Arthur Heymans (arthur@aheymans.xyz) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17597
-gerrit
commit 5450ab8cc30375d92870992f1410f0f704941841 Author: Arthur Heymans arthur@aheymans.xyz Date: Thu Nov 24 13:23:05 2016 +0100
nb/gm45/gma.c: Compute BLC_PWM_CTL value from PWM frequency
This allows to set the backlight PWM frequency and the duty cycle in the devicetree instead of using a plain BLC_PWM_CTL value.
Change-Id: I4d9a555ac7ea5605712c1fcda994a6fcabf9acf3 Signed-off-by: Arthur Heymans arthur@aheymans.xyz --- src/northbridge/intel/gm45/chip.h | 2 ++ src/northbridge/intel/gm45/gma.c | 21 +++++++++++++++++++-- 2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/src/northbridge/intel/gm45/chip.h b/src/northbridge/intel/gm45/chip.h index 836d6bb..2307d53 100644 --- a/src/northbridge/intel/gm45/chip.h +++ b/src/northbridge/intel/gm45/chip.h @@ -26,6 +26,8 @@ struct northbridge_intel_gm45_config { u16 gpu_panel_power_backlight_off_delay; /* Tx time sequence */ u8 gpu_panel_power_cycle_delay; /* T4 time sequence */ struct i915_gpu_controller_info gfx; + u32 pwm_freq; + u32 duty_cycle;
/* * Maximum PCI mmio size in MiB. diff --git a/src/northbridge/intel/gm45/gma.c b/src/northbridge/intel/gm45/gma.c index 3e9f508..37ba4cb 100644 --- a/src/northbridge/intel/gm45/gma.c +++ b/src/northbridge/intel/gm45/gma.c @@ -629,6 +629,19 @@ static u32 get_cdclk(struct device *const dev) } }
+static u32 freq_to_blc_pwm_ctl(struct device *const dev, + u16 pwm_freq, u16 duty_perc) +{ + u32 blc_mod; + + blc_mod = get_cdclk(dev) / (128 * pwm_freq); + + if (duty_perc <= 100) + return (blc_mod << 16) | (blc_mod * duty_perc / 100); + else + return (blc_mod << 16) | blc_mod; +} + static void gma_pm_init_post_vbios(struct device *const dev) { const struct northbridge_intel_gm45_config *const conf = dev->chip_info; @@ -661,10 +674,14 @@ static void gma_pm_init_post_vbios(struct device *const dev)
/* Enable Backlight */ gtt_write(BLC_PWM_CTL2, (1 << 31)); - if (conf->gfx.backlight == 0) + reg32 = 100; + if (conf->duty_cycle != 0) + reg32 = conf->duty_cycle; + if (conf->pwm_freq == 0) gtt_write(BLC_PWM_CTL, 0x06100610); else - gtt_write(BLC_PWM_CTL, conf->gfx.backlight); + gtt_write(BLC_PWM_CTL, freq_to_blc_pwm_ctl(dev, + conf->pwm_freq, reg32)); }
static void gma_func0_init(struct device *dev)