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drm/i915/bxt: BLC implementation
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Enabling BLC on BXT.
Includes register definition, and new functions for BXT.

In BXT, there are 2 sets of registers for BLC. Until there is clarity
about which set would be effective, set 1 is being used.
This would have to be re-visited if there is any change or when 2 LFPs are
enabled on BXT.

This patch enables brightness change which would be effected by use of
hot-keys or sysfs entry.

TODO:- BLC implementation will have to re-visited when
1. there is clarity about which set of registers has to be used and when.
2. CDCLK frequency is changed

v2: Jani's review comments
	- Modified comment in i915_reg.h
	- Renamed register defintions
	- Removed definition of duty cycle max. Not required now and its not 64-bit.

v3:
  - Rebase on top of VLV/CHV backlight changes, in particuliar
    bxt_set_backlight() now has a different prototype (Damien)

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Vandana Kannan <vandana.kannan@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Shankar, Uma <uma.shankar@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Vandana Kannan authored and Daniel Vetter committed May 8, 2015
1 parent b3da4a6 commit 0fb890c
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Showing 2 changed files with 98 additions and 1 deletion.
12 changes: 12 additions & 0 deletions drivers/gpu/drm/i915/i915_reg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3486,6 +3486,18 @@ enum skl_disp_power_wells {
#define UTIL_PIN_CTL 0x48400
#define UTIL_PIN_ENABLE (1 << 31)

/* BXT backlight register definition. */
#define BXT_BLC_PWM_CTL1 0xC8250
#define BXT_BLC_PWM_ENABLE (1 << 31)
#define BXT_BLC_PWM_POLARITY (1 << 29)
#define BXT_BLC_PWM_FREQ1 0xC8254
#define BXT_BLC_PWM_DUTY1 0xC8258

#define BXT_BLC_PWM_CTL2 0xC8350
#define BXT_BLC_PWM_FREQ2 0xC8354
#define BXT_BLC_PWM_DUTY2 0xC8358


#define PCH_GTC_CTL 0xe7000
#define PCH_GTC_ENABLE (1 << 31)

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87 changes: 86 additions & 1 deletion drivers/gpu/drm/i915/intel_panel.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -536,6 +536,14 @@ static u32 vlv_get_backlight(struct intel_connector *connector)
return _vlv_get_backlight(dev, pipe);
}

static u32 bxt_get_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;

return I915_READ(BXT_BLC_PWM_DUTY1);
}

static u32 intel_panel_get_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
Expand Down Expand Up @@ -616,6 +624,14 @@ static void vlv_set_backlight(struct intel_connector *connector, u32 level)
I915_WRITE(VLV_BLC_PWM_CTL(pipe), tmp | level);
}

static void bxt_set_backlight(struct intel_connector *connector, u32 level)
{
struct drm_device *dev = connector->base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;

I915_WRITE(BXT_BLC_PWM_DUTY1, level);
}

static void
intel_panel_actually_set_backlight(struct intel_connector *connector, u32 level)
{
Expand Down Expand Up @@ -741,6 +757,18 @@ static void vlv_disable_backlight(struct intel_connector *connector)
I915_WRITE(VLV_BLC_PWM_CTL2(pipe), tmp & ~BLM_PWM_ENABLE);
}

static void bxt_disable_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;
u32 tmp;

intel_panel_actually_set_backlight(connector, 0);

tmp = I915_READ(BXT_BLC_PWM_CTL1);
I915_WRITE(BXT_BLC_PWM_CTL1, tmp & ~BXT_BLC_PWM_ENABLE);
}

void intel_panel_disable_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
Expand Down Expand Up @@ -947,6 +975,33 @@ static void vlv_enable_backlight(struct intel_connector *connector)
I915_WRITE(VLV_BLC_PWM_CTL2(pipe), ctl2 | BLM_PWM_ENABLE);
}

static void bxt_enable_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_panel *panel = &connector->panel;
u32 pwm_ctl;

pwm_ctl = I915_READ(BXT_BLC_PWM_CTL1);
if (pwm_ctl & BXT_BLC_PWM_ENABLE) {
DRM_DEBUG_KMS("backlight already enabled\n");
pwm_ctl &= ~BXT_BLC_PWM_ENABLE;
I915_WRITE(BXT_BLC_PWM_CTL1, pwm_ctl);
}

I915_WRITE(BXT_BLC_PWM_FREQ1, panel->backlight.max);

intel_panel_actually_set_backlight(connector, panel->backlight.level);

pwm_ctl = 0;
if (panel->backlight.active_low_pwm)
pwm_ctl |= BXT_BLC_PWM_POLARITY;

I915_WRITE(BXT_BLC_PWM_CTL1, pwm_ctl);
POSTING_READ(BXT_BLC_PWM_CTL1);
I915_WRITE(BXT_BLC_PWM_CTL1, pwm_ctl | BXT_BLC_PWM_ENABLE);
}

void intel_panel_enable_backlight(struct intel_connector *connector)
{
struct drm_device *dev = connector->base.dev;
Expand Down Expand Up @@ -1299,6 +1354,30 @@ static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe
return 0;
}

static int
bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
{
struct drm_device *dev = connector->base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_panel *panel = &connector->panel;
u32 pwm_ctl, val;

pwm_ctl = I915_READ(BXT_BLC_PWM_CTL1);
panel->backlight.active_low_pwm = pwm_ctl & BXT_BLC_PWM_POLARITY;

panel->backlight.max = I915_READ(BXT_BLC_PWM_FREQ1);
if (!panel->backlight.max)
return -ENODEV;

val = bxt_get_backlight(connector);
panel->backlight.level = intel_panel_compute_brightness(connector, val);

panel->backlight.enabled = (pwm_ctl & BXT_BLC_PWM_ENABLE) &&
panel->backlight.level != 0;

return 0;
}

int intel_panel_setup_backlight(struct drm_connector *connector, enum pipe pipe)
{
struct drm_device *dev = connector->dev;
Expand Down Expand Up @@ -1350,7 +1429,13 @@ void intel_panel_init_backlight_funcs(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;

if (IS_BROADWELL(dev) || (INTEL_INFO(dev)->gen >= 9)) {
if (IS_BROXTON(dev)) {
dev_priv->display.setup_backlight = bxt_setup_backlight;
dev_priv->display.enable_backlight = bxt_enable_backlight;
dev_priv->display.disable_backlight = bxt_disable_backlight;
dev_priv->display.set_backlight = bxt_set_backlight;
dev_priv->display.get_backlight = bxt_get_backlight;
} else if (IS_BROADWELL(dev) || IS_SKYLAKE(dev)) {
dev_priv->display.setup_backlight = bdw_setup_backlight;
dev_priv->display.enable_backlight = bdw_enable_backlight;
dev_priv->display.disable_backlight = pch_disable_backlight;
Expand Down

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