imxfb: add pwmr controlled backlight support

Signed-off-by: Eric Bénard <eric@eukrea.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 71 insertions, 1 deletions

diff --git a/drivers/video/imxfb.c b/drivers/video/imxfb.c
index b4b6deceed15..43f0639b1c10 100644
--- a/drivers/video/imxfb.c
+++ b/drivers/video/imxfb.c
@@ -175,6 +175,7 @@ struct imxfb_info {
 
         struct imx_fb_videomode *mode;
         int                     num_modes;
+        struct backlight_device *bl;
 
         void (*lcd_power)(int);
         void (*backlight_power)(int);
@@ -449,6 +450,73 @@ static int imxfb_set_par(struct fb_info *info)
         return 0;
 }
 
+
+
+static int imxfb_bl_get_brightness(struct backlight_device *bl)
+{
+        struct imxfb_info *fbi = bl_get_data(bl);
+
+        return readl(fbi->regs + LCDC_PWMR) & 0xFF;
+}
+
+static int imxfb_bl_update_status(struct backlight_device *bl)
+{
+        struct imxfb_info *fbi = bl_get_data(bl);
+        int brightness = bl->props.brightness;
+
+        if (bl->props.power != FB_BLANK_UNBLANK)
+                brightness = 0;
+        if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+                brightness = 0;
+
+        fbi->pwmr = (fbi->pwmr & ~0xFF) | brightness;
+
+        if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+                clk_enable(fbi->clk);
+        writel(fbi->pwmr, fbi->regs + LCDC_PWMR);
+        if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+                clk_disable(fbi->clk);
+
+        return 0;
+}
+
+static const struct backlight_ops imxfb_lcdc_bl_ops = {
+        .update_status = imxfb_bl_update_status,
+        .get_brightness = imxfb_bl_get_brightness,
+};
+
+static void imxfb_init_backlight(struct imxfb_info *fbi)
+{
+        struct backlight_properties props;
+        struct backlight_device *bl;
+
+        if (fbi->bl)
+                return;
+
+        memset(&props, 0, sizeof(struct backlight_properties));
+        props.max_brightness = 0xff;
+        writel(fbi->pwmr, fbi->regs + LCDC_PWMR);
+
+        bl = backlight_device_register("imxfb-bl", &fbi->pdev->dev, fbi,
+                                       &imxfb_lcdc_bl_ops, &props);
+        if (IS_ERR(bl)) {
+                dev_err(&fbi->pdev->dev, "error %ld on backlight register\n",
+                                PTR_ERR(bl));
+                return;
+        }
+
+        fbi->bl = bl;
+        bl->props.power = FB_BLANK_UNBLANK;
+        bl->props.fb_blank = FB_BLANK_UNBLANK;
+        bl->props.brightness = imxfb_bl_get_brightness(bl);
+}
+
+static void imxfb_exit_backlight(struct imxfb_info *fbi)
+{
+        if (fbi->bl)
+                backlight_device_unregister(fbi->bl);
+}
+
 static void imxfb_enable_controller(struct imxfb_info *fbi)
 {
         pr_debug("Enabling LCD controller\n");
@@ -579,7 +647,6 @@ static int imxfb_activate_var(struct fb_var_screeninfo *var, struct fb_info *inf
                         fbi->regs + LCDC_SIZE);
 
         writel(fbi->pcr, fbi->regs + LCDC_PCR);
-        writel(fbi->pwmr, fbi->regs + LCDC_PWMR);
         writel(fbi->lscr1, fbi->regs + LCDC_LSCR1);
         writel(fbi->dmacr, fbi->regs + LCDC_DMACR);
 
@@ -779,6 +846,8 @@ static int __init imxfb_probe(struct platform_device *pdev)
         }
 
         imxfb_enable_controller(fbi);
+        fbi->pdev = pdev;
+        imxfb_init_backlight(fbi);
 
         return 0;
 
@@ -816,6 +885,7 @@ static int __devexit imxfb_remove(struct platform_device *pdev)
 
         imxfb_disable_controller(fbi);
 
+        imxfb_exit_backlight(fbi);
         unregister_framebuffer(info);
 
         pdata = pdev->dev.platform_data;