2 files changed, 124 insertions, 4 deletions

diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c
index 5d22ea532e42..fc65c02306dd 100644
--- a/drivers/video/atmel_lcdfb.c
+++ b/drivers/video/atmel_lcdfb.c
@@ -16,6 +16,7 @@
 #include <linux/fb.h>
 #include <linux/init.h>
 #include <linux/delay.h>
+#include <linux/backlight.h>
 
 #include <asm/arch/board.h>
 #include <asm/arch/cpu.h>
@@ -69,6 +70,107 @@ static void atmel_lcdfb_update_dma2d(struct atmel_lcdfb_info *sinfo,
 }
 #endif
 
+static const u32 contrast_ctr = ATMEL_LCDC_PS_DIV8
+                | ATMEL_LCDC_POL_POSITIVE
+                | ATMEL_LCDC_ENA_PWMENABLE;
+
+#ifdef CONFIG_BACKLIGHT_ATMEL_LCDC
+
+/* some bl->props field just changed */
+static int atmel_bl_update_status(struct backlight_device *bl)
+{
+        struct atmel_lcdfb_info *sinfo = bl_get_data(bl);
+        int                     power = sinfo->bl_power;
+        int                     brightness = bl->props.brightness;
+
+        /* REVISIT there may be a meaningful difference between
+         * fb_blank and power ... there seem to be some cases
+         * this doesn't handle correctly.
+         */
+        if (bl->props.fb_blank != sinfo->bl_power)
+                power = bl->props.fb_blank;
+        else if (bl->props.power != sinfo->bl_power)
+                power = bl->props.power;
+
+        if (brightness < 0 && power == FB_BLANK_UNBLANK)
+                brightness = lcdc_readl(sinfo, ATMEL_LCDC_CONTRAST_VAL);
+        else if (power != FB_BLANK_UNBLANK)
+                brightness = 0;
+
+        lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_VAL, brightness);
+        lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR,
+                        brightness ? contrast_ctr : 0);
+
+        bl->props.fb_blank = bl->props.power = sinfo->bl_power = power;
+
+        return 0;
+}
+
+static int atmel_bl_get_brightness(struct backlight_device *bl)
+{
+        struct atmel_lcdfb_info *sinfo = bl_get_data(bl);
+
+        return lcdc_readl(sinfo, ATMEL_LCDC_CONTRAST_VAL);
+}
+
+static struct backlight_ops atmel_lcdc_bl_ops = {
+        .update_status = atmel_bl_update_status,
+        .get_brightness = atmel_bl_get_brightness,
+};
+
+static void init_backlight(struct atmel_lcdfb_info *sinfo)
+{
+        struct backlight_device *bl;
+
+        sinfo->bl_power = FB_BLANK_UNBLANK;
+
+        if (sinfo->backlight)
+                return;
+
+        bl = backlight_device_register("backlight", &sinfo->pdev->dev,
+                        sinfo, &atmel_lcdc_bl_ops);
+        if (IS_ERR(sinfo->backlight)) {
+                dev_err(&sinfo->pdev->dev, "error %ld on backlight register\n",
+                                PTR_ERR(bl));
+                return;
+        }
+        sinfo->backlight = bl;
+
+        bl->props.power = FB_BLANK_UNBLANK;
+        bl->props.fb_blank = FB_BLANK_UNBLANK;
+        bl->props.max_brightness = 0xff;
+        bl->props.brightness = atmel_bl_get_brightness(bl);
+}
+
+static void exit_backlight(struct atmel_lcdfb_info *sinfo)
+{
+        if (sinfo->backlight)
+                backlight_device_unregister(sinfo->backlight);
+}
+
+#else
+
+static void init_backlight(struct atmel_lcdfb_info *sinfo)
+{
+        dev_warn(&sinfo->pdev->dev, "backlight control is not available\n");
+}
+
+static void exit_backlight(struct atmel_lcdfb_info *sinfo)
+{
+}
+
+#endif
+
+static void init_contrast(struct atmel_lcdfb_info *sinfo)
+{
+        /* have some default contrast/backlight settings */
+        lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR, contrast_ctr);
+        lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_VAL, ATMEL_LCDC_CVAL_DEFAULT);
+
+        if (sinfo->lcdcon_is_backlight)
+                init_backlight(sinfo);
+}
+
 
 static struct fb_fix_screeninfo atmel_lcdfb_fix __initdata = {
         .type           = FB_TYPE_PACKED_PIXELS,
@@ -390,10 +492,6 @@ static int atmel_lcdfb_set_par(struct fb_info *info)
         /* Disable all interrupts */
         lcdc_writel(sinfo, ATMEL_LCDC_IDR, ~0UL);
 
-        /* Set contrast */
-        value = ATMEL_LCDC_PS_DIV8 | ATMEL_LCDC_POL_POSITIVE | ATMEL_LCDC_ENA_PWMENABLE;
-        lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR, value);
-        lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_VAL, ATMEL_LCDC_CVAL_DEFAULT);
         /* ...wait for DMA engine to become idle... */
         while (lcdc_readl(sinfo, ATMEL_LCDC_DMACON) & ATMEL_LCDC_DMABUSY)
                 msleep(10);
@@ -597,6 +695,7 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
                 sinfo->default_monspecs = pdata_sinfo->default_monspecs;
                 sinfo->atmel_lcdfb_power_control = pdata_sinfo->atmel_lcdfb_power_control;
                 sinfo->guard_time = pdata_sinfo->guard_time;
+                sinfo->lcdcon_is_backlight = pdata_sinfo->lcdcon_is_backlight;
         } else {
                 dev_err(dev, "cannot get default configuration\n");
                 goto free_info;
@@ -690,6 +789,9 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
                 goto release_mem;
         }
 
+        /* Initialize PWM for contrast or backlight ("off") */
+        init_contrast(sinfo);
+
         /* interrupt */
         ret = request_irq(sinfo->irq_base, atmel_lcdfb_interrupt, 0, pdev->name, info);
         if (ret) {
@@ -741,6 +843,7 @@ free_cmap:
 unregister_irqs:
         free_irq(sinfo->irq_base, info);
 unmap_mmio:
+        exit_backlight(sinfo);
         iounmap(sinfo->mmio);
 release_mem:
         release_mem_region(info->fix.mmio_start, info->fix.mmio_len);
@@ -775,6 +878,7 @@ static int __exit atmel_lcdfb_remove(struct platform_device *pdev)
         if (!sinfo)
                 return 0;
 
+        exit_backlight(sinfo);
         if (sinfo->atmel_lcdfb_power_control)
                 sinfo->atmel_lcdfb_power_control(0);
         unregister_framebuffer(info);
@@ -801,6 +905,9 @@ static int __exit atmel_lcdfb_remove(struct platform_device *pdev)
 
 static struct platform_driver atmel_lcdfb_driver = {
         .remove         = __exit_p(atmel_lcdfb_remove),
+
+// FIXME need suspend, resume
+
         .driver         = {
                 .name   = "atmel_lcdfb",
                 .owner  = THIS_MODULE,
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 9609a6c676be..924e2551044a 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -50,6 +50,19 @@ config BACKLIGHT_CLASS_DEVICE
           To have support for your specific LCD panel you will have to
           select the proper drivers which depend on this option.
 
+config BACKLIGHT_ATMEL_LCDC
+        bool "Atmel LCDC Contrast-as-Backlight control"
+        depends on BACKLIGHT_CLASS_DEVICE && FB_ATMEL
+        default y if MACH_SAM9261EK || MACH_SAM9263EK
+        help
+          This provides a backlight control internal to the Atmel LCDC
+          driver.  If the LCD "contrast control" on your board is wired
+          so it controls the backlight brightness, select this option to
+          export this as a PWM-based backlight control.
+
+          If in doubt, it's safe to enable this option; it doesn't kick
+          in unless the board's description says it's wired that way.
+
 config BACKLIGHT_CORGI
         tristate "Generic (aka Sharp Corgi) Backlight Driver"
         depends on BACKLIGHT_CLASS_DEVICE