blc.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <stdint.h>
#include <commonlib/helpers.h>
#include <console/console.h>
#include <northbridge/intel/gm45/gm45.h>
#include <drivers/intel/gma/opregion.h>
 
static const struct blc_pwm_t blc_entries[] = {
        /* corrected to 320MHz CDClk, vendor set 753; works fine at both: */
        {"LTD121EQ3B", 447},
        {"LTD121EWVB", 165},
        {"LTD133EQ1B", 264},  /* Found on an X301 */
        {"B121EW03 V6 ", 165},
        /* datasheets: between 100 and 20k, typical 200 */
        /* TESTED: works best at 400 */
        {"B121EW09 V3 ", 400},
        {"HV121WX4-120", 110}, /* Aftermarket AFFS lcd, works well at low pwm */
        {"LTN121AT03001", 110},
        {"LTN121AP03001", 750},
        /* TODO: untested panels found on thinkwiki */
        /* Generally CCFL runs best at lower PWM */
        /* {"B121EW09 V2 ", 450}, */
        /* {"N121IB-L05", 450}, */
        {"LP121WX3-TLC1", 400}, /* TESTED to work best at this value */
        /* {"LP121WX3-TLA1" 450}, */
        /* {"B121EW03 V3 " 110}, */
        /* {"LTN121AP02001" 110}, */
};
 
int get_blc_values(const struct blc_pwm_t **entries)
{
        *entries = blc_entries;
        return ARRAY_SIZE(blc_entries);
}
 
const char *mainboard_vbt_filename(void)
{
        u16 pwm_freq;
 
        pwm_freq = get_blc_pwm_freq_value(NULL);
 
        if (pwm_freq == 0) {
                printk(BIOS_DEBUG,
                       "GMA: Display backlight type not found, assuming LED\n");
                return "data_led.vbt";
        } else if (pwm_freq > 200) {
                printk(BIOS_DEBUG, "GMA: Using LED backlight VBT\n");
                return "data_led.vbt";
        } else {
                printk(BIOS_DEBUG, "GMA: Using CCFL backlight VBT\n");
                return "data_ccfl.vbt";
        }
}