PWM was enabled in bios. i915 driver will save max duty to panel->backlight.max.
So *_hz_to_pwm will not be called if backlight.max not zero.
pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2);
panel->backlight.max = pch_ctl2 >> 16;
if (!panel->backlight.max)
panel->backlight.max = get_backlight_max_vbt(connector);
-----Original Message-----
From: Nikula, Jani
Sent: Monday, September 19, 2016 4:24 PM
To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Nikula, Jani <jani.nikula@xxxxxxxxx>; Lee, Shawn C <shawn.c.lee@xxxxxxxxx>
Subject: [PATCH v2 1/2] drm/i915/backlight: setup and cache pwm alternate increment value
This will also be needed later on when setting up the alternate increment in backlight enable.
Cc: Shawn Lee <shawn.c.lee@xxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_drv.h | 1 +
drivers/gpu/drm/i915/intel_panel.c | 14 +++++++++++---
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 8fd16adf069b..c3e65e515c9d 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -263,6 +263,7 @@ struct intel_panel {
bool enabled;
bool combination_mode; /* gen 2/4 only */
bool active_low_pwm;
+ bool alternate_pwm_increment; /* lpt+ */
/* PWM chip */
bool util_pin_active_low; /* bxt+ */
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index c10e9b0405e8..8bc43205d6a0 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -1242,10 +1242,10 @@ static u32 bxt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
*/
static u32 spt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz) {
- struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+ struct intel_panel *panel = &connector->panel;
u32 mul;
- if (I915_READ(SOUTH_CHICKEN1) & SPT_PWM_GRANULARITY)
+ if (panel->backlight.alternate_pwm_increment)
mul = 128;
else
mul = 16;
@@ -1261,9 +1261,10 @@ static u32 spt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz) static u32 lpt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz) {
struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+ struct intel_panel *panel = &connector->panel;
u32 mul, clock;
- if (I915_READ(SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY)
+ if (panel->backlight.alternate_pwm_increment)
mul = 16;
else
mul = 128;
@@ -1414,6 +1415,13 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus
struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
struct intel_panel *panel = &connector->panel;
u32 pch_ctl1, pch_ctl2, val;
+ bool alt;
+
+ if (HAS_PCH_LPT(dev_priv))
+ alt = I915_READ(SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY;
+ else
+ alt = I915_READ(SOUTH_CHICKEN1) & SPT_PWM_GRANULARITY;
+ panel->backlight.alternate_pwm_increment = alt;
pch_ctl1 = I915_READ(BLC_PWM_PCH_CTL1);
panel->backlight.active_low_pwm = pch_ctl1 & BLM_PCH_POLARITY;
--
2.1.4
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