gma500: continue abstracting platform specific code

Next obvious target - backlight support

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 137 insertions, 0 deletions

diff --git a/drivers/staging/gma500/mrst_device.c b/drivers/staging/gma500/mrst_device.c
index 5cd82838a052..daeeb18d9273 100644
--- a/drivers/staging/gma500/mrst_device.c
+++ b/drivers/staging/gma500/mrst_device.c
@@ -17,6 +17,7 @@
  *
  **************************************************************************/
 
+#include <linux/backlight.h>
 #include <drm/drmP.h>
 #include <drm/drm.h>
 #include "psb_drm.h"
@@ -42,7 +43,138 @@ static int mrst_output_init(struct drm_device *dev)
 }
 
 /*
+ *	Provide the low level interfaces for the Moorestown backlight
+ */
+
+#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
+
+#define MRST_BLC_MAX_PWM_REG_FREQ	    0xFFFF
+#define BLC_PWM_PRECISION_FACTOR 100	/* 10000000 */
+#define BLC_PWM_FREQ_CALC_CONSTANT 32
+#define MHz 1000000
+#define BLC_ADJUSTMENT_MAX 100
+
+static struct backlight_device *mrst_backlight_device;
+static int mrst_brightness;
+
+static int mrst_set_brightness(struct backlight_device *bd)
+{
+	struct drm_device *dev = bl_get_data(mrst_backlight_device);
+	struct drm_psb_private *dev_priv = dev->dev_private;
+	int level = bd->props.brightness;
+	u32 blc_pwm_ctl;
+	u32 max_pwm_blc;
+
+	/* Percentage 1-100% being valid */
+	if (level < 1)
+		level = 1;
+
+	if (gma_power_begin(dev, 0)) {
+		/* Calculate and set the brightness value */
+		max_pwm_blc = REG_READ(BLC_PWM_CTL) >> 16;
+		blc_pwm_ctl = level * max_pwm_blc / 100;
+
+		/* Adjust the backlight level with the percent in
+		 * dev_priv->blc_adj1;
+		 */
+		blc_pwm_ctl = blc_pwm_ctl * dev_priv->blc_adj1;
+		blc_pwm_ctl = blc_pwm_ctl / 100;
+
+		/* Adjust the backlight level with the percent in
+		 * dev_priv->blc_adj2;
+		 */
+		blc_pwm_ctl = blc_pwm_ctl * dev_priv->blc_adj2;
+		blc_pwm_ctl = blc_pwm_ctl / 100;
+
+		/* force PWM bit on */
+		REG_WRITE(BLC_PWM_CTL2, (0x80000000 | REG_READ(BLC_PWM_CTL2)));
+		REG_WRITE(BLC_PWM_CTL, (max_pwm_blc << 16) | blc_pwm_ctl);
+		gma_power_end(dev);
+	}
+	mrst_brightness = level;
+	return 0;
+}
+
+static int mrst_get_brightness(struct backlight_device *bd)
+{
+	/* return locally cached var instead of HW read (due to DPST etc.) */
+	/* FIXME: ideally return actual value in case firmware fiddled with
+	   it */
+	return mrst_brightness;
+}
+
+static int device_backlight_init(struct drm_device *dev)
+{
+	struct drm_psb_private *dev_priv = dev->dev_private;
+	unsigned long core_clock;
+	u16 bl_max_freq;
+	uint32_t value;
+	uint32_t blc_pwm_precision_factor;
+
+	dev_priv->blc_adj1 = BLC_ADJUSTMENT_MAX;
+	dev_priv->blc_adj2 = BLC_ADJUSTMENT_MAX;
+	bl_max_freq = 256;
+	/* this needs to be set elsewhere */
+	blc_pwm_precision_factor = BLC_PWM_PRECISION_FACTOR;
+
+	core_clock = dev_priv->core_freq;
+
+	value = (core_clock * MHz) / BLC_PWM_FREQ_CALC_CONSTANT;
+	value *= blc_pwm_precision_factor;
+	value /= bl_max_freq;
+	value /= blc_pwm_precision_factor;
+
+	if (gma_power_begin(dev, false)) {
+		if (value > (unsigned long long)MRST_BLC_MAX_PWM_REG_FREQ)
+				return -ERANGE;
+		else {
+			REG_WRITE(BLC_PWM_CTL2,
+					(0x80000000 | REG_READ(BLC_PWM_CTL2)));
+			REG_WRITE(BLC_PWM_CTL, value | (value << 16));
+		}
+		gma_power_end(dev);
+	}
+	return 0;
+}
+
+static const struct backlight_ops mrst_ops = {
+	.get_brightness = mrst_get_brightness,
+	.update_status  = mrst_set_brightness,
+};
+
+int mrst_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));
+	props.max_brightness = 100;
+	props.type = BACKLIGHT_PLATFORM;
+
+	mrst_backlight_device = backlight_device_register("mrst-bl",
+					NULL, (void *)dev, &mrst_ops, &props);
+					
+	if (IS_ERR(mrst_backlight_device))
+		return PTR_ERR(mrst_backlight_device);
+
+	ret = device_backlight_init(dev);
+	if (ret < 0) {
+		backlight_device_unregister(mrst_backlight_device);
+		return ret;
+	}
+	mrst_backlight_device->props.brightness = 100;
+	mrst_backlight_device->props.max_brightness = 100;
+	backlight_update_status(mrst_backlight_device);
+	dev_priv->backlight_device = mrst_backlight_device;
+	return 0;
+}
+
+#endif
+
+/*
  *	Provide the Moorestown specific chip logic and low level methods
+ *	for power management
  */
 
 static void mrst_init_pm(struct drm_device *dev)
@@ -221,6 +353,11 @@ static int mrst_power_up(struct drm_device *dev)
 
 const struct psb_ops mrst_chip_ops = {
 	.output_init = mrst_output_init,
+
+#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
+	.backlight_init = mrst_backlight_init,
+#endif
+	
 	.init_pm = mrst_init_pm,
 	.save_regs = mrst_save_display_registers,
 	.restore_regs = mrst_restore_display_registers,