort *d = (ushort *)dest;
>> +             ushort color;
>> +             int i;
>> +
>> +             for (i = 0; i < lcd_cursor_width; ++i) {
>> +                     color = *d;
>> +                     color ^= lcd_color_fg;
>> +                     *d = color;
>> +                     ++d;
>> +             }
>> +     }
>> +}
>> +
>> +void lcd_cursor_on(void)
>> +{
>> +     lcd_cursor_enabled = 1;
>> +     lcd_toggle_cursor();
>> +}
>> +void lcd_cursor_off(void)
>> +{
>> +     lcd_cursor_enabled = 0;
>> +     lcd_toggle_cursor();
>> +}
>> +
>> +char lcd_is_cursor_enabled(void)
>> +{
>> +     return lcd_cursor_enabled;
>> +}
>> +
>> +static void update_panel_size(struct fdt_disp_config *config)
>> +{
>> +     panel_info.vl_col = config->width;
>> +     panel_info.vl_row = config->height;
>> +     panel_info.vl_bpix = config->log2_bpp;
>> +}
>> +
>> +/*
>> + *  Main init function called by lcd driver.
>> + *  Inits and then prints test pattern if required.
>> + */
>> +
>> +void lcd_ctrl_init(void *lcdbase)
>> +{
>> +     int line_length, size;
>> +
>> +     assert(disp_config);
>> +
>> +     lcd_base = (void *)disp_config->frame_buffer;
>
> this is always NULL, because it is defined in a circular manner (see
> arch/arm/cpu/armv7/tegra20/display.c:383) and ...
>
>> +     /* Make sure that we can acommodate the selected LCD */
>> +     assert(disp_config->width <= LCD_MAX_WIDTH);
>> +     assert(disp_config->height <= LCD_MAX_HEIGHT);
>> +     assert(disp_config->log2_bpp <= LCD_MAX_LOG2_BPP);
>> +     if (disp_config->width <= LCD_MAX_WIDTH
>> +                     && disp_config->height <= LCD_MAX_HEIGHT
>> +                     && disp_config->log2_bpp <= LCD_MAX_LOG2_BPP)
>> +             update_panel_size(disp_config);
>> +     size = lcd_get_size(&line_length);
>> +
>> +     debug("LCD frame buffer at %p\n", lcd_base);
>> +}
>> +
>> +ulong calc_fbsize(void)
>> +{
>> +     return (panel_info.vl_col * panel_info.vl_row *
>> +             NBITS(panel_info.vl_bpix)) / 8;
>> +}
>> +
>> +void lcd_setcolreg(ushort regno, ushort red, ushort green, ushort blue)
>> +{
>> +}
>> +
>> +void tegra_lcd_early_init(const void *blob)
>> +{
>> +     /*
>> +      * Go with the maximum size for now. We will fix this up after
>> +      * relocation. These values are only used for memory alocation.
>> +      */
>> +     panel_info.vl_col = LCD_MAX_WIDTH;
>> +     panel_info.vl_row = LCD_MAX_HEIGHT;
>> +     panel_info.vl_bpix = LCD_MAX_LOG2_BPP;
>> +}
>> +
>> +/**
>> + * Decode the panel information from the fdt.
>> + *
>> + * @param blob               fdt blob
>> + * @param config     structure to store fdt config into
>> + * @return 0 if ok, -ve on error
>> + */
>> +static int fdt_decode_lcd(const void *blob, struct fdt_panel_config
>> *config) +{
>> +     int display_node;
>> +
>> +     disp_config = tegra_display_get_config();
>> +     if (!disp_config) {
>> +             debug("%s: Display controller is not configured\n", __func__);
>> +             return -1;
>> +     }
>> +     display_node = disp_config->panel_node;
>> +     if (display_node < 0) {
>> +             debug("%s: No panel configuration available\n", __func__);
>> +             return -1;
>> +     }
>> +
>> +     config->pwm_channel = pwm_request(blob, display_node, "nvidia,pwm");
>> +     if (config->pwm_channel < 0) {
>> +             debug("%s: Unable to request PWM channel\n", __func__);
>> +             return -1;
>> +     }
>> +
>> +     config->cache_type = fdtdec_get_int(blob, display_node,
>> +                                         "nvidia,cache-type",
>> +                                         FDT_LCD_CACHE_WRITE_BACK_FLUSH);
>> +
>> +     /* These GPIOs are all optional */
>> +     fdtdec_decode_gpio(blob, display_node, "nvidia,backlight-enable-gpios",
>> +                         &config->backlight_en);
>> +     fdtdec_decode_gpio(blob, display_node, "nvidia,lvds-shutdown-gpios",
>> +                        &config->lvds_shutdown);
>> +     fdtdec_decode_gpio(blob, display_node, "nvidia,backlight-vdd-gpios",
>> +                        &config->backlight_vdd);
>> +     fdtdec_decode_gpio(blob, display_node, "nvidia,panel-vdd-gpios",
>> +                        &config->panel_vdd);
>> +
>> +     return fdtdec_get_int_array(blob, display_node, "nvidia,panel-timings",
>> +                     config->panel_timings, FDT_LCD_TIMINGS);
>> +}
>> +
>> +/**
>> + * Handle the next stage of device init
>> + */
>> +static int handle_stage(const void *blob)
>> +{
>> +     debug("%s: stage %d\n", __func__, stage);
>> +
>> +     /* do the things for this stage */
>> +     switch (stage) {
>> +     case STAGE_START:
>> +             /* Initialize the Tegra display controller */
>> +             if (tegra_display_probe(gd->fdt_blob, lcd_base)) {
>
> .... here.

Yes, that should be gd->fb_base I think. I will update it.

>
>> +                     printf("%s: Failed to probe display driver\n",
>> +                     __func__);
>> +                     return -1;
>> +             }
>> +
>> +             /* get panel details */
>> +             if (fdt_decode_lcd(blob, &config)) {
>> +                     printf("No valid LCD information in device tree\n");
>> +                     return -1;
>> +             }
>> +
>> +             /*
>> +              * It is possible that the FDT has requested that the LCD be
>> +              * disabled. We currently don't support this. It would require
>> +              * changes to U-Boot LCD subsystem to have LCD support
>> +              * compiled in but not used. An easier option might be to
>> +              * still have a frame buffer, but leave the backlight off and
>> +              * remove all mention of lcd in the stdout environment
>> +              * variable.
>> +              */
>> +
>> +             funcmux_select(PERIPH_ID_DISP1, FUNCMUX_DEFAULT);
>> +
>> +             fdtdec_setup_gpio(&config.panel_vdd);
>> +             fdtdec_setup_gpio(&config.lvds_shutdown);
>> +             fdtdec_setup_gpio(&config.backlight_vdd);
>> +             fdtdec_setup_gpio(&config.backlight_en);
>> +
>> +             /*
>> +              * TODO: If fdt includes output flag we can omit this code
>> +              * since fdtdec_setup_gpio will do it for us.
>> +              */
>> +             if (fdt_gpio_isvalid(&config.panel_vdd))
>> +                     gpio_direction_output(config.panel_vdd.gpio, 1);
>> +             if (fdt_gpio_isvalid(&config.lvds_shutdown))
>> +                     gpio_direction_output(config.lvds_shutdown.gpio, 0);
>> +             if (fdt_gpio_isvalid(&config.backlight_vdd))
>> +                     gpio_direction_output(config.backlight_vdd.gpio, 0);
>> +             if (fdt_gpio_isvalid(&config.backlight_en))
>> +                     gpio_direction_output(config.backlight_en.gpio, 0);
>> +             break;
>> +     case STAGE_LVDS:
>> +             if (fdt_gpio_isvalid(&config.lvds_shutdown))
>> +                     gpio_set_value(config.lvds_shutdown.gpio, 1);
>> +             break;
>> +     case STAGE_BACKLIGHT_VDD:
>> +             if (fdt_gpio_isvalid(&config.backlight_vdd))
>> +                     gpio_set_value(config.backlight_vdd.gpio, 1);
>> +             break;
>> +     case STAGE_PWM:
>> +             /* Enable PWM at 15/16 high, 32768 Hz with divider 1 */
>> +             pinmux_set_func(PINGRP_GPU, PMUX_FUNC_PWM);
>> +             pinmux_tristate_disable(PINGRP_GPU);
>> +
>> +             pwm_enable(config.pwm_channel, 32768, 0xdf, 1);
>> +             break;
>> +     case STAGE_BACKLIGHT_EN:
>> +             if (fdt_gpio_isvalid(&config.backlight_en))
>> +                     gpio_set_value(config.backlight_en.gpio, 1);
>> +             break;
>> +     case STAGE_DONE:
>> +             break;
>> +     }
>> +
>> +     /* set up timer for next stage */
>> +     timer_next = timer_get_us() + config.panel_timings[stage] * 1000;
>> +
>> +     /* move to next stage */
>> +     stage++;
>> +     return 0;
>> +}
>> +
>> +int tegra_lcd_check_next_stage(const void *blob, int wait)
>> +{
>> +     if (stage == STAGE_DONE)
>> +             return 0;
>> +
>> +     do {
>> +             /* wait if we need to */
>> +             debug("%s: stage %d\n", __func__, stage);
>> +             if (stage != STAGE_START) {
>> +                     int delay = timer_next - timer_get_us();
>> +
>> +                     if (delay > 0) {
>> +                             if (wait)
>> +                                     udelay(delay);
>> +                             else
>> +                                     return 0;
>> +                     }
>> +             }
>> +
>> +             if (handle_stage(blob))
>> +                     return -1;
>> +     } while (wait && stage != STAGE_DONE);
>> +     if (stage == STAGE_DONE)
>> +             debug("%s: LCD init complete\n", __func__);
>> +
>> +     return 0;
>> +}
>> +
>> +void lcd_enable(void)
>> +{
>> +     /*
>> +      * Backlight and power init will be done separately in
>> +      * tegra_lcd_check_next_stage(), which should be called in
>> +      * board_late_init().
>> +      *
>> +      * U-Boot code supports only colour depth, selected at compile time.
>> +      * The device tree setting should match this. Otherwise the display
>> +      * will not look right, and U-Boot may crash.
>> +      */
>> +     if (disp_config->log2_bpp != LCD_BPP) {
>> +             printf("%s: Error: LCD depth configured in FDT (%d = %dbpp)"
>> +                     " must match setting of LCD_BPP (%d)\n", __func__,
>> +                    disp_config->log2_bpp, disp_config->bpp, LCD_BPP);
>> +     }
>> +}

Regards,
Simon


More information about the U-Boot mailing list