gma500: implement backlight functionality for Cedartrail devices

Basically a straight cut/paste from the reference driver code then
cleaned up a spot.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/gma500/cdv_device.c b/drivers/gpu/drm/gma500/cdv_device.c
index 62f9b735459bab58f52995a40623a342c2578b6c..726bfb7375fc5063c9070453029e50557a738dac 100644 (file)
--- a/drivers/gpu/drm/gma500/cdv_device.c
+++ b/drivers/gpu/drm/gma500/cdv_device.c
@@ -57,8 +57,7 @@ static int cdv_output_init(struct drm_device *dev)
        cdv_intel_crt_init(dev, &dev_priv->mode_dev);
        cdv_intel_lvds_init(dev, &dev_priv->mode_dev);
 
-       /* These bits indicate HDMI not SDVO on CDV, but we don't yet support
-          the HDMI interface */
+       /* These bits indicate HDMI not SDVO on CDV */
        if (REG_READ(SDVOB) & SDVO_DETECTED)
                cdv_hdmi_init(dev, &dev_priv->mode_dev, SDVOB);
        if (REG_READ(SDVOC) & SDVO_DETECTED)
@@ -69,76 +68,71 @@ static int cdv_output_init(struct drm_device *dev)
 #ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
 
 /*
- *     Poulsbo Backlight Interfaces
+ *     Cedartrail Backlght Interfaces
  */
 
-#define BLC_PWM_PRECISION_FACTOR 100   /* 10000000 */
-#define BLC_PWM_FREQ_CALC_CONSTANT 32
-#define MHz 1000000
-
-#define PSB_BLC_PWM_PRECISION_FACTOR    10
-#define PSB_BLC_MAX_PWM_REG_FREQ        0xFFFE
-#define PSB_BLC_MIN_PWM_REG_FREQ        0x2
-
-#define PSB_BACKLIGHT_PWM_POLARITY_BIT_CLEAR (0xFFFE)
-#define PSB_BACKLIGHT_PWM_CTL_SHIFT    (16)
-
-static int cdv_brightness;
 static struct backlight_device *cdv_backlight_device;
 
-static int cdv_get_brightness(struct backlight_device *bd)
+static int cdv_backlight_combination_mode(struct drm_device *dev)
 {
-       /* return locally cached var instead of HW read (due to DPST etc.) */
-       /* FIXME: ideally return actual value in case firmware fiddled with
-          it */
-       return cdv_brightness;
+       return REG_READ(BLC_PWM_CTL2) & PWM_LEGACY_MODE;
 }
 
-
-static int cdv_backlight_setup(struct drm_device *dev)
+static int cdv_get_brightness(struct backlight_device *bd)
 {
-       struct drm_psb_private *dev_priv = dev->dev_private;
-       unsigned long core_clock;
-       /* u32 bl_max_freq; */
-       /* unsigned long value; */
-       u16 bl_max_freq;
-       uint32_t value;
-       uint32_t blc_pwm_precision_factor;
-
-       /* get bl_max_freq and pol from dev_priv*/
-       if (!dev_priv->lvds_bl) {
-               dev_err(dev->dev, "Has no valid LVDS backlight info\n");
-               return -ENOENT;
-       }
-       bl_max_freq = dev_priv->lvds_bl->freq;
-       blc_pwm_precision_factor = PSB_BLC_PWM_PRECISION_FACTOR;
+       struct drm_device *dev = bl_get_data(bd);
+       u32 val = REG_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
 
-       core_clock = dev_priv->core_freq;
+       if (cdv_backlight_combination_mode(dev)) {
+               u8 lbpc;
 
-       value = (core_clock * MHz) / BLC_PWM_FREQ_CALC_CONSTANT;
-       value *= blc_pwm_precision_factor;
-       value /= bl_max_freq;
-       value /= blc_pwm_precision_factor;
+               val &= ~1;
+               pci_read_config_byte(dev->pdev, 0xF4, &lbpc);
+               val *= lbpc;
+       }
+       return val;
+}
 
-       if (value > (unsigned long long)PSB_BLC_MAX_PWM_REG_FREQ ||
-                value < (unsigned long long)PSB_BLC_MIN_PWM_REG_FREQ)
-                               return -ERANGE;
-       else {
-               /* FIXME */
+static u32 cdv_get_max_backlight(struct drm_device *dev)
+{
+       u32 max = REG_READ(BLC_PWM_CTL);
+
+       if (max == 0) {
+               DRM_DEBUG_KMS("LVDS Panel PWM value is 0!\n");
+               /* i915 does this, I believe which means that we should not
+                * smash PWM control as firmware will take control of it. */
+               return 1;
        }
-       return 0;
+
+       max >>= 16;
+       if (cdv_backlight_combination_mode(dev))
+               max *= 0xff;
+       return max;
 }
 
 static int cdv_set_brightness(struct backlight_device *bd)
 {
+       struct drm_device *dev = bl_get_data(bd);
        int level = bd->props.brightness;
+       u32 blc_pwm_ctl;
 
        /* Percentage 1-100% being valid */
        if (level < 1)
                level = 1;
 
-       /*cdv_intel_lvds_set_brightness(dev, level); FIXME */
-       cdv_brightness = level;
+       if (cdv_backlight_combination_mode(dev)) {
+               u32 max = cdv_get_max_backlight(dev);
+               u8 lbpc;
+
+               lbpc = level * 0xfe / max + 1;
+               level /= lbpc;
+
+               pci_write_config_byte(dev->pdev, 0xF4, lbpc);
+       }
+
+       blc_pwm_ctl = REG_READ(BLC_PWM_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+       REG_WRITE(BLC_PWM_CTL, (blc_pwm_ctl |
+                               (level << BACKLIGHT_DUTY_CYCLE_SHIFT)));
        return 0;
 }
 
@@ -150,7 +144,6 @@ static const struct backlight_ops cdv_ops = {
 static int cdv_backlight_init(struct drm_device *dev)
 {
        struct drm_psb_private *dev_priv = dev->dev_private;
-       int ret;
        struct backlight_properties props;
 
        memset(&props, 0, sizeof(struct backlight_properties));
@@ -162,14 +155,9 @@ static int cdv_backlight_init(struct drm_device *dev)
        if (IS_ERR(cdv_backlight_device))
                return PTR_ERR(cdv_backlight_device);
 
-       ret = cdv_backlight_setup(dev);
-       if (ret < 0) {
-               backlight_device_unregister(cdv_backlight_device);
-               cdv_backlight_device = NULL;
-               return ret;
-       }
-       cdv_backlight_device->props.brightness = 100;
-       cdv_backlight_device->props.max_brightness = 100;
+       cdv_backlight_device->props.brightness =
+                       cdv_get_brightness(cdv_backlight_device);
+       cdv_backlight_device->props.max_brightness = cdv_get_max_brightness;
        backlight_update_status(cdv_backlight_device);
        dev_priv->backlight_device = cdv_backlight_device;
        return 0;
@@ -244,11 +232,12 @@ static void cdv_init_pm(struct drm_device *dev)
 static void cdv_errata(struct drm_device *dev)
 {
        /* Disable bonus launch.
-        *      CPU and GPU competes for memory and display misses updates and flickers.
-        *      Worst with dual core, dual displays.
+        *      CPU and GPU competes for memory and display misses updates and
+        *      flickers. Worst with dual core, dual displays.
         *
-        *      Fixes were done to Win 7 gfx driver to disable a feature called Bonus
-        *      Launch to work around the issue, by degrading performance.
+        *      Fixes were done to Win 7 gfx driver to disable a feature called
+        *      Bonus Launch to work around the issue, by degrading
+        *      performance.
         */
         CDV_MSG_WRITE32(3, 0x30, 0x08027108);
 }