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drm/i915/bxt: add support for setting backlight freq from vbt

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The only missing piece is the function to convert frequency to PWM
register value. The PWM is based on 19.2 MHz clock, except for BXT A
step, which is based on CDCLK, and which we ignore.

Reviewed-by: Imre Deak <imre.deak@intel.com>
Tested-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448958232-26520-1-git-send-email-jani.nikula@intel.com
This commit is contained in:
Jani Nikula 2015-12-01 10:23:50 +02:00
parent 1802419957
commit 2dd6982e47
1 changed files with 9 additions and 0 deletions
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9
drivers/gpu/drm/i915/intel_panel.c
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@ -1263,6 +1263,14 @@ static void intel_backlight_device_unregister(struct intel_connector *connector)
}
#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
/*
* BXT: PWM clock frequency = 19.2 MHz.
*/
static u32 bxt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
{
return KHz(19200) / pwm_freq_hz;
}
/*
* SPT: This value represents the period of the PWM stream in clock periods
* multiplied by 16 (default increment) or 128 (alternate increment selected in
@ -1750,6 +1758,7 @@ intel_panel_init_backlight_funcs(struct intel_panel *panel)
panel->backlight.disable = bxt_disable_backlight;
panel->backlight.set = bxt_set_backlight;
panel->backlight.get = bxt_get_backlight;
panel->backlight.hz_to_pwm = bxt_hz_to_pwm;
} else if (HAS_PCH_LPT(dev) || HAS_PCH_SPT(dev)) {
panel->backlight.setup = lpt_setup_backlight;
panel->backlight.enable = lpt_enable_backlight;